Corporate-Owned and Franchisee-Owned Stores - Schedule of Changes in Corporate-owned and Franchisee-owned Stores (Detail) - store	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Number Of Stores [Roll Forward]
Stores operated at beginning of period	2,039	1,806	2,001	1,742
New stores opened	21	53	60	118
Stores acquired, debranded, sold or consolidated	(1)	0	(2)	(1)
Stores operated at end of period	2,059	1,859	2,059	1,859
Number of stores reopened	1,490		1,490
Franchisee-Owned Stores
Number Of Stores [Roll Forward]
Stores operated at beginning of period	1,940	1,730	1,903	1,666
New stores opened	21	53	59	118
Stores acquired, debranded, sold or consolidated	(1)	(4)	(2)	(5)
Stores operated at end of period	1,960	1,779	1,960	1,779
Number of stores reopened	1,451		1,451
Corporate-Owned Stores
Number Of Stores [Roll Forward]
Stores operated at beginning of period	99	76	98	76
New stores opened	0	0	1	0
Stores acquired from franchisees	0	4	0	4
Stores operated at end of period	99	80	99	80
Number of stores reopened	39		39