Hotel Management Agreements and Leases - Sonesta (Details) $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($) hotel	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)
Management Agreements and Leases [Line Items]
Capital improvements from leased facilities, funded	$ 32,731	$ 32,716
Sonesta agreements
Management Agreements and Leases [Line Items]
Procurement and construction supervision fees	$ 81	343
Hotel | Sonesta agreements
Management Agreements and Leases [Line Items]
Fixed minimum return as a percentage of invested capital	8.00%
Operating agreement annual rent and return	$ 90,227
Realized returns and rents	10,662	8,766
Related party transaction, management marketing and reservation system fees	5,729	5,300
Capital improvements from leased facilities, funded	$ 3,531
Percentage increase in minimum returns	8.00%
Forecast | Hotel | Sonesta agreements
Management Agreements and Leases [Line Items]
Capital improvements from leased facilities, funded			$ 17,409	$ 18,708
Sonesta Int'l Hotels Corp
Management Agreements and Leases [Line Items]
Due to related party, reimbursement of capital expenditures and other	$ 783	$ 5,484
Sonesta Int'l Hotels Corp | Full service hotel
Management Agreements and Leases [Line Items]
Number of real estate properties leased or managed | hotel	9
Sonesta Int'l Hotels Corp | Limited services hotel
Management Agreements and Leases [Line Items]
Number of real estate properties leased or managed | hotel	25