Note 12 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 41,026	$ 12,066	$ 16,975
Weighted average shares outstanding - basic (in shares)	15,075,134	14,945,165	14,937,786
Dilutive common stock equivalents (in shares)	433,286	321,243	534,347
Weighted average number of shares outstanding during the period, diluted (in shares)	15,508,420	15,266,408	15,472,133
Basic (in dollars per share)	$ 2.72	$ 0.81	$ 1.14
Diluted (in dollars per share)	$ 2.65	$ 0.79	$ 1.10