Loans, Allowance for Credit Losses and Credit Quality - Financing Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2025		Mar. 31, 2024		Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 169,984		$ 142,222		$ 142,222
Allowance for Loan and Lease Losses, Write-offs	(41,400)		(881)		(10,347)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	508		607
Ending balance	144,092	[1]	146,948	[1]	169,984
Provision for Loan and Lease Losses	15,000		5,000
Accounts Receivable, Noncurrent, Accrued Interest, Writeoff	344		385
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,800		33,317		33,317
Allowance for Loan and Lease Losses, Write-offs	(55)		0		(5,897)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	2		85
Ending balance	34,200	[1]	35,175	[1]	27,800
Provision for Loan and Lease Losses	6,453		1,773
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	92,535		60,074		60,074
Allowance for Loan and Lease Losses, Write-offs	(39,996)		0		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0		0
Ending balance	60,117	[1]	63,243	[1]	92,535
Provision for Loan and Lease Losses	7,578		3,169
Construction Loans [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	8,166		7,683		7,683
Allowance for Loan and Lease Losses, Write-offs	0		0		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0		0
Ending balance	8,377	[1]	7,573	[1]	8,166
Provision for Loan and Lease Losses	211		(110)
Small Business [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4,182		3,963		3,963
Allowance for Loan and Lease Losses, Write-offs	(112)		(109)		(696)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	13		39
Ending balance	4,318	[1]	4,028	[1]	4,182
Provision for Loan and Lease Losses	235		135
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	25,238		23,637		23,637
Allowance for Loan and Lease Losses, Write-offs	0		0		0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0		0
Ending balance	25,469	[1]	24,180	[1]	25,238
Provision for Loan and Lease Losses	231		543
Home Equity Loan [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	11,007		12,797		12,797
Allowance for Loan and Lease Losses, Write-offs	(96)		0		(380)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	18		133
Ending balance	10,846	[1]	12,042	[1]	11,007
Provision for Loan and Lease Losses	(83)		(888)
Consumer - Other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,056		751		751
Allowance for Loan and Lease Losses, Write-offs	(1,141)		(772)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	475		350
Ending balance	765	[1]	707	[1]	$ 1,056
Provision for Loan and Lease Losses	$ 375		$ 378

[1] Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $53.7 million and $59.3 million as of March 31, 2025 and March 31, 2024, respectively.