Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2025

Commitments and Contingencies Disclosure [Abstract]

Schedule of Financial Instruments with Off-balance Sheet Risk

Financial instruments with off-balance-sheet risk at the dates indicated follow:

	At December 31,
	2025		2024
	(In Thousands)
Financial instruments whose contract amounts represent credit risk:
Commitments to originate loans and leases:
Commercial real estate	$	99,457	$	11,126
Commercial	137,923		144,721
Residential mortgage	23,115		14,607
Home equity	9,022		—
Unadvanced portion of loans and leases	2,483,239		1,076,783
Unused lines of credit:
Home equity	1,175,702		780,214
Other consumer	148,358		113,838
Other commercial	—		398
Unused letters of credit:
Financial standby letters of credit	10,440		12,702
Performance standby letters of credit	25,025		24,325
Commercial and similar letters of credit	58,074		2,330
Interest rate derivatives (notional amounts)	192,468		225,000
Loan level derivatives (notional amounts):
Receive fixed, pay variable	3,505,840		1,672,948
Pay fixed, receive variable	3,505,840		1,672,948
Risk participation-out agreements	670,834		539,731
Risk participation-in agreements	153,185		102,198
Foreign exchange contracts (notional amounts):
Buys foreign currency, sells U.S. currency	2,785		5,849
Sells foreign currency, buys U.S. currency	2,800		5,408

Schedule of Lease Cost, Supplemental Cash Flow and Supplemental Balance Sheet Information

	At December 31, 2025			At December 31, 2024			At December 31, 2023
	(In Thousands)
The components of lease expense were as follow:
Operating lease cost	$	11,293		$	8,983		$	8,527
Supplemental cash flow information related to leases was as follows:
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	12,294		$	9,044		$	8,901
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases assets	$	46,186		$	18,093		$	15,073
Operating leases liabilities	$	53,127		$	18,093		$	16,672
Supplemental balance sheet information related to leases was as follows:
Operating Leases
Operating lease right-of-use assets	$	82,817		$	43,527		$	30,863
Operating lease liabilities	90,713			44,785			31,998
Weighted Average Remaining Lease Term
Operating leases	7.95 years			8.90			8.87
Weighted Average Discount Rate
Operating leases	4.2		%	4.1		%	4.0		%

Schedule of Maturities of Operating Leases

A summary of future minimum rental payments under such leases at the dates indicated follows:

Year ended December 31,	Minimum Rental Payments
	(In Thousands)
2026	$	18,702
2027	17,372
2028	14,712
2029	11,741
2030	9,166
Thereafter	34,280
Total	$	105,973
Less imputed interest	(15,260)
	$	90,713