Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Real Estate and Other Assets Held for Sale, Net of Accumulated Depreciation and Amortization	$ 18,773	$ 39,413
Leasing Intangibles, Accumulated Amortization	0	415
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10,000,000	10,000,000
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	150,000,000	150,000,000
Common Stock, shares issued	92,960,811	91,131,516
Common Stock, shares outstanding	88,636,697	86,807,402
Treasury Shares at cost, shares	4,324,114	4,324,114
Series F Preferred Stock [Member]
Preferred Stock, shares issued	500	500
Preferred Stock, shares outstanding	500	500
Preferred Stock, liquidation preference per share	$ 100,000	$ 100,000
Preferred Stock liquidation preference value	(50,000)	(50,000)
Series G Preferred Stock [Member]
Preferred Stock, shares issued	250	250
Preferred Stock, shares outstanding	250	250
Preferred Stock, liquidation preference per share	$ 100,000	$ 100,000
Preferred Stock liquidation preference value	(25,000)	(25,000)
Series J Preferred Stock [Member]
Preferred Stock, shares issued	600	600
Preferred Stock, shares outstanding	600	600
Preferred Stock, liquidation preference per share	$ 250,000	$ 250,000
Preferred Stock liquidation preference value	(150,000)	(150,000)
Series K Preferred Stock [Member]
Preferred Stock, shares issued	200	200
Preferred Stock, shares outstanding	200	200
Preferred Stock, liquidation preference per share	$ 250,000	$ 250,000
Preferred Stock liquidation preference value	$ (50,000)	$ (50,000)