Note 9 - Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income (loss)		$ 705	$ 2,213	$ (2,202)	$ 10,190
Weighted average shares outstanding (in shares)		10,429,091	10,296,891	10,366,373	10,282,841
Effect of stock options (in shares)	[1]	0	70,769	0	68,574
Weighted average shares outstanding - assuming dilution (in shares)		10,429,091	10,367,660	10,366,373	10,351,415
Net income (loss) per common share:
Basic (in dollars per share)		$ 0.07	$ 0.21	$ (0.21)	$ 0.99
Diluted (in dollars per share)		$ 0.07	$ 0.21	$ (0.21)	$ 0.98
Stock options not considered above because they were anti-dilutive (in shares)	[1]	939,425	511,250	939,425	516,250

[1] For the three months and nine months ended September 30, 2017, potentially dilutive shares from options were excluded from the diluted earnings per share calculations due to the antidilutive effect such shares would have on net loss per common share.