Note 8 - Income Tax (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			$ 9,300,000
Deferred Tax Assets, Valuation Allowance, Total	$ 0
Effective Income Tax Rate Reconciliation, Percent, Total	23.50%	22.50%	(184.50%)
Alternative Minimum Tax [Member]
Tax Credit Carryforward, Amount	$ 0	$ 0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	0	0
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	$ 0	$ 43,000