Summary of Significant Accounting Policies - Deferred Costs and Mortgage Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Deferred Costs [Line Items]
Loan costs	$ 2,104	$ 2,057
Franchise fees	4,409	4,471
Other	129	133
Deferred costs, gross	6,642	6,661
Less accumulated amortization	(2,371)	(1,591)
Deferred costs, net	4,271	5,070
Amortization of deferred franchise fees	247	237	$ 217
Amortization of deferred financing fees included in interest expense	912	902	648
Franchise
Schedule of Deferred Costs [Line Items]
Amortization of deferred franchise fees	200	200	200
Loans
Schedule of Deferred Costs [Line Items]
Amortization of deferred financing fees included in interest expense	900	900	600
Mortgages
Schedule of Deferred Costs [Line Items]
Amortization of deferred financing fees included in interest expense	$ 400	$ 400	$ 100