Securities (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Marketable Securities [Abstract]
Gain on sale of Visa Class B shares	$ 0	$ 7,386	$ 0
Proceeds from the sale of Visa Class B shares	$ 0	$ 7,386	$ 0

Amount of cash inflow from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as investing activity.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 19
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3444-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=123583714&loc=SL75117360-209713

Name:	us-gaap_ProceedsFromSaleOfEquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration