CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 141,590	$ 235,781
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	159,059	140,621
Amortization of deferred financing costs	2,007	1,826
Amortization of debt discount (premium)	419	(4,621)
Loss on extinguishment of debt, net	397	0
Amortization of stock-based compensation	4,029	4,319
Equity in loss of (income), and return on, unconsolidated real estate entities and noncontrolling interests, net of eliminations	1,486	(5,768)
Casualty and impairment (gain) loss, net	(58)	11,688
Abandonment of development pursuits	112	265
Cash flow hedge losses reclassified to earnings	1,756	1,752
Loss (gain) on sale of real estate assets	47	(97,012)
Increase in resident security deposits, prepaid expenses and other assets	(6,608)	(10,630)
Increase in accrued expenses, other liabilities and accrued interest payable	11,677	21,674
Net cash provided by operating activities	315,913	299,895
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs	(301,299)	(259,573)
Capital expenditures - existing real estate assets	(15,240)	(8,015)
Capital expenditures - non-real estate assets	(1,735)	(2,429)
Proceeds from sale of real estate, net of selling costs	603	159,985
Insurance proceeds for property damage claims	58	4,095
Mortgage note receivable lending	(2,006)	(4,795)
Mortgage note receivable payment	4,862	0
Decrease in payables for construction	(2,168)	(4,326)
Distributions from unconsolidated real estate entities	2,013	11,952
Investments in unconsolidated real estate entities	(4,368)	(5,774)
Net cash used in investing activities	(319,280)	(108,880)
Cash flows from financing activities:
Issuance of common stock, net	0	56,817
Dividends paid	(195,999)	(185,192)
Repayments of mortgage notes payable, including prepayment penalties	(28,584)	(21,905)
Issuance of unsecured notes	299,442	0
Payment of deferred financing costs	(3,244)	(2,315)
Payment of capital lease obligation	(267)	0
Receipts for termination of forward interest rate swaps	12,598	0
Payments related to tax withholding for share-based compensation	(10,483)	0
Distributions to DownREIT partnership unitholders	(11)	(11)
Contributions from joint venture and profit-sharing partners	0	1,038
Distributions to joint venture and profit-sharing partners	(104)	(104)
Preferred interest obligation redemption and dividends	(480)	(600)
Net cash provided by (used in) financing activities	72,868	(152,272)
Net increase in cash and cash equivalents	69,501	38,743
Cash and cash equivalents and restricted cash, beginning of period	201,906	329,977
Cash and cash equivalents and restricted cash, end of period	271,407	368,720
Cash paid during the period for interest, net of amount capitalized	33,936	34,503
Supplemental Cash Flow Information [Abstract]
Cash, cash equivalents and restricted cash reported in the Consolidated Statements of Cash Flows	$ 201,906	$ 329,977