SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Allowance for Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at January 1	$ 26,046	$ 19,066
Current period provision for credit losses	88,076	78,229
Write-offs charged against the credit loss reserve	(82,911)	(73,682)
Recoveries collected	2,441	2,433
Balance at December 31	$ 33,652	$ 26,046