v3.26.1
Commitments and Contingencies - Schedule of Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Commitments to originate loans and leases:    
Unadvanced portion of loans and leases $ 2,254,538 $ 2,483,239
Unused lines of credit:    
Home equity 1,177,379 1,175,702
Other consumer 176,127 148,358
Other commercial 0 0
Unused letters of credit:    
Financial standby letters of credit 9,971 10,440
Performance standby letters of credit 54,996 25,025
Commercial and similar letters of credit 4,499 58,074
Interest rate derivatives    
Unused letters of credit:    
Notional amount 149,679 192,468
Receive fixed, pay variable    
Unused letters of credit:    
Notional amount 3,500,284 3,505,840
Pay fixed, receive variable    
Unused letters of credit:    
Notional amount 3,504,381 3,505,840
Risk participation-out agreements    
Unused letters of credit:    
Notional amount 681,207 670,834
Risk participation-in agreements    
Unused letters of credit:    
Notional amount 147,069 153,185
Foreign exchange contracts | Buys foreign currency, sells U.S. currency    
Unused letters of credit:    
Notional amount 2,965 2,785
Foreign exchange contracts | Sells foreign currency, buys U.S. currency    
Unused letters of credit:    
Notional amount 2,978 2,800
Commercial real estate    
Commitments to originate loans and leases:    
Commitments to originate loans and leases 222,501 99,457
Commercial    
Commitments to originate loans and leases:    
Commitments to originate loans and leases 136,295 137,923
Residential mortgage    
Commitments to originate loans and leases:    
Commitments to originate loans and leases 7,100 23,115
Home equity    
Commitments to originate loans and leases:    
Commitments to originate loans and leases $ 10,926 $ 9,022