Acquisitions - Schedule of Net Purchase Prices Allocated to Assets Acquired and Liabilities Assumed (Parenthetical) (Detail) - Allied [Member]	Apr. 01, 2017
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated useful life	15 years
Trade Name [Member]
Business Acquisition [Line Items]
Estimated useful life	20 years
Minimum [Member] | Non-compete Agreements [Member]
Business Acquisition [Line Items]
Estimated useful life	3 years
Maximum [Member] | Non-compete Agreements [Member]
Business Acquisition [Line Items]
Estimated useful life	5 years