Retirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Cost (Detail) (Net Periodic Cost [Member])	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Periodic Cost [Member]
Net Periodic Benefit Cost Assumptions [Line Items]
Discount rate	3.31%	4.22%	4.71%
Health care cost trend: Initial	7.00%	8.00%	9.00%
Health care cost trend: Ultimate	4.75%	4.75%	4.75%
Year ultimate reached	2022	2016	2016
Corridor	10.00%	10.00%	10.00%
Recognition period for gains and losses	11 years	12 years	12 years 8 months 12 days

The interest rate used to adjust for the time value of money.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration