Loans Receivable and Allowance For Credit Losses (Modifications on Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 712	$ 10,146
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.01%	0.13%
Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	623	623
Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	89	9,523
One- to Four-Family Segment [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 682	$ 9,468
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.01%	0.15%
One- to Four-Family Segment [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
One- to Four-Family Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	623	623
One- to Four-Family Segment [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	59	8,845
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 682	$ 7,737
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.02%	0.19%
One- to Four-Family Segment [Member] | Originated [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
One- to Four-Family Segment [Member] | Originated [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Originated [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	623	623
One- to Four-Family Segment [Member] | Originated [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	59	7,114
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 1,731
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.08%
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	1,731
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 30	$ 678
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.05%
Commercial Segment [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	30	678
Commercial Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 192
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.01%
Commercial Segment [Member] | Commercial Real Estate [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Segment [Member] | Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial Real Estate [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial Real Estate [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial Real Estate [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	192
Commercial Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 30	$ 486
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.02%	0.37%
Commercial Segment [Member] | Commercial and Industrial [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Commercial Segment [Member] | Commercial and Industrial [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial and Industrial [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Commercial Segment [Member] | Commercial and Industrial [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	30	486
Consumer Segment [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Consumer Segment [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Home Equity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Consumer Segment [Member] | Home Equity [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Segment [Member] | Home Equity [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Home Equity [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Home Equity [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Other [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Consumer Segment [Member] | Other [Member] | Principal Forgiveness [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Consumer Segment [Member] | Other [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Other [Member] | Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Other [Member] | Extended Maturity [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	0
Consumer Segment [Member] | Other [Member] | Combination Extended Maturity and Payment Deferral [Member]
Financing Receivable, Modified [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0