Condensed Consolidated Statements 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, 2012	$ 572,711	$ 1,247	$ 3,562,642	$ (656,104)	$ (12,191)	$ 3,468,305	$ 24,135	$ 5,944	$ 30,079	$ 3,498,384
Balance (shares) at Dec. 31, 2012		125,140,783
Conversion of units to common stock		1	451			452	(452)		(452)
Conversion of units to common stock (shares)		42,128
Issuance of unvested restricted stock, net of forfeitures (shares)		110,875
Common stock offering costs			(553)			(553)				(553)
Exercise of stock options			230			230				230
Exercise of stock options (shares)		5,569								5,569
Issuance of series G preferred stock, net of offering costs	241,511					241,511				241,511
Conversion of Series D preferred stock	(119,348)	31	119,317
Conversion of Series D preferred stock (shares)		3,139,615
Amortization of unearned compensation regarding share based awards			12,580			12,580				12,580
Reclassification of vested share based awards			(8,999)			(8,999)	8,999		8,999
Dividends declared on preferred stock				(31,179)		(31,179)				(31,179)
Dividends and distributions on common stock and common and incentive units				(300,514)		(300,514)	(7,005)		(7,005)	(307,519)
Contributions from noncontrolling interests in consolidated joint ventures								399	399	399
Net income				259,785		259,785	4,517	480	4,997	264,782
Other comprehensive income (loss) - foreign currency translation adjustments					(6,102)	(6,102)	(88)		(88)	(6,190)
Other comprehensive income (loss) - fair value of interest rate swaps					3,112	3,112	63		63	3,175
Other comprehensive income - reclassification of accumulated other comprehensive loss to interest expense					4,854	4,854	95		95	4,949
Balance at Sep. 30, 2013	$ 694,874	$ 1,279	$ 3,685,668	$ (728,012)	$ (10,327)	$ 3,643,482	$ 30,264	$ 6,823	$ 37,087	$ 3,680,569
Balance (shares) at Sep. 30, 2013		128,438,970