Annual report pursuant to Section 13 and 15(d)

Schedule III - Real Estate and Accumulated Depreciation (Details)

v3.8.0.1
Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Real Estate and Accumulated Depreciation        
Encumbrances $ 164,506      
Initial Cost        
Land 697,810      
Building and Land Improvements 2,902,516      
Costs Capitalized Subsequent to Acquisition 380,487      
Gross Amounts Carried At Close of Period        
Land 697,810      
Building and Land Improvements 3,283,003      
Total 3,980,813 $ 3,874,715 $ 4,158,616 $ 4,014,336
Accumulated Depreciation (801,038) (715,951) (718,680) $ (703,083)
Additional information        
Debt excluded from encumbrances 1,828,333 1,904,001    
Net discounts and deferred financing costs 13,800      
Aggregate cost of assets for federal income tax purposes 3,500,000      
Impairment losses $ 15,123 101,391 $ 23,289  
Buildings improvements [Member] | Minimum [Member]        
Additional information        
Estimated lives over which depreciation is recognized 10 years      
Buildings improvements [Member] | Maximum [Member]        
Additional information        
Estimated lives over which depreciation is recognized 40 years      
Term Loan Facilities [Member]        
Additional information        
Debt excluded from encumbrances $ 347,959 $ 547,494    
Unsecured Senior Notes [Member]        
Additional information        
Debt excluded from encumbrances 1,200,000      
Unsecured notes payable [Member]        
Additional information        
Debt excluded from encumbrances 1,300      
Fixed rate mortgage loans [Member]        
Additional information        
Net discounts and deferred financing costs 668      
100 Light Street [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 49,378      
Initial Cost        
Land 26,715      
Building and Land Improvements 58,343      
Costs Capitalized Subsequent to Acquisition 5,286      
Gross Amounts Carried At Close of Period        
Land 26,715      
Building and Land Improvements 63,629      
Total 90,344      
Accumulated Depreciation (9,467)      
1000 Redstone Gateway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 10,730      
Initial Cost        
Land 0      
Building and Land Improvements 20,533      
Costs Capitalized Subsequent to Acquisition 5      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 20,538      
Total 20,538      
Accumulated Depreciation (2,465)      
1100 Redstone Gateway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 11,222      
Initial Cost        
Land 0      
Building and Land Improvements 19,593      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 19,593      
Total 19,593      
Accumulated Depreciation (1,945)      
114 National Business Parkway [Member]        
Initial Cost        
Land 364      
Building and Land Improvements 3,109      
Costs Capitalized Subsequent to Acquisition 118      
Gross Amounts Carried At Close of Period        
Land 364      
Building and Land Improvements 3,227      
Total 3,591      
Accumulated Depreciation (1,309)      
11751 Meadowville Lane [Member]        
Initial Cost        
Land 1,305      
Building and Land Improvements 52,098      
Costs Capitalized Subsequent to Acquisition 112      
Gross Amounts Carried At Close of Period        
Land 1,305      
Building and Land Improvements 52,210      
Total 53,515      
Accumulated Depreciation (14,845)      
1200 Redstone Gateway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 12,973      
Initial Cost        
Land 0      
Building and Land Improvements 22,389      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 22,389      
Total 22,389      
Accumulated Depreciation (2,264)      
1201 M Street [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 49,785      
Costs Capitalized Subsequent to Acquisition 8,590      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 58,375      
Total 58,375      
Accumulated Depreciation (12,800)      
1201 Winterson Road [Member]        
Initial Cost        
Land 1,288      
Building and Land Improvements 16,433      
Costs Capitalized Subsequent to Acquisition 460      
Gross Amounts Carried At Close of Period        
Land 1,288      
Building and Land Improvements 16,893      
Total 18,181      
Accumulated Depreciation (4,279)      
1220 12th Street, SE [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 42,464      
Costs Capitalized Subsequent to Acquisition 5,820      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 48,284      
Total 48,284      
Accumulated Depreciation (11,719)      
1243 Winterson Road [Member]        
Initial Cost        
Land 630      
Building and Land Improvements 0      
Gross Amounts Carried At Close of Period        
Land 630      
Building and Land Improvements 0      
Total 630      
131 National Business Parkway [Member]        
Initial Cost        
Land 1,906      
Building and Land Improvements 7,623      
Costs Capitalized Subsequent to Acquisition 3,868      
Gross Amounts Carried At Close of Period        
Land 1,906      
Building and Land Improvements 11,491      
Total 13,397      
Accumulated Depreciation (6,286)      
132 National Business Parkway [Member]        
Initial Cost        
Land 2,917      
Building and Land Improvements 12,259      
Costs Capitalized Subsequent to Acquisition 4,124      
Gross Amounts Carried At Close of Period        
Land 2,917      
Building and Land Improvements 16,383      
Total 19,300      
Accumulated Depreciation (8,715)      
133 National Business Parkway [Member]        
Initial Cost        
Land 2,517      
Building and Land Improvements 10,068      
Costs Capitalized Subsequent to Acquisition 5,544      
Gross Amounts Carried At Close of Period        
Land 2,517      
Building and Land Improvements 15,612      
Total 18,129      
Accumulated Depreciation (9,234)      
134 National Business Parkway [Member]        
Initial Cost        
Land 3,684      
Building and Land Improvements 7,517      
Costs Capitalized Subsequent to Acquisition 3,691      
Gross Amounts Carried At Close of Period        
Land 3,684      
Building and Land Improvements 11,208      
Total 14,892      
Accumulated Depreciation (5,419)      
1340 Ashton Road [Member]        
Initial Cost        
Land 905      
Building and Land Improvements 3,620      
Costs Capitalized Subsequent to Acquisition 1,470      
Gross Amounts Carried At Close of Period        
Land 905      
Building and Land Improvements 5,090      
Total 5,995      
Accumulated Depreciation (2,854)      
13450 Sunrise Valley Road [Member]        
Initial Cost        
Land 1,386      
Building and Land Improvements 5,576      
Costs Capitalized Subsequent to Acquisition 4,553      
Gross Amounts Carried At Close of Period        
Land 1,386      
Building and Land Improvements 10,129      
Total 11,515      
Accumulated Depreciation (4,808)      
13454 Sunrise Valley Road [Member]        
Initial Cost        
Land 2,899      
Building and Land Improvements 11,986      
Costs Capitalized Subsequent to Acquisition 7,071      
Gross Amounts Carried At Close of Period        
Land 2,899      
Building and Land Improvements 19,057      
Total 21,956      
Accumulated Depreciation (9,262)      
135 National Business Parkway [Member]        
Initial Cost        
Land 2,484      
Building and Land Improvements 9,750      
Costs Capitalized Subsequent to Acquisition 6,075      
Gross Amounts Carried At Close of Period        
Land 2,484      
Building and Land Improvements 15,825      
Total 18,309      
Accumulated Depreciation (7,970)      
1362 Mellon Road [Member]        
Initial Cost        
Land 950      
Building and Land Improvements 3,864      
Costs Capitalized Subsequent to Acquisition 206      
Gross Amounts Carried At Close of Period        
Land 950      
Building and Land Improvements 4,070      
Total 5,020      
Accumulated Depreciation (192)      
13857 McLearen Road [Member]        
Initial Cost        
Land 3,507      
Building and Land Improvements 30,177      
Costs Capitalized Subsequent to Acquisition 1,768      
Gross Amounts Carried At Close of Period        
Land 3,507      
Building and Land Improvements 31,945      
Total 35,452      
Accumulated Depreciation (10,100)      
140 National Business Parkway [Member]        
Initial Cost        
Land 3,407      
Building and Land Improvements 24,167      
Costs Capitalized Subsequent to Acquisition 1,487      
Gross Amounts Carried At Close of Period        
Land 3,407      
Building and Land Improvements 25,654      
Total 29,061      
Accumulated Depreciation (8,907)      
141 National Business Parkway [Member]        
Initial Cost        
Land 2,398      
Building and Land Improvements 9,538      
Costs Capitalized Subsequent to Acquisition 4,815      
Gross Amounts Carried At Close of Period        
Land 2,398      
Building and Land Improvements 14,353      
Total 16,751      
Accumulated Depreciation (7,409)      
14280 Park Meadow Drive [Member]        
Initial Cost        
Land 3,731      
Building and Land Improvements 15,953      
Costs Capitalized Subsequent to Acquisition 2,628      
Gross Amounts Carried At Close of Period        
Land 3,731      
Building and Land Improvements 18,581      
Total 22,312      
Accumulated Depreciation (7,326)      
1460 Dorsey Road [Member]        
Initial Cost        
Land 1,577      
Building and Land Improvements 33      
Gross Amounts Carried At Close of Period        
Land 1,577      
Building and Land Improvements 33      
Total 1,610      
14840 Conference Center Drive [Member]        
Initial Cost        
Land 1,572      
Building and Land Improvements 8,175      
Costs Capitalized Subsequent to Acquisition 3,092      
Gross Amounts Carried At Close of Period        
Land 1,572      
Building and Land Improvements 11,267      
Total 12,839      
Accumulated Depreciation (5,410)      
14850 Conference Center Drive [Member]        
Initial Cost        
Land 1,615      
Building and Land Improvements 8,358      
Costs Capitalized Subsequent to Acquisition 3,072      
Gross Amounts Carried At Close of Period        
Land 1,615      
Building and Land Improvements 11,430      
Total 13,045      
Accumulated Depreciation (5,857)      
14900 Conference Center Drive [Member]        
Initial Cost        
Land 3,436      
Building and Land Improvements 14,402      
Costs Capitalized Subsequent to Acquisition 6,239      
Gross Amounts Carried At Close of Period        
Land 3,436      
Building and Land Improvements 20,641      
Total 24,077      
Accumulated Depreciation (10,027)      
1501 South Clinton Street [Member]        
Initial Cost        
Land 27,964      
Building and Land Improvements 51,990      
Costs Capitalized Subsequent to Acquisition 13,670      
Gross Amounts Carried At Close of Period        
Land 27,964      
Building and Land Improvements 65,660      
Total 93,624      
Accumulated Depreciation (19,942)      
15049 Conference Center Drive [Member]        
Initial Cost        
Land 4,415      
Building and Land Improvements 20,365      
Costs Capitalized Subsequent to Acquisition 14,994      
Gross Amounts Carried At Close of Period        
Land 4,415      
Building and Land Improvements 35,359      
Total 39,774      
Accumulated Depreciation (12,097)      
15059 Conference Center Drive [Member]        
Initial Cost        
Land 5,753      
Building and Land Improvements 13,615      
Costs Capitalized Subsequent to Acquisition 3,645      
Gross Amounts Carried At Close of Period        
Land 5,753      
Building and Land Improvements 17,260      
Total 23,013      
Accumulated Depreciation (7,907)      
1550 West Nursery Road [Member]        
Initial Cost        
Land 14,071      
Building and Land Improvements 16,930      
Gross Amounts Carried At Close of Period        
Land 14,071      
Building and Land Improvements 16,930      
Total 31,001      
Accumulated Depreciation (4,802)      
1560 West Nursery Road [Member]        
Initial Cost        
Land 1,441      
Building and Land Improvements 113      
Gross Amounts Carried At Close of Period        
Land 1,441      
Building and Land Improvements 113      
Total 1,554      
Accumulated Depreciation (10)      
1610 West Nursery Road [Member]        
Initial Cost        
Land 259      
Building and Land Improvements 246      
Gross Amounts Carried At Close of Period        
Land 259      
Building and Land Improvements 246      
Total 505      
Accumulated Depreciation (5)      
1616 West Nursery Road [Member]        
Initial Cost        
Land 393      
Building and Land Improvements 2,919      
Gross Amounts Carried At Close of Period        
Land 393      
Building and Land Improvements 2,919      
Total 3,312      
Accumulated Depreciation (13)      
1622 West Nursery Road [Member]        
Initial Cost        
Land 393      
Building and Land Improvements 2,477      
Gross Amounts Carried At Close of Period        
Land 393      
Building and Land Improvements 2,477      
Total 2,870      
Accumulated Depreciation (53)      
16442 Commerce Drive [Member]        
Initial Cost        
Land 613      
Building and Land Improvements 2,582      
Costs Capitalized Subsequent to Acquisition 891      
Gross Amounts Carried At Close of Period        
Land 613      
Building and Land Improvements 3,473      
Total 4,086      
Accumulated Depreciation (1,538)      
16480 Commerce Drive [Member]        
Initial Cost        
Land 1,856      
Building and Land Improvements 7,425      
Costs Capitalized Subsequent to Acquisition 2,068      
Gross Amounts Carried At Close of Period        
Land 1,856      
Building and Land Improvements 9,493      
Total 11,349      
Accumulated Depreciation (3,279)      
16501 Commerce Drive [Member]        
Initial Cost        
Land 522      
Building and Land Improvements 2,090      
Costs Capitalized Subsequent to Acquisition 727      
Gross Amounts Carried At Close of Period        
Land 522      
Building and Land Improvements 2,817      
Total 3,339      
Accumulated Depreciation (975)      
16539 Commerce Drive [Member]        
Initial Cost        
Land 688      
Building and Land Improvements 2,860      
Costs Capitalized Subsequent to Acquisition 1,892      
Gross Amounts Carried At Close of Period        
Land 688      
Building and Land Improvements 4,752      
Total 5,440      
Accumulated Depreciation (2,325)      
16541 Commerce Drive [Member]        
Initial Cost        
Land 773      
Building and Land Improvements 3,094      
Costs Capitalized Subsequent to Acquisition 1,757      
Gross Amounts Carried At Close of Period        
Land 773      
Building and Land Improvements 4,851      
Total 5,624      
Accumulated Depreciation (2,026)      
16543 Commerce Drive [Member]        
Initial Cost        
Land 436      
Building and Land Improvements 1,742      
Costs Capitalized Subsequent to Acquisition 716      
Gross Amounts Carried At Close of Period        
Land 436      
Building and Land Improvements 2,458      
Total 2,894      
Accumulated Depreciation (839)      
1751 Pinnacle Drive [Member]        
Initial Cost        
Land 10,486      
Building and Land Improvements 42,339      
Costs Capitalized Subsequent to Acquisition 27,048      
Gross Amounts Carried At Close of Period        
Land 10,486      
