Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 185,745	$ 174,604
Costs in excess of billings	54,437	26,915
Total contract receivables	240,182	201,519
Less allowance for doubtful accounts	(3,738)	(3,529)	$ (5,951)	$ (6,170)
Accounts receivable	$ 236,444	$ 197,990