Note 9 - Income Taxes - Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Allowance for loan loss	$ 6,633,000	$ 5,567,000
Deferred compensation	5,758,000	4,703,000
Operating lease liability	3,427,000	0
State net operating loss	2,550,000	2,201,000
Accrued expenses	1,486,000	968,000
Securities	0	756,000
Investments in tax credit partnerships	655,000	543,000
Loans	501,000	434,000
Other assets	228,000	181,000
Write-downs and costs associated with other real estate owned	22,000	7,000
Total deferred tax assets	21,260,000	15,360,000
Property and equipment	1,054,000	1,154,000
Right-of-use operating lease asset	3,154,000	0
Securities	748,000	0
Loan costs	767,000	632,000
Mortgage servicing rights	299,000	193,000
Leases	266,000	336,000
Core deposit intangible	202,000	230,000
Other liabilities	183,000	267,000
Total deferred tax liabilities	6,673,000	2,812,000
Valuation allowance	(121,000)	(2,355,000)
Net deferred tax asset	$ 14,466,000	$ 10,193,000