Building and Land Improvements 69,387      
Total 79,873      
Accumulated Depreciation (29,582)      
1753 Pinnacle Drive [Member]        
Initial Cost        
Land 8,275      
Building and Land Improvements 34,353      
Costs Capitalized Subsequent to Acquisition 16,648      
Gross Amounts Carried At Close of Period        
Land 8,275      
Building and Land Improvements 51,001      
Total 59,276      
Accumulated Depreciation (18,757)      
206 Research Boulevard [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 132      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 132      
Total 132      
Accumulated Depreciation (132)      
209 Research Boulevard [Member]        
Initial Cost        
Land 134      
Building and Land Improvements 1,711      
Costs Capitalized Subsequent to Acquisition 175      
Gross Amounts Carried At Close of Period        
Land 134      
Building and Land Improvements 1,886      
Total 2,020      
Accumulated Depreciation (283)      
210 Research Boulevard [Member]        
Initial Cost        
Land 113      
Building and Land Improvements 1,402      
Costs Capitalized Subsequent to Acquisition 86      
Gross Amounts Carried At Close of Period        
Land 113      
Building and Land Improvements 1,488      
Total 1,601      
Accumulated Depreciation (174)      
2100 L Street [Member]        
Initial Cost        
Land 55,615      
Building and Land Improvements 9,073      
Gross Amounts Carried At Close of Period        
Land 55,615      
Building and Land Improvements 9,073      
Total 64,688      
2100 Rideout Road [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 5,003      
Costs Capitalized Subsequent to Acquisition 2,881      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 7,884      
Total 7,884      
Accumulated Depreciation (438)      
22289 Exploration Drive [Member]        
Initial Cost        
Land 1,422      
Building and Land Improvements 5,719      
Costs Capitalized Subsequent to Acquisition 1,829      
Gross Amounts Carried At Close of Period        
Land 1,422      
Building and Land Improvements 7,548      
Total 8,970      
Accumulated Depreciation (3,415)      
22299 Exploration Drive [Member]        
Initial Cost        
Land 1,362      
Building and Land Improvements 5,791      
Costs Capitalized Subsequent to Acquisition 2,308      
Gross Amounts Carried At Close of Period        
Land 1,362      
Building and Land Improvements 8,099      
Total 9,461      
Accumulated Depreciation (3,768)      
22300 Exploration Drive [Member]        
Initial Cost        
Land 1,094      
Building and Land Improvements 5,038      
Costs Capitalized Subsequent to Acquisition 1,489      
Gross Amounts Carried At Close of Period        
Land 1,094      
Building and Land Improvements 6,527      
Total 7,621      
Accumulated Depreciation (2,432)      
22309 Exploration Drive [Member]        
Initial Cost        
Land 2,243      
Building and Land Improvements 10,419      
Costs Capitalized Subsequent to Acquisition 7,967      
Gross Amounts Carried At Close of Period        
Land 2,243      
Building and Land Improvements 18,386      
Total 20,629      
Accumulated Depreciation (6,087)      
23535 Cottonwood Parkway [Member]        
Initial Cost        
Land 692      
Building and Land Improvements 3,051      
Costs Capitalized Subsequent to Acquisition 537      
Gross Amounts Carried At Close of Period        
Land 692      
Building and Land Improvements 3,588      
Total 4,280      
Accumulated Depreciation (1,527)      
250 W Pratt St [Member]        
Initial Cost        
Land 8,057      
Building and Land Improvements 34,588      
Costs Capitalized Subsequent to Acquisition 6,942      
Gross Amounts Carried At Close of Period        
Land 8,057      
Building and Land Improvements 41,530      
Total 49,587      
Accumulated Depreciation (6,972)      
2500 Riva Road [Member]        
Initial Cost        
Land 2,791      
Building and Land Improvements 12,145      
Costs Capitalized Subsequent to Acquisition 1      
Gross Amounts Carried At Close of Period        
Land 2,791      
Building and Land Improvements 12,146      
Total 14,937      
Accumulated Depreciation (5,105)      
2600 Park Tower Drive [Member]        
Initial Cost        
Land 20,304      
Building and Land Improvements 34,443      
Costs Capitalized Subsequent to Acquisition 517      
Gross Amounts Carried At Close of Period        
Land 20,304      
Building and Land Improvements 34,960      
Total 55,264      
Accumulated Depreciation (3,708)      
2691 Technology Drive [Member]        
Initial Cost        
Land 2,098      
Building and Land Improvements 17,334      
Costs Capitalized Subsequent to Acquisition 5,563      
Gross Amounts Carried At Close of Period        
Land 2,098      
Building and Land Improvements 22,897      
Total 24,995      
Accumulated Depreciation (9,630)      
2701 Technology Drive [Member]        
Initial Cost        
Land 1,737      
Building and Land Improvements 15,266      
Costs Capitalized Subsequent to Acquisition 4,398      
Gross Amounts Carried At Close of Period        
Land 1,737      
Building and Land Improvements 19,664      
Total 21,401      
Accumulated Depreciation (9,676)      
2711 Technology Drive [Member]        
Initial Cost        
Land 2,251      
Building and Land Improvements 21,611      
Costs Capitalized Subsequent to Acquisition 1,899      
Gross Amounts Carried At Close of Period        
Land 2,251      
Building and Land Improvements 23,510      
Total 25,761      
Accumulated Depreciation (11,727)      
2720 Technology Drive [Member]        
Initial Cost        
Land 3,863      
Building and Land Improvements 29,272      
Costs Capitalized Subsequent to Acquisition 1,218      
Gross Amounts Carried At Close of Period        
Land 3,863      
Building and Land Improvements 30,490      
Total 34,353      
Accumulated Depreciation (10,261)      
2721 Technology Drive [Member]        
Initial Cost        
Land 4,611      
Building and Land Improvements 14,597      
Costs Capitalized Subsequent to Acquisition 1,270      
Gross Amounts Carried At Close of Period        
Land 4,611      
Building and Land Improvements 15,867      
Total 20,478      
Accumulated Depreciation (7,484)      
2730 Hercules Road [Member]        
Initial Cost        
Land 8,737      
Building and Land Improvements 31,612      
Costs Capitalized Subsequent to Acquisition 8,697      
Gross Amounts Carried At Close of Period        
Land 8,737      
Building and Land Improvements 40,309      
Total 49,046      
Accumulated Depreciation (18,673)      
30 Light Street [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 4,153      
Initial Cost        
Land 0      
Building and Land Improvements 12,101      
Costs Capitalized Subsequent to Acquisition 629      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 12,730      
Total 12,730      
Accumulated Depreciation (753)      
300 Sentinel Drive [Member]        
Initial Cost        
Land 1,517      
Building and Land Improvements 59,165      
Costs Capitalized Subsequent to Acquisition 925      
Gross Amounts Carried At Close of Period        
Land 1,517      
Building and Land Improvements 60,090      
Total 61,607      
Accumulated Depreciation (11,562)      
302 Sentinel Drive [Member]        
Initial Cost        
Land 2,648      
Building and Land Improvements 29,687      
Costs Capitalized Subsequent to Acquisition 468      
Gross Amounts Carried At Close of Period        
Land 2,648      
Building and Land Improvements 30,155      
Total 32,803      
Accumulated Depreciation (7,579)      
304 Sentinel Drive [Member]        
Initial Cost        
Land 3,411      
Building and Land Improvements 24,917      
Costs Capitalized Subsequent to Acquisition 202      
Gross Amounts Carried At Close of Period        
Land 3,411      
Building and Land Improvements 25,119      
Total 28,530      
Accumulated Depreciation (7,610)      
306 Sentinel Drive [Member]        
Initial Cost        
Land 3,260      
Building and Land Improvements 22,592      
Costs Capitalized Subsequent to Acquisition 961      
Gross Amounts Carried At Close of Period        
Land 3,260      
Building and Land Improvements 23,553      
Total 26,813      
Accumulated Depreciation (6,631)      
308 Sentinel Drive [Member]        
Initial Cost        
Land 1,422      
Building and Land Improvements 26,208      
Costs Capitalized Subsequent to Acquisition 2,396      
Gross Amounts Carried At Close of Period        
Land 1,422      
Building and Land Improvements 28,604      
Total 30,026      
Accumulated Depreciation (4,370)      
310 Sentinel Way [Member]        
Initial Cost        
Land 2,372      
Building and Land Improvements 38,865      
Gross Amounts Carried At Close of Period        
Land 2,372      
Building and Land Improvements 38,865      
Total 41,237      
Accumulated Depreciation (1,977)      
310 The Bridge Street [Member]        
Initial Cost        
Land 261      
Building and Land Improvements 26,531      
Costs Capitalized Subsequent to Acquisition 3,762      
Gross Amounts Carried At Close of Period        
Land 261      
Building and Land Improvements 30,293      
Total 30,554      
Accumulated Depreciation (7,430)      
312 Sentinel Way [Member]        
Initial Cost        
Land 3,138      
Building and Land Improvements 27,797      
Gross Amounts Carried At Close of Period        
Land 3,138      
Building and Land Improvements 27,797      
Total 30,935      
Accumulated Depreciation (2,304)      
314 Sentinel Way [Member]        
Initial Cost        
Land 1,254      
Building and Land Improvements 7,741      
Gross Amounts Carried At Close of Period        
Land 1,254      
Building and Land Improvements 7,741      
Total 8,995      
Accumulated Depreciation (548)      
316 Sentinel Way [Member]        
Initial Cost        
Land 2,748      
Building and Land Improvements 38,156      
Costs Capitalized Subsequent to Acquisition 145      
Gross Amounts Carried At Close of Period        
Land 2,748      
Building and Land Improvements 38,301      
Total 41,049      
Accumulated Depreciation (5,507)      
318 Sentinel Way [Member]        
Initial Cost        
Land 2,185      
Building and Land Improvements 28,426      
Costs Capitalized Subsequent to Acquisition 560      
Gross Amounts Carried At Close of Period        
Land 2,185      
Building and Land Improvements 28,986      
Total 31,171      
Accumulated Depreciation (8,416)      
320 Sentinel Way [Member]        
Initial Cost        
Land 2,067      
Building and Land Improvements 21,623      
Gross Amounts Carried At Close of Period        
Land 2,067      
Building and Land Improvements 21,623      
Total 23,690      
Accumulated Depreciation (5,391)      
322 Sentinel Way [Member]        
Initial Cost        
Land 2,605      
Building and Land Improvements 22,827      
Costs Capitalized Subsequent to Acquisition 1,900      
Gross Amounts Carried At Close of Period        
Land 2,605      
Building and Land Improvements 24,727      
Total 27,332      
Accumulated Depreciation (6,286)      
324 Sentinel Way [Member]        
Initial Cost        
Land 1,656      
Building and Land Improvements 23,018      
Gross Amounts Carried At Close of Period        
Land 1,656      
Building and Land Improvements 23,018      
Total 24,674      
Accumulated Depreciation (4,229)      
4000 Market Street [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 466      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 466      
Total 466      
4100 Market Street [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 1,013      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 1,013      
Total 1,013      
410 National Business Parkway [Member]        
Initial Cost        
Land 1,831      
Building and Land Improvements 23,257      
Costs Capitalized Subsequent to Acquisition 119      
Gross Amounts Carried At Close of Period        
Land 1,831      
Building and Land Improvements 23,376      
Total 25,207      
Accumulated Depreciation (2,904)      
420 National Business Parkway [Member]        
Initial Cost        
Land 2,370      
Building and Land Improvements 27,750      
Costs Capitalized Subsequent to Acquisition 108      
Gross Amounts Carried At Close of Period        
Land 2,370      
Building and Land Improvements 27,858      
Total 30,228      
Accumulated Depreciation (2,635)      
430 National Business Parkway [Member]        
Initial Cost        
Land 1,852      
Building and Land Improvements 21,563      
Costs Capitalized Subsequent to Acquisition 126      
Gross Amounts Carried At Close of Period        
Land 1,852      
Building and Land Improvements 21,689      
Total 23,541      
Accumulated Depreciation (3,127)      
44408 Pecan Court [Member]        
Initial Cost        
Land 817      
Building and Land Improvements 1,583      
Costs Capitalized Subsequent to Acquisition 1,490      
Gross Amounts Carried At Close of Period        
Land 817      
Building and Land Improvements 3,073      
Total 3,890      
Accumulated Depreciation (838)      
44414 Pecan Court [Member]        
Initial Cost        
Land 405      
Building and Land Improvements 1,619      
Costs Capitalized Subsequent to Acquisition 1,033      
Gross Amounts Carried At Close of Period        
Land 405      
Building and Land Improvements 2,652      
Total 3,057      
Accumulated Depreciation (954)      
44417 Pecan Court [Member]        
Initial Cost        
Land 434      
Building and Land Improvements 3,822      
Costs Capitalized Subsequent to Acquisition 148      
Gross Amounts Carried At Close of Period        
Land 434      
Building and Land Improvements 3,970      
Total 4,404      
Accumulated Depreciation (1,448)      
44420 Pecan Court [Member]        
Initial Cost        
Land 344      
Building and Land Improvements 890      
Costs Capitalized Subsequent to Acquisition 168      
Gross Amounts Carried At Close of Period        
Land 344      
Building and Land Improvements 1,058      
Total 1,402      
Accumulated Depreciation (368)      
44425 Pecan Court [Member]        
Initial Cost        
Land 1,309      
Building and Land Improvements 3,506      
Costs Capitalized Subsequent to Acquisition 1,881      
Gross Amounts Carried At Close of Period        
Land 1,309      
Building and Land Improvements 5,387      
Total 6,696      
Accumulated Depreciation (2,419)      
45310 Abell House Lane [Member]        
Initial Cost        
Land 2,272      
Building and Land Improvements 13,808      
Costs Capitalized Subsequent to Acquisition 147      
Gross Amounts Carried At Close of Period        
Land 2,272      
Building and Land Improvements 13,955      
Total 16,227      
Accumulated Depreciation (2,094)      
46579 Expedition Drive [Member]        
Initial Cost        
Land 1,406      
Building and Land Improvements 5,796      
Costs Capitalized Subsequent to Acquisition 1,680      
Gross Amounts Carried At Close of Period        
Land 1,406      
Building and Land Improvements 7,476      
Total 8,882      
Accumulated Depreciation (3,421)      
46591 Expedition Drive [Member]        
Initial Cost        
Land 1,200      
Building and Land Improvements 7,199      
Costs Capitalized Subsequent to Acquisition 1,226      
Gross Amounts Carried At Close of Period        
