Commitments and Contingencies (Details) (USD $)
1 Months Ended 0 Months Ended
Aug. 31, 2010
Apr. 15, 2015
Mar. 31, 2015
Property
Tax incremental financing obligation      
The amount of tax incremental financing bonds issued by Anne Arundel County, Maryland $ 30,000,000    
Liability recognized with regard to tax incremental financing obligation at end of current period     1,400,000
Environmental Indemnity Agreement      
Number of lease properties which were provided environmental indemnifications     3
Environmental indemnification to the tenant against losses covered under prior owner's indemnity agreement     5,000,000.0
Maximum environmental indemnification to the tenant against consequential damages after acquisition of property     12,500,000.0
Additional costs agreed to be paid by the entity related to construction and environmental regulatory activities (as a percent)     50.00%
Maximum annual additional costs agreed to be paid by the entity related to construction and environmental regulatory activities     300,000
Maximum additional costs agreed to be paid by the entity related to construction and environmental regulatory activities     1,500,000.0
Subsequent Event | 2600 Park Tower Drive | Virginia      
Other Commitments [Line Items]      
Square footage of real estate properties (in square feet)   240,000  
Acquired property percentage leased   100.00%  
Total acquisition cost   $ 83,000,000