CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 168,006	$ 170,418
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	177,911	162,057
Amortization of deferred financing costs	1,882	1,692
Amortization of debt discount	411	394
Loss on extinguishment of debt, net	9,170	280
Amortization of stock-based compensation	5,338	5,621
Equity in loss of, and return on, unconsolidated real estate entities and noncontrolling interests, net of eliminations	1,871	5,517
Abandonment of development pursuits	1,988	208
Cash flow hedge losses reclassified to earnings	1,949	1,468
Gain on sale of real estate assets	(24,479)	(15,102)
Gain (Loss) on Sale of Other Investments	(4,903)	0
Increase in resident security deposits, prepaid expenses and other assets	(1,239)	(3,087)
Increase in accrued expenses, other liabilities and accrued interest payable	3,799	32,320
Net cash provided by operating activities	341,704	361,786
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs	(245,789)	(278,075)
Acquisition of real estate assets, including partnership interest	0	(91,548)
Capital expenditures - existing real estate assets	(32,922)	(20,069)
Capital expenditures - non-real estate assets	(10,663)	(488)
Mortgage note receivable payments	462	5,444
Increase in payables for construction	63,073	71,455
Proceeds from Sale of Other Real Estate	98,790	0
Insurance proceeds for property damage claims	(179)	(159)
Mortgage note receivable lending	960	978
Investments in unconsolidated real estate entities	(9,799)	(724)
Net cash used in investing activities	(136,067)	(313,186)
Cash flows from financing activities:
Issuance of common stock, net	125	155,561
Dividends paid	(213,671)	(203,499)
Proceeds from Unsecured Lines of Credit	750,000	0
Proceeds from Notes Payable	51,000	0
Repayments of mortgage notes payable, including prepayment penalties	(51,484)	(1,668)
Issuance of unsecured notes	699,252	0
Repayments of Unsecured Debt	(658,655)	0
Payment of deferred financing costs	(5,988)	(6,841)
Payment for termination of forward interest rate swaps	(20,314)	0
Payments to Noncontrolling Interests	(35)	0
Payments related to tax withholding for share-based compensation	(14,346)	(14,206)
Distributions to DownREIT partnership unitholders	(12)	(11)
Distributions to joint venture and profit-sharing partners	(102)	(113)
Preferred interest obligation redemption and dividends	(600)	(480)
Net cash provided by (used in) financing activities	535,170	(71,257)
Net increase (decrease) in cash and cash equivalents	740,807	(22,657)
Cash and cash equivalents and restricted cash, beginning of period	127,614	217,864
Cash and cash equivalents and restricted cash, end of period	868,421	195,207
Cash paid during the period for interest, net of amount capitalized	36,895	25,513
Supplemental Cash Flow Information [Abstract]
Cash, cash equivalents and restricted cash reported in the Condensed Consolidated Statements of Cash Flows	$ 868,421	$ 195,207