STOCK AWARD PLANS - Total Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 40,812	$ 10,776	$ 93,962	$ 33,127
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4,070	5,081	12,064	15,119
Stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	36,012	5,042	79,361	15,736
Company expense on ESPP discount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 730	$ 653	$ 2,537	$ 2,272