EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
EARNINGS PER SHARE
Weighted-average anti-dilutive stock options outstanding (in shares)	200,000	30,000
Basic earnings per share
Net income	$ 47,055	$ 52,850
Income attributable to unvested stock-based compensation awards	(119)	(130)
Income available to common shareholders	$ 46,936	$ 52,720
Weighted-average common shares outstanding - basic (in shares)	53,993,000	53,845,000
Basic earnings per share	$ 0.87	$ 0.98
Diluted earnings per share
Net income	$ 47,055	$ 52,850
Income attributable to unvested stock-based compensation awards	(119)	(130)
Income available to common shareholders	$ 46,936	$ 52,720
Weighted-average common shares outstanding (in shares)	53,993,000	53,845,000
Assumed exercise of stock options (in shares)	386,000	438,000
Weighted-average common shares outstanding - diluted (in shares)	54,379,000	54,283,000
Diluted earnings per share	$ 0.86	$ 0.97
Cash dividends declared per share (in dollars per share)	$ 0.43	$ 0.42
Stock Repurchase Program
Number of common shares authorized to be repurchased (in shares)			2,700,000	2,680,000
Number of common shares repurchased (in shares)	50,000