STOCK-BASED COMPENSATION (Restricted Stock and Restricted Stock Units Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Service Period \| Equity Classified Award \| Equity-Settled Award \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 1,276
Weighted-average remaining requisite service period	2 years 4 months 24 days
Service Period \| Equity Classified Award \| Equity-Settled Award \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 89,043
Weighted-average remaining requisite service period	3 years
Service Period \| Liability Classified Award \| Cash-Settled Award \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 28,651
Weighted-average remaining requisite service period	2 years 7 months 6 days
Performance Target \| Equity Classified Award \| Equity-Settled Award \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 934
Weighted-average remaining requisite service period	3 years 4 months 24 days
Performance Target \| Equity Classified Award \| Equity-Settled Award \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 2,526
Weighted-average remaining requisite service period	3 years
Accrued compensation and benefits expenses \| Service Period \| Liability Classified Award \| Cash-Settled Award \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability associated with RSUs	$ 8,253	$ 21,902
2020 Acquisition \| Performance Target \| Equity Classified Award \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award value	$ 2,171
Estimated future operating results, period	2 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years

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