Investment in Unconsolidated Joint Ventures (Charlotte Gateway Village, LLC) (Details) (Charlotte Gateway Village LLC [Member], USD $)	12 Months Ended
	Dec. 31, 2012 sqft
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet)	1,100,000
Percentage of real estate property leased (percent)	100.00%
Compounded rate of return received by Company (percent)	11.46%
Percentage of Company's income (loss) received in final step of distribution	0.5
Maximum IRR on project (percent)	17.00%
Cash balance of joint venture	$ 1,700,000
Secured Mortgage Note Payable [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding amount of mortgage note payable of joint venture	$ 68,200,000
Maturity date of debt instrument	Dec. 01, 2016
Interest rate on mortgage loan (percent)	6.41%