Segment Information (Segment Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net Interest Income	$ 33,641		$ 27,469		$ 67,232	$ 53,079
Net Gains on Sales of Loans	1,030		905		2,011	1,555
Net Gains on Securities	516		74		671	344
Trust and Investment Product Fees	1,913		1,677		3,480	3,450
Insurance Revenues	1,929		1,696		5,134	4,626
Noncash Items:
Provision for Loan Losses	250		1,220		925	1,570
Depreciation and Amortization	2,063		1,402		4,073	2,601
Income Tax Expense (Benefit)	3,011		2,326		5,759	4,810
Segment Profit (Loss)	15,271	$ 15,067	11,097	$ 11,813	30,338	22,910
Segment Assets	3,970,739				3,970,739		$ 3,929,090
Operating Segments | Core Banking
Segment Reporting Information [Line Items]
Net Interest Income	34,182		27,672		68,317	53,462
Net Gains on Sales of Loans	1,030		905		2,011	1,555
Net Gains on Securities	516		74		671	344
Trust and Investment Product Fees	1		0		2	2
Insurance Revenues	4		5		7	6
Noncash Items:
Provision for Loan Losses	250		1,220		925	1,570
Depreciation and Amortization	1,976		1,316		3,903	2,431
Income Tax Expense (Benefit)	3,437		2,487		6,092	4,731
Segment Profit (Loss)	15,068		11,478		29,567	22,240
Segment Assets	3,944,736				3,944,736		3,926,242
Operating Segments | Trust and Investment Advisory Services
Segment Reporting Information [Line Items]
Net Interest Income	4		(1)		6	2
Net Gains on Sales of Loans	0		0		0	0
Net Gains on Securities	0		0		0	0
Trust and Investment Product Fees	1,912		1,677		3,478	3,448
Insurance Revenues	4		2		25	4
Noncash Items:
Provision for Loan Losses	0		0		0	0
Depreciation and Amortization	2		1		3	2
Income Tax Expense (Benefit)	128		96		204	232
Segment Profit (Loss)	372		269		587	654
Segment Assets	3,324				3,324		2,658
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Net Interest Income	4		3		9	5
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	1,921		1,689		5,102	4,616
Noncash Items:
Provision for Loan Losses	0		0		0	0
Depreciation and Amortization	21		21		39	40
Income Tax Expense (Benefit)	50		13		407	334
Segment Profit (Loss)	147		30		1,237	969
Segment Assets	8,784				8,784		11,368
Other
Segment Reporting Information [Line Items]
Net Interest Income	(549)		(205)		(1,100)	(390)
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	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)	(604)		(270)		(944)	(487)
Segment Profit (Loss)	(316)		$ (680)		(1,053)	$ (953)
Segment Assets	$ 13,895				$ 13,895		$ (11,178)