Note 12 - Fair Value Measurements and Fair Values of Financial Instruments - Assets Measured at Fair Value (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Total, fair value	$ 342,416,000	$ 346,723,000
Marketable equity security	994,000	979,000
Unpaid principal - with allowance	6,709,000	3,375,000
Valuation allowance	(2,227,000)	(1,051,000)
Impaired loans, net	6,709,000	3,375,000
US Government Agencies Debt Securities [Member]
Total, fair value	16,408,000	17,000,000
Obligations of States and Political Subdivisions Tax Exempt [Member]
Total, fair value	81,072,000	70,760,000
Obligations of States and Political Subdivisions Taxable [Member]
Total, fair value	37,074,000	36,303,000
Residential Pass-Through Securities [Member]
Total, fair value	55,752,000	59,210,000
Residential Collateralized Mortgage Obligations [Member]
Total, fair value	103,556,000	114,723,000
Commercial Mortgage Backed Securities [Member]
Total, fair value	48,554,000	48,727,000
Fair Value, Recurring [Member]
Total, fair value	342,416,000	346,723,000
Marketable equity security	994,000	979,000
Servicing rights	1,226,000	1,277,000
Total asset fair value measurements	344,636,000	348,979,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Marketable equity security	994,000	979,000
Servicing rights	0	0
Total asset fair value measurements	994,000	979,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	342,416,000	346,723,000
Marketable equity security	0	0
Servicing rights	0	0
Total asset fair value measurements	342,416,000	346,723,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Marketable equity security	0	0
Servicing rights	1,226,000	1,277,000
Total asset fair value measurements	1,226,000	1,277,000
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member]
Total, fair value	16,408,000	17,000,000
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	16,408,000	17,000,000
Fair Value, Recurring [Member] \| US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Tax Exempt [Member]
Total, fair value	81,072,000	70,760,000
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Tax Exempt [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Tax Exempt [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	81,072,000	70,760,000
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Tax Exempt [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Taxable [Member]
Total, fair value	37,074,000	36,303,000
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Taxable [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Taxable [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	37,074,000	36,303,000
Fair Value, Recurring [Member] \| Obligations of States and Political Subdivisions Taxable [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Residential Pass-Through Securities [Member]
Total, fair value	55,752,000	59,210,000
Fair Value, Recurring [Member] \| Residential Pass-Through Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Residential Pass-Through Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	55,752,000	59,210,000
Fair Value, Recurring [Member] \| Residential Pass-Through Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Residential Collateralized Mortgage Obligations [Member]
Total, fair value	103,556,000	114,723,000
Fair Value, Recurring [Member] \| Residential Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Residential Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	103,556,000	114,723,000
Fair Value, Recurring [Member] \| Residential Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member]
Total, fair value	48,554,000	48,727,000
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Total, fair value	0	0
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Total, fair value	48,554,000	48,727,000
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Total, fair value	0	0
Fair Value, Nonrecurring [Member]
Total asset fair value measurements	6,167,000	5,210,000
Unpaid principal - with allowance	6,709,000	3,375,000
Valuation allowance	(2,227,000)	(1,051,000)
Impaired loans, net	4,482,000	2,324,000
Foreclosed assets held for sale	1,685,000	2,886,000
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total asset fair value measurements	0	0
Unpaid principal - with allowance	0	0
Valuation allowance	0	0
Impaired loans, net	0	0
Foreclosed assets held for sale	0	0
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Total asset fair value measurements	0	0
Unpaid principal - with allowance	0	0
Valuation allowance	0	0
Impaired loans, net	0	0
Foreclosed assets held for sale	0	0
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Total asset fair value measurements	6,167,000	5,210,000
Unpaid principal - with allowance	6,709,000	3,375,000
Valuation allowance	(2,227,000)	(1,051,000)
Impaired loans, net	4,482,000	2,324,000
Foreclosed assets held for sale	$ 1,685,000	$ 2,886,000

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of allowance for credit losses related to recorded investment.

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Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

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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.

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