EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator for basic and diluted earnings per share:
Net income	$ 89,719	$ 109,046
Numerator for basic earnings per share	89,719	109,046
Numerator for diluted earnings per share	$ 89,719	$ 109,046
Denominator:
Weighted average common shares for basic earnings per share (in shares)	56,915	56,170
Net effect of dilutive stock options, restricted stock units, restricted stock awards and stock issuable under the ESPP (in shares)	2,026	2,608
Weighted average common shares for diluted earnings per share (in shares)	58,941	58,778
Net income per share:
Basic (in usd per share)	$ 1.58	$ 1.94
Diluted (in usd per share)	$ 1.52	$ 1.86
Anti-dilutive options not included in the calculation (in shares)	137	16