Note 9 - Fair Value Accounting and Measurement - Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Total investment securities, estimated fair value	$ 369,111	$ 315,580
Accrued interest receivable	7,367	3,931
Reported Value Measurement [Member]
Cash and cash equivalents	16,776	48,739
Total investment securities, estimated fair value	369,111	315,580
Loans held for sale	4,754	503
Loans receivable, net	1,061,417	878,437
FHLB stock	5,944	6,034
Accrued interest receivable	7,367	3,931
Mortgage servicing rights, net	1,545	871
Borrowings	109,150	112,930
Accrued interest payable	51	373
Reported Value Measurement [Member] \| Demand Deposits [Member]
Demand deposits	960,916	693,565
Reported Value Measurement [Member] \| Time Deposits [Member]
Demand deposits	293,540	308,080
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	16,776	48,739
Total investment securities, estimated fair value	369,111	315,580
Loans held for sale	4,754	503
Loans receivable, net		858,101
FHLB stock	5,944	6,034
Accrued interest receivable	7,367	3,931
Mortgage servicing rights, net	1,710	1,486
Borrowings		113,076
Accrued interest payable	51	373
Estimate of Fair Value Measurement [Member] \| Demand Deposits [Member]
Demand deposits	960,916	693,565
Estimate of Fair Value Measurement [Member] \| Time Deposits [Member]
Demand deposits		308,819
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	16,776	48,739
Total investment securities, estimated fair value		0
Loans held for sale		0
Loans receivable, net		0
FHLB stock		0
Accrued interest receivable		0
Mortgage servicing rights, net		0
Borrowings		0
Accrued interest payable		0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member] \| Demand Deposits [Member]
Demand deposits	960,916	693,565
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member] \| Time Deposits [Member]
Demand deposits		0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents		0
Total investment securities, estimated fair value	369,111	315,580
Loans held for sale	4,754	503
Loans receivable, net		0
FHLB stock	5,944	6,034
Accrued interest receivable	7,367	3,931
Mortgage servicing rights, net		0
Borrowings		113,076
Accrued interest payable	51	373
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member] \| Demand Deposits [Member]
Demand deposits		0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member] \| Time Deposits [Member]
Demand deposits		308,819
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents		0
Total investment securities, estimated fair value		0
Loans held for sale		0
Loans receivable, net		858,101
FHLB stock		0
Accrued interest receivable		0
Mortgage servicing rights, net	$ 1,710	1,486
Borrowings		0
Accrued interest payable		0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Demand Deposits [Member]
Demand deposits		0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Time Deposits [Member]
Demand deposits		$ 0

The fair value portion of interest payable.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
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-Publisher FASB
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-Section 45
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-Publisher FASB
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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

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- Definition

Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

+ References

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-Publisher FASB
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- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

No definition available.

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/subtopic&trid=2196772

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

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-Publisher FASB
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