Loans Receivable And Allowance For Credit Losses (Allowance For Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	$ 31,196	$ 8,619	$ 9,226	$ 8,463
Charge-offs	(5)	(61)	(428)	(129)
Recoveries	24	28	117	252
Provision for credit losses	0	450	22,300	450
Ending Balance	31,215	9,036	31,215	9,036
One- to Four-Family Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	10,379	4,367	3,890	5,739
Charge-offs	0	(45)	(64)	(101)
Recoveries	0	3	3	114
Provision for credit losses	(338)	(272)	6,212	(1,699)
Ending Balance	10,041	4,053	10,041	4,053
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	6,467	2,173	2,000	2,953
Charge-offs	0	(45)	(64)	(75)
Recoveries	0	3	3	8
Provision for credit losses	(121)	(95)	4,407	(850)
Ending Balance	6,346	2,036	6,346	2,036
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	3,355	1,392	1,203	1,861
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	(166)	(117)	1,986	(586)
Ending Balance	3,189	1,275	3,189	1,275
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	557	802	687	925
Charge-offs	0	0	0	(26)
Recoveries	0	0	0	106
Provision for credit losses	(51)	(60)	(181)	(263)
Ending Balance	506	742	506	742
Commercial Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	20,328	4,088	5,171	2,556
Charge-offs	0	0	(349)	0
Recoveries	17	17	98	44
Provision for credit losses	359	727	15,784	2,232
Ending Balance	20,704	4,832	20,704	4,832
Consumer Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Beginning Balance	489	164	165	168
Charge-offs	(5)	(16)	(15)	(28)
Recoveries	7	8	16	94
Provision for credit losses	(21)	(5)	304	(83)
Ending Balance	$ 470	$ 151	$ 470	$ 151