Summary of Significant Accounting Policies - Schedule of Intangible and Other Assets, Estimated Useful Life (Detail)	12 Months Ended
	Dec. 31, 2014
Customer Supply Contracts
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful lives description	Over the shorter of the estimated useful lives or the terms of the agreements
Noncompetition Agreements
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful lives description	Over the shorter of the estimated useful lives or the terms of the agreements
Deferred Financing Costs
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful lives description	Over the terms of the related debt
Minimum | Customer Relationships
Summary Of Significant Accounting Policies [Line Items]
Identifiable intangible assets, Useful Life	5 years
Minimum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Identifiable intangible assets, Useful Life	5 years
Maximum | Customer Relationships
Summary Of Significant Accounting Policies [Line Items]
Identifiable intangible assets, Useful Life	15 years
Maximum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Identifiable intangible assets, Useful Life	15 years