TRADE ACCOUNTS RECEIVABLE, NET OF ALLOWANCE (Tables)

9 Months Ended

Sep. 30, 2017

Schedule of Trade Accounts Receivable

(in thousands)	September 30, 2017			December 31, 2016
Trade accounts receivable	$	164,530		$	234,473
Unbilled trade accounts receivable		32,820			34,681
Total trade accounts receivable		197,350			269,154
Allowance for sales credit memos		(6,189	)		(4,126	)
	$	191,161		$	265,028