ACCOUNTS RECEIVABLE, NET - Schedule of Allowance for Doubtful Accounts and Expected Credit Losses (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Allowance for expected credit losses:
Balance at Beginning of Period	$ 5,581	$ 4,472	$ 4,472
Charged to Expenses	1,268	$ 1,423	2,229
Deductions Note	906		1,120
Balance at End of Period	$ 5,943		$ 5,581