Note 8 - Business Combination, Goodwill and Other Intangible Assets (Details Textual) - USD ($)		12 Months Ended
	May 10, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 10, 2018	Dec. 31, 2017
Goodwill, Ending Balance		$ 1,107,000	$ 1,107,000	$ 1,728,000		$ 1,728,000
Goodwill, Purchase Accounting Adjustments			(621,000)
Goodwill, Impairment Loss		0
Amortization of Intangible Assets, Total		74,000	75,000	50,000
Impairment of Intangible Assets, Finite-lived		$ 206,000
Core Deposits [Member]
Finite-Lived Intangible Asset, Useful Life (Year)		10 years
Amortization of Intangible Assets, Total		$ 74,000	$ 75,000	50,000
Impairment of Intangible Assets, Finite-lived		$ 206,000
Prime Bank [Member]
Goodwill, Ending Balance	$ 1,100,000			1,700,000	$ 2,100,000
Goodwill, Purchase Accounting Adjustments	$ (621,000)
Business Acquisition, Goodwill, Tax Deductible Period (Year)		15 years
Prime Bank [Member] | Project Expenses [Member]
Goodwill, Purchase Accounting Adjustments		$ 556,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred		$ 556,000
Hana SBL [Member]
Business Combination, Acquisition Related Costs				$ 1,150,000