Management Agreements and Leases - Net Lease Portfolio and TA Leases (Details) $ in Thousands		1 Months Ended	3 Months Ended
	Mar. 12, 2020 USD ($) ft²	Jan. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) ft² tenant travel_center agreement retail_property property brand industry	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Management Agreements and Leases [Line Items]
Number of properties owned | property			7
Square feet | ft²			821,068
Revenues			$ 483,776	$ 524,908
Adjustments necessary to record rent on straight line basis			$ (3,543)	1,132
Number of properties to be sold or rebranded | property			6
Rental income
Management Agreements and Leases [Line Items]
Revenues			$ 100,072	68,673
Net Lease Property
Management Agreements and Leases [Line Items]
Number of properties owned | retail_property			813
Square feet | ft²	6,696		14,500,000
Operating agreement annual rent and return	$ 387		$ 379,503
Weighted average remaining lease term			11 years 1 month 6 days
Percentage of portfolio leased by tenants			98.00%
Number of tenants | tenant			187
Number of brands | brand			128
Number of industries | industry			22
Number of properties to be sold or rebranded | property			6
Travel centers
Management Agreements and Leases [Line Items]
Number of properties owned | travel_center			179
Travel Centers of America LLC | Travel centers
Management Agreements and Leases [Line Items]
Number of properties owned | travel_center			179
Operating agreement annual rent and return			$ 246,110
Quarterly payments to deferred rent receivable		$ 4,404
Remaining balance of previously deferred rents			52,843
Adjustments necessary to record rent on straight line basis			3,344	(1,214)
Accruals for unpaid rent, including deferred rent			$ 65,109		$ 79,710
Increase in annual rent fixed interest rate			8.50%
Deferred rent receivable from TA agreement, during the period			$ 725	1,069
Travel Centers of America LLC | Travel centers | Rental income
Management Agreements and Leases [Line Items]
Revenues			$ 61,528	$ 63,075
Travel Centers of America LLC | Travel centers | Customer concentration risk | Annual minimum rents
Management Agreements and Leases [Line Items]
Percentage of total annual minimum rents			25.50%
Travel Centers of America LLC | Travel centers | TA agreements
Management Agreements and Leases [Line Items]
Number of operating agreements | agreement			5