Debt - Summary of Debt (Parenthetical) (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Senior Secured Credit Facilities [Member] | Term Loan Facility B3 Loans, Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year	2018	2018
Senior Secured Credit Facilities [Member] | Term Loan Facility B4 Loans, Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year	2018	2018
Senior Secured Notes, Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year	2018	2018
Junior Lien Secured Notes, Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year	2018	2018
Senior Notes, Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year	2018	2018