Financial Instruments and Fair Value Measurements - Carrying Value and Estimated Fair Values (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Interest rate swap	$ 1,588	$ 1,964
Carrying Amount
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Interest rate swap	1,588	1,964
Carrying Amount | Credit Facility | Senior Secured Term B Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	377,218	378,074
Carrying Amount | Credit Facility | 2018 Term A Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	27,894	28,721
Carrying Amount | Credit Facility | 2020 Term A Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	206,657	212,661
Fair Value
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Interest rate swap	1,588	1,964
Fair Value | Credit Facility | Senior Secured Term B Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	382,080	383,491
Fair Value | Credit Facility | 2018 Term A Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	28,168	29,268
Fair Value | Credit Facility | 2020 Term A Loan
Carrying Amounts and Fair Values of Financial Instruments [Line Items]
Senior secured term loan	$ 208,232	$ 213,872