EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
EARNINGS PER SHARE [Abstract]
Weighted-average anti-dilutive stock options outstanding (in shares)	200,000	500,000
Basic earnings per share [Abstract]
Net income	$ 40,134	$ 41,946
Income attributable to unvested stock-based compensation awards	(146)	(109)
Income available to common shareholders	$ 39,988	$ 41,837
Weighted-average common shares outstanding - basic (in shares)	52,036,000	51,520,000
Basic earnings per share (in dollars per share)	$ 0.77	$ 0.81
Diluted earnings per share [Abstract]
Net income	$ 40,134	$ 41,946
Income attributable to unvested stock-based compensation awards	(146)	(109)
Income available to common shareholders	$ 39,988	$ 41,837
Weighted-average common shares outstanding - basic (in shares)	52,036,000	51,520,000
Assumed exercise of stock options (in shares)	420,000	541,000
Weighted-average common shares outstanding - diluted (in shares)	52,456,000	52,061,000
Diluted earnings per share (in dollars per share)	$ 0.76	$ 0.80
Stock Repurchase Program [Abstract]
Number of common shares authorized to be repurchased (in shares)			2,600,000	2,500,000
Number of common shares repurchased (in shares)	0	0