Long-Term Debt - 2017 Credit Facility - Additional Information (Detail) - 2017 Credit Facility - USD ($) $ in Millions		12 Months Ended
	Nov. 30, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Agreement date	Nov. 30, 2017
Additional borrowing capacity	$ 100.0
First lien net leverage ratio	4.00%
Percentage of repricing fee	1.00%
Certain customary events of default, number of business days to default in the payment of interest on borrowings		3 days
Certain customary events of default, number of days default continue for compliance with other agreement		30 days
Certain customary events of default, number of days default continue for financial statement delivery obligations		10 days
Certain customary events of default, indebtedness aggregate amount		$ 15.0
Certain customary events of default, failure in payment of final judgments aggregate amount		$ 15.0
Certain customary events of default, failure in payment of final judgments aggregate amount period		30 days
Eurodollar Rate
Debt Instrument [Line Items]
Variable interest rate basis spread on debt	2.75%
Base Rate Margin
Debt Instrument [Line Items]
Variable interest rate basis spread on debt	1.75%
Term Loan B Facility
Debt Instrument [Line Items]
Senior Secured debt	$ 300.0
Maturity date of revolving credit facility	Nov. 30, 2024
Period considered for applicability of repricing fees	6 months