Segment Information (Segment Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Interest Income	$ 27,469	$ 24,813	$ 53,079	$ 49,538
Net Gains on Sales of Loans	905	959	1,555	1,646
Net Gains on Securities	74	0	344	0
Trust and Investment Product Fees	1,677	1,350	3,450	2,593
Insurance Revenues	1,696	1,744	4,626	4,384
Noncash Items:
Provision for Loan Losses	1,220	350	1,570	850
Depreciation and Amortization	1,402	1,190	2,601	2,317
Income Tax Expense (Benefit)	2,326	3,425	4,810	7,246
Segment Profit (Loss)	11,097	9,839	22,910	19,395
Segment Assets	3,344,544		3,344,544		$ 3,144,360
Operating Segments | Core Banking
Segment Reporting Information [Line Items]
Net Interest Income	27,672	24,999	53,462	49,908
Net Gains on Sales of Loans	905	959	1,555	1,646
Net Gains on Securities	74	0	344	0
Trust and Investment Product Fees	0	1	2	2
Insurance Revenues	5	12	6	14
Noncash Items:
Provision for Loan Losses	1,220	350	1,570	850
Depreciation and Amortization	1,316	1,103	2,431	2,144
Income Tax Expense (Benefit)	2,487	3,615	4,731	7,237
Segment Profit (Loss)	11,478	9,791	22,240	18,756
Segment Assets	3,346,765		3,346,765		3,142,096
Operating Segments | Trust and Investment Advisory Services
Segment Reporting Information [Line Items]
Net Interest Income	(1)	1	2	2
Net Gains on Sales of Loans	0	0	0	0
Net Gains on Securities	0	0	0	0
Trust and Investment Product Fees	1,677	1,350	3,448	2,594
Insurance Revenues	2	8	4	13
Noncash Items:
Provision for Loan Losses	0	0	0	0
Depreciation and Amortization	1	4	2	7
Income Tax Expense (Benefit)	96	49	232	83
Segment Profit (Loss)	269	66	654	110
Segment Assets	1,886		1,886		1,987
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Net Interest Income	3	2	5	4
Net Gains on Sales of Loans	0	0	0	0
Net Gains on Securities	0	0	0	0
Trust and Investment Product Fees	0	0	0	0
Insurance Revenues	1,689	1,724	4,616	4,357
Noncash Items:
Provision for Loan Losses	0	0	0	0
Depreciation and Amortization	21	19	40	38
Income Tax Expense (Benefit)	13	48	334	475
Segment Profit (Loss)	30	74	969	747
Segment Assets	11,013		11,013		10,078
Other
Segment Reporting Information [Line Items]
Net Interest Income	(205)	(189)	(390)	(376)
Net Gains on Sales of Loans	0	0	0	0
Net Gains on Securities	0	0	0	0
Trust and Investment Product Fees	0	(1)	0	(3)
Insurance Revenues	0	0	0	0
Noncash Items:
Provision for Loan Losses	0	0	0	0
Depreciation and Amortization	64	64	128	128
Income Tax Expense (Benefit)	(270)	(287)	(487)	(549)
Segment Profit (Loss)	(680)	$ (92)	(953)	$ (218)
Segment Assets	$ (15,120)		$ (15,120)		$ (9,801)