Hotel Management Agreements and Leases - Narrative and Marriott No. 1 (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017 USD ($) agreement hotel travelcenter lease_agreement	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)
Management Agreements and Leases [Line Items]
Number of operating agreements | agreement	14
Capital improvements from leased facilities, funded	$ 32,731	$ 32,716
Hotel
Management Agreements and Leases [Line Items]
Number of properties owned | hotel	308
Number of properties leased to taxable REIT subsidiaries | hotel	305
Number of properties leased to third parties | hotel	3
Number of operating agreements | lease_agreement	9
Hotel | Marriott No. 1 agreement
Management Agreements and Leases [Line Items]
Number of properties owned | hotel	53
Operating agreement annual rent and return	$ 68,835
Additional returns realized		839
Capital improvements from leased facilities, funded	$ 1,990
Percentage increase In minimum returns after funding for capital improvements	10.00%
Travel centers
Management Agreements and Leases [Line Items]
Number of properties owned | travelcenter	198
Forecast | Hotel | Marriott No. 1 agreement
Management Agreements and Leases [Line Items]
Capital improvements from leased facilities, funded			$ 2,110
Minimum | Hotel
Management Agreements and Leases [Line Items]
Number of real estate properties leased or managed | hotel	1
Hotel management agreements and leases, renewal period	20 years
Minimum | Hotel | Marriott No. 1 agreement
Management Agreements and Leases [Line Items]
Realized returns and rents	$ 17,188	$ 17,093
Maximum | Hotel
Management Agreements and Leases [Line Items]
Number of real estate properties leased or managed | hotel	96
Hotel management agreements and leases, renewal period	60 years
Travel Centers of America LLC | Travel centers
Management Agreements and Leases [Line Items]
Number of properties owned | travelcenter	198
Capital improvements from leased facilities, funded	$ 24,908
Travel Centers of America LLC | Forecast | Travel centers
Management Agreements and Leases [Line Items]
Capital improvements from leased facilities, funded			$ 53,769