Loans Receivable And Allowance For Loan Losses: Past Due Status of Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2023		Sep. 30, 2022
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		$ 1,229,650		$ 1,150,450
Loans receivable, Non-Accrual	[1]	1,969		2,059
Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		216,639		176,116
Loans receivable, Non-Accrual	[1]	378		388
Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		103,870		95,025
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		547,876		536,650
Loans receivable, Non-Accrual	[1]	694		657
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		71,750		67,091
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		7,785		8,364
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		23,145		29,059
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		50,758		34,354
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		14,250		13,582
Loans receivable, Non-Accrual	[1]	0		0
Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		24,520		26,854
Loans receivable, Non-Accrual	[1]	362		450
Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		36,896		35,187
Loans receivable, Non-Accrual	[1]	241		252
Consumer loans, other
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		2,283		2,128
Loans receivable, Non-Accrual	[1]	1		3
Commercial business loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		129,306		125,039
Loans receivable, Non-Accrual		293	[1]	309
SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		572		1,001
Loans receivable, Non-Accrual		0		0	[1]
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		222		37
30 to 59 Days Past Due | Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		28		37
30 to 59 Days Past Due | Consumer loans, other
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
30 to 59 Days Past Due | Commercial business loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		194		0
30 to 59 Days Past Due | SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Consumer loans, other
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | Commercial business loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
60 to 89 Days Past Due | SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Past Due 90 Days or More and Still Accruing
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Consumer loans, other
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | Commercial business loans
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Past Due 90 Days or More and Still Accruing | SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Still Accruing		0		0
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		2,191		2,096
Financial Asset, Past Due | Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		378		388
Financial Asset, Past Due | Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		694		657
Financial Asset, Past Due | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Past Due | Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		362		450
Financial Asset, Past Due | Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		269		289
Financial Asset, Past Due | Consumer loans, other
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		1		3
Financial Asset, Past Due | Commercial business loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		487		309
Financial Asset, Past Due | SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		0		0
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		1,227,459		1,148,354
Financial Asset, Not Past Due | Mortgage loans, one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		216,261		175,728
Financial Asset, Not Past Due | Mortgage loans, multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		103,870		95,025
Financial Asset, Not Past Due | Mortgage loans, commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		547,182		535,993
Financial Asset, Not Past Due | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		71,750		67,091
Financial Asset, Not Past Due | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		7,785		8,364
Financial Asset, Not Past Due | Mortgage loans, construction – commercial
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		23,145		29,059
Financial Asset, Not Past Due | Mortgage loans, construction - Multi-family
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		50,758		34,354
Financial Asset, Not Past Due | Mortgage loans, construction - Land development
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		14,250		13,582
Financial Asset, Not Past Due | Mortgage loans, land
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		24,158		26,404
Financial Asset, Not Past Due | Consumer loans, home equity and second mortgage
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		36,627		34,898
Financial Asset, Not Past Due | Consumer loans, other
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		2,282		2,125
Financial Asset, Not Past Due | Commercial business loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		128,819		124,730
Financial Asset, Not Past Due | SBA PPP Loans
Financing Receivable, Past Due [Line Items]
Loans receivable, Total Past Due		$ 572		$ 1,001

[1] Includes non-accrual loans past due 90 days or more and other loans classified as non-accrual.