Long-Term Debt - Schedule of Long-Term Debt (Parenthetical) (Detail) $ in Millions		3 Months Ended	5 Months Ended	12 Months Ended
	Jul. 31, 2015	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Unamortized long-term debt reduction		$ 8.2	$ 8.2	$ 8.2
Term Facility [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	1.00%		1.00%
Principal pre-payment on Term Facility				$ 135.0
Quarterly principal payments		$ 17.7
Debt instrument, basis spread on variable rate	3.00%		2.75%
First lien net leverage ratio		4.50	4.50	4.50
First lien net leverage ratio, description				First lien net leverage ratio of less than 4.50 to 1.00
Unamortized long-term debt reduction		$ 8.2	$ 8.2	$ 8.2	$ 9.6
Accrued interest				$ 16.5	$ 18.6
LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate				0.36%	0.16%