Note 15 - Shares Outstanding and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted average basic shares outstanding (in shares)	11,416	11,420	11,415	11,488	11,444	11,444	11,435	11,418	11,509	11,432	11,381
Assumed exercise of stock options and issuance of stock awards (in shares)										8
Weighted average diluted shares outstanding (in shares)	11,416	11,420	11,415	11,488	11,444	11,446	11,435	11,418	11,509	11,440	11,381
Net income	$ (890)	$ 591	$ 2,081	$ 2,074	$ (1,316)	$ 11,599	$ 15,848	$ 7,629	$ 3,856	$ 33,759	$ 18,963
Basic earnings per share (in dollars per share)	$ (0.08)	$ 0.05	$ 0.18	$ 0.18	$ (0.11)	$ 1.01	$ 1.39	$ 0.67	$ 0.34	$ 2.95	$ 1.67
Diluted earnings per share (in dollars per share)	$ (0.08)	$ 0.05	$ 0.18	$ 0.18	$ (0.11)	$ 1.01	$ 1.39	$ 0.67	$ 0.34	$ 2.95	$ 1.67
Unvested RSUs (in shares)									216	91	65