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CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Major Customers
Revenues	$ 1,961,720	$ 2,002,857	$ 1,796,220
Trade receivables	$ 161,679	$ 174,914
Revenue \| Geographic Concentration Risk
Major Customers
Concentration of risk (as a percent)	17.90%	27.80%	17.40%
Revenue \| Customer Concentration Risk \| Customer A
Major Customers
Revenues	$ 228,500	$ 219,115
Revenue \| Customer Concentration Risk \| Customer B
Major Customers
Revenues	213,319
Trade accounts receivable \| Customer Concentration Risk \| Major customers
Major Customers
Trade receivables	$ 26,300
Trade accounts receivable \| Customer Concentration Risk \| Customer A
Major Customers
Trade receivables		$ 12,800