Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Accrued Liabilities and Other Liabilities [Abstract]
Employee compensation and benefits	$ 53,297	$ 57,846
Project related reimbursable expenses	108,310	91,839
Other	11,585	9,601
Total accrued expenses	$ 173,192	$ 159,286