Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flow from operating activities:
Net income	$ 386,138	$ 900,143	$ 435,880
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	355,320	344,527	273,093
Impairment charges	93,266	45,464	217,858
Deferred taxes	55,068	4,498	15,128
Early extinguishment of debt charges	45,674
Equity award expense	19,071	18,465	17,879
Gain on sale of operating properties	(92,823)	(132,907)	(203,889)
Gain on sale of marketable securities		(39,852)
Gain on change in control of interests, net	(57,386)	(149,234)	(107,235)
Equity in income of joint ventures, net	(218,714)	(480,395)	(159,560)
Equity in income from other real estate investments, net	(27,773)	(36,090)	(38,042)
Distributions from joint ventures and other real estate investments	90,589	126,263	255,532
Change in accounts and notes receivable	(6,571)	(2,867)	(8,060)
Change in accounts payable and accrued expenses	(7,886)	164	(1,095)
Change in Canadian withholding tax receivable	23,571	(37,040)
Change in other operating assets and liabilities	(65,448)	(67,438)	(68,146)
Net cash flow provided by operating activities	592,096	493,701	629,343
Cash flow from investing activities:
Acquisition of operating real estate and other related net assets	(203,190)	(661,423)	(384,828)
Improvements to operating real estate	(143,489)	(166,670)	(131,795)
Acquisition of real estate under development	(51,588)	(16,355)	(65,724)
Improvements to real estate under development	(72,759)	(16,861)	(418)
Investment in marketable securities	(2,466)	(257)	(11,445)
Proceeds from sale/repayments of marketable securities	1,937	76,170	3,780
Investments and advances to real estate joint ventures	(86,453)	(91,609)	(93,845)
Reimbursements of investments and advances to real estate joint ventures	71,656	94,053	222,590
Distributions from liquidation of real estate joint ventures	138,475	373,833
Return of investment from liquidation of real estate joint ventures	191,902	88,672
Investment in other real estate investments	(233)	(641)	(4,338)
Reimbursements of investments and advances to other real estate investments	11,019	40,556	16,312
Investment in mortgage loans receivable			(50,000)
Collection of mortgage loans receivable	921	55,145	8,302
Investment in other investments		(190,278)
Reimbursements of other investments	500
Proceeds from sale of operating properties	304,600	437,030	612,748
Proceeds from sale of development properties	4,551		5,366
Net cash flow provided by investing activities	165,383	21,365	126,705
Cash flow from financing activities:
Principal payments on debt, excluding normal amortization	(700,853)	(555,627)	(327,963)
Principal payments on rental property debt	(19,039)	(28,632)	(22,841)
Proceeds from mortgage loan financings			15,700
Proceeds/(repayments) under the unsecured revolving credit facility, net	26,445	(100,000)	(94,354)
Proceeds from issuance of unsecured term loan/notes	1,400,000	1,500,030	500,000
Repayments under unsecured term loan/notes	(1,261,850)	(750,000)	(370,842)
Financing origination costs	(25,679)	(19,017)	(11,911)
Payment of early extinguishment of debt charges	(45,674)	0	0
Change in tenants' security deposits	1,367	2,116
Contributions from noncontrolling interests		106,154	1,917
Conversion/distribution of noncontrolling interests	(12,594)	(55,753)	(3,201)
Dividends paid	(474,045)	(455,833)	(427,873)
Proceeds from issuance of stock	307,395	18,708	23,874
Redemption of preferred stock		(175,000)
Net cash flow used for financing activities	(804,527)	(512,854)	(717,494)
Change in cash and cash equivalents	(47,048)	2,212	38,554
Cash and cash equivalents, beginning of year	189,534	187,322	148,768
Cash and cash equivalents, end of year	142,486	189,534	187,322
Interest paid during the year including payment of early extinguishment of debt charges of $45,674, $0 and $0, respectively (net of capitalized interest of $9,247, $5,618 and $2,383, respectively)	252,482	232,950	207,632
Income taxes paid during the year (net of refunds received of $113,934, $0 and $0, respectively)	$ 6,090	$ 100,366	$ 23,292