Note 10 - Other Benefit Plans (Details Textual) - USD ($)		12 Months Ended
	Feb. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan, Cost		$ 347,000	$ 200,000	$ 189,000
Defined Benefit Plan Vesting Period			10 years
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total		77,000	$ 121,000	121,000
Liability, Other Postretirement Defined Benefit Plan		1,300,000	1,300,000
Bank Owned Life Insurance		15,646,000	15,229,000
Earning on Bank Owned Life Insurance		$ 437,000	$ 412,000	$ 417,000
Subsequent Event [Member]
Defined Benefit Plan, Termination Expense	$ 0
Matched Contribution Equal to 100 of First 1% [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent		100.00%
Matched Contribution Equal to 50 of Next 5% [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent		50.00%
Matched Contribution Equal to 50% of First 4% [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent			50.00%	50.00%