Contingencies - Additional Information (Detail) $ in Millions	Dec. 11, 2015 USD ($)
Capital cost
Commitments and Contingencies Disclosure [Line Items]
Remedial alternative, EPA preferred remedy	$ 7.3

Best estimate of the loss exposure for reasonably possible environmental contingencies at an individual site for which no accrual has been recorded.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 10
-Subparagraph (c),(d)(2)
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 10
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859

Name:	us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration