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Federal Income Taxes - Reconciliation of Differences between Federal Income Tax Expense (Benefit) Recorded and Amount Computed by Applying Federal Statutory Rate to Income Before Income Taxes (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Tax at statutory rate (35%)	$ 8,794,000	$ 6,360,000	$ 3,543,000
Increase (decrease) from Tax-exempt interest	(347,000)	(486,000)	(595,000)
Bank owned life insurance	(465,000)	(535,000)	(622,000)
Change in valuation allowance	0	0	(29,640,000)
Other	110,000	297,000	(47,000)
Tax expense (benefit)	$ 8,092,000	$ 5,636,000	$ (27,361,000)

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Amount of the difference between reported income tax expense (benefit) and expected tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from bank owned life insurance that is exempt from income taxes.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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