Loans, Allowance for Credit Losses and Credit Quality - Finance Receivable, Nonaccrual (Details) - USD ($)		Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance	[1]	$ 53,196,000	$ 51,809,000
Financing Receivable, Nonaccrual, No Allowance	[1]	3,016,000	3,072,000
Financing Receivable, Nonaccrual	[1]	56,212,000	54,881,000
TDRs on nonaccrual			11,520,000
Commercial And Industrial [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		26,045,000	26,395,000
Financing Receivable, Nonaccrual, No Allowance		298,000	298,000
Financing Receivable, Nonaccrual		26,343,000	26,693,000
Commercial Real Estate [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		15,324,000	12,961,000
Financing Receivable, Nonaccrual, No Allowance		2,714,000	2,769,000
Financing Receivable, Nonaccrual		18,038,000	15,730,000
Small Business [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		238,000	99,000
Financing Receivable, Nonaccrual, No Allowance		4,000	5,000
Financing Receivable, Nonaccrual		242,000	104,000
Residential Real Estate [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		8,178,000	8,479,000
Financing Receivable, Nonaccrual, No Allowance		0
Financing Receivable, Nonaccrual		8,178,000	8,479,000
Home Equity Loan [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		3,282,000	3,400,000
Financing Receivable, Nonaccrual, No Allowance		0	0
Financing Receivable, Nonaccrual		3,282,000	3,400,000
Consumer - Other [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		129,000	475,000
Financing Receivable, Nonaccrual, No Allowance		0	0
Financing Receivable, Nonaccrual		$ 129,000	$ 475,000

[1] included $11.5 million of nonaccruing troubled debt restructures ("TDRs").