CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Cash flows from operating activities:
Net income (loss)	$ 422,634	$ 639,926	$ (546,418)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization of real estate, in-place lease and other intangibles: Continuing operations	534,726	568,108	504,905
Depreciation and amortization of real estate, in-place lease and other intangibles: Discontinued operations	0	4,890	5,880
Amortization of deferred compensation	14,258	22,884	26,127
Amortization of deferred financing costs	14,569	20,014	20,222
Straight-line rents	(23,933)	(18,003)	(28,859)
Loan and direct financing lease non-cash interest, net: continuing operations	(613)	599	(5,648)
Loan and direct financing lease non-cash interest, net: discontinued operations	0	0	(90,065)
Equity loss (income) from unconsolidated joint ventures	(10,901)	(11,360)	(57,313)
Distributions of earnings from unconsolidated joint ventures	44,142	26,492	15,111
Loss (gain) on sales of real estate, net	(356,641)	(164,698)	(6,377)
Lease and management fee termination loss (income), net	54,641	0	(1,103)
Deferred income tax expense (benefit)	(5,523)	47,195	0
Impairments (recoveries), net	166,384	0	1,449,748
Loss on extinguishment of debt	54,227	46,020	0
Casualty-related loss (recoveries), net	12,053	0	0
Loss (gain) on sale of marketable securities	(50,895)	0	0
Other non-cash items	(2,122)	(2,968)	(11,286)
Decrease (increase) in accounts receivable and other assets, net	(24,782)	(6,992)	(29,022)
Increase (decrease) accounts payable and accrued liabilities	4,817	42,024	(23,757)
Net cash provided by (used in) operating activities	847,041	1,214,131	1,222,145
Cash flows from investing activities:
Acquisition of RIDEA III, net	0	0	(768,413)
Acquisitions of other real estate	(560,753)	(467,162)	(613,252)
Development and redevelopment of real estate	(373,479)	(421,322)	(281,017)
Leasing costs, tenant improvements, and recurring capital expenditures	(115,260)	(91,442)	(84,282)
Proceeds from sales of real estate, net	1,314,325	647,754	73,149
Contributions to unconsolidated joint ventures	(46,334)	(10,186)	(69,936)
Distributions in excess of earnings from unconsolidated joint ventures	37,023	28,366	30,989
Proceeds from the RIDEA II transaction, net	462,242	0	0
Proceeds from sales/principal repayments on debt investments and direct financing leases	558,769	231,990	628,049
Investments in loans receivable, direct financing leases and other	(30,276)	(273,693)	(575,652)
Purchase of securities for debt defeasance	0	(73,278)	0
Net cash provided by (used in) investing activities	1,246,257	(428,973)	(1,660,365)
Cash flows from financing activities:
Borrowings under bank line of credit, net	1,244,189	1,108,417	98,743
Repayments under bank line of credit	(1,150,596)	(540,000)	(511,521)
Proceeds related to QCP Spin-Off, net	0	1,685,172	0
Issuance and borrowings of debt, excluding bank line of credit	5,395	0	2,269,031
Repayments and repurchase of debt, excluding bank line of credit	(1,468,446)	(2,316,774)	(457,845)
Payments for debt extinguishment and deferred financing costs	(51,415)	(54,856)	(19,995)
Issuance of common stock and exercise of options	28,121	67,650	206,471
Repurchase of common stock	(4,785)	(8,685)	(8,738)
Dividends paid on common stock	(694,955)	(979,542)	(1,046,638)
Issuance of noncontrolling interests	1,615	11,834	110,775
Distributions to and purchase of noncontrolling interests	(57,584)	(27,481)	(26,196)
Net cash provided by (used in) financing activities	(2,148,461)	(1,054,265)	614,087
Effect of foreign exchanges on cash, cash equivalents and restricted cash	376	(1,019)	(1,537)
Net increase (decrease) in cash, cash equivalents and restricted cash	(54,787)	(270,126)	174,330
Cash, cash equivalents and restricted cash, beginning of year	136,990	407,116	232,786
Cash, cash equivalents and restricted cash, end of year	82,203	136,990	407,116
Less: cash, cash equivalents and restricted cash of discontinued operations	0	0	(6,058)
Cash, cash equivalents and restricted cash of continuing operations, end of year	$ 82,203	$ 136,990	$ 401,058