Condensed Consolidated Statement Of Equity (USD $) In Thousands, except Share data	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Dividends In Excess Of Earnings [Member]	Accumulated Other Comprehensive Loss, Net [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interests In Operating Partnership [Member]	Noncontrolling Interests In Consolidated Joint Ventures [Member]	Total Noncontrolling Interests [Member]	Total
Balance at Dec. 31, 2011	$ 569,781	$ 1,057	$ 2,496,651	$ (488,692)	$ (55,880)	$ 2,522,917	$ 45,057	$ 12,437	$ 57,494	$ 2,580,411
Balance (shares) at Dec. 31, 2011		106,039,279
Conversion of units to common stock		5	4,893			4,898	(4,898)		(4,898)
Conversion of units to common stock (shares)		460,192
Issuance of restricted stock, net of forfeitures (shares)		93,276
Net proceeds from issuance of common stock		125	859,786			859,911				859,911
Net proceeds from issuance of common stock (shares)		12,456,818
Exercise of stock options		1	4,172			4,173				4,173
Exercise of stock options (shares)		207,550								207,550
Issuance of series F preferred stock, net of offering costs	176,071					176,071				176,071
Conversion of convertible preferred stock/units	(169,239)	40	169,199
Conversion of convertible preferred stock/units (shares)		4,004,275
Amortization of unearned compensation regarding share based awards			12,339			12,339				12,339
Reclassification of vested share based awards			(8,544)			(8,544)	8,544		8,544
Dividends declared on preferred stock				(28,921)		(28,921)				(28,921)
Dividends and distributions on common stock and common and incentive units				(248,492)		(248,492)	(10,483)		(10,483)	(258,975)
Contributions from noncontrolling interests in consolidated joint ventures								2,323	2,323	2,323
Purchase of noncontrolling interests in consolidated joint venture			(2,033)			(2,033)		(10,351)	(10,351)	(12,384)
Net income				155,768		155,768	4,821	(437)	4,384	160,152
Other comprehensive income (loss) - foreign currency translation adjustments					35,053	35,053	1,233		1,233	36,286
Other comprehensive income (loss) - fair value of interest rate swaps					(6,553)	(6,553)	(241)		(241)	(6,794)
Reclassification to interest expense from interest rate swaps					2,856	2,856	108		108	2,964
Balance at Sep. 30, 2012	$ 576,613	$ 1,228	$ 3,536,463	$ (610,337)	$ (24,524)	$ 3,479,443	$ 44,141	$ 3,972	$ 48,113	$ 3,527,556
Balance (shares) at Sep. 30, 2012		123,261,390