Note 3 - Loans Receivable - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Past due	$ 2,542	$ 4,019
Current	1,070,314	879,738
Total loans	1,072,856	883,757
Financial Asset, 30 to 59 Days Past Due [Member]
Past due	724	2,688
Financial Asset, 60 to 89 Days Past Due [Member]
Past due	1,113	601
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	705	730
Real Estate Portfolio Segment [Member]
Past due	1,210	1,174
Current	802,708	693,847
Total loans	803,918	695,021
Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	966
Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	685	92
Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	525	116
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member]
Past due	1,185	1,136
Current	316,570	304,878
Total loans	317,755	306,014
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	928
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	685	92
Real Estate Portfolio Segment [Member] | One-to-four Family Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	500	116
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member]
Past due	0	0
Current	127,569	96,098
Total loans	127,569	96,098
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Multi-family Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member]
Past due	0	0
Current	283,390	255,722
Total loans	283,390	255,722
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Past due	25	38
Current	75,179	37,149
Total loans	75,204	37,187
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	38
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	25	0
Consumer Portfolio Segment [Member]
Past due	1,332	2,730
Current	144,570	144,435
Total loans	145,902	147,165
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	724	1,722
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	428	394
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	180	614
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Past due	12	323
Current	34,108	34,723
Total loans	34,120	35,046
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	299
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	12	24
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member]
Past due	1,320	2,407
Current	110,462	109,712
Total loans	111,782	112,119
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	724	1,423
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	416	370
Consumer Portfolio Segment [Member] | Automobile and Other Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	180	614
Commercial Portfolio Segment [Member]
Past due	0	115
Current	123,036	41,456
Total loans	123,036	41,571
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	115
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	$ 0	$ 0