Note 6 - Dividends (Details Textual) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2016
Paid Quarterly [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025	$ 0.025
Line Of Credit Facility Dividend Restrictions Percentage Of Net Income Limit							25.00%