Segments - Summary of Financial Information for the Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 140,550	$ 107,316	$ 261,882	$ 198,418
Total Segment EBITDA	56,928	45,211	104,503	86,899
Corporate And Other Non Segment
Segment Reporting Information [Line Items]
Total Segment EBITDA	(9,236)	(9,925)	(17,978)	(17,057)
Franchise revenue
Segment Reporting Information [Line Items]
Revenue	58,150	37,794	112,762	74,591
Franchise revenue | Operating Segments
Segment Reporting Information [Line Items]
Total Segment EBITDA	40,041	32,487	76,719	64,519
Franchise revenue | US
Segment Reporting Information [Line Items]
Revenue	57,252	37,017	110,697	73,445
Franchise revenue | International
Segment Reporting Information [Line Items]
Revenue	898	777	2,065	1,146
Corporate-owned Stores
Segment Reporting Information [Line Items]
Revenue	34,252	28,285	66,959	55,326
Corporate-owned Stores | Operating Segments
Segment Reporting Information [Line Items]
Total Segment EBITDA	14,666	12,840	26,837	23,533
Corporate-owned Stores | US
Segment Reporting Information [Line Items]
Revenue	33,125	27,210	64,697	53,183
Corporate-owned Stores | International
Segment Reporting Information [Line Items]
Revenue	1,127	1,075	2,262	2,143
Equipment revenue
Segment Reporting Information [Line Items]
Revenue	48,148	41,237	82,161	68,501
Equipment revenue | Operating Segments
Segment Reporting Information [Line Items]
Total Segment EBITDA	11,457	9,809	18,925	15,904
Equipment revenue | US
Segment Reporting Information [Line Items]
Revenue	$ 48,148	$ 41,237	$ 82,161	$ 68,501