Goodwill and intangible assets - Summary of Goodwill and Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Dec. 31, 2016
Goodwill And Intangible Assets [Line Items]
Gross carrying amount	$ 216,329	$ 201,567
Accumulated amortization	(128,299)	(112,210)
Net carrying Amount	88,030	89,357
Total intangible assets, Gross carrying amount	362,629	347,867
Total intangible assets, Net carrying Amount	234,330	235,657	$ 235,657
Goodwill, Gross carrying amount	199,513	176,981
Goodwill, Accumulated amortization	0	0
Total consolidated goodwill	199,513	176,981	$ 176,981	$ 176,981
Trade and brand names
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible, Net carrying Amount	$ 146,300	$ 146,300
Customer relationships
Goodwill And Intangible Assets [Line Items]
Weighted average amortization period (years)	11 years	11 years 1 month 6 days
Gross carrying amount	$ 173,063	$ 171,782
Accumulated amortization	(99,439)	(86,501)
Net carrying Amount	$ 73,624	$ 85,281
Noncompete agreements
Goodwill And Intangible Assets [Line Items]
Weighted average amortization period (years)	5 years	5 years
Gross carrying amount	$ 14,500	$ 14,500
Accumulated amortization	(14,500)	(14,500)
Net carrying Amount	$ 0	$ 0
Favorable leases
Goodwill And Intangible Assets [Line Items]
Weighted average amortization period (years)	8 years	7 years 6 months
Gross carrying amount	$ 4,017	$ 2,935
Accumulated amortization	(2,345)	(1,972)
Net carrying Amount	$ 1,672	$ 963
Order backlog
Goodwill And Intangible Assets [Line Items]
Weighted average amortization period (years)	4 months 24 days	4 months 24 days
Gross carrying amount	$ 3,400	$ 3,400
Accumulated amortization	(3,400)	(3,400)
Net carrying Amount	$ 0	$ 0
Reacquired franchise rights
Goodwill And Intangible Assets [Line Items]
Weighted average amortization period (years)	7 years	5 years 9 months 18 days
Gross carrying amount	$ 21,349	$ 8,950
Accumulated amortization	(8,615)	(5,837)
Net carrying Amount	$ 12,734	$ 3,113