CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 492,866,000	$ 272,908,000	$ 29,666,000
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	23,782,000	40,386,000	73,169,000
Net amortization of debt discounts, premiums and deferred financing fees	204,000	2,553,000	3,135,000
Straight line rental income	(418,000)	(4,971,000)	(14,425,000)
Amortization of acquired real estate leases	158,000	2,187,000	8,994,000
Other amortization	4,009,000	6,127,000	9,989,000
Amortization of right-of-use asset	736,000
Share-based compensation	14,426,000	19,697,000	21,414,000
Loss on asset impairment	0	12,087,000	19,714,000
Loss on early extinguishment of debt	6,374,000	7,122,000	493,000
Loss on sale of marketable securities	0	4,987,000	0
Net gain on sale of properties	(422,172,000)	(251,417,000)	(15,498,000)
Loss on sale of real estate mortgage receivable	0	2,117,000	0
Change in assets and liabilities:
Rents receivable and other assets	(13,099,000)	(19,886,000)	(23,708,000)
Accounts payable, accrued expenses and other	(5,311,000)	(704,000)	(9,384,000)
Rent collected in advance	(2,610,000)	(3,657,000)	(3,563,000)
Cash provided by operating activities	98,945,000	89,536,000	99,996,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate improvements	(26,052,000)	(49,930,000)	(64,813,000)
Insurance proceeds received	0	1,443,000	4,000,000
Principal payments received from real estate mortgages receivable	0	0	313,000
Proceeds from sale of properties, net	771,787,000	961,079,000	802,324,000
Proceeds from sale of real estate mortgage receivable	0	5,599,000	0
Purchase of marketable securities	0	0	(276,238,000)
Proceeds from sale of marketable securities	0	23,933,000	0
Proceeds from maturity of marketable securities	250,000,000	0	0
Cash provided by investing activities	995,735,000	942,124,000	465,586,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchase and retirement of common shares	(5,487,000)	(93,976,000)	(3,188,000)
Payments on borrowings	(255,842,000)	(581,460,000)	(295,053,000)
Contributions from holders of noncontrolling interest	0	1,000	31,000
Distributions to common shareholders	(428,649,000)	(304,612,000)	0
Distributions to preferred shareholders	(7,988,000)	(7,988,000)	(7,988,000)
Distributions to holders of noncontrolling interest	(170,000)	(114,000)	0
Cash used in financing activities	(698,136,000)	(988,149,000)	(306,198,000)
Increase in cash, cash equivalents, and restricted cash	396,544,000	43,511,000	259,384,000
Cash, cash equivalents, and restricted cash at beginning of year	2,404,101,000	2,360,590,000	2,101,206,000
Cash, cash equivalents, and restricted cash at end of year	2,800,645,000	2,404,101,000	2,360,590,000
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	13,032,000	27,117,000	56,796,000
Taxes paid, net	2,933,000	2,264,000	910,000
NON-CASH INVESTING ACTIVITIES:
Recognition of right-of-use asset and lease liability	1,503,000
Accrued capital expenditures	1,383,000	13,540,000	7,168,000
NON-CASH FINANCING ACTIVITIES:
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 2,404,101,000	$ 2,360,590,000	$ 2,360,590,000