Accounting for the Impairment or Disposal of Long-Lived Assets Asset Impairment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Impairment - real estate assets	$ 0	$ 0	$ 16,775,000	$ 0
Maryland [Member]
Property, Plant and Equipment [Line Items]
Impairment - real estate assets			1,000,000
Richmond Hampton Roads [Member]
Property, Plant and Equipment [Line Items]
Impairment - real estate assets			13,400,000
Southeastern PA [Member]
Property, Plant and Equipment [Line Items]
Impairment - real estate assets			$ 2,300,000