RECEIVABLES - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021		Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 9,918	[1]	$ 9,990
Adoption of account pronouncement ASC 326	9,031			$ 9,918
Provision for expected credit losses	352		(45)
Write-offs	(1,212)		(1,441)
Foreign exchange effects	(27)		(240)
Balance at end of period	$ 9,031		$ 9,674
Revision of Prior Period, Accounting Standards Update, Adjustment | Accounting Standards Update 2016-13
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Adoption of account pronouncement ASC 326				$ 0	$ 1,410

[1] Due to the initial adoption of ASC 326 as of January 1, 2020.