INCOME TAXES - Reconciliation of Luxembourg Statutory Tax Rate to Effective Tax Rate (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Income Tax Provision to the Luxembourg income tax rate
Statutory tax rate	24.94%	24.94%	26.01%
Change in valuation allowance	(29.79%)	2526.53%	43.08%
State tax expense	(1.25%)	(1.63%)	28.58%
Tax credits	0.10%	0.00%	0.00%
Uncertain tax positions	(2.94%)	39.60%	114.18%
Unrecognized tax loss	0.00%	(67.18%)	0.00%
Income tax rate change	(2.40%)	0.00%	0.00%
Tax rate differences on foreign earnings	(6.62%)	28.75%	73.11%
Other	3.04%	7.85%	7.96%
Effective tax rate	(14.92%)	2558.86%	292.92%

Effective Income Tax Rate Reconciliation, Uncertain Taxes, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Topic 740
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

+ References

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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