Land 1,200      
Building and Land Improvements 8,425      
Total 9,625      
Accumulated Depreciation (2,652)      
4851 Stonecroft Boulevard [Member]        
Initial Cost        
Land 1,878      
Building and Land Improvements 11,558      
Costs Capitalized Subsequent to Acquisition 21      
Gross Amounts Carried At Close of Period        
Land 1,878      
Building and Land Improvements 11,579      
Total 13,457      
Accumulated Depreciation (3,827)      
540 National Business Parkway [Member]        
Initial Cost        
Land 2,035      
Building and Land Improvements 29,490      
Gross Amounts Carried At Close of Period        
Land 2,035      
Building and Land Improvements 29,490      
Total 31,525      
Accumulated Depreciation (260)      
5520 Research Park Drive [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 20,072      
Costs Capitalized Subsequent to Acquisition 1,018      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 21,090      
Total 21,090      
Accumulated Depreciation (4,260)      
5522 Research Park Drive [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 4,550      
Costs Capitalized Subsequent to Acquisition 210      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 4,760      
Total 4,760      
Accumulated Depreciation (1,185)      
5801 University Research Court [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 9,423      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 9,423      
Total 9,423      
Accumulated Depreciation (36)      
5825 University Research Court [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 21,284      
Initial Cost        
Land 0      
Building and Land Improvements 22,771      
Costs Capitalized Subsequent to Acquisition 666      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 23,437      
Total 23,437      
Accumulated Depreciation (5,020)      
5850 University Research Court [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 22,517      
Initial Cost        
Land 0      
Building and Land Improvements 31,906      
Costs Capitalized Subsequent to Acquisition 405      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 32,311      
Total 32,311      
Accumulated Depreciation (6,306)      
6700 Alexander Bell Drive [Member]        
Initial Cost        
Land 1,755      
Building and Land Improvements 7,019      
Costs Capitalized Subsequent to Acquisition 6,866      
Gross Amounts Carried At Close of Period        
Land 1,755      
Building and Land Improvements 13,885      
Total 15,640      
Accumulated Depreciation (6,916)      
6708 Alexander Bell Drive [Member]        
Initial Cost        
Land 897      
Building and Land Improvements 11,984      
Costs Capitalized Subsequent to Acquisition 1,605      
Gross Amounts Carried At Close of Period        
Land 897      
Building and Land Improvements 13,589      
Total 14,486      
Accumulated Depreciation (3,839)      
6711 Columbia Gateway Drive [Member]        
Initial Cost        
Land 2,683      
Building and Land Improvements 23,239      
Costs Capitalized Subsequent to Acquisition 1,278      
Gross Amounts Carried At Close of Period        
Land 2,683      
Building and Land Improvements 24,517      
Total 27,200      
Accumulated Depreciation (6,817)      
6716 Alexander Bell Drive [Member]        
Initial Cost        
Land 1,242      
Building and Land Improvements 4,969      
Costs Capitalized Subsequent to Acquisition 3,754      
Gross Amounts Carried At Close of Period        
Land 1,242      
Building and Land Improvements 8,723      
Total 9,965      
Accumulated Depreciation (5,129)      
6721 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,753      
Building and Land Improvements 34,090      
Costs Capitalized Subsequent to Acquisition 102      
Gross Amounts Carried At Close of Period        
Land 1,753      
Building and Land Improvements 34,192      
Total 35,945      
Accumulated Depreciation (7,514)      
6724 Alexander Bell Drive [Member]        
Initial Cost        
Land 449      
Building and Land Improvements 5,039      
Costs Capitalized Subsequent to Acquisition 1,374      
Gross Amounts Carried At Close of Period        
Land 449      
Building and Land Improvements 6,413      
Total 6,862      
Accumulated Depreciation (2,670)      
6731 Columbia Gateway Drive [Member]        
Initial Cost        
Land 2,807      
Building and Land Improvements 19,098      
Costs Capitalized Subsequent to Acquisition 4,872      
Gross Amounts Carried At Close of Period        
Land 2,807      
Building and Land Improvements 23,970      
Total 26,777      
Accumulated Depreciation (10,176)      
6740 Alexander Bell Drive [Member]        
Initial Cost        
Land 1,424      
Building and Land Improvements 5,696      
Costs Capitalized Subsequent to Acquisition 3,321      
Gross Amounts Carried At Close of Period        
Land 1,424      
Building and Land Improvements 9,017      
Total 10,441      
Accumulated Depreciation (5,698)      
6741 Columbia Gateway Drive [Member]        
Initial Cost        
Land 675      
Building and Land Improvements 1,711      
Costs Capitalized Subsequent to Acquisition 124      
Gross Amounts Carried At Close of Period        
Land 675      
Building and Land Improvements 1,835      
Total 2,510      
Accumulated Depreciation (466)      
6750 Alexander Bell Drive [Member]        
Initial Cost        
Land 1,263      
Building and Land Improvements 12,461      
Costs Capitalized Subsequent to Acquisition 3,959      
Gross Amounts Carried At Close of Period        
Land 1,263      
Building and Land Improvements 16,420      
Total 17,683      
Accumulated Depreciation (8,761)      
6760 Alexander Bell Drive [Member]        
Initial Cost        
Land 890      
Building and Land Improvements 3,561      
Costs Capitalized Subsequent to Acquisition 3,358      
Gross Amounts Carried At Close of Period        
Land 890      
Building and Land Improvements 6,919      
Total 7,809      
Accumulated Depreciation (3,932)      
6940 Columbia Gateway Drive [Member]        
Initial Cost        
Land 3,545      
Building and Land Improvements 9,916      
Costs Capitalized Subsequent to Acquisition 7,095      
Gross Amounts Carried At Close of Period        
Land 3,545      
Building and Land Improvements 17,011      
Total 20,556      
Accumulated Depreciation (8,164)      
6950 Columbia Gateway Drive [Member]        
Initial Cost        
Land 3,596      
Building and Land Improvements 14,269      
Costs Capitalized Subsequent to Acquisition 3,238      
Gross Amounts Carried At Close of Period        
Land 3,596      
Building and Land Improvements 17,507      
Total 21,103      
Accumulated Depreciation (8,787)      
7000 Columbia Gateway Drive [Member]        
Initial Cost        
Land 3,131      
Building and Land Improvements 12,103      
Costs Capitalized Subsequent to Acquisition 5,085      
Gross Amounts Carried At Close of Period        
Land 3,131      
Building and Land Improvements 17,188      
Total 20,319      
Accumulated Depreciation (6,178)      
7005 Columbia Gateway Drive [Member]        
Initial Cost        
Land 3,036      
Building and Land Improvements 753      
Gross Amounts Carried At Close of Period        
Land 3,036      
Building and Land Improvements 753      
Total 3,789      
7015 Albert Einstein Drive [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 829      
Initial Cost        
Land 2,058      
Building and Land Improvements 6,093      
Costs Capitalized Subsequent to Acquisition 2,178      
Gross Amounts Carried At Close of Period        
Land 2,058      
Building and Land Improvements 8,271      
