Fair Value Measurements - Outstanding Interest Rate Swaps (Detail)	6 Months Ended
	Jun. 30, 2017 USD ($)
US Dollar term loan floating-to-fixed rate swaps maturing on September 2017
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	Sep. 01, 2017
US Dollar term loan floating-to-fixed rate swaps maturing on May 2018
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	May 01, 2018
US Dollar term loan floating-to-fixed rate swaps maturing on April 2019
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 150,000,000
Maturity Date	Apr. 01, 2019
US Dollar term loan floating-to-fixed rate swaps maturing on June 2019
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	Jun. 01, 2019
US Dollar term loan floating-to-fixed rate swaps maturing on July 2019
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 150,000,000
Maturity Date	Jul. 01, 2019
US Dollar term loan floating-to-fixed rate swaps maturing on July 2020
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	Jul. 01, 2020
US Dollar term loan floating-to-fixed rate swaps maturing on July 2020
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	Jul. 01, 2020
US Dollar term loan floating-to-fixed rate swaps maturing on July 2022
Derivative Instruments Gain Loss [Line Items]
Notional Amount	$ 250,000,000
Maturity Date	Jul. 01, 2022