Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Term Loan	$ 246,200	$ 299,300
Less current maturities	3,000	3,000
Long term debt, net current portion	243,200	296,300
Unamortized debt issuance costs	2,709	3,761
Long-term debt, less current maturities, net of unamortized debt issuance costs of $2,709 and $3,761	$ 240,541	$ 292,489