Annual report pursuant to Section 13 and 15(d)

Condensed Consolidating Financial Information - Narrative (Details)

v3.8.0.1
Condensed Consolidating Financial Information - Narrative (Details) - USD ($)
Dec. 31, 2017
Oct. 11, 2017
Dec. 21, 2016
Oct. 31, 2016
Oct. 14, 2016
Apr. 21, 2015
Aug. 18, 2014
Guarantors              
Condensed Financial Statements, Captions [Line Items]              
Other ownership interest, percentage 100.00%            
Senior notes | 7.75% Senior Notes Due 2020              
Condensed Financial Statements, Captions [Line Items]              
Aggregate principal amount             $ 600,000,000.0
Repurchased face amount       $ 600,000,000.0 $ 196,500,000    
Senior notes | 6.625% Senior Notes Due 2023              
Condensed Financial Statements, Captions [Line Items]              
Aggregate principal amount           $ 350,000,000.0  
Senior notes | 6.000% Senior Notes Due 2024              
Condensed Financial Statements, Captions [Line Items]              
Aggregate principal amount         $ 650,000,000.0    
Senior notes | 6.375% Senior Notes Due 2025              
Condensed Financial Statements, Captions [Line Items]              
Aggregate principal amount     $ 600,000,000        
Senior notes | 6.375% Senior Notes Due 2026              
Condensed Financial Statements, Captions [Line Items]              
Aggregate principal amount   $ 450,000,000