CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total Stockholders' Equity	Common Stock	Additional Paid-In Capital	Cumulative Dividends In Excess Of Earnings	Accumulated Other Comprehensive Income (Loss)	Total Noncontrolling Interests	Total
Balance at Dec. 31, 2015	$ 9,343,643	$ 465,488	$ 11,647,039	$ (2,738,414)	$ (30,470)	$ 402,674	$ 9,746,317
Balance (in shares) at Dec. 31, 2015		465,488
Increase (Decrease) in Stockholders' Equity
Net income	116,119			116,119		3,626	119,745
Other comprehensive income	(1,203)				(1,203)		(1,203)
Issuance of common stock, net	35,406	$ 1,428	33,978				35,406
Issuance of common stock, net (in shares)		1,428
Conversion of DownREIT units to common stock						(4,136)	4,136
Repurchase of common stock	(3,628)	$ (102)	(3,526)				(3,628)
Repurchase of common stock (in shares)		(102)
Exercise of stock options	2,852	$ 111	2,741				2,852
Exercise of stock options (in shares)		111
Amortization of deferred compensation	5,345		5,345				5,345
Common dividends	(268,186)			(268,186)			(268,186)
Distributions to noncontrolling interests	(36)		(36)			(4,853)	(4,889)
Issuance of noncontrolling interests						2,200	2,200
Deconsolidation of noncontrolling interests	435			435		67	502
Balance at Mar. 31, 2016	9,230,747	$ 466,925	11,685,541	(2,890,046)	(31,673)	399,578	9,630,325
Balance (in shares) at Mar. 31, 2016		466,925
Balance at Dec. 31, 2016	5,547,595	$ 468,081	8,198,890	(3,089,734)	(29,642)	393,713	5,941,308
Balance (in shares) at Dec. 31, 2016		468,081
Increase (Decrease) in Stockholders' Equity
Net income	461,145			461,145		3,032	464,177
Other comprehensive income	984				984		984
Issuance of common stock, net	3,472	$ 427	3,045				3,472
Issuance of common stock, net (in shares)		427
Conversion of DownREIT units to common stock	1,548	$ 54	1,494			(1,548)	1,548
Conversion of DownREIT units (in shares)		54
Repurchase of common stock	(3,532)	$ (116)	(3,416)				(3,532)
Repurchase of common stock (in shares)		(116)
Amortization of deferred compensation	3,765		3,765				3,765
Common dividends	(173,629)			(173,629)			(173,629)
Distributions to noncontrolling interests						(5,659)	(5,659)
Issuance of noncontrolling interests						650	650
Deconsolidation of noncontrolling interests						(58,061)	(58,061)
Balance at Mar. 31, 2017	$ 5,841,348	$ 468,446	$ 8,203,778	$ (2,802,218)	$ (28,658)	$ 332,127	$ 6,173,475
Balance (in shares) at Mar. 31, 2017		468,446