Condensed Consolidating Statements of Cash Flows (Parenthetical) (Detail)
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
May 09, 2016
Senior Notes 5.875 Percent Due 2024      
Condensed Cash Flow Statements Captions [Line Items]      
Debt instrument interest rate 5.875% 5.875%  
Debt instrument due year 2024 2024  
Senior Notes 7.875 Percent Due 2020      
Condensed Cash Flow Statements Captions [Line Items]      
Debt instrument interest rate 7.875% 7.875% 7.875%
Debt instrument due year 2020 2020