Acquisition - Purchase Consideration Allocation (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Aug. 10, 2018	Jan. 01, 2018
Business Acquisition [Line Items]
Goodwill	$ 199,513	$ 199,513
Colorado Acquisition
Business Acquisition [Line Items]
Fixed assets			$ 3,873
Other assets			143
Goodwill			8,476
Liabilities assumed, including deferred revenues			(83)
Net assets acquired			17,239
Long Island Acquisition
Business Acquisition [Line Items]
Fixed assets				$ 4,672
Other assets				275
Goodwill				14,056
Liabilities assumed, including deferred revenues				(310)
Net assets acquired				28,153
Reacquired franchise rights | Colorado Acquisition
Business Acquisition [Line Items]
Intangible assets			4,610
Reacquired franchise rights | Long Island Acquisition
Business Acquisition [Line Items]
Intangible assets				7,640
Customer relationships | Colorado Acquisition
Business Acquisition [Line Items]
Intangible assets			140
Customer relationships | Long Island Acquisition
Business Acquisition [Line Items]
Intangible assets				1,150
Favorable leases, net | Colorado Acquisition
Business Acquisition [Line Items]
Intangible assets			$ 80
Favorable leases, net | Long Island Acquisition
Business Acquisition [Line Items]
Intangible assets				520
Reacquired area development rights | Long Island Acquisition
Business Acquisition [Line Items]
Intangible assets				$ 150