Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Net interest income		$ 32,243	$ 31,654	$ 30,945	$ 32,602	$ 31,994	$ 32,978	$ 33,858	$ 34,584	$ 127,444	[1]	$ 133,414	[1]	$ 132,290	[1]
Asset-based wealth management revenues	[1]									34,363		35,806		37,343
Transaction-based wealth management revenues	[1]									1,091		1,042		998
Total wealth management revenues	[1]									35,454		36,848		38,341
Mortgage banking revenues	[1]									47,377		14,795		10,381
Card interchange fees	[1]									4,287		4,214		3,768
Service charges on deposit accounts	[1]									2,742		3,684		3,628
Loan related derivative income	[1]									3,991		3,993		2,461
Income from bank-owned life insurance	[1]									2,491		2,354		2,196
Net realized losses on securities	[1]									0		(53)		0
Other income	[1]									3,100		1,245		1,339
Total noninterest income		$ 27,727	$ 25,468	$ 26,320	$ 19,927	$ 16,618	$ 18,342	$ 16,753	$ 15,367	99,442	[1]	67,080	[1]	62,114	[1]
Total revenues	[1]									226,886		200,494		194,404
Revenues from contracts with customers										45,152		45,930		47,066
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]									34,363		35,806		37,343
Transaction-based Wealth Management Revenues [Member]
Revenues from contracts with customers	[2]									1,091		1,042		998
Investment Advisory, Management and Administrative Service [Member]
Revenues from contracts with customers	[2]									35,454		36,848		38,341
Mortgage Banking [Member]
Revenues from contracts with customers	[2]									0		0		0
Card Interchange Fees [Member]
Revenues from contracts with customers	[2]									4,287		4,214		3,768
Deposit Account [Member]
Revenues from contracts with customers	[2]									2,742		3,684		3,628
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]									2,669		1,184		1,329
Total noninterest income in scope of Topic 606 [Member]
Revenues from contracts with customers	[2]									45,152		45,930		47,066
Total revenues in scope of Topic 606 [Member]
Revenues from contracts with customers	[2]									$ 45,152		$ 45,930		$ 47,066

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

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