Note 5 - Income Taxes (Details Textual) - USD ($)		3 Months Ended
	Dec. 22, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Expense (Benefit), Total		$ 387,000	$ 374,000
Effective Income Tax Rate Reconciliation, Percent, Total		10.50%	23.30%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%