EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator for basic and diluted earnings per share:
Net income	$ 18,604	$ 89,719	$ 114,671	$ 109,046	$ 108,323	$ 223,717
Numerator for basic earnings per share	18,604		114,671		108,323	223,717
Numerator for diluted earnings per share	$ 18,604		$ 114,671		$ 108,323	$ 223,717
Denominator:
Weighted average common shares for basic earnings per share (in shares)	57,240		56,463		57,078	56,317
Net effect of dilutive stock options, restricted stock units, restricted stock awards and stock issuable under the ESPP (in shares)	1,780		2,548		1,903	2,579
Weighted average common shares for diluted earnings per share (in shares)	59,020		59,011		58,981	58,896
Net income per share:
Basic (in usd per share)	$ 0.33		$ 2.03		$ 1.90	$ 3.97
Diluted (in usd per share)	$ 0.32		$ 1.94		$ 1.84	$ 3.80
Anti-dilutive options not included in the calculation (in shares)	461		83		299	49