SIGNIFICANT ACCOUNTING POLICIES - Allowances for Doubtful Accounts And Revenue Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at January 1,	$ 24,634	$ 22,493	$ 26,368
Additions charged to earnings	8,018	10,133	2,408
Deductions from reserves, net of recoveries	(8,516)	(7,992)	(6,283)
Balance at December 31,	24,136	24,634	22,493
Revenue Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at January 1,	20,115	16,218	17,947
Additions charged to earnings	34,319	45,784	35,549
Deductions from reserves, net of recoveries	(38,430)	(41,887)	(37,278)
Balance at December 31,	$ 16,004	$ 20,115	$ 16,218