Investment Securities - Summary of Gross Realized Gains and Losses on Calls and Sales of Held to Maturity Securities Included in Earnings (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Amortized Cost And Fair Value Debt Securities [Abstract]
Gross realized gains	$ 114	$ 352	$ 1
Gross realized losses	$ 0	$ 0	$ 0

Gross realized losses on calls and sales of held to maturity securities included in earnings as a result of those calls and sales.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration