SHAREHOLDERS' EQUITY - Employee Stock Purchase Plan (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Class of Stock [Line Items]
Non-cash compensation expense recognized	$ 4,428	$ 1,945	$ 9,780	$ 6,168
Employee Stock Purchase Plan
Class of Stock [Line Items]
Number of shares purchased (in shares)			39	166
Non-cash compensation expense recognized			$ 21	$ 43

Number of shares of capital stock issued (purchased by employees) in connection with an employee stock ownership plan.

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Period Type:	duration