Investments In Unconsolidated Joint Ventures (Gale Jefferson, L.L.C.) (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended
	Jan. 04, 2013	Mar. 31, 2013 sqft	Mar. 31, 2012
One Jefferson [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture		8.33%
Mortgage loans, carrying amount		$ 20,200,000
Spread over LIBOR		1.60%
Mortgage loan, maturity date		October 2013
Gale Jefferson, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Rentable Square Feet		100,010
Lease expiration date		Aug. 01, 2025
Venture sale of real estate	3,200,000
Share of gain on sale of real estate	1,100,000
Management, leasing and other services fees		$ 16,000	$ 48,000