Income Taxes - Narrative (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Section 1231 gain (loss)									$ 0
Income (loss) from continuing operations before income taxes									151,000,000	$ 170,000,000	$ 833,000,000
Income (loss) before income taxes	$ (2,866,000)	$ 13,957,000	$ 78,182,000	$ 128,410,000	$ 149,329,000	$ (19,062,000)	$ 25,708,000	$ 20,345,000	217,683,000	176,320,000	838,577,000
Income tax benefit (expense)									10,000,000	12,000,000	13,000,000
Deferred income tax expense (benefit)									(14,573,000)	(18,253,000)	(18,525,000)
Net operating loss carryforward	68,444,000				33,771,000				68,444,000	33,771,000	20,559,000
Unrecognized Tax Benefits	469,000				469,000				469,000	469,000	0	$ 0
Accrued interest	70,000								70,000
Amount that tax basis of net assets is less than reported amounts	1,500,000,000				$ 1,200,000,000				1,500,000,000	1,200,000,000	1,400,000,000
UK
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes											(11,000,000)
Down R E I T
Operating Loss Carryforwards [Line Items]
Income (loss) from continuing operations before income taxes									80,000,000	200,000,000	852,000,000
TRS
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes									71,000,000	$ (30,000,000)	$ (8,000,000)
Deferred income tax expense (benefit)									33,000,000
Net operating loss carryforward	283,000,000								283,000,000
Net operating loss carryforwards subject to expiration	22,000,000								22,000,000
Net operating loss carryforwards not subject to expiration	$ 261,000,000								$ 261,000,000