Intangible Assets and Goodwill - Components of Company's Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Net Balance	$ 95,407		$ 95,407		$ 103,157
Amortization expense	5,100	$ 4,700	10,300	$ 9,100
Franchise agreements
Finite Lived Intangible Assets [Line Items]
Initial Cost	180,867		180,867		180,867
Accumulated Amortization	(85,460)		(85,460)		(77,710)
Net Balance	95,407		$ 95,407		103,157
Franchise agreements | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			12 years 6 months
Other intangible assets
Finite Lived Intangible Assets [Line Items]
Initial Cost	33,847		$ 33,847		30,875
Accumulated Amortization	(10,369)		(10,369)		(7,910)
Net Balance	23,478		$ 23,478		22,965
Other intangible assets | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			4 years 10 months 24 days
Software
Finite Lived Intangible Assets [Line Items]
Initial Cost	25,111		$ 25,111		20,579
Accumulated Amortization	(7,605)		(7,605)		(5,802)
Net Balance	17,506		$ 17,506		14,777
Software | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			4 years 3 months 18 days
Trademarks
Finite Lived Intangible Assets [Line Items]
Initial Cost	1,886		$ 1,886		1,857
Accumulated Amortization	(938)		(938)		(839)
Net Balance	948		$ 948		1,018
Trademarks | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			9 years 3 months 18 days
Software Development
Finite Lived Intangible Assets [Line Items]
Capitalized software development costs	7,400		$ 7,400		4,500
Non-compete agreements
Finite Lived Intangible Assets [Line Items]
Initial Cost	3,700		3,700		3,700
Accumulated Amortization	(1,221)		(1,221)		(896)
Net Balance	2,479		$ 2,479		2,804
Non-compete agreements | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			7 years 8 months 12 days
Training materials
Finite Lived Intangible Assets [Line Items]
Initial Cost	2,350		$ 2,350		2,350
Accumulated Amortization	(392)		(392)		(157)
Net Balance	1,958		$ 1,958		2,193
Training materials | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			3 years
Other
Finite Lived Intangible Assets [Line Items]
Initial Cost	800		$ 800		2,389
Accumulated Amortization	(213)		(213)		(216)
Net Balance	$ 587		$ 587		$ 2,173
Other | Weighted Average
Finite Lived Intangible Assets [Line Items]
Useful life of intangible assets			5 years