Annual report pursuant to Section 13 and 15(d)

Summary of Long-Term Debt (Detail)

Summary of Long-Term Debt (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Debt Instrument [Line Items]    
Credit facility 2 [1] $ 321,000 $ 77,000
Second Lien Facility 200,000 200,000
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums [2] 9,625 11,733
Debt Instrument, Unamortized Discount [2] (3,159) (3,839)
Unamortized Debt Issuance Expense [2] (6,466) (7,894)
Long-term Debt 521,000 277,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net $ 511,375 $ 265,267
Second Lien Facility [Member]    
Debt Instrument [Line Items]    
Credit facility interest rate option one, applicable margin rate over Adjusted LIBOR 7.00%  
Second Lien Facility, Interest Rate 9.53%  
[1] 2 Issuance costs of the Credit Facility, which represent costs attributable to the access to credit over its contractual term, have been presented as a component of Other assets (see Note 13) and are being amortized over the term of the Credit Facility using the straight-line method.
[2] 1 Discount and issuance costs of the Second Lien Facility are being amortized over the term of the underlying loan using the effective-interest method.