Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Preferred Stock [Member]	Dec. 31, 2011 Preferred Stock [Member]	Jun. 30, 2012 Series F Preferred Stock [Member]	Dec. 31, 2011 Series F Preferred Stock [Member]	Jun. 30, 2012 Series G Preferred Stock [Member]	Dec. 31, 2011 Series G Preferred Stock [Member]	Jun. 30, 2012 Series H Preferred Stock [Member]	Dec. 31, 2011 Series H Preferred Stock [Member]	Jun. 30, 2012 Series I Preferred Stock [Member]	Dec. 31, 2011 Series I Preferred Stock [Member]
Operating real estate, accumulated depreciation (in Dollars)	$ 1,743,276	$ 1,693,090
Preferred Stock, Par Value (in Dollars per share)			$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Preferred Stock, Shares Authorized			5,109,200	5,146,000	700,000	700,000	184,000	184,000	70,000	70,000	18,400	0
Preferred Stock, Shares Issued					700,000	700,000	184,000	184,000	70,000	70,000	16,000	0
Preferred Stock, Shares Outstanding					700,000	700,000	184,000	184,000	70,000	70,000	16,000	0
Preferred Stock, Aggregate Liquidation Preference (in Dollars)					$ 175,000	$ 175,000	$ 460,000	$ 460,000	$ 175,000	$ 175,000	$ 400,000	$ 0
Common Stock, Par Value (in Dollars per share)	$ 0.01	$ 0.01
Common Stock, Shares Authorized	750,000,000	750,000,000
Common Stock, Shares Issued	406,891,427	406,937,830
Common Stock, Shares Outstanding	406,891,427	406,937,830