Note 4 - Allowance for Credit Losses on Loans - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022
Balance			$ 15,747,000	$ 16,116,000	[1]	$ 15,124,000
Write-offs	$ (731,000)		(265,000)	(2,668,000)		(475,000)
Recoveries	501,000		41,000	93,000		374,000
Provision for credit losses	880,000		750,000	1,195,000		1,250,000
Balance	16,945,000	[1]	16,273,000	16,945,000	[1]	16,273,000
Recoveries	(501,000)		(41,000)	(93,000)		(374,000)
Allowance for Credit Loss	16,945,000	[1]	16,273,000	16,945,000	[1]	16,273,000		$ 16,116,000	[1]
General reserve								16,084,000
Specific reserve								32,000
Gross loans								1,534,380,000
Loans collectively evaluated (1)								1,531,346,000
Loans individually evaluated (2)	4,100,000		1,500,000	4,100,000		1,500,000	$ 2,700,000	3,034,000
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	17,297,000			18,325,000
Allowance for Credit Loss							17,297,000	18,325,000
Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				2,209,000
Allowance for Credit Loss								2,209,000
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member]
Balance			3,026,000	3,343,000		3,184,000
Write-offs	0		0	0		0
Recoveries	0		0	4,000		32,000
Provision for credit losses	526,000		188,000	620,000		(2,000)
Balance	3,538,000		3,214,000	3,538,000		3,214,000
Recoveries	0		0	(4,000)		(32,000)
Allowance for Credit Loss	3,538,000		3,214,000	3,538,000		3,214,000		3,343,000
General reserve								3,321,000
Specific reserve								22,000
Gross loans								343,825,000
Loans collectively evaluated (1)								341,171,000
Loans individually evaluated (2)								2,654,000
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	3,012,000			2,914,000
Allowance for Credit Loss							3,012,000	2,914,000
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				(429,000)
Allowance for Credit Loss								(429,000)
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member]
Balance			2,168,000	2,468,000		1,816,000
Write-offs	0		0	0		0
Recoveries	0		0	0		0
Provision for credit losses	230,000		164,000	252,000		516,000
Balance	1,271,000		2,332,000	1,271,000		2,332,000
Recoveries	0		0	0		0
Allowance for Credit Loss	1,271,000		2,332,000	1,271,000		2,332,000		2,468,000
General reserve								2,468,000
Specific reserve								0
Gross loans								253,551,000
Loans collectively evaluated (1)								253,551,000
Loans individually evaluated (2)								0
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	1,041,000			1,019,000
Allowance for Credit Loss							1,041,000	1,019,000
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				(1,449,000)
Allowance for Credit Loss								(1,449,000)
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member]
Balance			4,154,000	4,217,000		3,996,000
Write-offs	0		0	0		0
Recoveries	0		0	0		0
Provision for credit losses	(390,000)		(45,000)	(1,079,000)		113,000
Balance	2,534,000		4,109,000	2,534,000		4,109,000
Recoveries	0		0	0		0
Allowance for Credit Loss	2,534,000		4,109,000	2,534,000		4,109,000		4,217,000
General reserve								4,217,000
Specific reserve								0
Gross loans								390,246,000
Loans collectively evaluated (1)								390,196,000
Loans individually evaluated (2)								50,000
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	2,924,000			3,613,000
Allowance for Credit Loss							2,924,000	3,613,000
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				(604,000)
Allowance for Credit Loss								(604,000)
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Balance			2,550,000	2,344,000		2,672,000
Write-offs	0		0	0		0
Recoveries	0		0	0		2,000
Provision for credit losses	(352,000)		(36,000)	(1,716,000)		(160,000)
Balance	2,183,000		2,514,000	2,183,000		2,514,000
Recoveries	0		0	0		(2,000)
Allowance for Credit Loss	2,183,000		2,514,000	2,183,000		2,514,000		2,344,000
General reserve								2,343,000
Specific reserve								1,000
Gross loans								194,646,000
Loans collectively evaluated (1)								194,630,000
Loans individually evaluated (2)								16,000
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	2,535,000			3,899,000
Allowance for Credit Loss							2,535,000	3,899,000
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				1,555,000
Allowance for Credit Loss								1,555,000
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Balance			486,000	549,000		407,000
Write-offs	0		0	(11,000)		0
Recoveries	0		12,000	5,000		29,000
Provision for credit losses	178,000		9,000	414,000		71,000
Balance	1,303,000		507,000	1,303,000		507,000
Recoveries	0		(12,000)	(5,000)		(29,000)
Allowance for Credit Loss	1,303,000		507,000	1,303,000		507,000		549,000
General reserve								545,000
Specific reserve								4,000
Gross loans								52,322,000
Loans collectively evaluated (1)								52,100,000
Loans individually evaluated (2)								222,000
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	1,125,000			895,000
Allowance for Credit Loss							1,125,000	895,000
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				346,000
Allowance for Credit Loss								346,000
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member]
Balance			2,367,000	2,024,000		2,221,000
Write-offs	(731,000)		(265,000)	(2,657,000)		(475,000)
Recoveries	501,000		29,000	84,000		169,000
Provision for credit losses	601,000		428,000	2,332,000		644,000
Balance	4,164,000		2,559,000	4,164,000		2,559,000
Recoveries	(501,000)		(29,000)	(84,000)		(169,000)
Allowance for Credit Loss	4,164,000		2,559,000	4,164,000		2,559,000		2,024,000
General reserve								2,019,000
Specific reserve								5,000
Gross loans								222,794,000
Loans collectively evaluated (1)								222,702,000
Loans individually evaluated (2)								92,000
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	4,795,000			4,405,000
Allowance for Credit Loss							4,795,000	4,405,000
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				2,381,000
Allowance for Credit Loss								2,381,000
Commercial Portfolio Segment [Member]
Balance			680,000	786,000		470,000
Write-offs	0		0	0		0
Recoveries	0		0	0		142,000
Provision for credit losses	87,000		14,000	372,000		82,000
Balance	1,952,000		694,000	1,952,000		694,000
Recoveries	0		0	0		(142,000)
Allowance for Credit Loss	1,952,000		694,000	1,952,000		694,000		786,000
General reserve								786,000
Specific reserve								0
Gross loans								76,996,000
Loans collectively evaluated (1)								76,996,000
Loans individually evaluated (2)								0
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance	1,865,000			1,580,000
Allowance for Credit Loss							$ 1,865,000	1,580,000
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				794,000
Allowance for Credit Loss								794,000
Unallocated Financing Receivables [Member]
Balance			316,000	385,000		358,000
Write-offs			0	0		0
Recoveries			0	0		0
Provision for credit losses			28,000	0		(14,000)
Balance	0		344,000	0		344,000
Recoveries			0	0		0
Allowance for Credit Loss	$ 0		$ 344,000	0		$ 344,000		385,000
General reserve								385,000
Specific reserve								0
Gross loans								0
Loans collectively evaluated (1)								0
Loans individually evaluated (2)								0
Unallocated Financing Receivables [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance				0
Allowance for Credit Loss								0
Unallocated Financing Receivables [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance				$ (385,000)
Allowance for Credit Loss								$ (385,000)

[1] Allowance for credit losses on loans in 2023 reported using the CECL method and in 2022 reported using the incurred loss method.