Corporate-Owned and Franchisee-Owned Stores - Schedule of Changes in Corporate-owned and Franchisee-owned Stores (Detail) - store	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Number Of Stores [Roll Forward]
Stores operated at beginning of period	1,859	1,608	1,742	1,518
New stores opened	41	41	159	132
Stores acquired, debranded, sold or consolidated	(1)	(3)	(2)	(4)
Stores operated at end of period	1,899	1,646	1,899	1,646
Franchisee-Owned Stores
Number Of Stores [Roll Forward]
Stores operated at beginning of period	1,779	1,540	1,666	1,456
New stores opened	39	40	157	131
Stores acquired, debranded, sold or consolidated	(1)	(7)	(6)	(14)
Stores operated at end of period	1,817	1,573	1,817	1,573
Corporate-Owned Stores
Number Of Stores [Roll Forward]
Stores operated at beginning of period	80	68	76	62
New stores opened	2	1	2	1
Stores acquired from franchisees	0	4	4	10
Stores operated at end of period	82	73	82	73