Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) (USD $) In Thousands, unless otherwise specified	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, Amount	$ 19,867	$ 19,814	$ 5,213
Income Tax Reconciliation, Bank Owned Life Insurance Income	(1,939)	(2,048)	(1,959)
Tax-exempt interest income, net, Amount	(2,600)	(2,789)	(3,453)
Tax credits, Amount	(144)	(267)	(270)
Other, Amount	97	(52)	89
Total tax provision (benefit), Amount	$ 15,281	$ 14,658	$ (380)
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax at statutory rate, Pretax Income	35.00%	35.00%	35.00%
Income from bank owned life insurance, Pretax Income	(3.00%)	(4.00%)	(13.00%)
Tax-exempt interest income, net, Pretax Income	(5.00%)	(5.00%)	(23.00%)
Tax credits, Pretax Income	0.00%	0.00%	(2.00%)
Other, Pretax Income	0.00%	0.00%	0.00%
Total tax provision (benefit), Pretax Income	27.00%	26.00%	(3.00%)

Effective Income Tax Rate Reconciliation Bank Owned Life Insurance

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Income Tax Reconciliation, Bank Owned Life Insurance Income

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A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to all other items not otherwise listed in the existing taxonomy.

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The sum of the differences between the effective income tax rate and domestic federal statutory income tax rate that can be explained by all tax credits generated or utilized under enacted tax laws during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to income that is exempt from income taxes under enacted tax laws.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the year/accounting period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to all other items not otherwise listed in the existing taxonomy.

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The sum of the differences between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to tax credits.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to income that is exempt from income taxes under enacted tax laws.

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