Fair Value of Derivative Financial Instruments (Detail) $ in Millions	Jun. 30, 2015 USD ($)
Accrued Liabilities \| Metal
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Fair value of derivative liabilities	$ 1.3

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant