Accounts Receivable - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract receivables	$ 49,826	$ 58,881
Allowance for doubtful accounts	(2,961)	(2,582)
Total accounts receivable	58,274	68,434
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 11,409	$ 12,135