Executive Benefit Agreements and Employee Savings Plans - Life Insurance Premiums (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Executive Benefit Agreements and Employee Savings Plans [Line Items]
Cost of life insurance premiums	$ 851	$ 851	$ 851
Increases in cash surrender values	(479)	(499)	(496)
Net cost of life insurance premiums included in SG&A	$ 372	$ 352	$ 355

The change in cash surrender or contract value during the period which adjusted the amount of premiums paid in determining the expense or income recognized under the contract for the period.

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

-Publisher FASB

-Name FASB Technical Bulletin (FTB)

-Number 85-4

-Paragraph 2

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 325

-SubTopic 30

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6384439&loc=d3e42048-111605

Name:	us-gaap_LifeInsuranceCorporateOrBankOwnedChangeInValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration