Consolidated Statements of Equity (USD $)	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series I Preferred Stock Preferred Stock
Beginning Balance at Dec. 31, 2013	$ 7,016,876,000	$ 986,000	$ 5,015,904,000	$ (317,356,000)	$ (15,211,000)	$ 1,619,150,000	$ 491,471,000	$ 221,932,000
Shares outstanding (shares) at Dec. 31, 2013		94,993,000
Increase (Decrease) in Stockholders' Equity
Net income	151,318,000					149,828,000	1,490,000
Other comprehensive income	339,000				339,000
Preferred dividends	(3,738,000)					(3,738,000)
DRIP proceeds	15,000		15,000
Conversion of units of the Operating Partnership to common stock	16,583,000	2,000	16,581,000
Conversion of units of the Operating Partnership to common stock (in shares)		168,000
Reallocation of noncontrolling interest in the Operating Partnership	(29,464,000)					(29,464,000)
Deferred compensation plan and stock award, net	(1,425,000)	0	1,295,000	(2,720,000)
Deferred compensation plan and stock award, net (in shares)		2,000
Amortization of deferred compensation plan	6,713,000		6,713,000
Issuance of common stock	24,000	0	24,000
Issuance of common stock (shares)		0
Proceeds from stock options exercised	8,977,000	2,000	8,975,000
Proceeds from issuance of common stock (in shares)		156,000
Contributions to consolidated joint venture interest	517,000						517,000
Cash distributions to noncontrolling interests	(1,586,000)						(1,586,000)
Cash distributions declared ($0.50 per common share, none of which represented a return of capital for federal income tax purposes)	(47,565,000)					(47,565,000)
Ending Balance at Mar. 31, 2014	$ 7,117,584,000	$ 990,000	$ 5,049,507,000	$ (320,076,000)	$ (14,872,000)	$ 1,688,211,000	$ 491,892,000	$ 221,932,000
Shares outstanding (shares) at Mar. 31, 2014		95,319,000