v3.26.3
SHORT-TERM BORROWINGS AND LONG-TERM DEBT - Subordinated Debentures (Details) - Junior Subordinated Debt - USD ($)
$ in Thousands
6 Months Ended 9 Months Ended
Jun. 30, 2026
Sep. 30, 2026
Dec. 31, 2025
Debt Instrument [Line Items]      
Subordinated Debentures   $ 51,547 $ 51,547
CPB Capital Trust IV ("Trust IV")      
Debt Instrument [Line Items]      
Subordinated Debentures   $ 30,928 30,928
CPB Capital Trust IV ("Trust IV") | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate      
Debt Instrument [Line Items]      
Interest Rate and Maturity Date 0.26% 0.26%  
CPB Capital Trust IV ("Trust IV") | Tenor Spread Adjustment      
Debt Instrument [Line Items]      
Interest Rate and Maturity Date 2.45% 2.45%  
CPB Statutory Trust V ("Trust V")      
Debt Instrument [Line Items]      
Subordinated Debentures   $ 20,619 $ 20,619
CPB Statutory Trust V ("Trust V") | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate      
Debt Instrument [Line Items]      
Interest Rate and Maturity Date 0.26% 0.26%  
CPB Statutory Trust V ("Trust V") | Tenor Spread Adjustment      
Debt Instrument [Line Items]      
Interest Rate and Maturity Date 1.87% 1.87%