Note 16 - Shares Outstanding and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Weighted average basic shares outstanding (in shares)	11,573	11,551	11,492
Assumed exercise of stock options and issuance of stock awards (in shares)	5	8	11
Weighted average diluted shares outstanding (in shares)	11,578	11,559	11,503
Net income	$ 44,529	$ 90,931	$ 121,051
Basic earnings per share (in dollars per share)	$ 3.85	$ 7.87	$ 10.53
Diluted earnings per share (in dollars per share)	$ 3.85	$ 7.87	$ 10.52
Unvested RSUs and PSUs (in shares)	207	194	206