CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (134,307)	$ (82,878)	$ 292,414
Adjustments to reconcile net (loss) income to cash provided by operating activities:
Depreciation and amortization	270,147	289,025	286,235
Net amortization of debt premiums, discounts and issuance costs	8,022	6,032	6,221
Straight line rental income	(6,069)	(4,508)	(10,227)
Amortization of acquired real estate leases	(7,405)	(6,791)	(5,787)
Loss on early extinguishment of debt	51	44	22
Gain on lease termination	(22,896)	0	0
Impairment of assets	106,972	115,201	66,346
Gain on sale of properties	(6,487)	(39,696)	(261,916)
Gains and losses on equity securities, net	(34,106)	41,898	20,724
Other non-cash adjustments, net	(2,203)	(3,771)	(3,772)
Equity in earnings of an investee	0	(400)	(516)
Distribution of earnings from Affiliates Insurance Company	0	2,574	0
Change in assets and liabilities:
Other assets	(33,867)	1,794	(3,586)
Accrued interest	(305)	(2,105)	8,195
Other liabilities	20,997	(50,574)	(1,513)
Net cash provided by operating activities	158,544	265,845	392,840
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions and deposits	(2,526)	(50,636)	(129,494)
Real estate improvements	(185,585)	(222,417)	(103,804)
Proceeds from sale of properties, net	147,388	254,241	332,389
Proceeds from sale of RMR Inc. common shares, net	0	98,557	0
Distributions in excess of earnings from Affiliates Insurance Company	287	6,426	0
Net cash (used in) provided by investing activities	(40,436)	86,171	99,091
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of senior unsecured notes, net	985,000	0	491,560
Proceeds from borrowings on revolving credit facility	430,500	994,500	727,000
Repayments of borrowings on revolving credit facility	(968,000)	(596,000)	(1,184,000)
Repayment of senior unsecured notes	(200,000)	(400,000)	0
Repayment of term loan	(250,000)	(100,000)	0
Repayment of other debt	(5,941)	(46,345)	(107,116)
Loss on early extinguishment of debt settled in cash	(376)	0	(150)
Payment of debt issuance costs	(5,378)	(417)	(4,296)
Repurchase of common shares	(171)	(299)	(411)
Distributions to noncontrolling interest	(22,292)	(21,583)	(21,022)
Distributions to shareholders	(42,825)	(199,719)	(370,746)
Net cash used in financing activities	(79,483)	(369,863)	(469,181)
Increase (decrease) in cash and cash equivalents and restricted cash	38,625	(17,847)	22,750
Cash and cash equivalents and restricted cash at end of period	90,849	52,224	70,071
Cash and cash equivalents and restricted cash at beginning of period	$ 52,224	$ 70,071	$ 47,321