Loans Receivable And Allowance For Credit Losses (Allowance For Credit Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	$ 19,823
Beginning Balance		$ 31,527	$ 9,226
Charge-offs	70	715
Charge-offs			443
Recoveries	256	237
Recoveries			444
Provision for credit losses	(3,638)	(6,465)
Provision for credit losses	(4,630)	(8,510)	22,300
Ending Balance	16,371	19,823
Ending Balance			31,527
Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(4,761)
Ending Balance			(4,761)
Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		26,766
Ending Balance			26,766
One- to Four-Family Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	3,978
Beginning Balance		9,243	3,890
Charge-offs	9	185
Charge-offs			64
Recoveries	138	144
Recoveries			306
Provision for credit losses	899	(841)
Provision for credit losses			5,111
Ending Balance	5,006	3,978
Ending Balance			9,243
One- to Four-Family Segment [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(4,383)
Ending Balance			(4,383)
One- to Four-Family Segment [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		4,860
Ending Balance			4,860
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	1,612
Beginning Balance		6,085	2,000
Charge-offs	9	164
Charge-offs			64
Recoveries	138	144
Recoveries			41
Provision for credit losses	325	(1)
Provision for credit losses			4,108
Ending Balance	2,066	1,612
Ending Balance			6,085
One- to Four-Family Segment [Member] | Originated [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(4,452)
Ending Balance			(4,452)
One- to Four-Family Segment [Member] | Originated [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		1,633
Ending Balance			1,633
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	2,062
Beginning Balance		2,691	1,203
Charge-offs	0	0
Charge-offs			0
Recoveries	0	0
Recoveries			0
Provision for credit losses	672	(262)
Provision for credit losses			1,488
Ending Balance	2,734	2,062
Ending Balance			2,691
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(367)
Ending Balance			(367)
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		2,324
Ending Balance			2,324
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	304
Beginning Balance		467	687
Charge-offs	0	21
Charge-offs			0
Recoveries	0	0
Recoveries			265
Provision for credit losses	(98)	(578)
Provision for credit losses			(485)
Ending Balance	206	304
Ending Balance			467
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		436
Ending Balance			436
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		903
Ending Balance			903
Commercial Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	15,652
Beginning Balance		21,800	5,171
Charge-offs	40	515
Charge-offs			349
Recoveries	101	50
Recoveries			110
Provision for credit losses	(4,593)	(5,490)
Provision for credit losses			16,868
Ending Balance	11,120	15,652
Ending Balance			21,800
Commercial Segment [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(193)
Ending Balance			(193)
Commercial Segment [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		21,607
Ending Balance			21,607
Consumer Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	193
Beginning Balance		484	165
Charge-offs	21	15
Charge-offs			30
Recoveries	17	43
Recoveries			28
Provision for credit losses	56	(134)
Provision for credit losses			321
Ending Balance	$ 245	193
Ending Balance			484
Consumer Segment [Member] | Adoption of CECL [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		(185)
Ending Balance			(185)
Consumer Segment [Member] | Balance at October 1, 2020 [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance		$ 299
Ending Balance			$ 299