Borrowed Funds (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Debt Disclosure [Abstract]
Interest rate swaps, notional amount	$ 365,000		$ 365,000		$ 365,000
FHLB advances, variable rate	365,000		$ 365,000		$ 365,000
Interest rate swaps, remaining term to maturity			2 years 3 months 18 days		3 years 1 month 6 days
Interest rate swaps, fair value	$ 12,400		$ 12,400		$ 12,500
Derivative Asset, balance sheet location	Other assets		Other assets
Interest rate swaps, amount reclassified from AOCI	$ (1,667)	$ 1,301	$ (3,724)	$ 4,797
Interest rate swaps, future amount to be reclassified from AOCI			(8,900)
Interest rate swaps, collateral held	$ (13,100)		$ (13,100)		$ (12,100)