Fair Value of Assets (Liabilities) Not Measured at Fair Value In Consolidated Balance Sheets (Parenthetical) (Detail) (Fixed Rate, USD $)	Dec. 31, 2012	Dec. 31, 2011
Fixed Rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt, carrying value	$ 125,000,000	$ 137,000,000
Long term debt, fair value	$ 127,300,000	$ 135,000,000

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant