Information by Business Segment (Details) - USD ($)
$ in Thousands |
3 Months Ended |
12 Months Ended |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
$ 138,482
|
$ 137,411
|
$ 146,743
|
$ 155,476
|
$ 164,567
|
$ 157,017
|
$ 151,435
|
$ 139,801
|
$ 578,112
|
$ 612,820
|
$ 574,328
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(201,035)
|
(190,964)
|
(197,530)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
4,818
|
4,805
|
2,145
|
| Segment assets |
3,656,005
|
|
|
|
3,595,205
|
|
|
|
3,656,005
|
3,595,205
|
|
| Segment assets [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
3,084,862
|
|
|
|
3,028,005
|
|
|
|
3,084,862
|
3,028,005
|
|
| Real estate operations [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
517,253
|
509,980
|
525,964
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(201,035)
|
(190,964)
|
(197,530)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
4,818
|
4,805
|
2,145
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
321,036
|
323,821
|
330,579
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
74,742
|
73,341
|
70,324
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
166,143
|
202,211
|
184,640
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
421,053
|
408,122
|
406,210
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(153,004)
|
(146,558)
|
(148,705)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
4,818
|
4,805
|
2,145
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
272,867
|
266,369
|
259,650
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
53,676
|
44,352
|
57,131
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
163,839
|
202,185
|
184,943
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Fort Meade/BW Corridor [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
248,927
|
245,613
|
245,354
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(82,975)
|
(80,697)
|
(83,684)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
165,952
|
164,916
|
161,670
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
38,612
|
26,659
|
26,267
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
35,648
|
43,370
|
49,937
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Northern Virginia Defense/IT [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
53,518
|
47,118
|
48,964
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(20,330)
|
(16,938)
|
(17,824)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
33,188
|
30,180
|
31,140
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
7,956
|
8,115
|
17,344
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
10,231
|
48,328
|
28,230
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Lackland Air Force Base [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
46,286
|
47,209
|
46,803
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(26,888)
|
(27,812)
|
(27,357)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
19,398
|
19,397
|
19,446
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
0
|
71
|
0
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
14,718
|
0
|
240
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Navy Support Locations [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
31,927
|
29,540
|
28,197
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(13,536)
|
(12,619)
|
(12,690)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
18,391
|
16,921
|
15,507
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
6,535
|
8,451
|
9,168
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
(116)
|
474
|
0
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Redstone Arsenal [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
14,745
|
14,322
|
13,056
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(6,050)
|
(5,783)
|
(4,476)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
8,695
|
8,539
|
8,580
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
573
|
1,056
|
4,352
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
4,167
|
2,159
|
3,169
|
| Real estate operations [Member] | Defense/Information Technology Sector [Member] | Data Center Shells [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
25,650
|
24,320
|
23,836
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(3,225)
|
(2,709)
|
(2,674)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
4,818
|
4,805
|
2,145
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
27,243
|
26,416
|
23,307
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
99,191
|
107,854
|
103,367
|
| Real estate operations [Member] | Regional Office [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
61,181
|
68,262
|
85,805
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(30,253)
|
(28,982)
|
(34,095)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
30,928
|
39,280
|
51,710
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
19,730
|
25,299
|
12,559
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
0
|
0
|
82
|
| Real estate operations [Member] | Operating wholesale data centers [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
31,892
|
28,875
|
26,869
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(16,342)
|
(13,551)
|
(11,512)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
15,550
|
15,324
|
15,357
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
856
|
3,580
|
299
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
2,304
|
8
|
(377)
|
| Real estate operations [Member] | Other [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Revenues from real estate operations |
|
|
|
|
|
|
|
|
3,127
|
4,721
|
7,080
|
| Property operating expenses |
|
|
|
|
|
|
|
|
(1,436)
|
(1,873)
|
(3,218)
|
| UJV NOI allocable to COPT |
|
|
|
|
|
|
|
|
0
|
0
|
0
|
| NOI from real estate operations |
|
|
|
|
|
|
|
|
1,691
|
2,848
|
3,862
|
| Additions to long-lived assets |
|
|
|
|
|
|
|
|
480
|
110
|
335
|
| Transfers from non-operating properties |
|
|
|
|
|
|
|
|
0
|
18
|
(8)
|
| Real estate operations [Member] | Segment assets [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
3,084,862
|
|
|
|
3,028,005
|
|
|
|
3,084,862
|
3,028,005
|
3,022,360
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
2,468,727
|
|
|
|
2,398,989
|
|
|
|
2,468,727
|
2,398,989
|
2,326,302
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Fort Meade/BW Corridor [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
1,279,571
|
|
|
|
1,263,567
|
|
|
|
1,279,571
|
1,263,567
|
1,255,230
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Northern Virginia Defense/IT [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
399,339
|
|
|
|
402,076
|
|
|
|
399,339
|
402,076
|
404,438
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Lackland Air Force Base [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
139,731
|
|
|
|
128,755
|
|
|
|
139,731
|
128,755
|
131,957
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Navy Support Locations [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
188,911
|
|
|
|
194,476
|
|
|
|
188,911
|
194,476
|
196,486
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Redstone Arsenal [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
108,010
|
|
|
|
108,119
|
|
|
|
108,010
|
108,119
|
110,395
|
| Real estate operations [Member] | Segment assets [Member] | Defense/Information Technology Sector [Member] | Data Center Shells [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
353,165
|
|
|
|
301,996
|
|
|
|
353,165
|
301,996
|
227,796
|
| Real estate operations [Member] | Segment assets [Member] | Regional Office [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
395,380
|
|
|
|
400,512
|
|
|
|
395,380
|
400,512
|
442,811
|
| Real estate operations [Member] | Segment assets [Member] | Operating wholesale data centers [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
216,640
|
|
|
|
224,422
|
|
|
|
216,640
|
224,422
|
231,954
|
| Real estate operations [Member] | Segment assets [Member] | Other [Member] |
|
|
|
|
|
|
|
|
|
|
|
| Segment financial information for real estate operations |
|
|
|
|
|
|
|
|
|
|
|
| Segment assets |
$ 4,115
|
|
|
|
$ 4,082
|
|
|
|
$ 4,115
|
$ 4,082
|
$ 21,293
|