Note 7 - Income Tax (Details Textual) - USD ($)			3 Months Ended								12 Months Ended
	Dec. 17, 2018	Sep. 14, 2018	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Total			$ 504,446	$ 394,468	$ 284,000						$ 1,182,914
Income Taxes Paid											970,000
Deferred Taxes, Business Combination, Valuation Allowance, Available to Reduce Income Tax Expense											174,737
Deferred Tax Assets, Gross, Total			36,695								36,695
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Income Taxes Paid	$ 540,000	$ 430,000
Accrued Income Taxes, Total			$ 212,914								$ 212,914