Annual report pursuant to Section 13 and 15(d)

Real Estate Joint Ventures (Details)

v3.8.0.1
Real Estate Joint Ventures (Details)
$ in Thousands
1 Months Ended 12 Months Ended
Jul. 21, 2016
USD ($)
Jan. 31, 2016
USD ($)
Dec. 31, 2017
USD ($)
ft²
Dec. 31, 2016
USD ($)
Property
Dec. 31, 2015
USD ($)
Investments in consolidated real estate joint ventures          
Increase in property and redeemable noncontrolling interests in connection with property contribution by redeemable noncontrolling interests in a joint venture     $ 0 $ 22,600 $ 0
Distributions paid to redeemable noncontrolling interests     8,215 15,206 $ 2,993
Non-real estate equity method investments     2,412 $ 2,355  
Consolidated real estate joint ventures [Member]          
Investments in consolidated real estate joint ventures          
Total Assets     303,983    
Encumbered Assets     120,953    
Total Liabilities     116,830    
Notes receivable from City of Huntsville [Member]          
Investments in consolidated real estate joint ventures          
Amount of advanced     37,800    
Single-tenant data centers [Member] | Operating office properties [Member]          
Investments in consolidated real estate joint ventures          
Increase in property and redeemable noncontrolling interests in connection with property contribution by redeemable noncontrolling interests in a joint venture $ 147,600        
Ownership percentage sold (percent) 50.00%        
Ownership percentage 50.00%        
Data Center Shells [Member] | Operating properties, net [Member] | Single-tenant data centers [Member] | Operating office properties [Member]          
Investments in consolidated real estate joint ventures          
Number of properties contributed | Property       6  
LW Redstone Company, LLC [Member]          
Investments in consolidated real estate joint ventures          
Partner's capital account upon formation     $ 9,000    
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company     85.00%    
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the entity's partners     15.00%    
Number of years following construction commencement threshold achievement before partner's interest can be purchased at fair value     5 years    
Construction commencement threshold (in square feet) | ft²     4,400,000.0    
Construction commencement completed (in sqft) | ft²     674,000    
LW Redstone Company, LLC [Member] | Maximum [Member]          
Investments in consolidated real estate joint ventures          
Infrastructure costs anticipated to be funded by entity for reimbursement by the City of Huntsville (in dollars)     $ 76,000    
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company     85.00%    
Stevens Investors, LLC [Member] | Minimum [Member]          
Investments in consolidated real estate joint ventures          
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company     60.00%    
M Square Associates, LLC [Member]          
Investments in consolidated real estate joint ventures          
Percentage of residual amounts distributed to each member     50.00%    
GI-COPT [Member]          
Investments in consolidated real estate joint ventures          
Non-real estate equity method investments     $ 25,100 $ 25,500  
Difference between cost basis and share of underlying equity     $ 16,700 18,100  
LW Redstone Company, LLC [Member] | Primary Beneficiary [Member]          
Investments in consolidated real estate joint ventures          
Ownership (as a percent)     85.00%    
Total Assets     $ 158,891    
Encumbered Assets     75,569    
Total Liabilities     $ 51,180    
M Square Associates, LLC [Member] | Primary Beneficiary [Member]          
Investments in consolidated real estate joint ventures          
Ownership (as a percent)     50.00%    
Total Assets     $ 73,116    
Encumbered Assets     45,384    
Total Liabilities     $ 45,745    
Stevens Investors, LLC [Member] | Primary Beneficiary [Member]          
Investments in consolidated real estate joint ventures          
Ownership (as a percent)     95.00%    
Total Assets     $ 71,976    
Encumbered Assets     0    
Total Liabilities     19,905    
Increase in property and redeemable noncontrolling interests in connection with property contribution by redeemable noncontrolling interests in a joint venture   $ 22,600      
Distributions paid to redeemable noncontrolling interests     $ 6,700 $ 13,400