Revenue From Contracts with Customers (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income		$ 42,429	$ 42,645	$ 42,635	$ 41,523	$ 41,377	$ 40,423	$ 38,990	$ 37,272	$ 169,232	[1]	$ 158,062	[1]	$ 143,176	[1]
Insurance commission and fee income										16,571		15,658		14,788
Bank owned life insurance income	[1]									3,179		3,174		3,988
Net gain on sales of investment securities	[1]									54		10		48
Net gain on mortgage banking activities	[1]									3,946		3,125		4,023
Other income	[2]									2,619		262		746
Noninterest income		$ 16,170	$ 16,599	$ 16,356	$ 16,297	$ 14,416	$ 14,861	$ 15,314	$ 15,582	65,422		60,173		59,240
Trust fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										7,826		7,882		8,055
Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										5,946		5,632		5,482
Investment advisory commission and fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										15,940		15,098		13,454
Other service fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income	[2]									9,341		9,332		8,656
Banking [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	[1]									174,202		163,042		148,180
Insurance commission and fee income										0		0		0
Bank owned life insurance income	[1]									2,849		3,284		3,616
Net gain on sales of investment securities	[1]									54		10		45
Net gain on mortgage banking activities	[1]									3,946		3,125		4,023
Other income	[2]									2,539		417		745
Noninterest income										23,748		20,815		21,838
Banking [Member] | Trust fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Banking [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										5,946		5,632		5,482
Banking [Member] | Investment advisory commission and fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Banking [Member] | Other service fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income	[2]									8,414		8,347		7,927
Wealth Management [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	[1]									41		32		8
Insurance commission and fee income										0		0		0
Bank owned life insurance income	[1]									0		0		0
Net gain on sales of investment securities	[1]									0		0		0
Net gain on mortgage banking activities	[1]									0		0		0
Other income	[2]									0		0		0
Noninterest income										23,946		23,179		21,707
Wealth Management [Member] | Trust fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										7,826		7,882		8,055
Wealth Management [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Wealth Management [Member] | Investment advisory commission and fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										15,940		15,098		13,454
Wealth Management [Member] | Other service fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income	[2]									180		199		198
Insurance [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	[1]									0		0		0
Insurance commission and fee income										16,571		15,658		14,788
Bank owned life insurance income	[1]									0		0		0
Net gain on sales of investment securities	[1]									0		0		0
Net gain on mortgage banking activities	[1]									0		0		0
Other income	[2]									0		(2)		1
Noninterest income										17,318		16,442		15,320
Insurance [Member] | Trust fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Insurance [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Insurance [Member] | Investment advisory commission and fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Insurance [Member] | Other service fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income	[2]									747		786		531
Other Segments [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	[1]									(5,011)		(5,012)		(5,012)
Insurance commission and fee income										0		0		0
Bank owned life insurance income	[1]									330		(110)		372
Net gain on sales of investment securities	[1]									0		0		3
Net gain on mortgage banking activities	[1]									0		0		0
Other income	[2]									80		(153)		0
Noninterest income										410		(263)		375
Other Segments [Member] | Trust fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Other Segments [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Other Segments [Member] | Investment advisory commission and fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income										0		0		0
Other Segments [Member] | Other service fee income
Segment Reporting, Revenue Reconciling Item [Line Items]
Noninterest income	[2]									$ 0		$ 0		$ 0

[1] Net interest income as well as many other revenues for financial assets and liabilities including loans, leases, securities, and derivatives are excluded from the scope of FASB ASC 606 "Revenue from Contracts with Customers" (FASB ASC 606). Noninterest income streams that are out of scope of FASB ASC 606 include bank owned life insurance income, sales of investment securities and mortgage banking activities.

[2] Other service fee income and other income include certain items that are in scope and certain items that are out of scope of FASB ASC 606 are described further in the following paragraphs.