RECEIVABLES (Tables)

9 Months Ended

Sep. 30, 2018

Receivables [Abstract]

Summary of Accounts Receivable

A summary of accounts receivable as of September 30, 2018 and December 31, 2017 is as follows (in thousands):

	September 30, 2018			December 31, 2017
	(unaudited)
Trade accounts receivable	$	227,325		$	244,133
Unbilled receivables	93,002			69,138
Allowance for doubtful accounts	(18,415		)	(11,308		)
Total	$	301,912		$	301,963