Business Combinations - Additional Information (Detail) - Titan Acquisition $ in Millions		6 Months Ended
	Jul. 01, 2015 USD ($) Stores	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Estimate of expected liability			$ 2.0
Reduction in goodwill		$ 0.8
Asset Purchase Agreement
Business Acquisition [Line Items]
Business acquisition, effective date of completion	Jul. 01, 2015
Payments to acquire businesses, gross	$ 36.0
Number of retail stores | Stores	83
Business combination, liabilities assumed	$ 2.3