Note 8 - Fair Values - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial assets
Securities available-for-sale	$ 239,633	$ 267,954
Reported Value Measurement [Member]
Financial assets
Cash and cash equivalents	91,236	66,970
Securities available-for-sale	239,633	267,954
Net loans	916,845	869,620
Federal Home Loan Bank of San Francisco stock	5,892	4,536
Financial liabilities
Deposits	1,144,761	1,102,732
Term debt	14,293	16,958
Junior subordinated debenture	10,310	10,310
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and cash equivalents	91,236	66,970
Securities available-for-sale
Net loans
Federal Home Loan Bank of San Francisco stock	5,892	4,536
Financial liabilities
Deposits
Term debt
Junior subordinated debenture
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and cash equivalents
Securities available-for-sale	239,633	267,954
Net loans
Federal Home Loan Bank of San Francisco stock
Financial liabilities
Deposits	1,142,046	1,101,523
Term debt	14,285	16,918
Junior subordinated debenture	10,254	10,206
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and cash equivalents
Securities available-for-sale
Net loans	910,262	873,660
Federal Home Loan Bank of San Francisco stock
Financial liabilities
Deposits
Term debt
Junior subordinated debenture

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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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.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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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.

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

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

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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
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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