Investment Securities (Narrative) (Details)	3 Months Ended
	Dec. 31, 2019 USD ($) security	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Schedule of Investments [Line Items]
Available-for-sale Securities Pledged as Collateral		$ 244,763,000	$ 102,959,000
Debt Securities, Available-for-sale, Restriction Type [Extensible List]		http://fasb.org/us-gaap/2021-01-31#CollateralPledgedMember	http://fasb.org/us-gaap/2021-01-31#CollateralPledgedMember
FHLB [Member]
Schedule of Investments [Line Items]
Letter of credit outstanding, amount		$ 450,850,000	$ 288,950,000
ASU 2019-04 [Member]
Schedule of Investments [Line Items]
Debt securities, held-to-maturity with an aggregate amortized cost	$ 67,096,000
Gain (loss) on sale of debt securities	$ 1,779,000
Number of held-to-maturity debt securities | security	113
Number of held-to-maturity debt securities sold | security	113