Loans - Troubled Debt Restructuring Removed from Classification (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013 Contract	Mar. 31, 2012 Contract
Financing Receivable Modifications Number Of Contracts [Line Items]
Carrying balance	$ 5,842	$ 2,222
Count	8	2

Financing Receivable Modifications Number Of Contracts One

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