Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details)

v3.19.1
FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Unamortized debt issuance costs $ 29,628 $ 30,733
Senior notes | 6.625% senior unsecured notes due 2023    
Debt Instrument [Line Items]    
Unamortized debt issuance costs 4,200  
Senior notes | 6.000% senior unsecured notes due 2024    
Debt Instrument [Line Items]    
Unamortized debt issuance costs 8,400  
Senior notes | 6.375% senior unsecured notes due 2025    
Debt Instrument [Line Items]    
Unamortized debt issuance costs 12,100  
Senior notes | 6.375% senior unsecured notes due 2026    
Debt Instrument [Line Items]    
Unamortized debt issuance costs 4,900  
Carry value | Senior notes    
Debt Instrument [Line Items]    
Carrying value of notes 2,000,000  
Fair value | Senior notes    
Debt Instrument [Line Items]    
Carrying value of notes $ 1,900,000