Investment in Unconsolidated Joint Ventures (EP I LLC) (Details) (USD $)	1 Months Ended	12 Months Ended
	Jun. 28, 2011	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]
Variable rate basis		LIBOR
Basis spread on variable rate (percent)		1.50%
EP I LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage equity method investment (percent)			75.00%
Approximate cash contribution of Company in joint venture	$ 8,100,000
Transfer from predevelopment assets to investment in joint venture	6,200,000
Maximum amount available under construction facility, revised		61,100,000
Outstanding balance of mortgage loan		43,500,000
Basis spread on variable rate (percent)		1.85%
Maturity date of mortgage loans		Jun. 28, 2014
Extension of mortgage loans maturity, conditions		two, one-year periods if certain conditions are met
Approximate amount of loans guaranteed by Company		11,500,000
Cash balance of joint venture		475,000
Gables Realty Limited [Member] | EP I LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage equity method investment (percent)			25.00%
Approximate cash contribution of Company in joint venture	3,800,000
Approximate amount of loans guaranteed by Company		$ 3,800,000
LIBOR [Member]
Schedule of Equity Method Investments [Line Items]
Variable rate basis		LIBOR
Basis spread on variable rate (percent)		1.00%
LIBOR [Member] | EP I LLC [Member]
Schedule of Equity Method Investments [Line Items]
Variable rate basis		LIBOR