v3.8.0.1
REVENUE - Contract Balances - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Contract With Customer Asset And Liability [Abstract]    
Accounts Receivable Net Current $ 272,315 $ 341,989
ContractWithCustomerAssetNetCurrent 0 0
Deferred Revenue, Current 15,895 17,519
Deferred Revenue, Noncurrent 14,250 13,000
Contract Liabilities [Member]    
Contract Assets or Liabilities Line Items [Line Items}    
Beginning Balance   $ 30,519
Satisfaction of Liability (3,250)  
Additional amounts recognized 2,876  
Ending Balance $ 30,145