Note 10 - Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax provision computed at federal statutory rate									$ (1,018)	$ 2,143	$ 2,095
State income tax, net of federal benefit									(260)	(340)
Tax exempt interest									(425)	(430)	(573)
Deferred tax only items										199
Effect of change in tax rate											7,661
Deferred tax asset valuation allowance adjustment											(12,214)
Other									353	6	112
Total provision (benefit) for income taxes	$ (1,031)	$ (516)	$ 105	$ 92	$ 54	$ 622	$ 530	$ 372	$ (1,350)	$ 1,578	$ (2,919)