INCOME TAXES (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed statutory federal income tax provision	$ 20,055	$ 21,904	$ 18,364
State taxes, net of federal tax benefit	2,553	3,101	2,598
Nontaxable interest, net	(542)	(661)	(564)
Tax credits	(6,567)	(6,238)	(6,932)
Increase in cash surrender value of life insurance and tax exempt gain on death proceeds	(1,612)	(1,109)	(1,117)
Merger and other related costs (non-deductible)	404	0	0
Other, net	382	151	(122)
Total expense	$ 14,673	$ 17,148	$ 12,227
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Computed statutory federal income tax provision	35.00%	35.00%	35.00%
State taxes, net of federal tax benefit	4.46%	4.95%	4.95%
Nontaxable interest, net	(0.95%)	(1.06%)	(1.07%)
Tax credits	(11.46%)	(9.97%)	(13.21%)
Increase in cash surrender value of life insurance and tax exempt gain on death proceeds	(2.81%)	(1.77%)	(2.13%)
Merger and other related costs (non-deductible)	0.71%	0.00%	0.00%
Other, net	0.66%	0.25%	(0.24%)
Total expense	25.61%	27.40%	23.30%

Effective Income Tax Rate Reconciliation, Merger and Other Related Costs

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Income Tax Reconciliation, Merger and Other Related Costs

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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.

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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 the effective income tax rate and domestic federal statutory income tax rate attributable to nondeductible life insurance premiums under enacted tax laws.

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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 portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense or benefit, net of the federal tax benefit (expense) thereon, recorded during the period.

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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 pretax Income or Loss from continuing operations; income tax expense or benefit may include interest and penalties on tax uncertainties based on the entity's accounting policy.

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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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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 nondeductible life insurance premiums under enacted tax laws.

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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, that is attributable to state and local income tax expense or benefit.

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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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