Accounts Receivable

12 Months Ended

Dec. 31, 2014

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

Accounts Receivable

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

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

Charges to income from operations represent charges to bad debt expense for increases in the allowance for doubtful accounts and reductions to revenue for increases in reserves for cash basis customers.