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Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015 Segment
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating segments	4
Eastern Region [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating segments	1
Western Region [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating segments	1
Recycling [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating segments	1
Other [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating segments	1

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- Definition

Organization Consolidation And Presentation Of Financial Statements [Line Items]

+ References

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

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