Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current [Abstract]
Federal	$ 7,941	$ 11,497	$ 12,252
State	4,345	4,357	4,281
Total Current	12,286	15,854	16,533
Deferred [Abstract]
Federal	3,116	(998)	(2,041)
State	(308)	(635)	(507)
Total Deferred	2,808	(1,633)	(2,548)
Total Provision for Taxes	15,094	14,221	13,985
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax Provision at Federal Statutory Rate	14,174	13,399	13,067
Interest on Obligations of States and Political Subdivisions exempt from Federal Taxation	(805)	(894)	(917)
State and Local Income Taxes, Net of Federal Income Tax Benefit	2,624	2,419	2,453
Bank Owned Life Insurance	(696)	(702)	(675)
Low-Income Housing Tax Credit	(126)	(129)	0
Other, Net	(77)	128	57
Total Provision for Taxes	15,094	14,221	13,985
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax Provision at Federal Statutory Rate (in hundredths)	35.00%	35.00%	35.00%
Interest on Obligations of States and Political Subdivisions exempt from Federal Taxation (in hundredths)	(2.00%)	(2.30%)	(2.50%)
State and Local Income Taxes, Net of Federal Income Tax Benefit (in hundredths)	6.50%	6.30%	6.60%
Bank Owned Life Insurance (in hundredths)	(1.70%)	(1.80%)	(1.80%)
Low-Income Housing Tax Credit (in hundredths)	(0.30%)	(0.30%)	0.00%
Other, Net (in hundredths)	(0.20%)	0.30%	0.20%
Total Provision for Taxes (in hundredths)	37.30%	37.10%	37.50%
Deferred Tax Assets [Abstract]
Allowance for Credit Losses	14,944	14,470
Accrued Liabilities	8,184	7,723
Deferred Compensation	10,006	8,859
State Franchise Tax	1,521	1,525
Capital Loss Carry Forward	0	0
Interest on Non-Accrual Loans	2	15
ORE Write down and Holding Costs	1,724	1,713
Unrealized Loss on Securities Available-for-Sale	0	1,790
Low-Income Housing Investments	58	21
Total Deferred Tax Assets	36,439	36,116
Deferred Tax Liabilities [Abstract]
Premises and Equipment	(286)	(213)
Securities Accretion	(298)	(966)
Unrealized Gain on Securities Available-for-Sale	(1,838)	0
Leasing Activities	(7,018)	(1,501)
Other	(786)	(787)
Total Deferred Tax Liabilities	(10,226)	(3,467)
Net Deferred Tax Assets	$ 26,213	$ 32,649