SHARE-BASED COMPENSATION - RSU Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs issued (in shares)	3,793	1,955	1,292
RSUs forfeited (in shares)	(403)	(323)	(396)
Net RSUs issued and increase (decrease) to paid-in capital (in shares)	3,390	1,632	896
RSUs issued	$ 10,073	$ 12,926	$ 10,078
RSUs forfeited - service based	(624)	(1,753)	(1,228)
Net RSUs issued and increase (decrease) to paid-in capital	$ 9,449	$ 11,173	$ 8,850
Weighted average grant date fair value per share (in dollars per share)	$ 2.66	$ 6.61	$ 9.71
Fair value of shares vested per share (in dollars per share)	$ 7.53	$ 10.72	$ 11.07
RSUs released (in shares)	(1,712)	(1,456)	(1,496)
Restricted Stock Units With Service Conditions \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization period of grant in years	1 year
Restricted Stock Units With Service Conditions \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization period of grant in years	3 years

Amortization period of RSUs granted.

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Change in Paid in Capital as a result of net restricted stock units issued

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

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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 net total number of shares (or other type of equity) under an equity-based award plan, other than a stock option plan, that were granted, vested and forfeited during the reporting period.

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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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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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Value of stock related to Restricted Stock Awards forfeited during the period.

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Aggregate value of stock related to Restricted Stock Awards issued during the period.

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