CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Preferred Shares Series B	Preferred Shares Series C	Preferred Shares Series D	Preferred Shares Series E	Cumulative Preferred Distributions	Common Shares	Cumulative Common Distributions	Additional Paid in Capital	Cumulative Net Income	Cumulative Other Comprehensive Income (Loss)	Noncontrolling Interest in Consolidated Subsidiary	Comprehensive Income (Loss)
Balance at Dec. 31, 2009	$ 2,889,066	$ 169,079	$ 145,015	$ 368,270		$ (382,596)	$ 560	$ (2,576,582)	$ 2,925,845	$ 2,236,928	$ 2,547
Balance (in shares) at Dec. 31, 2009		7,000,000	6,000,000	15,180,000			55,965,061
Comprehensive income (loss):
Net (loss) income	135,409									135,409			135,409
Unrealized loss on derivative instruments	(9,501)										(9,501)		(9,501)
Unrealized income on investment in available for sale securities	19										19		19
Foreign currency translation adjustments	11,641										11,641		11,641
Total comprehensive income (loss)	137,568												137,568
Issuance of shares, net	430,778						161		430,617
Issuance of shares, net (in shares)							16,125,000
Redemption of shares	(175,000)	(169,079)							(5,921)
Redemption of shares (in shares)		(7,000,000)
Share grants	896								896
Share grants (in shares)							48,625
Distributions	(149,030)					(49,656)		(99,374)
Purchase of noncontrolling equity interest	(2,588)								(2,588)
Balance at Dec. 31, 2010	3,131,690		145,015	368,270		(432,252)	721	(2,675,956)	3,348,849	2,372,337	4,706
Balance (in shares) at Dec. 31, 2010			6,000,000	15,180,000			72,138,686
Comprehensive income (loss):
Net (loss) income	109,984									109,984			109,984
Unrealized loss on derivative instruments	(8,840)										(8,840)		(8,840)
Realized gain on sale of investment in available for sale securities	(19)										(19)		(19)
Foreign currency translation adjustments	(632)										(632)		(632)
Increase in share of investees other comprehensive income	76										76		76
Total comprehensive income (loss)	100,569												100,569
Issuance of shares, net	529,698				265,391		115		264,192
Issuance of shares, net (in shares)					11,000,000		11,500,000
Share grants	1,039						1		1,038
Share grants (in shares)							83,050
Distributions	(194,479)					(44,405)		(150,074)
Balance at Dec. 31, 2011	3,568,517		145,015	368,270	265,391	(476,657)	837	(2,826,030)	3,614,079	2,482,321	(4,709)
Balance (in shares) at Dec. 31, 2011			6,000,000	15,180,000	11,000,000		83,721,736
Comprehensive income (loss):
Net (loss) income	(79,845)									(95,421)		15,576	(79,845)
Unrealized loss on derivative instruments	(828)										(828)		(828)
Foreign currency translation adjustments	6,062										6,062		6,062
Increase in share of investees other comprehensive income	47										40	7	47
Total comprehensive income (loss)	(74,564)												(74,564)
Issuance of shares of subsidiary, net	363,657											363,657
Adjustments to noncontrolling interest resulting from changes in ownership of subsidiary									(24,817)			24,817
Redemption of shares	(150,000)		(145,015)						(4,985)
Redemption of shares (in shares)			(6,000,000)
Share grants	1,493						1		1,123			369
Share grants (in shares)							82,332
Distributions	(207,635)					(52,710)		(146,539)				(8,386)
Balance at Dec. 31, 2012	$ 3,501,468			$ 368,270	$ 265,391	$ (529,367)	$ 838	$ (2,972,569)	$ 3,585,400	$ 2,386,900	$ 565	$ 396,040
Balance (in shares) at Dec. 31, 2012				15,180,000	11,000,000		83,804,068