XML 59 R48.htm IDEA: XBRL DOCUMENT v3.25.3
INVESTMENTS (Narrative) (Detail) - USD ($)
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Jun. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Schedule of Investments [Line Items]              
Trading securities $ 5,581,000       $ 5,581,000   $ 5,243,000
AFS debt securities, allowance 0       0   0
Net unrealized loss on debt securities, net of tax 36,500,000       36,500,000   62,200,000
Deferred tax assets, unrealized losses on available for sale securities 10,500,000       10,500,000   17,000,000
Provision for credit losses, HTM debt securities 0   $ 1,800,000   0 $ (910,000) 0
HTM debt securities, excluding accrued interest from amortized cost 1,500,000       1,500,000   1,600,000
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Recovery 0 $ 910,000          
Write off, accrued interest, HTM debt securities   $ 910,000          
Asset Pledged as Collateral              
Schedule of Investments [Line Items]              
AFS and HTM debt securities, amortized cost 809,200,000       809,200,000   519,900,000
AFS and HTM debt securities, fair value 762,400,000       762,400,000   449,000,000.0
Available-for-sale Securities              
Schedule of Investments [Line Items]              
Interest receivable 2,500,000       2,500,000   1,700,000
Transferred Securities              
Schedule of Investments [Line Items]              
AFS debt securities transferred to HTM, fair value       $ 520,300,000      
AFS debt securities, transfer, unrealized loss       $ 72,100,000      
Net unrealized loss on debt securities, net of tax (37,900,000)       (37,900,000)   (41,800,000)
Deferred tax assets, unrealized losses on available for sale securities $ 11,000,000       $ 11,000,000   $ 11,400,000