v3.26.1
SHORT-TERM BORROWINGS AND LONG-TERM DEBT - Narrative (Details)
 1 Months Ended 6 Months Ended
Dec. 31, 2004
USD ($)
Sep. 30, 2004
USD ($)
Jun. 30, 2026
USD ($)
period
Dec. 31, 2025
USD ($)
Debt Instrument [Line Items]        
Long-term debt     $ 76,547,000 $ 76,547,000
Investment securities     $ 1,380,593,000 1,310,603,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]     Secured Overnight Financing Rate (SOFR) [Member]  
Junior subordinated debentures        
Debt Instrument [Line Items]        
Long-term debt     $ 51,547,000 51,547,000
Number of periods interest can be deferred | period     20  
Junior subordinated debentures | Maximum        
Debt Instrument [Line Items]        
Redemption period     90 days  
C P B Capital Trust I V        
Debt Instrument [Line Items]        
Trust preferred securities issued value   $ 30,000,000.0    
Common securities issued to company   $ 900,000    
C P B Capital Trust I V | Junior subordinated debentures        
Debt Instrument [Line Items]        
Long-term debt     $ 30,900,000  
C P B Capital Trust V        
Debt Instrument [Line Items]        
Trust preferred securities issued value $ 20,000,000.0      
Common securities issued to company $ 600,000      
C P B Capital Trust V | Junior subordinated debentures        
Debt Instrument [Line Items]        
Long-term debt     20,600,000  
Federal Home Loan Bank Borrowings        
Debt Instrument [Line Items]        
Line of Credit, maximum borrowing capacity     1,870,000,000 1,800,000,000
Unused borrowings available     1,750,000,000 1,680,000,000
FHLB advances and other short-term borrowings     0 0
Long-term debt     $ 25,000,000.0 $ 25,000,000.0
Long term borrowings, interest rate     4.02% 4.02%
Letters of Credit, outstanding     $ 95,600,000 $ 95,600,000
Federal Home Loan Bank Borrowings | Asset Pledged as Collateral        
Debt Instrument [Line Items]        
Net loans and leases     2,720,000,000 2,760,000,000
Federal Reserve discount window line of credit        
Debt Instrument [Line Items]        
Unused borrowings available     201,500,000 206,400,000
Federal Reserve discount window line of credit | Asset Pledged as Collateral        
Debt Instrument [Line Items]        
Net loans and leases     95,400,000 98,900,000
Investment securities     165,800,000 172,000,000.0
Pacific Coast Bankers' Bank ("PCBB")        
Debt Instrument [Line Items]        
Unused borrowings available     $ 75,000,000.0 $ 75,000,000.0
CPB Capital Trust IV ("Trust IV") | Junior Subordinated Debt        
Debt Instrument [Line Items]        
Basis spread on variable rate   2.45%    
CPB Statutory Trust V ("Trust V") | Junior Subordinated Debt        
Debt Instrument [Line Items]        
Basis spread on variable rate 1.87%      
Trust IV and Trust V | Junior Subordinated Debt        
Debt Instrument [Line Items]        
Basis spread on variable rate     0.26%