Commitments And Contingent Liabilities (Narrative) (Details) $ in Thousands	6 Months Ended
	Mar. 31, 2020 USD ($)
Unfunded Commitments, Equity Lines of Credit Including Suspended Accounts
Unfunded And Commitments To Originate [Line Items]
Unfunded commitments on home equity lines of credit (including commitments for suspended accounts)	$ 2,397,219
Minimum
Unfunded And Commitments To Originate [Line Items]
Fixed expiration of commitments to extend credit (in days)	60 days
Home equity line of credit unfunded commitments expiration, years	5 years
Maximum
Unfunded And Commitments To Originate [Line Items]
Fixed expiration of commitments to extend credit (in days)	360 days
Home equity line of credit unfunded commitments expiration, years	10 years