Acquisitions - Summary of Purchase Price Allocation (Parenthetical) (Detail) - Series of Individually Immaterial Business Acquisitions	9 Months Ended
Sep. 30, 2016
Trade Names [Member]
Business Acquisition [Line Items]
Estimated useful lives	20 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated useful lives	10 years

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration