Loans - Troubled Debt Restructuring Removed from Classification (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012 Contract	Dec. 31, 2011 Contract
Financing Receivable, Modifications [Line Items]
Carrying balance	$ 6,018	$ 1,152
Count	19	2

Financing Receivable Modifications Number Of Contracts One

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