CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands		Total	Common Stock	Additional Paid-In Capital	Cumulative Dividends In Excess Of Earnings	Accumulated Other Comprehensive Income (Loss)	Total Stockholders’ Equity	Total Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Cumulative effect of new accounting principle	[1]	$ 79,144			$ 79,144		$ 79,144
Adjusted balance, January 1		5,674,082	$ 469,436	$ 8,226,113	(3,291,376)	$ (24,024)	5,380,149	$ 293,933
Balance at Dec. 31, 2017		5,594,938	$ 469,436	8,226,113	(3,370,520)	(24,024)	5,301,005	293,933
Balance (in shares) at Dec. 31, 2017			469,436
Increase (Decrease) in Stockholders' Equity
Net income (loss)		239,091			229,545		229,545	9,546
Other comprehensive income (loss)		19,727				19,727	19,727
Issuance of common stock, net		4,310	$ 601	3,709			4,310
Issuance of common stock, net (in shares)			601
Repurchase of common stock		(3,342)	$ (138)	(3,204)			(3,342)
Repurchase of common stock (in shares)			(138)
Exercise of stock options		376	$ 17	359			376
Exercise of stock options (in shares)			17
Amortization of deferred compensation		13,098		13,098			13,098
Common dividends (usd per share)		(522,566)			(522,566)		(522,566)
Distributions to noncontrolling interests		(13,924)		0				(13,924)
Issuances of noncontrolling interests		298,929						298,929
Purchase of noncontrolling interests		(69,406)		(50,129)			(50,129)	(19,277)
Balance at Sep. 30, 2018		5,640,375	$ 469,916	8,189,946	(3,584,397)	(4,297)	5,071,168	569,207
Balance (in shares) at Sep. 30, 2018			469,916
Balance at Dec. 31, 2017		5,594,938	$ 469,436	8,226,113	(3,370,520)	(24,024)	5,301,005	293,933
Balance (in shares) at Dec. 31, 2017			469,436
Balance at Dec. 31, 2018		6,512,591	$ 477,496	8,398,847	(2,927,196)	(4,708)	5,944,439	568,152
Balance (in shares) at Dec. 31, 2018			477,496
Balance at Jun. 30, 2018		5,416,723	$ 469,830	8,187,385	(3,509,641)	(4,080)	5,143,494	273,229
Balance (in shares) at Jun. 30, 2018			469,830
Increase (Decrease) in Stockholders' Equity
Net income (loss)		102,926			99,371		99,371	3,555
Other comprehensive income (loss)		(217)				(217)	(217)
Issuance of common stock, net		877	$ 90	787			877
Issuance of common stock, net (in shares)			90
Repurchase of common stock		(564)	$ (21)	(543)			(564)
Repurchase of common stock (in shares)			(21)
Exercise of stock options		376	$ 17	359			376
Exercise of stock options (in shares)			17
Amortization of deferred compensation		2,880		2,880			2,880
Common dividends (usd per share)		(174,127)			(174,127)		(174,127)
Distributions to noncontrolling interests		(4,458)		0				(4,458)
Issuances of noncontrolling interests		297,934						297,934
Purchase of noncontrolling interests		(1,975)		(922)			(922)	(1,053)
Balance at Sep. 30, 2018		5,640,375	$ 469,916	8,189,946	(3,584,397)	(4,297)	5,071,168	569,207
Balance (in shares) at Sep. 30, 2018			469,916
Increase (Decrease) in Stockholders' Equity
Cumulative effect of new accounting principle	[2]	590			590		590
Adjusted balance, January 1		6,513,181	$ 477,496	8,398,847	(2,926,606)	(4,708)	5,945,029	568,152
Balance at Dec. 31, 2018		6,512,591	$ 477,496	8,398,847	(2,927,196)	(4,708)	5,944,439	568,152
Balance (in shares) at Dec. 31, 2018			477,496
Increase (Decrease) in Stockholders' Equity
Net income (loss)		12,702			2,010		2,010	10,692
Other comprehensive income (loss)		(515)				(515)	(515)
Issuance of common stock, net		509,242	$ 17,272	491,970			509,242
Issuance of common stock, net (in shares)			17,272
Conversion of DownREIT units to common stock		0	$ 184	3,890			4,074	(4,074)
Conversion of DownREIT units to common stock (in shares)			184
Repurchase of common stock		(4,931)	$ (159)	(4,772)			(4,931)
Repurchase of common stock (in shares)			(159)
Exercise of stock options		1,435	$ 55	1,380			1,435
Exercise of stock options (in shares)			55
Amortization of deferred compensation		14,529		14,529			14,529
Common dividends (usd per share)		(536,660)			(536,660)		(536,660)
Distributions to noncontrolling interests		(17,724)						(17,724)
Issuances of noncontrolling interests		33,318						33,318
Purchase of noncontrolling interests		(1,218)		(1,079)			(1,079)	(139)
Balance at Sep. 30, 2019		6,523,359	$ 494,848	8,904,765	(3,461,256)	(5,223)	5,933,134	590,225
Balance (in shares) at Sep. 30, 2019			494,848
Balance at Jun. 30, 2019		6,619,272	$ 491,109	8,801,037	(3,233,283)	(4,459)	6,054,404	564,868
Balance (in shares) at Jun. 30, 2019			491,109
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(42,308)			(45,863)		(45,863)	3,555
Other comprehensive income (loss)		(764)				(764)	(764)
Issuance of common stock, net		102,429	$ 3,703	98,726			102,429
Issuance of common stock, net (in shares)			3,703
Repurchase of common stock		(349)	$ (10)	(339)			(349)
Repurchase of common stock (in shares)			(10)
Exercise of stock options		1,216	$ 46	1,170			1,216
Exercise of stock options (in shares)			46
Amortization of deferred compensation		4,171		4,171			4,171
Common dividends (usd per share)		(182,110)			(182,110)		(182,110)
Distributions to noncontrolling interests		(7,901)		0				(7,901)
Issuances of noncontrolling interests		29,703						29,703
Purchase of noncontrolling interests		0		0			0	0
Balance at Sep. 30, 2019		$ 6,523,359	$ 494,848	$ 8,904,765	$ (3,461,256)	$ (5,223)	$ 5,933,134	$ 590,225
Balance (in shares) at Sep. 30, 2019			494,848

[1] On January 1, 2018, the Company adopted ASU No. 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets (“ASU 2017-05”), and recognized the cumulative-effect of adoption to beginning retained earnings. Refer to Note 2 for a detailed impact of adoption.

[2] On January 1, 2019, the Company adopted a series of Accounting Standards Updates (“ASUs”) related to accounting for leases, and recognized the cumulative-effect of adoption to beginning retained earnings. Refer to Note 2 for a detailed impact of adoption.