Quarterly report pursuant to Section 13 or 15(d)

Long-term Debt - Summary of Components of Notes (Details)

v3.19.3
Long-term Debt - Summary of Components of Notes (Details) - USD ($)
Sep. 30, 2019
Jul. 31, 2019
Dec. 31, 2018
Senior Unsecured Notes [Member]      
Debt Instrument [Line Items]      
Principal $ 150,000,000    
Senior Unsecured Notes [Member] | 2024 Notes [Member]      
Debt Instrument [Line Items]      
Principal 500,000,000 $ 350,000,000  
Accrued interest 7,000,000    
Unamortized premium 7,000,000    
Less: Unamortized financing costs (8,000,000)    
Carrying value of convertible notes 506,000,000    
Convertible Senior Notes [Member] | 4.125% Convertible Senior Notes Due September 1, 2022 [Member]      
Debt Instrument [Line Items]      
Principal 150,000,000   $ 150,000,000
Accrued interest 1,000,000   2,000,000
Less: Unamortized financing costs (3,000,000)   (4,000,000)
Carrying value of convertible notes $ 148,000,000   $ 148,000,000