EARNINGS PER SHARE - Earnings Per Share Computations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
EARNINGS PER SHARE
Net income	$ 22,983	$ 17,299
Weighted-average common shares outstanding	25,457,659	25,622,988
Basic earnings per common share	$ 0.90	$ 0.68
Diluted earnings per common share:
Net income	$ 22,983	$ 17,299
BASIC WEIGHTED AVERAGE COMMON SHARES	25,457,659	25,622,988
Add: Dilutive effect of assumed exercises of stock options and awards	92,452	112,838
Average shares and dilutive potential common shares	25,550,111	25,735,826
Diluted earnings per common share	$ 0.90	$ 0.67