Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flow from operating activities:
Net income	$ 305,452,000	$ 521,432,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	264,436,000	258,432,000
Asset Impairment Charges	68,126,000	27,989,000
Deferred taxes	56,143,000	4,716,000
Early extinguishment of debt charges	45,674,000
Equity award expense	15,292,000	15,312,000
Gain on sale of operating properties	(81,873,000)	(88,497,000)
Gain on sale of marketable securities		(38,488,000)
Gain on change in control of interests, net	(53,096,000)	(146,143,000)
Equity in income of joint ventures, net	(190,155,000)	(130,808,000)
Equity in income from other real estate investments, net	(22,532,000)	(31,236,000)
Distributions from joint ventures and other real estate investments	70,043,000	94,499,000
Change in accounts and notes receivable	3,779,000	(372,000)
Change in accounts payable and accrued expenses	23,931,000	38,703,000
Change in Canadian withholding tax receivable	(5,257,000)	(6,919,000)
Change in other operating assets and liabilities	(55,437,000)	(55,978,000)
Net cash flow provided by operating activities	444,526,000	462,642,000
Cash flow from investing activities:
Acquisition of operating real estate and other related net assets	(181,548,000)	(619,622,000)
Improvements to operating real estate	(102,084,000)	(111,740,000)
Acquisition of real estate under development	(51,588,000)	(3,074,000)
Improvements to real estate under development	(42,042,000)	(8,922,000)
Investment in marketable securities	(2,466,000)	(257,000)
Proceeds from sale/repayments of marketable securities	1,907,000	71,562,000
Investments and advances to real estate joint ventures	(50,058,000)	(87,953,000)
Reimbursements of investments and advances to real estate joint ventures	70,669,000	98,741,000
Distributions from liquidation of real estate joint ventures	135,648,000	54,642,000
Return of investment from liquidation of real estate joint ventures	190,102,000	26,114,000
Investment in other real estate investments	(233,000)	(545,000)
Reimbursements of investments and advances to other real estate investments	11,489,000	14,442,000
Collection of mortgage loans receivable	688,000	52,963,000
Investment in other investments		(190,278,000)
Reimbursements of other investments	500,000
Proceeds from sale of operating properties	262,708,000	238,444,000
Proceeds from sale of development properties	4,551,000
Net cash flow provided by/(used for) investing activities	248,243,000	(465,483,000)
Cash flow from financing activities:
Principal payments on debt, excluding normal amortization of rental property debt	(602,079,000)	(444,150,000)
Principal payments on rental property debt	(15,316,000)	(22,452,000)
Proceeds from unsecured revolving credit facility, net	226,447,000	325,000,000
Proceeds from issuance of unsecured term loan/notes	650,000,000	1,000,000,000
Repayments under unsecured term loan/notes	(861,850,000)	(600,000,000)
Financing origination costs	(14,033,000)	(11,137,000)
Payment of early extinguishment of debt charges	(45,674,000)	0
Change in tenants' security deposits	1,240,000	2,005,000
Contributions from noncontrolling interests		106,154,000
Redemption of noncontrolling interests	(3,190,000)	(33,810,000)
Dividends paid	(354,112,000)	(340,745,000)
Proceeds from issuance of stock, net	306,809,000	15,567,000
Net cash flow used for financing activities	(711,758,000)	(3,568,000)
Change in cash and cash equivalents	(18,989,000)	(6,409,000)
Cash and cash equivalents, beginning of period	189,534,000	187,322,000
Cash and cash equivalents, end of period	170,545,000	180,913,000
Interest paid during the period including payment of early extinguishment of debt charges of $45,674 and $0, respectively (net of capitalized interest of $6,783, and $3,784, respectively)	194,234,000	150,625,000
Income taxes paid during the period (net of refunds received of $86,100, and $0, respectively)	$ 34,296,000	$ 21,681,000