Note 13 - Federal and State Income Taxes (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized tax benefits that would impact effective tax rate		$ 1,000,000
Unrecognized tax benefits, interest on income taxes accrued	$ 150,000	$ 205,000	$ 150,000
Effective income tax rate		21.00%	35.00%	35.00%
Re-measurement of deferred tax asset to incorporate newly enacted tax rates	$ (2,900,000)		$ 2,918,606
Domestic Tax Authority [Member]
Deferred tax assets, operating loss carryforwards, subject to expiration		$ 4,000,000
State and Local Jurisdiction [Member]
Deferred tax assets, operating loss carryforwards, subject to expiration		$ 2,100,000