v3.26.1
BORROWINGS (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Debt Instrument [Line Items]    
Repurchase Agreements $ 263,429 $ 254,780
Total short-term borrowings 513,429 581,780
Long-term borrowings 1,000  
Junior Subordinated Debt | Subsidiary One    
Debt Instrument [Line Items]    
Long-term Debt 36,083 36,083
Junior Subordinated Debt | Subsidiary Two    
Debt Instrument [Line Items]    
Long-term Debt 8,248 8,248
Junior Subordinated Debt | Subsidiary Three    
Debt Instrument [Line Items]    
Long-term Debt 8,630 8,592
Junior Subordinated Debt | Subsidiary Four    
Debt Instrument [Line Items]    
Long-term Debt 8,629 8,592
Subordinated Debt and Junior Subordinated Debt    
Debt Instrument [Line Items]    
Long-term Debt 61,590 61,515
FHLBB and Correspondent Bank Overnight Borrowings    
Debt Instrument [Line Items]    
Long-term borrowings 1,000 1,000
Short-term Debt [Member]    
Debt Instrument [Line Items]    
Total short-term borrowings 513,429 581,780
Short-term Debt [Member] | Customer Repurchase Agreements    
Debt Instrument [Line Items]    
Repurchase Agreements 263,429 254,780
Short-term Debt [Member] | FHLBB and Correspondent Bank Overnight Borrowings    
Debt Instrument [Line Items]    
FHLBB and Correspondent Bank Overnight Borrowings $ 250,000 $ 327,000