Consolidated Statement of Equity - 3 months ended Mar. 31, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series C Preferred Stock Preferred Stock	Series I Preferred Stock Preferred Stock
Beginning Balance at Dec. 31, 2015	$ 7,719,317	$ 1,001	$ 5,439,735	$ (10,000)	$ (8,749)	$ 1,643,546	$ 431,852	$ 0	$ 221,932
Beginning Balance (in shares) at Dec. 31, 2015		99,976
Increase (Decrease) in Stockholders' Equity
Net income	28,933					26,959	1,974
Other comprehensive loss	(8,473)				(8,473)
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds	45		45
Conversion of units of the Operating Partnership to common stock (in shares)		63
Conversion of units of the Operating Partnership to common stock	7,153	$ 1	7,152
Reallocation of noncontrolling interest in the Operating Partnership	25,867					25,867
Deferred compensation plan and stock award, net (in shares)		25
Deferred compensation plan and stock award, net	(2,220)		(2,220)
Amortization of deferred compensation plan	5,864		5,864
Proceeds from stock options exercised (in shares)		17
Proceeds from stock options exercised	1,211		1,211
Contributions to consolidated joint venture interests	934						934
Cash distributions to noncontrolling interests	(7,905)						(7,905)
Cash distributions declared ($0.72 per common share, none of which represented a return of capital for federal income tax purposes)	(71,965)					(71,965)
Ending Balance at Mar. 31, 2016	$ 7,695,023	$ 1,002	$ 5,451,787	$ (10,000)	$ (17,222)	$ 1,620,669	$ 426,855	$ 0	$ 221,932
Ending Balance (in shares) at Mar. 31, 2016		100,081