Segment Information (Segment Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Interest Income	$ 25,610	$ 24,725
Net Gains on Sales of Loans	650	687
Net Gains on Securities	270	0
Trust and Investment Product Fees	1,773	1,243
Insurance Revenues	2,930	2,640
Noncash Items:
Provision for Loan Losses	350	500
Depreciation and Amortization	1,199	1,127
Income Tax Expense (Benefit)	2,484	3,821
Segment Profit (Loss)	11,813	9,556
Segment Assets	3,125,018		$ 3,144,360
Operating Segments | Core Banking
Segment Reporting Information [Line Items]
Net Interest Income	25,790	24,909
Net Gains on Sales of Loans	650	687
Net Gains on Securities	270	0
Trust and Investment Product Fees	2	1
Insurance Revenues	1	2
Noncash Items:
Provision for Loan Losses	350	500
Depreciation and Amortization	1,115	1,041
Income Tax Expense (Benefit)	2,244	3,622
Segment Profit (Loss)	10,762	8,965
Segment Assets	3,126,137		3,142,096
Operating Segments | Trust and Investment Advisory Services
Segment Reporting Information [Line Items]
Net Interest Income	3	1
Net Gains on Sales of Loans	0	0
Net Gains on Securities	0	0
Trust and Investment Product Fees	1,771	1,244
Insurance Revenues	2	5
Noncash Items:
Provision for Loan Losses	0	0
Depreciation and Amortization	1	3
Income Tax Expense (Benefit)	136	34
Segment Profit (Loss)	385	44
Segment Assets	2,461		1,987
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Net Interest Income	2	2
Net Gains on Sales of Loans	0	0
Net Gains on Securities	0	0
Trust and Investment Product Fees	0	0
Insurance Revenues	2,927	2,633
Noncash Items:
Provision for Loan Losses	0	0
Depreciation and Amortization	19	19
Income Tax Expense (Benefit)	321	427
Segment Profit (Loss)	939	673
Segment Assets	11,165		10,078
Other
Segment Reporting Information [Line Items]
Net Interest Income	(185)	(187)
Net Gains on Sales of Loans	0	0
Net Gains on Securities	0	0
Trust and Investment Product Fees	0	(2)
Insurance Revenues	0	0
Noncash Items:
Provision for Loan Losses	0	0
Depreciation and Amortization	64	64
Income Tax Expense (Benefit)	(217)	(262)
Segment Profit (Loss)	(273)	$ (126)
Segment Assets	$ (14,745)		$ (9,801)