STOCK-BASED COMPENSATION - SUMMARY OF EQUITY INCENTIVE PROGRAM (Details) - shares shares in Thousands	Mar. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares available for grant (in shares)	3,271
Standard and market condition-based stock options outstanding (in shares)	521
Non-option equity instruments outstanding (in shares)		802
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Standard and market condition-based stock options outstanding (in shares)	521	828
PSUs outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-option equity instruments outstanding (in shares)	250
RSUs outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-option equity instruments outstanding (in shares)	565
RSAs outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-option equity instruments outstanding (in shares)	130	130

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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