Investment in Unconsolidated Joint Ventures (CF Murfreesboro Associates) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Variable rate basis	LIBOR
Basis spread on variable rate (percent)	1.50%
CF Murfreesboro Associates [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage of partner joint venture (percent)	50.00%
Square footage of real estate property (square feet)	751,000
Amount drawn on construction loan	94,500,000
Basis spread on variable rate (percent)	3.00%
Guarantee of indebtedness	26,200,000
Maximum amount available under construction facility, previous	113,200,000
Maximum amount available under construction facility, revised	97,500,000
Cash balance of joint venture	6,900,000
LIBOR [Member]
Schedule of Equity Method Investments [Line Items]
Variable rate basis	LIBOR
Basis spread on variable rate (percent)	1.00%
LIBOR [Member] | CF Murfreesboro Associates [Member]
Schedule of Equity Method Investments [Line Items]
Variable rate basis	LIBOR
August 2013 revised variable interest rate [Member] | CF Murfreesboro Associates [Member]
Schedule of Equity Method Investments [Line Items]
Basis spread on variable rate (percent)	2.50%