TRADE ACCOUNTS RECEIVABLE, NET OF ALLOWANCE (Tables)

12 Months Ended

Dec. 31, 2014

Schedule of Trade Accounts Receivable

Unbilled trade accounts receivable relate to services earned under time and material arrangements and maintenance and license arrangements that have not been invoiced.

	December 31,
(in thousands)	2014			2013
Trade accounts receivable	$	128,757		$	129,020
Unbilled accounts receivable		27,627			38,618
Total accounts receivable		156,384			167,638
Allowance for sales credit memos		(1,540	)		(1,997	)
	$	154,844		$	165,641

Activity of Allowance for Sales Credit Memos

The following reflects the activity of the allowance for sales credit memos:

	Year Ended December 31,
(in thousands)	2014			2013			2012
Balance at beginning of year	$	1,997		$	963		$	895
Provision for credit memos		2,164			5,374			1,773
Credit memos issued		(2,621	)		(4,340	)		(1,705	)
	$	1,540		$	1,997		$	963