CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net income/(loss)	$ 199,579	$ 221,542	$ 132,655
Adjustments to reconcile net income/(loss) to net cash provided by/(used in) operating activities:
Depreciation and amortization	507,923	435,679	436,462
(Gain)/loss on sale of real estate owned	(5,282)	(136,197)	(43,404)
(Income)/loss from unconsolidated entities	(137,873)	5,055	(31,257)
Return on investment in unconsolidated joint ventures	5,179	4,248	4,416
Amortization of share-based compensation	24,330	14,244	12,862
Other	39,958	4,998	20,467
Changes in operating assets and liabilities:
(Increase)/decrease in operating assets	(10,956)	(13,880)	(9,008)
Increase/(decrease) in operating liabilities	7,846	24,987	(4,278)
Net cash provided by/(used in) operating activities	630,704	560,676	518,915
Investing Activities
Acquisition of real estate assets	(1,370,770)		(96,791)
Proceeds from sales of real estate investments, net	38,000	247,031	71,235
Development of real estate assets	(25,401)	(150,238)	(248,546)
Capital expenditures and other major improvements - real estate assets	(167,188)	(112,359)	(124,728)
Capital expenditures - non-real estate assets	(17,159)	(4,850)	(1,384)
Investment in unconsolidated joint ventures	(93,059)	(112,025)	(123,842)
Distributions received from unconsolidated joint ventures	72,441	42,683	116,329
Purchase deposits on pending acquisitions	(12,160)	(1,000)
Repayment/(issuance) of notes receivable, net	(111,391)	(22,790)	321
Net cash provided by/(used in) investing activities	(1,686,687)	(113,548)	(407,406)
Financing Activities
Payments on secured debt	(162,253)	(279,243)	(326,346)
Proceeds from the issuance of secured debt	162,500	80,000
Payments on unsecured debt	(700,000)		(300,000)
Net proceeds from the issuance of unsecured debt	1,099,816	299,994	598,095
Net proceeds/(repayment) of commercial paper	198,885	(198,885)	300,000
Net proceeds/(repayment) of revolving bank debt	16,567	(21,751)	417
Proceeds from the issuance of common shares through public offering, net	725,315	299,825
Repurchase of common shares		(19,988)
Distributions paid to redeemable noncontrolling interests	(31,580)	(32,457)	(31,089)
Distributions paid to preferred stockholders	(4,063)	(3,836)	(3,708)
Distributions paid to common stockholders	(383,079)	(342,241)	(327,793)
Other	(41,725)	(41,485)	(21,361)
Net cash provided by/(used in) financing activities	880,383	(260,067)	(111,785)
Net increase/(decrease) in cash, cash equivalents, and restricted cash	(175,600)	187,061	(276)
Cash, cash equivalents, and restricted cash, beginning of year	208,891	21,830	22,106
Cash, cash equivalents, and restricted cash, end of year	33,291	208,891	21,830
Supplemental Information:
Interest paid during the period, net of amounts capitalized	169,558	132,466	126,348
Cash paid/(refunds received) for income taxes	1,519	625	1,660
Non-cash transactions:
Transfer of investment in and advances to unconsolidated joint ventures to real estate owned	288,108		140,549
Transfer of investment in and advances to unconsolidated joint ventures to joint venture member	60,625
Secured debt assumed in the consolidation of unconsolidated joint ventures	551,800
Recognition of operating lease right-of-use assets	94,349
Recognition of operating lease liabilities	88,336
Right-of-use assets obtained in exchange for operating lease liabilities remeasurements	111,055
Vesting of LTIP Units	14,742	4,397	2,317
Development costs and capital expenditures incurred but not yet paid	16,635	10,304	43,930
Conversion of Operating Partnership and DownREIT Partnership noncontrolling interests to common stock (3,165,780 shares in 2019; 348,057 shares in 2018; and 389,033 shares in 2017)	134,031	13,328	14,544
Dividends declared but not yet paid	$ 109,382	$ 97,666	$ 91,455