INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Tax benefit from deferred tax change	$ 3,000
Excess tax benefits from share-based compensation	(11,625)	$ (15,370)	$ (13,400)
U.S. Global Intangible Low-Taxed Income ("GILTI") and Base Erosion Anti-Abuse Tax ("BEAT")	(3,909)	(1,485)	5,625
Deferred Tax Assets, Valuation Allowance	23,105	23,320
Net operating loss carryforwards	19,353	24,941
Amount of state tax credit carryforwards subject to expiration	7,000
Tax-effected net operating loss carryforwards not subject to expiration	15,800
Tax-effected net operating loss subject to expiration	3,600
Contingent foreign income tax payable on uncertain tax positions	1,500
Unrecognized tax benefits that would impact effective tax rate	4,500
Decrease in unrecognized tax benefits is reasonably possible	2,600
Unrecognized tax benefits, income tax penalties and interest accrued	3,600	1,700	1,900
Unrecognized tax expense (benefit), income tax penalties and interest expense	0	$ (200)	$ 400
Minimum | Foreign Tax Authority
Valuation Allowance [Line Items]
Estimated additional tax payable on previously unremitted earnings	15,000
Maximum | Foreign Tax Authority
Valuation Allowance [Line Items]
Estimated additional tax payable on previously unremitted earnings	25,000
Deferred tax assets for specified locations
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance	16,700
Deferred tax assets related to tax credit carryforwards, U.S. state
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 3,700