Note 12 - Shares Outstanding and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Weighted average basic shares outstanding (in shares)	11,444	11,386	11,427	11,384
Assumed issuance related to stock awards (in shares)	2
Weighted average diluted shares outstanding (in shares)	11,446	11,386	11,427	11,384
Net income	$ 11,599	$ 2,280	$ 35,076	$ 14,776
Basic earnings per share (in dollars per share)	$ 1.01	$ 0.20	$ 3.07	$ 1.30
Diluted earnings per share (in dollars per share)	$ 1.01	$ 0.20	$ 3.07	$ 1.30
Anti-dilutive securities outstanding (in shares)	91	65	91	65