RESTRUCTURING AND RELATED CHARGES - Schedule of Restructuring Costs by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Restructuring Cost and Reserve [Line Items]
Employee Severance and Benefit Costs (Credits)	$ 12,595	$ 24,700	$ 19,497	$ 24,700
Legal and Advisory Costs	474	749	1,259	749
Property, Equipment and Software Impairments		4,752		4,752
Right-of-Use Assets Impairments and Lease-related Charges (Credits)		10,277		10,277
Lease-related Charges (Credits)	1,176		911
Restructuring and related charges	14,245	40,478	21,667	40,478
North America
Restructuring Cost and Reserve [Line Items]
Employee Severance and Benefit Costs (Credits)	(10)	16,059	432	16,059
Legal and Advisory Costs	424	8	1,231	8
Property, Equipment and Software Impairments		4,720		4,720
Right-of-Use Assets Impairments and Lease-related Charges (Credits)		9,311		9,311
Lease-related Charges (Credits)	623		1,364
Restructuring and related charges	1,037	30,098	3,027	30,098
International
Restructuring Cost and Reserve [Line Items]
Employee Severance and Benefit Costs (Credits)	12,605	8,641	19,065	8,641
Legal and Advisory Costs	50	741	28	741
Property, Equipment and Software Impairments		32		32
Right-of-Use Assets Impairments and Lease-related Charges (Credits)		966		966
Lease-related Charges (Credits)	553		(453)
Restructuring and related charges	$ 13,208	$ 10,380	$ 18,640	$ 10,380

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Restructuring Costs, Legal And Advisory

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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-Topic 230
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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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