Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2014

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

Schedule of Accounts Receivable

Net accounts receivable consisted of the following as of December 31, 2014 and 2013 (in thousands):

	December 31, 2014			December 31, 2013
Trade accounts receivable	$	222,531		$	175,391
Unbilled accounts receivable	116,070			100,300
Gross accounts receivable	338,601			275,691
Allowance for doubtful accounts	(1,033		)	(708		)
Reserve for cash-basis customers	(7,990		)	(2,995		)
Total accounts receivable reserves	(9,023		)	(3,703		)
Accounts receivable, net	$	329,578		$	271,988

Schedule of Activity in the Accounts Receivable Reserves

A summary of activity in the accounts receivable reserves for the years ended December 31, 2014, 2013 and 2012, is as follows (in thousands):

	2014			2013			2012
Beginning balance	$	3,703		$	3,807		$	4,555
Charges to income from operations	32,293			17,900			15,599
Collections from cash basis customers and write-offs	(26,973		)	(18,004		)	(16,347		)
Ending balance	$	9,023		$	3,703		$	3,807