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	(35,838)					(34,867)	(971)	(35,838)	24,275	(59,142)	(1,277)		306	(36,144)
Other comprehensive income	780				780			780				780		780
Issuance of common shares	150,786		111	150,675
Capital contribution from the General Partner								150,786		150,786				150,786
Stock based compensation plan activity	2,111		11	3,769		(1,669)		2,136		2,136				2,136
Conversion of Limited Partner Units			24	28,984			(29,008)			29,008	(29,008)
Distributions to preferred shareholders	(24,275)					(24,275)
Distributions to Preferred Unitholders								(24,275)	(24,275)					(24,275)
Redemption of preferred shares	(168,272)	(168,272)		5,730		(5,730)
Redemption of Preferred Units								(168,272)	(168,272)					(168,272)
Distributions to common shareholders ($0.34 per share)	(89,219)					(89,219)
Distributions to Partners ($0.34 per Common Unit)								(91,016)		(89,260)	(1,756)			(91,016)
Contributions from (Distributions to) noncontrolling interests, net	3,647						3,647	5,403					5,403
Ending Balance - Partnership at Jun. 30, 2012								2,619,286	625,638	1,957,414	24,213	1,767	10,254	2,609,032
Ending Balance - General Partner at Jun. 30, 2012	2,619,378	625,638	2,675	3,783,746	1,767	(1,833,088)	38,640
Beginning Balance - Partnership at Mar. 31, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(17,728)							(17,728)
Other comprehensive income	261							261
Ending Balance - Partnership at Jun. 30, 2012								2,619,286
Ending Balance - General Partner at Jun. 30, 2012	$ 2,619,378