v3.26.1
Securities (Narrative) (Details) - USD ($)
$ in Thousands
6 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Sep. 30, 2025
Marketable Securities [Line Items]      
AFS securities $ 809,566   $ 867,216
Non-taxable securities 0 $ 0  
Residential MBS [Member]      
Marketable Securities [Line Items]      
AFS securities 734,800   793,800
Commercial MBS [Member]      
Marketable Securities [Line Items]      
AFS securities $ 70,900   $ 69,700