REVENUE - Contract Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Contract With Customer Asset And Liability [Abstract]
Receivables, included in "Accounts receivable net of allowance for doubtful accounts"	$ 354,702	$ 330,983
Deferred Revenue, Current	16,113	22,692
Deferred Revenue, Noncurrent	2,130	1,138
Receivables Not Generated From ustomers	8,400	$ 11,800
Significant changes in the contract liabilities balances
Beginning balance	23,830
Revenue recognized during the period that was included in the beginning balance of contract liabilities	(20,104)
Additional amounts recognized	14,517
Ending balance	$ 18,243
Revenue, Performance Obligation Satisfied over Time [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Explanation	The Company has contracts with customers which will result in the recognition of revenue beyond one year.
Remaining revenue expeted to be recognized in excess of one year	$ 2,100