Consolidated Statement of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Distributions in Excess of Net Income [Member]	Non-controlling Interest [Member]	Subsidiary of Common Parent [Member]	Subsidiary of Common Parent [Member] Preferred Stock [Member]	Subsidiary of Common Parent [Member] Common Stock [Member]	Subsidiary of Common Parent [Member] Limited Partner [Member]	Subsidiary of Common Parent [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Subsidiary of Common Parent [Member] Non-controlling Interest [Member]	Subsidiary of Common Parent [Member] Stockholders' Equity, Total [Member]
Beginning Balance - Partnership at Dec. 31, 2011								$ 2,779,582	$ 793,910	$ 1,923,886	$ 56,254	$ 987	$ 4,545	$ 2,775,037
Beginning Balance - General Partner at Dec. 31, 2011	2,779,658	793,910	2,529	3,594,588	987	(1,677,328)	64,972
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(53,387)					(52,016)	(1,371)	(53,387)	35,356	(87,372)	(1,736)		365	(53,752)
Other comprehensive income	1,190				1,190			1,190				1,190		1,190
Issuance of common shares	235,829		169	235,660
Capital contribution from the General Partner								235,829		235,829				235,829
Stock based compensation plan activity	3,882		13	6,199		(2,330)		3,907		3,907				3,907
Conversion of Limited Partner Units			24	28,978			(29,002)			29,002	(29,002)
Distributions to preferred shareholders/unitholders	(35,356)					(35,356)		(35,356)	(35,356)					(35,356)
Redemption of preferred shares/units	(168,272)	(168,272)		5,730		(5,730)		(168,272)	(168,272)					(168,272)
Distributions to common shareholders ($0.51 per share)	(135,083)					(135,083)
Distributions to Partners ($0.51 per Common Unit)								(137,662)		(135,139)	(2,523)			(137,662)
Contributions from (distributions to) noncontrolling interests, net	2,788						2,788	5,311					5,311
Buyout of noncontrolling interests	(6,208)					(4,959)	(1,249)	(6,208)		(4,959)			(1,249)	(4,959)
Ending Balance - Partnership at Sep. 30, 2012								2,624,934	625,638	1,965,154	22,993	2,177	8,972	2,615,962
Ending Balance - General Partner at Sep. 30, 2012	2,625,041	625,638	2,735	3,871,155	2,177	(1,912,802)	36,138
Beginning Balance - Partnership at Jun. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(17,549)							(17,549)
Other comprehensive income	410							410
Ending Balance - Partnership at Sep. 30, 2012								2,624,934
Ending Balance - General Partner at Sep. 30, 2012	$ 2,625,041