Accumulated Other Comprehensive Loss - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Equity [Abstract]
Comprehensive income (loss)	$ 0	$ 0
Reclassified comprehensive income loss, Before tax	$ 100,000	$ (100,000)

Amount before tax and reclassification adjustments of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement benefit plans.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (i-k)

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

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