CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flow from operating activities:
Net (loss) income	$ (243,132)	$ 61,199	$ (70,310)
Adjustments to reconcile net (loss) income to net cash flow provided by operating activities:
Depreciation and amortization	346,204	389,519	402,045
Stock-based compensation	11,493	7,765	7,895
Amortization and write-off of debt issuance costs and fair market value of debt adjustments	7,472	2,147	(5,315)
Loss on extinguishments of debt	63,204	0	0
Accretion of convertible debt discount	0	0	9,953
Equity in net (income) loss of joint ventures	(8,837)	(15,699)	3,135
Reserve of preferred equity interests	61,000	0	0
Impairment of joint venture investments	0	0	1,909
Net (gain) loss on sale and change in control of interests	(368)	1,087	(7,772)
Operating cash distributions from joint ventures	7,413	8,210	8,382
Gain on disposition of real estate	(161,164)	(73,386)	(167,571)
Impairment charges	345,580	110,906	279,021
Valuation allowance of prepaid tax asset	10,794	0	0
Assumption of buildings due to lease terminations	(8,585)	0	0
Change in notes receivable accrued interest	(2,705)	(9,487)	(8,048)
Net change in accounts receivable	2,470	1,410	(3,107)
Net change in accounts payable and accrued expenses	(3,661)	(9,775)	174
Net change in other operating assets and liabilities	(16,771)	(13,233)	(16,915)
Total adjustments	653,539	399,464	503,786
Net cash flow provided by operating activities	410,407	460,663	433,476
Cash flow from investing activities:
Real estate acquired, net of liabilities and cash assumed	(86,079)	(145,975)	(176,020)
Real estate developed and improvements to operating real estate	(115,361)	(162,926)	(305,725)
Proceeds from disposition of real estate	624,250	758,064	488,229
Hurricane casualty insurance advance proceeds	10,000	0	0
Equity contributions to joint ventures	(69,240)	(6,849)	(6,142)
Repayment (issuance) of joint venture advances, net	56,085	10,000	(82,634)
Distributions from unconsolidated joint ventures	27,885	26,793	18,123
Issuance of notes receivable	0	(11,139)	0
Repayment of notes receivable	31,068	5,065	9,521
Net cash flow provided by (used for) investing activities	478,608	473,033	(54,648)
Cash flow from financing activities:
(Repayment of) proceeds from revolving credit facilities, net	0	(210,000)	182,371
Proceeds from issuance of senior notes, net of offering expenses	791,113	0	884,786
Repayment of senior notes	(958,509)	(240,000)	(502,996)
Proceeds from other debt	0	0	400,000
Repayment of term loans and mortgage debt	(542,486)	(195,495)	(1,068,924)
Payment of debt issuance costs	(7,295)	(43)	(4,605)
Proceeds from issuance of preferred shares, net of offering expenses	168,870	0	0
Issuance of common shares in conjunction with equity award plans and dividend reinvestment plan	21,677	13,536	2,325
Redemption of operating partnership units	(232)	0	0
Distributions to non-controlling interests and redeemable operating partnership units	(835)	(1,085)	(6,452)
Dividends paid	(305,819)	(293,905)	(265,277)
Net cash flow used for financing activities	(833,516)	(926,992)	(378,772)
Effect of foreign exchange rate changes on cash and cash equivalents	0	1	152
Net increase in cash, cash equivalents and restricted cash	55,499	6,704	56
Cash, cash equivalents and restricted cash, beginning of year	39,225	32,520	32,312
Cash, cash equivalents and restricted cash, end of year	$ 94,724	$ 39,225	$ 32,520