Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Compensation And Retirement Disclosure [Abstract]
Expected contribution for defined benefit plans and other postretirement plans	$ 2.4

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

No definition available.

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