Unrealized Holding Gains and Losses and Fair Value of Available for Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Net unrealized holding losses included in other comprehensive income	$ (4)
Net gains (losses) reclassified from accumulated other comprehensive income (loss) into earnings

Net of tax amount of the income statement impact of the reclassification adjustment for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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+ Details

- Definition

Net of tax amount of unrealized holding gain (loss) before reclassification adjustments and transfers on available-for-sale securities.

+ References

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

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-Name Accounting Research Bulletin (ARB)

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+ Details