v3.8.0.1
FAIR VALUE OF FINANCIAL INSTRUMENTS - Carrying Value (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Schedule of Cost-method Investments Line Items    
Original Cost $ 9,955 $ 255
Other Than Temporary Impairment 0 0
Carrying Amount Not Evaluated for Impairment 9,955 255
Payments to Acquire Restricted Investments 1,250 9,700
Cost Method Invetsment, after adjustments 11,205 9,955
Senior Notes    
Fair Value Of Instruments [Line Items]    
Carrying value of debt 400,000 400,000
Fair value of debt 407,500 422,876
Finance Method Lease Obligations    
Fair Value Of Instruments [Line Items]    
Carrying value of debt 955 70
Letter of credit    
Fair Value Of Instruments [Line Items]    
Carrying value of debt 4,176 1,856
New Term B Loan [Member]    
Fair Value Of Instruments [Line Items]    
Carrying value of debt 1,326,675 1,330,000
Fair value of debt 1,334,967 1,336,650
New Revolver [Member]    
Fair Value Of Instruments [Line Items]    
Carrying value of debt 125,000 143,000
Fair value of debt $ 125,000 $ 143,000