Prepaid Expenses and Other Assets - Summary of Prepaid Expenses and Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Prepaid Expense and Other Assets [Abstract]
Prepaid expenses	$ 9,195	$ 7,285
Revenues in excess of billings	10,094	8,879
Income tax receivable		7,823
Other	493	1,323
Total prepaid expenses and other assets	$ 19,782	$ 25,310