Consolidated Statement of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series C Preferred Units Preferred Stock	Series I Preferred Units Preferred Stock
Balance at Dec. 31, 2012	$ 6,907,103	$ 950	$ 4,667,900	$ (322,858)	$ (29,587)	$ 1,701,092	$ 487,301	$ 180,340	$ 221,965
Balance (in shares) at Dec. 31, 2012		91,250,000
Increase (Decrease) in Stockholders' Equity
Net income	103,320					94,514	8,806
Other comprehensive income	10,338				10,338
Preferred dividends	(18,144)					(18,144)
DRIP proceeds	57		57
Conversion of units	17,287	2	17,285
Conversion of units of the Operating Partnership to common stock (in shares)		224,000
Reallocation of noncontrolling interest in the Operating Partnership	(38,452)					(38,452)
Deferred compensation plan (shares)		10,000
Deferred compensation plan	434		655	(221)
Amortization of deferred compensation plan	19,702		19,702
Redemption of preferred stock	(192,500)					(12,160)		(180,340)
Preferred stock issuance costs	(33)								(33)
Issuance of common stock	41,791	5	41,786
Issuance of common stock (in shares)		462,000
Sale of treasury stock	6,090			6,090
Sale of treasury stock (in shares)		83,000
Proceeds from stock options exercised	10,395	2	10,393
Proceeds from stock options exercised (in shares)		185,000
Contributions to consolidated joint venture	3,781						3,781
Cash distributions to noncontrolling interests	(11,809)						(11,809)
Cash distribution declared ($0.66 per common share, none of which represented a return of capital for federal income tax purposes)	(90,266)					(90,266)
Balance at Sep. 30, 2013	$ 6,769,094	$ 959	$ 4,757,778	$ (316,989)	$ (19,249)	$ 1,636,584	$ 488,079	$ 0	$ 221,932
Balance (in shares) at Sep. 30, 2013		92,214,000