v3.26.1
LOANS & ALLOWANCE FOR CREDIT LOSSES - NARRATIVE (Details)
12 Months Ended
Dec. 07, 2023
loanPortfolio
Jun. 30, 2026
USD ($)
segment
Jun. 30, 2025
USD ($)
Financing Receivable, Impaired [Line Items]      
Number of loan portfolio segments 2 5  
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]   Other assets Other assets
Accrued interest receivable   $ 135,600,000 $ 109,600,000
Advances, collateral pledged   3,761,600,000 4,284,700,000
FRBSF and FRB, loans pledged   11,115,100,000 8,227,700,000
Nonaccrual loans, without an allowance   0 0
Interest recognized on performing loans temporarily modified as TDRs   0 0
Loans past due ninety days or more and still accruing   0  
Mortgage loans in process of foreclosure, amount   $ 47,100,000 $ 30,400,000
California | Financing Receivable | Geographic Concentration Risk | Single Family - Mortgage & Warehouse      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage   67.30% 70.50%
California | Financing Receivable | Geographic Concentration Risk | Multifamily Loan Category      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage   46.80% 48.50%
New York | Financing Receivable | Geographic Concentration Risk | Single Family - Mortgage & Warehouse      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage     8.60%
New York | Financing Receivable | Geographic Concentration Risk | Multifamily Loan Category      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage   38.60% 37.10%
New York | Financing Receivable | Geographic Concentration Risk | Commercial Real Estate      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage   52.70% 36.80%
Florida | Financing Receivable | Geographic Concentration Risk | Commercial Real Estate      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage     19.50%
Texas | Financing Receivable | Geographic Concentration Risk | Commercial Real Estate      
Financing Receivable, Impaired [Line Items]      
Concentration risk percentage     10.20%