RESTRUCTURING - Summary of Costs Incurred by Segment Related to Restructuring (Details) $ in Thousands	12 Months Ended			31 Months Ended
	Dec. 31, 2019 USD ($) numberofcountries	Dec. 31, 2018 USD ($) country	Dec. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Stock-based compensation	$ 81,615	$ 64,821	$ 82,044
Number of countries in which operations were ceased within | numberofcountries	15
Restructuring charges (credits)	$ 31	(136)	18,828
Employee Severance and Benefit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Costs				$ 80,100
Restructuring charges (credits)	31	(353)	12,986
Asset Impairments Related to Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Costs				$ 7,500
Other Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credits)	0	217	5,842
North America
Restructuring Cost and Reserve [Line Items]
Stock-based compensation	72,800	59,700	76,100
Restructuring charges (credits)	0	177	11,998
North America | Employee Severance and Benefit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credits)	0	0	8,172
North America | Other Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credits)	0	177	3,826
International
Restructuring Cost and Reserve [Line Items]
Stock-based compensation	8,800	5,000	5,700
Restructuring charges (credits)	31	(313)	6,830
International | Employee Severance and Benefit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credits)	31	(353)	4,814
International | Other Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges (credits)	0	$ 40	2,016
Facility Closing | International
Restructuring Cost and Reserve [Line Items]
Number of countries in which operations were ceased within | country		17
OrderUp Intangible [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs		$ 2,600
Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Stock-based compensation	$ 0	$ 0	$ 849