Debt and Financing Arrangements - Summary of Reconciliation of Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Finance Leases, described below	$ 55,171	$ 70,976
Total debt	55,171	70,976
Less: current portion of long-term debt	20,245	20,588
Long-term debt, less current portion	$ 34,926	$ 50,388