Accounts Receivable (Tables)

6 Months Ended

Jun. 30, 2018

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

Schedule of Accounts Receivable

Net accounts receivable consisted of the following as of June 30, 2018 and December 31, 2017 (in thousands):

	June 30, 2018			December 31, 2017
Trade accounts receivable	$	343,526		$	320,001
Unbilled accounts receivable	137,404			142,737
Gross accounts receivable	480,930			462,738
Allowance for doubtful accounts and other reserves	(1,065		)	(1,281		)
Accounts receivable, net	$	479,865		$	461,457