Loans, Allowance for Credit Losses and Credit Quality - Financing Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		$ 142,222	$ 152,419
Allowance for Loan and Lease Losses, Write-offs		(881)	(815)
Recoveries			277
Provision for credit losses		5,000	7,250
Ending balance	[1]	146,948	159,131
Allowance for Loan and Lease Loss, Recovery of Bad Debts		607
Provision for Loan and Lease Losses		5,000
Accounts Receivable, Noncurrent, Accrued Interest, Writeoff		385	80
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		19,243	27,559
Allowance for Loan and Lease Losses, Write-offs		0	(281)
Recoveries			5
Provision for credit losses			9,649
Ending balance	[1]	20,489	36,932
Allowance for Loan and Lease Loss, Recovery of Bad Debts		85
Provision for Loan and Lease Losses		1,161
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		74,148	77,799
Allowance for Loan and Lease Losses, Write-offs		0	0
Recoveries			0
Provision for credit losses			(1,601)
Ending balance	[1]	77,929	76,198
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		3,781
Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		7,683	10,762
Allowance for Loan and Lease Losses, Write-offs		0	0
Recoveries			0
Provision for credit losses			(1,514)
Ending balance	[1]	7,573	9,248
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		(110)
Small Business [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		3,963	2,834
Allowance for Loan and Lease Losses, Write-offs		(109)	(28)
Recoveries			31
Provision for credit losses			501
Ending balance	[1]	4,028	3,338
Allowance for Loan and Lease Loss, Recovery of Bad Debts		39
Provision for Loan and Lease Losses		135
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		23,637	20,973
Allowance for Loan and Lease Losses, Write-offs		0	0
Recoveries			0
Provision for credit losses			(519)
Ending balance	[1]	24,180	20,454
Allowance for Loan and Lease Loss, Recovery of Bad Debts		0
Provision for Loan and Lease Losses		543
Home Equity Loan [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		12,797	11,504
Allowance for Loan and Lease Losses, Write-offs		0	0
Recoveries			16
Provision for credit losses			908
Ending balance	[1]	12,042	12,428
Allowance for Loan and Lease Loss, Recovery of Bad Debts		133
Provision for Loan and Lease Losses		(888)
Consumer - Other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		751	988
Allowance for Loan and Lease Losses, Write-offs		(772)	(506)
Recoveries			225
Provision for credit losses			(174)
Ending balance	[1]	707	$ 533
Allowance for Loan and Lease Loss, Recovery of Bad Debts		350
Provision for Loan and Lease Losses		$ 378

[1] Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $59.3 million and $52.7 million as of March 31, 2024 and March 31, 2023, respectively.