Equity Investment in Select Income REIT - Income Statement Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Oct. 09, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Rental income											$ 91,076	$ 45,261	$ 30,998
Total revenues	$ 160,184	$ 167,411	$ 176,032	$ 174,777	$ 103,656	$ 106,102	$ 108,085	$ 108,717			678,404	426,560	316,532
Real estate taxes											73,717	49,708	37,942
Other operating expenses											120,943	89,610	65,349
Depreciation and amortization											289,885	162,488	109,588
Acquisition and transaction related costs											682	14,508	0
General and administrative											32,728	24,922	18,847
Loss on impairment of real estate assets											22,255	8,630	9,490
Total expenses											574,512	376,291	262,214
Gain on sale of real estate											105,131	20,661	0
Dividend income											1,960	1,337	1,216
Unrealized gain on equity securities											(44,007)	(7,552)	0
Interest income											1,045	639	1,962
Interest expense											(134,880)	(89,865)	(65,406)
Loss on early extinguishment of debt											(769)	(709)	(1,715)
Income (loss) from continuing operations before income tax expense and equity in net losses of investees											32,372	(25,220)	(9,625)
Income tax expense											(778)	(117)	(101)
Equity in net losses of investees											(1,259)	(2,269)	(13)
Net income (loss)											$ 30,335	$ (21,884)	$ 12,090
Weighted average common shares outstanding (basic) (in shares)											48,062	24,830	21,158
Weighted average common shares outstanding (diluted) (in shares)											48,062	24,830	21,158
Net income attributed to SIR per common share (basic and diluted) (in dollars per share)	$ 1.35	$ (0.08)	$ (1.35)	$ 0.71	$ (2.31)	$ (0.02)	$ 1.20	$ 0.25			$ 0.63	$ (0.90)	$ 0.56
SIR
Schedule of Equity Method Investments [Line Items]
Equity in net losses of investees									$ 24,358				$ 21,584
SIR | SIR
Schedule of Equity Method Investments [Line Items]
Rental income										$ 298,003
Rental income												$ 392,285
Tenant reimbursements and other income										60,514
Tenant reimbursements and other income												75,818
Total revenues										358,517		468,103
Real estate taxes										36,748		44,131
Other operating expenses										43,714		55,567
Depreciation and amortization										105,326		137,672
Acquisition and transaction related costs										3,796		1,075
General and administrative										47,353		54,909
Write-off of straight line rent receivable, net										10,626		12,517
Loss on asset impairment										0		4,047
Loss on impairment of real estate assets										9,706		229
Total expenses										257,269		310,147
Gain on sale of real estate										4,075		0
Dividend income										1,190		1,587
Unrealized gain on equity securities										53,159		0
Interest income										753		91
Interest expense										(69,446)		(92,870)
Loss on early extinguishment of debt										(1,192)		0
Income (loss) from continuing operations before income tax expense and equity in net losses of investees										89,787		66,764
Income tax expense										(446)		(466)
Equity in net losses of investees										882		608
Net income										90,223		66,906
Net income allocated to noncontrolling interest										(15,841)		0
Net income (loss)										$ 74,382		$ 66,906
Weighted average common shares outstanding (basic) (in shares)										89,395		89,351
Weighted average common shares outstanding (diluted) (in shares)										89,411		89,370
Net income attributed to SIR per common share (basic and diluted) (in dollars per share)										$ 0.83		$ 0.75