Income Taxes Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Computed Tax Expense at Statutory Rate	$ 11,144	$ 11,076	$ 11,076
Tax-Exempt Income	(2,132)	(2,199)	(2,236)
Nondeductible Interest Expense	95	152	176
State Taxes, Net of Federal Income Tax Benefit	814	788	723
Other Items, Net	(260)	(103)	15
Income Tax Expense (Benefit), Continuing Operations	$ 9,661	$ 9,714	$ 9,754