Schedule of Measurement Dates (Detail)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Benefit Obligation
Defined Benefit Plan Disclosure [Line Items]
Measurement Dates	12/31/2014	12/31/2013
Fair Value Of Plan Assets
Defined Benefit Plan Disclosure [Line Items]
Measurement Dates	12/31/2014	12/31/2013

The date(s) used to measure (at least the majority of) plan assets and benefit obligations for defined benefit pension and other postretirement benefit plans. Disclosure required by FAS 132R paragraph 5k prior to being amended by FAS 158.

No definition available.

Name:	us-gaap_DefinedBenefitPlanMeasurementDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration