Note 8 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 364	$ 340	$ 315
Age Attained to be Eligible for ESOP	21 years
Employee Stock Ownership Plan (ESOP), Cash Contributions to ESOP	$ 300	200	150
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	192,250
Age of Employees Required to Diversify Allocated ESOP Shares	55 years
Years of Plan Participation Required to Diversify Allocated ESOP Shares	10 years
Percentage of Allocated ESOP Shares That Can be Diversified	50.00%
Accrued Expenses for Salary Continuation Plan	$ 255	$ 272	$ 242
Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	65.00%
Fixed Income Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	35.00%
Hedge Funds [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%