Total 10,329      
Accumulated Depreciation (3,343)      
7061 Columbia Gateway Drive [Member]        
Initial Cost        
Land 729      
Building and Land Improvements 3,094      
Costs Capitalized Subsequent to Acquisition 2,018      
Gross Amounts Carried At Close of Period        
Land 729      
Building and Land Improvements 5,112      
Total 5,841      
Accumulated Depreciation (2,191)      
7063 Columbia Gateway Drive [Member]        
Initial Cost        
Land 902      
Building and Land Improvements 3,684      
Costs Capitalized Subsequent to Acquisition 3,151      
Gross Amounts Carried At Close of Period        
Land 902      
Building and Land Improvements 6,835      
Total 7,737      
Accumulated Depreciation (3,113)      
7065 Columbia Gateway Drive [Member]        
Initial Cost        
Land 919      
Building and Land Improvements 3,763      
Costs Capitalized Subsequent to Acquisition 3,095      
Gross Amounts Carried At Close of Period        
Land 919      
Building and Land Improvements 6,858      
Total 7,777      
Accumulated Depreciation (3,637)      
7067 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,829      
Building and Land Improvements 11,823      
Costs Capitalized Subsequent to Acquisition 3,051      
Gross Amounts Carried At Close of Period        
Land 1,829      
Building and Land Improvements 14,874      
Total 16,703      
Accumulated Depreciation (7,037)      
7125 Columbia Gateway Drive [Member]        
Initial Cost        
Land 3,361      
Building and Land Improvements 2,354      
Costs Capitalized Subsequent to Acquisition 279      
Gross Amounts Carried At Close of Period        
Land 3,361      
Building and Land Improvements 2,633      
Total 5,994      
7125 Columbia Gateway Drive [Member]        
Initial Cost        
Land 17,126      
Building and Land Improvements 46,994      
Costs Capitalized Subsequent to Acquisition 15,786      
Gross Amounts Carried At Close of Period        
Land 17,126      
Building and Land Improvements 62,780      
Total 79,906      
Accumulated Depreciation (20,876)      
7130 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,350      
Building and Land Improvements 4,359      
Costs Capitalized Subsequent to Acquisition 2,534      
Gross Amounts Carried At Close of Period        
Land 1,350      
Building and Land Improvements 6,893      
Total 8,243      
Accumulated Depreciation (3,192)      
7134 Columbia Gateway Drive [Member]        
Initial Cost        
Land 704      
Building and Land Improvements 4,707      
Costs Capitalized Subsequent to Acquisition 353      
Gross Amounts Carried At Close of Period        
Land 704      
Building and Land Improvements 5,060      
Total 5,764      
Accumulated Depreciation (1,422)      
7138 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,104      
Building and Land Improvements 3,518      
Costs Capitalized Subsequent to Acquisition 2,729      
Gross Amounts Carried At Close of Period        
Land 1,104      
Building and Land Improvements 6,247      
Total 7,351      
Accumulated Depreciation (3,459)      
7142 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,342      
Building and Land Improvements 4,657      
Costs Capitalized Subsequent to Acquisition 2,608      
Gross Amounts Carried At Close of Period        
Land 1,342      
Building and Land Improvements 7,265      
Total 8,607      
Accumulated Depreciation (2,796)      
7150 Columbia Gateway Drive [Member]        
Initial Cost        
Land 1,032      
Building and Land Improvements 3,429      
Costs Capitalized Subsequent to Acquisition 813      
Gross Amounts Carried At Close of Period        
Land 1,032      
Building and Land Improvements 4,242      
Total 5,274      
Accumulated Depreciation (1,439)      
7150 Riverwood Drive [Member]        
Initial Cost        
Land 1,821      
Building and Land Improvements 4,388      
Costs Capitalized Subsequent to Acquisition 1,774      
Gross Amounts Carried At Close of Period        
Land 1,821      
Building and Land Improvements 6,162      
Total 7,983      
Accumulated Depreciation (2,343)      
7160 Riverwood Drive [Member]        
Initial Cost        
Land 2,732      
Building and Land Improvements 7,006      
Costs Capitalized Subsequent to Acquisition 2,455      
Gross Amounts Carried At Close of Period        
Land 2,732      
Building and Land Improvements 9,461      
Total 12,193      
Accumulated Depreciation (3,778)      
7170 Riverwood Drive [Member]        
Initial Cost        
Land 1,283      
Building and Land Improvements 3,096      
Costs Capitalized Subsequent to Acquisition 1,465      
Gross Amounts Carried At Close of Period        
Land 1,283      
Building and Land Improvements 4,561      
Total 5,844      
Accumulated Depreciation (1,798)      
7175 Riverwood Drive [Member]        
Initial Cost        
Land 1,788      
Building and Land Improvements 7,269      
Gross Amounts Carried At Close of Period        
Land 1,788      
Building and Land Improvements 7,269      
Total 9,057      
Accumulated Depreciation (752)      
7200 Redstone Gateway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 6,303      
Initial Cost        
Land 0      
Building and Land Improvements 8,348      
Costs Capitalized Subsequent to Acquisition 5      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 8,353      
Total 8,353      
Accumulated Depreciation (752)      
7200 Riverwood Road [Member]        
Initial Cost        
Land 4,089      
Building and Land Improvements 22,630      
Costs Capitalized Subsequent to Acquisition 4,532      
Gross Amounts Carried At Close of Period        
Land 4,089      
Building and Land Improvements 27,162      
Total 31,251      
Accumulated Depreciation (10,180)      
7205 Riverwood Drive [Member]        
Initial Cost        
Land 1,367      
Building and Land Improvements 21,419      
Gross Amounts Carried At Close of Period        
Land 1,367      
Building and Land Improvements 21,419      
Total 22,786      
Accumulated Depreciation (2,381)      
7272 Park Circle Drive [Member]        
Initial Cost        
Land 1,479      
Building and Land Improvements 6,300      
Costs Capitalized Subsequent to Acquisition 4,578      
Gross Amounts Carried At Close of Period        
Land 1,479      
Building and Land Improvements 10,878      
Total 12,357      
Accumulated Depreciation (3,898)      
7318 Parkway Drive [Member]        
Initial Cost        
Land 972      
Building and Land Improvements 3,888      
Costs Capitalized Subsequent to Acquisition 1,239      
Gross Amounts Carried At Close of Period        
Land 972      
Building and Land Improvements 5,127      
Total 6,099      
Accumulated Depreciation (2,398)      
7400 Redstone Gateway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 6,914      
Initial Cost        
Land 0      
Building and Land Improvements 9,223      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 9,223      
Total 9,223      
Accumulated Depreciation (582)      
7467 Ridge Road [Member]        
Initial Cost        
Land 1,565      
Building and Land Improvements 3,116      
Costs Capitalized Subsequent to Acquisition 4,264      
Gross Amounts Carried At Close of Period        
Land 1,565      
Building and Land Improvements 7,380      
Total 8,945      
Accumulated Depreciation (1,930)      
7740 Milestone Parkway [Member]        
Real Estate and Accumulated Depreciation        
Encumbrances 18,203      
Initial Cost        
Land 3,825      
Building and Land Improvements 34,176      
Costs Capitalized Subsequent to Acquisition 567      
Gross Amounts Carried At Close of Period        
Land 3,825      
