Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flow from operating activities:
Net income	$ 347,000	$ 440,348
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	167,609	154,724
Asset Impairment Charges	58,053	21,931
Equity award expense	11,552	12,154
Gain on sale of operating properties	(72,101)	(58,731)
Gain on sale of marketable securities		(32,435)
Gain on change in control of interests, net	(46,512)	(139,801)
Equity in income of joint ventures, net	(178,618)	(119,914)
Equity in income from other real estate investments, net	(18,758)	(19,917)
Distributions from joint ventures and other real estate investments	54,029	66,076
Change in accounts and notes receivable	2,551	(5,383)
Change in accounts payable and accrued expenses	(4,697)	(381)
Change in Canadian withholding tax receivable	(66,911)	(6,743)
Change in other operating assets and liabilities	(37,350)	(25,933)
Net cash flow provided by operating activities	215,847	285,995
Cash flow from investing activities:
Acquisition of operating real estate and other related net assets	(95,801)	(586,321)
Improvements to operating real estate	(70,333)	(72,642)
Acquisition of real estate under development	(50,778)
Improvements to real estate under development	(18,448)	(4,362)
Investment in marketable securities	(1,325)	(257)
Proceeds from sale/repayments of marketable securities	1,850	59,318
Investments and advances to real estate joint ventures	(26,160)	(57,148)
Reimbursements of investments and advances to real estate joint ventures	56,431	41,380
Distributions from liquidation of real estate joint ventures	136,005	53,450
Return of investment from liquidation of real estate joint ventures	149,296	20,889
Investment in other real estate investments	(233)	(458)
Reimbursements of investments and advances to other real estate investments	10,475	22,887
Collection of mortgage loans receivable	461	50,729
Investment in other investments		(190,278)
Reimbursements of other investments	500
Proceeds from sale of operating properties	214,858	183,332
Proceeds from sale of development properties	4,551
Net cash flow provided by/(used for) investing activities	311,349	(479,481)
Cash flow from financing activities:
Principal payments on debt, excluding normal amortization of rental property debt	(233,303)	(308,728)
Principal payments on rental property debt	(10,380)	(14,628)
Proceeds under the unsecured revolving credit facility, net	100,019	125,000
Proceeds from issuance of unsecured term loan/notes	150,000	1,000,000
Repayments under unsecured term loan/notes	(300,000)	(500,000)
Financing origination costs	(4,697)	(10,218)
Change in tenants' security deposits	963	1,315
Contributions from noncontrolling interests		106,154
Redemption of noncontrolling interests	(2,572)	(33,348)
Dividends paid	(235,458)	(227,023)
Proceeds from issuance of stock, net	156,513	13,472
Net cash flow (used for)/provided by financing activities	(378,915)	151,996
Change in cash and cash equivalents	148,281	(41,490)
Cash and cash equivalents, beginning of period	189,534	187,322
Cash and cash equivalents, end of period	337,815	145,832
Interest paid during the period (net of capitalized interest of $3,762, and $2,424, respectively)	111,761	112,582
Income taxes paid during the period (net of refunds received of $18,723 and $0, respectively)	$ 94,639	$ 10,829