Investment in Unconsolidated Joint Ventures (Crawford Long—CPI, LLC) (Details) ft² in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Outstanding Amount of Mortgage Note Payable of Joint Venture	$ 402,000,000
Crawford Long CPI LLC [Member]
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet) | ft²	0.4
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	$ 74,300,000
Cash balance of joint venture	$ 762,000
Charlotte Gateway Village LLC [Member]
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet) | ft²	1.1
Cash balance of joint venture	$ 2,300,000
EP II LLC [Member]
Schedule of Equity Method Investments [Line Items]
Mortgage Loans on Real Estate, Carrying Amount of Mortgages	40,900,000
Cash balance of joint venture	$ 1,300,000
Secured Mortgage Note Payable [Member] | Crawford Long CPI LLC [Member]
Schedule of Equity Method Investments [Line Items]
Interest rate on mortgage loan (percent)	3.50%
Debt Instrument of Equity Investee Maturity Date	Jun. 01, 2023
Secured Mortgage Note Payable [Member] | Charlotte Gateway Village LLC [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding Amount of Mortgage Note Payable of Joint Venture	$ 17,500,000
Interest rate on mortgage loan (percent)	6.41%
Debt Instrument of Equity Investee Maturity Date	Dec. 01, 2016
Secured Mortgage Note Payable [Member] | EP II LLC [Member]
Schedule of Equity Method Investments [Line Items]
Debt Instrument of Equity Investee Maturity Date		Oct. 09, 2016
Emory University [Member] | Crawford Long CPI LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage of Partner in Joint Venture	5000.00%	5000.00%