CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Thousands	Total	Preferred Shares [Member]	Common Shares [Member]	Paid-in Capital [Member]	Accumulated Distributions in Excess of Net Income (Loss) [Member]	Deferred Compensation Obligation [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock at Cost [Member]	Non-Controlling Interests [Member]
Balance at Dec. 31, 2009	$ 2,952,336	$ 555,000	$ 20,174	$ 3,374,528	$ (1,098,661)	$ 17,838	$ 9,549	$ (15,866)	$ 89,774
Cumulative effect of adoption of a new accounting standard (Note 1)	(20,232)	0	0	0	(7,848)	0	0	0	(12,384)
Deconsolidation of interests	3,876	0	0	0	0	0	0	0	3,876
Issuance of common shares related to stock plans	1,362	0	21	1,232	0	0	0	109	0
Issuance of common shares for cash	440,430	0	5,279	433,473	0	0	0	1,678	0
Convertible debt instruments	52,497	0	0	52,497	0	0	0	0	0
Issuance of preferred shares	0
Issuance of restricted stock	(847)	0	153	(199)	0	741	0	(1,542)	0
Vesting of restricted stock	1,483	0	0	4,761	0	(4,261)	0	983	0
Stock-based compensation	2,698	0	0	2,698	0	0	0	0	0
Contributions from non-controlling interests	746	0	0	0	0	0	0	0	746
Distributions to non-controlling interests	(2,886)	0	0	0	0	0	0	0	(2,886)
Dividends declared-common shares	(20,205)	0	0	0	(20,205)	0	0	0	0
Dividends declared-preferred shares	(42,269)	0	0	0	(42,269)	0	0	0	0
Comprehensive loss	(234,302)	0	0	0	(209,358)	0	16,097	0	(41,041)
Balance at Dec. 31, 2010	3,134,687	555,000	25,627	3,868,990	(1,378,341)	14,318	25,646	(14,638)	38,085
Issuance of common shares related to stock plans	1,429	0	18	979	0	0	0	432	0
Issuance of common shares related to exercise of warrants	134,310	0	1,000	133,310	0	0	0	0	0
Issuance of common shares for cash	129,665	0	950	128,715	0	0	0	0	0
Issuance of preferred shares	0
Issuance of restricted stock	527	0	116	(6,357)	0	530	0	6,238	0
Vesting of restricted stock	(4,978)	0	0	2,985	0	(914)	0	(7,049)	0
Stock-based compensation	3,788	0	0	3,788	0	0	0	0	0
Contributions from non-controlling interests	374	0	0	0	0	0	0	0	374
Distributions to non-controlling interests	(2,308)	0	0	0	0	0	0	0	(2,308)
Redemption of preferred shares	(180,000)	(180,000)	0	6,402	(6,402)	0	0	0	0
Dividends declared-common shares	(60,527)	0	0	0	(60,527)	0	0	0	0
Dividends declared-preferred shares	(32,229)	0	0	0	(32,229)	0	0	0	0
Comprehensive loss	(46,846)	0	0	0	(15,854)	0	(27,049)	0	(3,943)
Balance at Dec. 31, 2011	3,077,892	375,000	27,711	4,138,812	(1,493,353)	13,934	(1,403)	(15,017)	32,208
Issuance of common shares related to stock plans	3,035	0	32	2,741	0	0	0	262	0
Issuance of common shares for cash	492,129	0	3,634	485,752	0	0	0	2,743	0
Issuance of preferred shares	192,855	200,000	0	(7,145)	0	0	0	0	0
Issuance of restricted stock	749	0	147	(2,334)	0	910	0	2,026	0
Vesting of restricted stock	(2,936)	0	0	2,818	0	712	0	(6,466)	0
Stock-based compensation	2,809	0	0	2,809	0	0	0	0	0
Contributions from non-controlling interests	492	0	0	0	0	0	0	0	492
Distributions to non-controlling interests	(9,145)	0	0	0	0	0	0	0	(9,145)
Redemption of preferred shares	(170,000)	(170,000)	0	5,804	(5,804)	0	0	0	0
Dividends declared-common shares	(141,152)	0	0	0	(141,152)	0	0	0	0
Dividends declared-preferred shares	(28,691)	0	0	0	(28,691)	0	0	0	0
Comprehensive loss	(51,577)	0	0	0	(25,822)	0	(26,522)	0	767
Balance at Dec. 31, 2012	$ 3,366,460	$ 405,000	$ 31,524	$ 4,629,257	$ (1,694,822)	$ 15,556	$ (27,925)	$ (16,452)	$ 24,322