NOTE 6 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share
Net income	$ 12,918	$ 10,550
Basic earnings per common share (in dollars per share)	$ 0.82	$ 0.76
Diluted earnings per common share (in dollars per share)	$ 0.81	$ 0.74
Weighted average common shares outstanding (in shares)	15,693,345	13,888,661
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan** (in shares)	229,595	316,923
Weighted average common and common equivalent shares outstanding (in shares)	15,922,940	14,205,584