Debt - Summary of Company's Long-term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Long-term debt
Unamortized discount and debt issuance costs on first lien term loan	$ (6,292)	$ (8,034)
Long-term debt, net	599,202	602,306
First Lien Term Loan [Member]
Current portion of long-term debt
First lien term loan	6,461	13,147
First Lien Term Loan Due June 19, 2024 [Member]
Long-term debt
Unamortized discount and debt issuance costs on first lien term loan	$ 605,494	$ 610,340

Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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