Income Tax (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Currently Payable:
Federal	$ (906)	$ 818
State
Deferred:
Federal	5,574	4,682
State
Total Income Tax Expense	4,668	5,500
Reconciliation of Federal Statutory to Actual Tax Expense:
Federal statutory income tax at 35%	5,787	6,955
Tax-exempt interest income	(897)	(931)
Stock compensation	11	16
Earnings on life insurance	(245)	(483)
Tax credits	(18)	(18)
Other	30	(39)
Total Income Tax Expense	$ 4,668	$ 5,500
Federal statutory income tax rate	35.00%	35.00%

The component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted federal tax law to the domestic taxable Income or Loss from continuing operations.

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The component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted state and local tax law to relevant amounts of taxable Income or Loss from continuing operations.

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The component of total income tax expense for the period comprised of the increase (decrease) in the entity's state and local deferred tax assets and liabilities attributable to continuing operations as determined by applying the provisions of the applicable enacted tax laws.

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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.

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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 other deductions received under enacted tax laws not otherwise listed in the existing taxonomy.

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