Note 4 - Qualified Affordable Housing Project Investment (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Investment Amortization	$ 96,000	$ 82,000	$ 265,000	$ 247,000
Tax Credits and Other Tax Benefits	123,000	$ 98,000	371,000	$ 295,000
Other Assets [Member]
Investments, Total	3,300,000		3,300,000		$ 3,600,000
Other Liabilities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 2,200,000		$ 2,200,000		$ 2,900,000