NOTE 6 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share
Net income	$ 13,504	$ 12,918	$ 10,445	$ 10,550	$ 26,422	$ 20,995
Basic earnings per common share (in dollars per share)	$ 0.86		$ 0.75		$ 1.68	$ 1.51
Diluted earnings per common share (in dollars per share)	$ 0.85		$ 0.73		$ 1.66	$ 1.48
Weighted average common shares outstanding (in shares)	15,714,588		13,919,565		15,703,967	13,904,113
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan** (in shares)	223,789		312,858		226,692	314,890
Weighted average common and common equivalent shares outstanding (in shares)	15,938,377		14,232,423		15,930,659	14,219,003