Note 8 - Fair Value Measurements - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Securities available for sale	$ 251,438	$ 271,172
Securities held to maturity		1
Reported Value Measurement [Member]
Cash and cash equivalents	61,886	25,915
Interest-bearing time deposits	7,770	9,258
Securities available for sale	251,438	271,172
Loans held for sale	2,056	2,630
Loans, net	419,360	409,618
FHLB and other stock	1,988	1,979
Accrued interest receivable	2,676	2,694
Deposits	701,836	664,562
Accrued interest payable	113	107
Securities held to maturity		1
FHLB advances		10,000
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	61,886	25,915
Interest-bearing time deposits	7,686	9,220
Securities available for sale	251,438	271,172
Loans held for sale	2,104	2,678
Loans, net	411,787	404,931
Accrued interest receivable	2,676	2,694
Deposits	699,878	663,006
Accrued interest payable	113	107
Securities held to maturity		1
FHLB advances		10,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	61,886	25,915
Interest-bearing time deposits
Securities available for sale
Loans held for sale
Loans, net
Accrued interest receivable
Deposits
Accrued interest payable
Securities held to maturity
FHLB advances
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Interest-bearing time deposits	7,686	9,220
Securities available for sale	251,438	271,172
Loans held for sale	2,104	2,678
Loans, net
Accrued interest receivable	2,676	2,694
Deposits
Accrued interest payable	113	107
Securities held to maturity		1
FHLB advances		10,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Interest-bearing time deposits
Securities available for sale
Loans held for sale
Loans, net	411,787	404,931
Accrued interest receivable
Deposits	699,878	663,006
Accrued interest payable
Securities held to maturity
FHLB advances

Represents the fair value of accrued interest receivable.

No definition available.

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- Definition

Represents the fair value of interest payable.

+ References

No definition available.

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- Definition

Fair value portion of interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

+ References

No definition available.

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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 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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

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