Segments - Summary of Financial Information for the Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 174,359	$ 136,656	$ 140,550	$ 121,333	$ 134,028	$ 97,496	$ 107,316	$ 91,102	$ 572,898	$ 429,942	$ 378,241
Total Segment EBITDA									213,129	496,225	148,535
Corporate and other
Segment Reporting Information [Line Items]
Total Segment EBITDA									(43,753)	284,372	(26,007)
Franchise revenue
Segment Reporting Information [Line Items]
Total revenue									224,140	150,155	116,488
Franchise revenue | Operating segments
Segment Reporting Information [Line Items]
Total Segment EBITDA									152,571	126,459	97,256
Franchise revenue | US
Segment Reporting Information [Line Items]
Total revenue									219,506	147,787	114,717
Franchise revenue | International
Segment Reporting Information [Line Items]
Total revenue									4,634	2,368	1,771
Corporate-owned stores
Segment Reporting Information [Line Items]
Total revenue									138,599	112,114	104,721
Corporate-owned stores | Operating segments
Segment Reporting Information [Line Items]
Total Segment EBITDA									56,704	46,855	40,847
Corporate-owned stores | US
Segment Reporting Information [Line Items]
Total revenue									134,174	107,712	100,541
Corporate-owned stores | International
Segment Reporting Information [Line Items]
Total revenue									4,425	4,402	4,180
Equipment revenue
Segment Reporting Information [Line Items]
Total revenue									210,159	167,673	157,032
Equipment revenue | Operating segments
Segment Reporting Information [Line Items]
Total Segment EBITDA									47,607	38,539	36,439
Equipment revenue | US
Segment Reporting Information [Line Items]
Total revenue									$ 210,159	$ 167,673	$ 157,032