Pension and Postretirement Benefits - Additional Information (Detail) (USD $)	9 Months Ended
Sep. 30, 2014
Pension and Other Postretirement Benefits Disclosure [Line Items]
Estimated contributions to the pension plans in calendar-year 2014	$ 25,500,000
Estimated contributions to the pension plans in the quarter ending December 31, 2014	$ 1,380,000

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2709-114920

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