Premises and Equipment (Equipment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Total cost	$ 54,077	$ 49,902
Accumulated depreciation and amortization	(26,018)	(25,789)
Premises and equipment, net	28,059	24,113
Depreciation and amortization	2,500	2,300	2,300
Land and land improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	3,310	2,567
Buildings and leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	31,195	30,552
Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 19,572	$ 16,783