CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 170,418	$ 141,590
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	162,057	159,059
Amortization of deferred financing costs	1,692	2,007
Amortization of debt discount	394	419
Loss on extinguishment of debt, net	280	397
Amortization of stock-based compensation	5,621	4,029
Equity in loss of, and return on, unconsolidated real estate entities and noncontrolling interests, net of eliminations	5,517	1,486
Casualty and impairment gain, net	0	(58)
Abandonment of development pursuits	208	112
Cash flow hedge losses reclassified to earnings	1,468	1,756
(Gain) loss on sale of real estate assets	(15,102)	47
Increase in resident security deposits, prepaid expenses and other assets	(3,087)	(6,608)
Increase in accrued expenses, other liabilities and accrued interest payable	32,587	11,677
Net cash provided by operating activities	362,053	315,913
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs	(278,075)	(301,299)
Acquisition of real estate assets, including partnership interest	(91,548)	0
Capital expenditures - existing real estate assets	(20,069)	(15,240)
Capital expenditures - non-real estate assets	(488)	(1,735)
Mortgage note receivable payments	5,444	(2,168)
Increase (decrease) in payables for construction	71,455	603
Proceeds from sale of real estate, net of selling costs	0	58
Insurance proceeds for property damage claims	(159)	(2,006)
Mortgage note receivable lending	978	4,862
Distributions from unconsolidated real estate entities	0	2,013
Investments in unconsolidated real estate entities	(724)	(4,368)
Net cash used in investing activities	(313,186)	(319,280)
Cash flows from financing activities:
Issuance of common stock, net	155,561	0
Dividends paid	(203,499)	(195,999)
Repayments of mortgage notes payable, including prepayment penalties	(1,668)	(28,584)
Issuance of unsecured notes	0	299,442
Payment of deferred financing costs	(6,841)	(3,244)
Payment of financing lease obligation	(267)
Payment of financing lease obligation		(267)
Receipts for termination of forward interest rate swaps	0	12,598
Payments related to tax withholding for share-based compensation	(14,206)	(10,483)
Distributions to DownREIT partnership unitholders	(11)	(11)
Distributions to joint venture and profit-sharing partners	(113)	(104)
Preferred interest obligation redemption and dividends	(480)	(480)
Net cash (used in) provided by financing activities	(71,524)	72,868
Net (decrease) increase in cash and cash equivalents	(22,657)	69,501
Cash and cash equivalents and restricted cash, beginning of period	217,864	201,906
Cash and cash equivalents and restricted cash, end of period	195,207	271,407
Cash paid during the period for interest, net of amount capitalized	25,513	33,936
Supplemental Cash Flow Information [Abstract]
Cash, cash equivalents and restricted cash reported in the Condensed Consolidated Statements of Cash Flows	$ 217,864	$ 201,906