Building and Land Improvements 34,743      
Total 38,568      
Accumulated Depreciation (6,482)      
7770 Backlick Road [Member]        
Initial Cost        
Land 6,387      
Building and Land Improvements 76,315      
Costs Capitalized Subsequent to Acquisition 142      
Gross Amounts Carried At Close of Period        
Land 6,387      
Building and Land Improvements 76,457      
Total 82,844      
Accumulated Depreciation (9,075)      
7880 Milestone Parkway [Member]        
Initial Cost        
Land 4,857      
Building and Land Improvements 24,677      
Costs Capitalized Subsequent to Acquisition 62      
Gross Amounts Carried At Close of Period        
Land 4,857      
Building and Land Improvements 24,739      
Total 29,596      
Accumulated Depreciation (1,382)      
8621 Robert Fulton Drive [Member]        
Initial Cost        
Land 2,317      
Building and Land Improvements 12,642      
Costs Capitalized Subsequent to Acquisition 537      
Gross Amounts Carried At Close of Period        
Land 2,317      
Building and Land Improvements 13,179      
Total 15,496      
Accumulated Depreciation (4,097)      
8661 Robert Fulton Drive [Member]        
Initial Cost        
Land 1,510      
Building and Land Improvements 3,764      
Costs Capitalized Subsequent to Acquisition 2,453      
Gross Amounts Carried At Close of Period        
Land 1,510      
Building and Land Improvements 6,217      
Total 7,727      
Accumulated Depreciation (2,655)      
8671 Robert Fulton Drive [Member]        
Initial Cost        
Land 1,718      
Building and Land Improvements 4,280      
Costs Capitalized Subsequent to Acquisition 4,052      
Gross Amounts Carried At Close of Period        
Land 1,718      
Building and Land Improvements 8,332      
Total 10,050      
Accumulated Depreciation (3,688)      
870 Elkridge Landing Road [Member]        
Initial Cost        
Land 2,003      
Building and Land Improvements 9,442      
Costs Capitalized Subsequent to Acquisition 8,735      
Gross Amounts Carried At Close of Period        
Land 2,003      
Building and Land Improvements 18,177      
Total 20,180      
Accumulated Depreciation (9,370)      
891 Elkridge Landing Road [Member]        
Initial Cost        
Land 1,165      
Building and Land Improvements 4,772      
Costs Capitalized Subsequent to Acquisition 3,466      
Gross Amounts Carried At Close of Period        
Land 1,165      
Building and Land Improvements 8,238      
Total 9,403      
Accumulated Depreciation (4,186)      
901 Elkridge Landing Road [Member]        
Initial Cost        
Land 1,156      
Building and Land Improvements 4,437      
Costs Capitalized Subsequent to Acquisition 2,704      
Gross Amounts Carried At Close of Period        
Land 1,156      
Building and Land Improvements 7,141      
Total 8,297      
Accumulated Depreciation (3,608)      
911 Elkridge Landing Road [Member]        
Initial Cost        
Land 1,215      
Building and Land Improvements 4,861      
Costs Capitalized Subsequent to Acquisition 2,191      
Gross Amounts Carried At Close of Period        
Land 1,215      
Building and Land Improvements 7,052      
Total 8,267      
Accumulated Depreciation (3,899)      
938 Elkridge Landing Road [Member]        
Initial Cost        
Land 922      
Building and Land Improvements 4,748      
Costs Capitalized Subsequent to Acquisition 1,446      
Gross Amounts Carried At Close of Period        
Land 922      
Building and Land Improvements 6,194      
Total 7,116      
Accumulated Depreciation (2,621)      
939 Elkridge Landing Road [Member]        
Initial Cost        
Land 939      
Building and Land Improvements 3,756      
Costs Capitalized Subsequent to Acquisition 4,438      
Gross Amounts Carried At Close of Period        
Land 939      
Building and Land Improvements 8,194      
Total 9,133      
Accumulated Depreciation (4,254)      
940 Elkridge Landing Road [Member]        
Initial Cost        
Land 842      
Building and Land Improvements 4      
Gross Amounts Carried At Close of Period        
Land 842      
Building and Land Improvements 4      
Total 846      
9651 Hornbaker Road [Member]        
Initial Cost        
Land 6,050      
Building and Land Improvements 249,142      
Costs Capitalized Subsequent to Acquisition 3,868      
Gross Amounts Carried At Close of Period        
Land 6,050      
Building and Land Improvements 253,010      
Total 259,060      
Accumulated Depreciation (39,294)      
Arundel Preserve [Member]        
Initial Cost        
Land 13,401      
Building and Land Improvements 9,578      
Gross Amounts Carried At Close of Period        
Land 13,401      
Building and Land Improvements 9,578      
Total 22,979      
Bethlehem Tech Park-DC18 [Member]        
Initial Cost        
Land 3,599      
Building and Land Improvements 25,992      
Gross Amounts Carried At Close of Period        
Land 3,599      
Building and Land Improvements 25,992      
Total 29,591      
Accumulated Depreciation (306)      
Bethlehem Tech Park-DC19 [Member]        
Initial Cost        
Land 3,708      
Building and Land Improvements 16,362      
Gross Amounts Carried At Close of Period        
Land 3,708      
Building and Land Improvements 16,362      
Total 20,070      
Accumulated Depreciation (455)      
Bethlehem Tech Park-DC20 [Member]        
Initial Cost        
Land 3,599      
Building and Land Improvements 23,625      
Gross Amounts Carried At Close of Period        
Land 3,599      
Building and Land Improvements 23,625      
Total 27,224      
Accumulated Depreciation (370)      
Bethlehem Tech Park - DC 23 [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 479      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 479      
Total 479      
BLC 1 [Member]        
Initial Cost        
Land 12,035      
Building and Land Improvements 368      
Gross Amounts Carried At Close of Period        
Land 12,035      
Building and Land Improvements 368      
Total 12,403      
BLC 2 [Member]        
Initial Cost        
Land 12,035      
Building and Land Improvements 292      
Gross Amounts Carried At Close of Period        
Land 12,035      
Building and Land Improvements 292      
Total 12,327      
Canton Crossing Land [Member]        
Initial Cost        
Land 16,085      
Building and Land Improvements 2,698      
Gross Amounts Carried At Close of Period        
Land 16,085      
Building and Land Improvements 2,698      
Total 18,783      
Canton Crossing Util Distr Ctr [Member]        
Initial Cost        
Land 7,300      
Building and Land Improvements 15,556      
Costs Capitalized Subsequent to Acquisition 986      
Gross Amounts Carried At Close of Period        
Land 7,300      
Building and Land Improvements 16,542      
Total 23,842      
Accumulated Depreciation (4,475)      
Columbia Gateway - Southridge [Member]        
Initial Cost        
Land 6,387      
Building and Land Improvements 3,719      
Gross Amounts Carried At Close of Period        
Land 6,387      
Building and Land Improvements 3,719      
Total 10,106      
Dahlgren Technology Center [Member]        
Initial Cost        
Land 978      
Building and Land Improvements 178      
Gross Amounts Carried At Close of Period        
Land 978      
Building and Land Improvements 178      
Total 1,156      
Expedition VII [Member]        
Initial Cost        
Land 705      
Building and Land Improvements 729      
Gross Amounts Carried At Close of Period        
Land 705      
Building and Land Improvements 729      
Total 1,434      
Innovation Park [Member]        
Initial Cost        
Land 4,443      
Building and Land Improvements 120      
