Investment Securities - Amortized Cost and Fair Value of Held-to-Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 19,707	$ 15,902
Gross Unrealized Gains	539	872
Gross Unrealized Losses	709
Fair Value	19,537	16,774
Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	11,965	14,819
Gross Unrealized Gains	525	856
Gross Unrealized Losses
Fair Value	12,490	15,675
States & Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,742	1,083
Gross Unrealized Gains	14	16
Gross Unrealized Losses	709
Fair Value	$ 7,047	$ 1,099

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

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- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

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