REVENUE - Contract Balances - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Contract With Customer Asset And Liability [Abstract]
Accounts Receivable Net Current	$ 303,161	$ 341,989
ContractWithCustomerAssetNetCurrent	0	0
Deferred Revenue, Current	24,625	17,519
Deferred Revenue, Noncurrent	7,888	13,000
Contract Assets [Member]
Contract Assets or Liabilities Line Items [Line Items}
Beginning Balance		0
Satisfaction of Liability	0
Additional amounts recognized	0
Ending Balance	0
Contract Liabilities [Member]
Contract Assets or Liabilities Line Items [Line Items}
Beginning Balance		$ 30,519
Satisfaction of Liability	(7,537)
Additional amounts recognized	9,531
Ending Balance	$ 32,513