Fair Value Measurements (Gross Amounts and Fair Value of Debt) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Term loan
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Gross value	$ 1,728,614	$ 1,810,266
Term loan | Fair value - Level 2
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value - Level 2	1,408,820	1,226,455
7.75% senior notes
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Gross value	610,000	610,000
7.75% senior notes | Fair value - Level 2
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value - Level 2	$ 179,950	$ 249,673