Gross Amounts Carried At Close of Period        
Land 4,443      
Building and Land Improvements 120      
Total 4,563      
M Square Research Park [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 3,571      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 3,571      
Total 3,571      
MR Land [Member]        
Initial Cost        
Land 18,827      
Building and Land Improvements 293      
Gross Amounts Carried At Close of Period        
Land 18,827      
Building and Land Improvements 293      
Total 19,120      
National Business Park North [Member]        
Initial Cost        
Land 28,066      
Building and Land Improvements 47,802      
Gross Amounts Carried At Close of Period        
Land 28,066      
Building and Land Improvements 47,802      
Total 75,868      
North Gate Business Park [Member]        
Initial Cost        
Land 1,755      
Building and Land Improvements 0      
Gross Amounts Carried At Close of Period        
Land 1,755      
Building and Land Improvements 0      
Total 1,755      
Northwest Crossroads [Member]        
Initial Cost        
Land 7,430      
Building and Land Improvements 847      
Gross Amounts Carried At Close of Period        
Land 7,430      
Building and Land Improvements 847      
Total 8,277      
NOVA Office A [Member]        
Initial Cost        
Land 2,096      
Building and Land Improvements 46,835      
Gross Amounts Carried At Close of Period        
Land 2,096      
Building and Land Improvements 46,835      
Total 48,931      
Accumulated Depreciation (3,403)      
NOVA Office B [Member]        
Initial Cost        
Land 739      
Building and Land Improvements 27,128      
Gross Amounts Carried At Close of Period        
Land 739      
Building and Land Improvements 27,128      
Total 27,867      
Accumulated Depreciation (1,128)      
NOVA Office D [Member]        
Initial Cost        
Land 6,587      
Building and Land Improvements 38,758      
Gross Amounts Carried At Close of Period        
Land 6,587      
Building and Land Improvements 38,758      
Total 45,345      
Accumulated Depreciation (437)      
Old Annapolis Road [Member]        
Initial Cost        
Land 1,637      
Building and Land Improvements 5,500      
Costs Capitalized Subsequent to Acquisition 5,241      
Gross Amounts Carried At Close of Period        
Land 1,637      
Building and Land Improvements 10,741      
Total 12,378      
Accumulated Depreciation (3,509)      
Paragon Park - DC 21 [Member]        
Initial Cost        
Land 7,828      
Building and Land Improvements 17,992      
Gross Amounts Carried At Close of Period        
Land 7,828      
Building and Land Improvements 17,992      
Total 25,820      
Accumulated Depreciation (100)      
Paragon Park - DC 22 [Member]        
Initial Cost        
Land 7,828      
Building and Land Improvements 17,445      
Gross Amounts Carried At Close of Period        
Land 7,828      
Building and Land Improvements 17,445      
Total 25,273      
Accumulated Depreciation (68)      
Patriot Point - DC15 [Member]        
Initial Cost        
Land 12,156      
Building and Land Improvements 17,069      
Gross Amounts Carried At Close of Period        
Land 12,156      
Building and Land Improvements 17,069      
Total 29,225      
Accumulated Depreciation (752)      
Patriot Point - DC16 [Member]        
Initial Cost        
Land 12,156      
Building and Land Improvements 16,973      
Gross Amounts Carried At Close of Period        
Land 12,156      
Building and Land Improvements 16,973      
Total 29,129      
Accumulated Depreciation (709)      
Patriot Point - DC17 [Member]        
Initial Cost        
Land 6,078      
Building and Land Improvements 16,347      
Gross Amounts Carried At Close of Period        
Land 6,078      
Building and Land Improvements 16,347      
Total 22,425      
Accumulated Depreciation (520)      
Patriot Ridge [Member]        
Initial Cost        
Land 18,517      
Building and Land Improvements 14,467      
Gross Amounts Carried At Close of Period        
Land 18,517      
Building and Land Improvements 14,467      
Total 32,984      
Redstone Gateway [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 19,152      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 19,152      
Total 19,152      
Route 15/Biggs Ford Road [Member]        
Initial Cost        
Land 1,129      
Building and Land Improvements 0      
Gross Amounts Carried At Close of Period        
Land 1,129      
Building and Land Improvements 0      
Total 1,129      
Sentry Gateway [Member]        
Initial Cost        
Land 8,275      
Building and Land Improvements 3,704      
Gross Amounts Carried At Close of Period        
Land 8,275      
Building and Land Improvements 3,704      
Total 11,979      
Sentry Gateway - T [Member]        
Initial Cost        
Land 14,020      
Building and Land Improvements 38,804      
Costs Capitalized Subsequent to Acquisition 13      
Gross Amounts Carried At Close of Period        
Land 14,020      
Building and Land Improvements 38,817      
Total 52,837      
Accumulated Depreciation (10,561)      
Sentry Gateway - V [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 1,066      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 1,066      
Total 1,066      
Accumulated Depreciation (241)      
Sentry Gateway - W [Member]        
Initial Cost        
Land 0      
Building and Land Improvements 1,884      
Costs Capitalized Subsequent to Acquisition 71      
Gross Amounts Carried At Close of Period        
Land 0      
Building and Land Improvements 1,955      
Total 1,955      
Accumulated Depreciation (392)      
Sentry Gateway - X [Member]        
Initial Cost        
Land 1,964      
Building and Land Improvements 21,178      
Gross Amounts Carried At Close of Period        
Land 1,964      
Building and Land Improvements 21,178      
Total 23,142      
Accumulated Depreciation (3,787)      
Sentry Gateway - Y [Member]        
Initial Cost        
Land 1,964      
Building and Land Improvements 21,298      
Gross Amounts Carried At Close of Period        
Land 1,964      
Building and Land Improvements 21,298      
Total 23,262      
Accumulated Depreciation (3,810)      
Sentry Gateway - Z [Member]        
Initial Cost        
Land 1,964      
Building and Land Improvements 30,573      
Gross Amounts Carried At Close of Period        
Land 1,964      
Building and Land Improvements 30,573      
Total 32,537      
Accumulated Depreciation (2,144)      
Westfields - Park Center [Member]        
Initial Cost        
Land 16,418      
Building and Land Improvements 11,264      
Gross Amounts Carried At Close of Period        
Land 16,418      
Building and Land Improvements 11,264      
Total 27,682      
Westfields Corporate Center [Member]        
Initial Cost        
Land 7,141      
Building and Land Improvements 1,649      
Gross Amounts Carried At Close of Period        
Land 7,141      
Building and Land Improvements 1,649      
Total 8,790      
Other Developments, including intercompany eliminations [Member]        
Initial Cost        
Land 4      
Building and Land Improvements 283      
Costs Capitalized Subsequent to Acquisition 256      
Gross Amounts Carried At Close of Period        
Land 4      
Building and Land Improvements 539      
Total 543      
Accumulated Depreciation (58)      
Fair value measurement on a nonrecurring basis [Member] | Real Estate Held [Member]        
Additional information        
Impairment losses 13,700      
Fair value measurement on a nonrecurring basis [Member] | Real Estate Investment Properties, Net [Member]        
Additional information        
Impairment losses $ 15,100