Revenue from Contracts with Customers (Disaggregation of Revenue) (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
Net interest income		$ 31,994	$ 32,978	$ 33,858	$ 34,584	$ 33,878	$ 33,449	$ 33,111	$ 31,852	$ 133,414	[1]	$ 132,290	[1]	$ 119,531	[1]
Asset-based wealth management revenues	[1]									35,806		37,343		38,125
Transaction-based wealth management revenues	[1]									1,042		998		1,221
Total wealth management revenues	[1]									36,848		38,341		39,346
Mortgage banking revenues	[1]									14,795		10,381		11,392
Card interchange fees	[1]									4,214		3,768		3,502
Service charges on deposit accounts	[1]									3,684		3,628		3,672
Loan related derivative income	[1]									3,993		2,461		3,214
Income from bank-owned life insurance	[1]									2,354		2,196		2,161
Net realized losses on securities	[1]									(53)		0		0
Other income	[1]									1,245		1,339		1,522
Total noninterest income		$ 16,618	$ 18,342	$ 16,753	$ 15,367	$ 15,163	$ 15,215	$ 15,993	$ 15,743	67,080	[1]	62,114	[1]	64,809	[1]
Total revenues	[1]									200,494		194,404		184,340
Revenues from contracts with customers										45,930		47,066		47,989
Net Interest Income [Member]
Revenues from contracts with customers	[2]									0		0		0
Asset-based Wealth Management Revenues [Member]
Revenues from contracts with customers	[2]									35,806		37,343		38,125
Transaction-based Wealth Management Revenues [Member]
Revenues from contracts with customers	[2]									1,042		998		1,221
Investment Advisory, Management and Administrative Service [Member]
Revenues from contracts with customers	[2]									36,848		38,341		39,346
Mortgage Banking [Member]
Revenues from contracts with customers	[2]									0		0		0
Card Interchange Fees [Member]
Revenues from contracts with customers	[2]									4,214		3,768		3,502
Deposit Account [Member]
Revenues from contracts with customers	[2]									3,684		3,628		3,672
Loan Related Derivative Income [Member]
Revenues from contracts with customers	[2]									0		0		0
Income From Bank-owned Life Insurance [Member]
Revenues from contracts with customers	[2]									0		0		0
Net Realized Gain (Loss) on Securities [Member]
Revenues from contracts with customers	[2]									0		0		0
Other Noninterest Income [Member]
Revenues from contracts with customers	[2]									1,184		1,329		1,469
Total noninterest income in scope of Topic 606 [Member]
Revenues from contracts with customers	[2]									45,930		47,066		47,989
Total revenues in scope of Topic 606 [Member]
Revenues from contracts with customers	[2]									$ 45,930		$ 47,066		$ 47,989

[1] As reported in the Consolidated Statements of Income.

[2] Revenue from contracts with customers in scope of ASC 606.