Note 9 - Cash Dividends (Details Textual) - USD ($)	1 Months Ended	6 Months Ended
	Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Payments of Dividends, Total		$ 2,587,000	$ 2,564,000
Dividends Accrued		$ 34,631	$ 38,463
Subsequent Event [Member]
Quarterly Indicated Per Share Dividend Rate	$ 0.05
Annual Indicated per Share Dividend Rate	$ 0.20
Dividends Payable, Date to be Paid	Feb. 12, 2019
Dividends Payable, Date of Record	Feb. 04, 2019