Securities (Schedule Of Carrying Value Of Securities Pledged As Collateral) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Sep. 30, 2021
Marketable Securities [Line Items]
AFS Securities	$ 1,694,160	$ 2,014,608
Asset Pledged as Collateral [Member]
Marketable Securities [Line Items]
AFS Securities	193,969	395,848
Asset Pledged as Collateral [Member] | Public unit deposits [Member]
Marketable Securities [Line Items]
AFS Securities	123,889	264,885
Asset Pledged as Collateral [Member] | FRB of Kansas City [Member]
Marketable Securities [Line Items]
AFS Securities	52,394	64,707
Asset Pledged as Collateral [Member] | Commercial deposits [Member]
Marketable Securities [Line Items]
AFS Securities	$ 17,686	$ 66,256