Note 10 - Federal Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Allowance for loan losses	$ 7,973,000	$ 5,017,000
Deferred compensation	511,000	577,000
Stock compensation	541,000	720,000
Nonaccrual loan interest income	211,000	239,000
Deferred loan fees	924,000	104,000
Deferred Tax Assets, Capital Loss Carryforwards	0	94,000
Fair value write-downs on foreclosed properties	537,000	26,000
Other	938,000	683,000
Deferred tax asset before valuation allowance	11,635,000	7,460,000
Valuation allowance	0	(94,000)
Deferred tax asset after valuation allowance	11,635,000	7,366,000
Depreciation	1,175,000	1,743,000
Prepaid expenses	297,000	269,000
Core deposit intangible	498,000	787,000
Mortgage loan servicing rights	1,720,000	977,000
Unrealized gain on securities	1,458,000	982,000
Business combination adjustments	2,142,000	2,058,000
Other	521,000	485,000
Deferred tax liability	7,811,000	7,301,000
Total net deferred tax asset	$ 3,824,000	$ 65,000