Consolidated Statement of Equity - 9 months ended Sep. 30, 2015 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings	Noncontrolling Interests	Series I Preferred Stock Preferred Stock
Beginning Balance at Dec. 31, 2014	$ 7,459,216	$ 1,010	$ 5,289,479	$ (320,471)	$ (6,980)	$ 1,752,404	$ 521,842	$ 221,932
Beginning Balance (in shares) at Dec. 31, 2014		97,325
Increase (Decrease) in Stockholders' Equity
Net income	192,260					179,043	13,217
Acquisition of subsidiary interest from noncontrolling interest	(20,650)		(9,566)				(11,084)
Other comprehensive loss	(8,841)				(8,841)
Preferred dividends	(11,214)					(11,214)
DRSPP proceeds (in shares)		776
DRSPP proceeds	99,529	$ 8	99,521
Conversion of units of the Operating Partnership to common stock (in units)		353
Conversion of units of the Operating Partnership to common stock	41,605	$ 4	41,601
Reallocation of noncontrolling interest in the Operating Partnership	(31,664)					(31,664)
Reallocation of capital account relating to sale	(10,144)						(10,144)
Deferred compensation plan and stock award, net (in shares)		28
Deferred compensation plan and stock award, net	(3,096)	$ 0	1,744	(4,840)
Amortization of deferred compensation plan	20,994		20,994
Issuance of common stock (in shares)		1,007
Issuance of common stock	127,022	$ 10	137,012	(10,000)
Proceeds from stock options exercised (in shares)		170
Proceeds from stock options exercised	12,870	$ 2	12,868
Contributions from consolidated joint venture interests	34,435						34,435
Cash distributions to noncontrolling interests	(114,828)						(114,828)
Cash distributions declared ($1.80 per common share, none of which represented a return of capital for federal income tax purposes)	(179,064)					(179,064)
Ending Balance at Sep. 30, 2015	$ 7,671,758	$ 1,034	$ 5,593,653	$ (335,311)	$ (15,821)	$ 1,772,833	$ 433,438	$ 221,932
Ending Balance (in shares) at Sep. 30, 2015		99,659