Interes Rates on Senior Secured Credit Facilities (Detail) - Senior Secured Credit Facilities	6 Months Ended
	Jun. 30, 2017
Term Loan A
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	2.98%
Term Loan A-1 Facility
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	2.98%
Term Loan B2 Facility
Debt Instrument [Line Items]
Debt instrument, interest rate at period end	3.73%
LIBOR | Term Loan A
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
LIBOR | Term Loan A-1 Facility
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
LIBOR | Term Loan B2 Facility
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	2.50%
LIBOR | Revolving Facility
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%	[1]

[1] Includes unused commitment fee of 0.35% and letter of credit fee of 1.75% not reflected in interest rate above.