Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total Cost	$ 62,817	$ 60,225
Accumulated Depreciation and Amortization	(35,198)	(33,287)
Net Premises and Equipment	27,619	26,938
Land and Bank Premises [Member]
Property, Plant and Equipment [Line Items]
Total Cost	35,254	35,017
Equipment, Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total Cost	25,662	23,604
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total Cost	$ 1,901	$ 1,604