Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Summary of Company's Current Debt Portfolio (Detail)

v3.8.0.1
Long-Term Debt - Summary of Company's Current Debt Portfolio (Detail) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Debt Instrument [Line Items]    
Long-term Debt $ 585,000 $ 585,000
Less: unamortized debt issuance costs (7,450) (8,674)
Long-term Debt, Excluding Current Maturities 577,550 576,326
6.75% Senior Notes, due July 2022 [Member]    
Debt Instrument [Line Items]    
Long-term Debt 360,000 360,000
7.50% Senior Notes, due August 2020 [Member]    
Debt Instrument [Line Items]    
Long-term Debt $ 225,000 $ 225,000