Accounts Receivable - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Trade Accounts Receivable	$ 131,990	$ 150,764
Unbilled Recoverable Costs and Accrued Profits	19,567	33,030
Total Receivables, Gross	151,557	183,794
Less Allowance for Doubtful Accounts	(3,559)	(1,486)
Accounts Receivable	$ 147,998	$ 182,308