Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current [Abstract]
Federal	$ 12,252	$ 10,168	$ 10,115
State	4,281	3,734	3,931
Total Current	16,533	13,902	14,046
Deferred [Abstract]
Federal	(2,041)	(685)	(1,323)
State	(507)	(575)	(554)
Total Deferred	(2,548)	(1,260)	(1,877)
Total Provision for Taxes, Amount	13,985	12,642	12,169
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax Provision at Federal Statutory Rate, Amount	13,067	12,198	11,650
Tax Provision at Federal Statutory Rate, Rate (in hundredths)	35.00%	35.00%	35.00%
Interest on Obligations of States and Political Subdivisions Exempt from Federal Taxation, Amount	(917)	(884)	(943)
Interest on Obligations of States and Political Subdivisions Exempt from Federal Taxation, Rate (in hundredths)	(2.50%)	(2.50%)	(2.80%)
State and Local Income Taxes, Net of Federal Income Tax Benefit, Amount	2,453	2,053	2,195
State and Local Income Taxes, Net of Federal Income Tax Benefit, Rate (in hundredths)	6.60%	5.90%	6.60%
Bank Owned Life Insurance, Amount	(675)	(663)	(664)
Bank Owned Life Insurance, Rate (in hundredths)	(1.80%)	(1.90%)	(2.00%)
Other, Net, Amount	57	(62)	(69)
Other, Net, Rate (in hundredths)	0.20%	(0.20%)	(0.20%)
Total Provision for Taxes, Amount	13,985	12,642	12,169
Total Provision for Taxes, Rate (in hundredths)	37.50%	36.30%	36.60%
Deferred Tax Assets [Abstract]
Allowance for Loan Losses	14,446	13,942
Accrued Liabilities	6,283	5,766
Deferred Compensation	7,015	5,712
State Franchise Tax	1,498	1,307
Capital Loss Carry Forward	210	210
Interest on Non-Accrual Loans	96	162
ORE Write down and Holding Costs	1,852	1,841
Total Deferred Tax Assets	31,400	28,940
Deferred Tax Liabilities [Abstract]
Premises and Equipment	(415)	(639)
Securities Accretion	(996)	(875)
Unrealized Gain on Securities Available-for-Sale	(5,078)	(3,386)
Other	(763)	(748)
Total Deferred Tax Liabilities	(7,252)	(5,648)
Deferred Tax Assets, Net, Total	$ 24,148	$ 23,292