Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flow from operating activities:
Net income	$ 413,561	$ 498,463	$ 439,671
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	277,879	310,380	360,811
Impairment charges	48,743	79,207	67,331
Deferred taxes	0	0	807
Early extinguishment of debt charges	0	12,762	1,753
Equity award expense	20,200	18,221	21,563
Gain on sale of properties/change in control of interests	(79,218)	(229,840)	(93,538)
Gain on change in control of joint venture interests	0	0	(71,160)
Distributions from joint ventures and other real estate investments	93,877	104,626	58,189
Change in accounts and notes receivable	(34,160)	5,229	(7,934)
Change in accounts payable and accrued expenses	(3,611)	(9,175)	4,417
Change in Canadian withholding tax receivable	0	0	12,996
Change in other operating assets and liabilities	(55,405)	(51,220)	(52,961)
Net cash flow provided by operating activities	583,628	637,936	614,181
Cash flow from investing activities:
Acquisition of operating real estate and other related net assets	(1,957)	(5,407)	(153,854)
Improvements to operating real estate	(324,821)	(290,874)	(206,800)
Acquisition of real estate under development	0	(4,592)	(10,010)
Improvements to real estate under development	(118,841)	(235,988)	(160,257)
Investment in marketable securities	(244)	(63)	(9,822)
Proceeds from sale/repayments of marketable securities	2,023	957	3,146
Investments in and advances to real estate joint ventures	(27,665)	(36,139)	(35,291)
Reimbursements of investments in and advances to real estate joint ventures	21,759	21,127	55,839
Investment in and advances to other real estate investments	(12,816)	(524)	(666)
Reimbursements of investments in and advances to other real estate investments	5,960	12,878	40,709
Investment in other financing receivable	(48)	(125)	0
Collection of mortgage loans receivable	10,449	22,299	1,405
Investment in other investments	(2,500)	(857)	0
Proceeds from sale of operating properties	324,280	754,731	181,321
Proceeds from insurance casualty claims	4,000	16,222	0
Net cash flow provided by/(used for) investing activities	(120,421)	253,645	(294,280)
Cash flow from financing activities:
Principal payments on debt, excluding normal amortization of rental property debt	(6,539)	(204,746)	(687,117)
Principal payments on rental property debt	(12,212)	(13,113)	(15,186)
Proceeds from mortgage and construction loan financings	16,028	50,972	206,000
Proceeds/(repayments) under the unsecured revolving credit facility, net	100,000	92,254	(17,143)
Proceeds from issuance of unsecured notes	350,000	0	1,250,000
Repayments under unsecured notes/term loan	0	(315,095)	(550,000)
Financing origination costs	(7,707)	(1,221)	(23,305)
Payment of early extinguishment of debt charges	(1,531)	(13,308)	(2,631)
Contributions from noncontrolling interests	0	109	1,422
Redemption/distribution of noncontrolling interests	(15,134)	(6,660)	(96,599)
Dividends paid	(531,565)	(529,756)	(506,172)
Proceeds from issuance of stock, net	204,012	33,705	440,946
Redemption of preferred stock	(575,000)	0	(225,000)
Repurchase of common stock	0	(75,126)	0
Change in other financing liabilities	(3,193)	(4,528)	911
Net cash flow used for financing activities	(482,841)	(986,513)	(223,874)
Net change in cash and cash equivalents	(19,634)	(94,932)	96,027
Cash and cash equivalents, beginning of year	143,581	238,513	142,486
Cash and cash equivalents, end of year	123,947	143,581	238,513
Interest paid during the year including payment of early extinguishment of debt charges of $1,531, $13,308 and $2,631, respectively (net of capitalized interest of $15,690, $17,549 and $14,480, respectively)	169,026	199,701	192,155
Income taxes (received)/paid during the year (net of refunds received of $3,452, $1,007 and $16,118, respectively)	(1,106)	514	(14,456)
Joint Ventures [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income	(72,162)	(71,617)	(60,763)
Other Real Estate Investments [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income	$ (26,076)	$ (29,100)	$ (67,001)