STOCK-BASED COMPENSATION Performance-based Awards and Restricted Stock Units (Details) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($) $ / shares shares
Restricted Stock Units (RSUs)
Shares
Outstanding at January 1, 2021	1,518,000
Granted	89,000
Vested	(209,000)
Forfeited	(39,000)
Outstanding at March 31, 2021	1,359,000
Outstanding and expected to vest at March 31, 2021	1,273,000
Weighted- Average Grant Date Fair Value Per Share (in dollars per share)
Outstanding at January 1, 2021 \| $ / shares	$ 35.51
Granted \| $ / shares	82.50
Vested \| $ / shares	34.57
Forfeited \| $ / shares	35.73
Outstanding at March 31, 2021 \| $ / shares	$ 38.72
Weighted-Average Remaining Contractual Term (In years)
Outstanding at March 31, 2021	1 year 9 months 29 days
Outstanding and expected to vest at March 31, 2021	1 year 4 months 17 days
Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2021 \| $	$ 110,731
Outstanding and expected to vest at March 31, 2021 \| $	$ 103,716
Long-term Performance Based Units (PRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based period	3 years
Shares
Outstanding at January 1, 2021	301,000
Granted	97,000
Vested	(6,000)
Forfeited	(15,000)
Outstanding at March 31, 2021	377,000
Outstanding and expected to vest at March 31, 2021	377,000
Weighted- Average Grant Date Fair Value Per Share (in dollars per share)
Outstanding at January 1, 2021 \| $ / shares	$ 41.90
Granted \| $ / shares	83.01
Vested \| $ / shares	29.95
Forfeited \| $ / shares	40.05
Outstanding at March 31, 2021 \| $ / shares	$ 52.75
Weighted-Average Remaining Contractual Term (In years)
Outstanding at March 31, 2021	1 year 7 months 24 days
Outstanding and expected to vest at March 31, 2021	1 year 7 months 24 days
Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2021 \| $	$ 30,737
Outstanding and expected to vest at March 31, 2021 \| $	$ 30,737
Performance Based Awards (PSUs)
Shares
Outstanding at January 1, 2021	150,000
Granted	57,000
Vested	(150,000)
Forfeited	0
Outstanding at March 31, 2021	57,000
Outstanding and expected to vest at March 31, 2021	57,000
Weighted- Average Grant Date Fair Value Per Share (in dollars per share)
Outstanding at January 1, 2021 \| $ / shares	$ 46.27
Granted \| $ / shares	84.05
Vested \| $ / shares	46.27
Forfeited \| $ / shares	0
Outstanding at March 31, 2021 \| $ / shares	$ 84.05
Weighted-Average Remaining Contractual Term (In years)
Outstanding at March 31, 2021	9 months
Outstanding and expected to vest at March 31, 2021	9 months
Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2021 \| $	$ 4,682
Outstanding and expected to vest at March 31, 2021 \| $	$ 4,682
Minimum [Member] \| Long-term Performance Based Units (PRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Performance Based Awards Shares Released As Percentage Of Target Number	0.00%
Minimum [Member] \| Performance Based Awards (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Performance Based Awards Shares Released As Percentage Of Target Number	0.00%
Maximum [Member] \| Long-term Performance Based Units (PRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Performance Based Awards Shares Released As Percentage Of Target Number	200.00%
Maximum [Member] \| Performance Based Awards (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Performance Based Awards Shares Released As Percentage Of Target Number	200.00%

Number of Performance Based Awards Shares Released as Percentage of Target Number.

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Aggregate Intrinsic Value

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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