Accounts Receivable (Tables)

3 Months Ended

Mar. 31, 2019

Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]

Schedule of Accounts Receivable

Net accounts receivable consisted of the following as of March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019			December 31, 2018
Trade accounts receivable	$	380,241		$	337,445
Unbilled accounts receivable	150,183			143,978
Gross accounts receivable	530,424			481,423
Allowance for doubtful accounts and other reserves	(1,078		)	(1,534		)
Accounts receivable, net	$	529,346		$	479,889