Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2013

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

Schedule of Accounts Receivable

Net accounts receivable consisted of the following as of September 30, 2013 and December 31, 2012 (in thousands):

	September 30, 2013			December 31, 2012
Trade accounts receivable	$	169,873		$	143,533
Unbilled accounts	90,164			79,051
Gross accounts receivable	260,037			222,584
Allowance for doubtful accounts	(824		)	(1,154		)
Reserve for cash-basis customers	(2,760		)	(2,653		)
Total accounts receivable reserves	(3,584		)	(3,807		)
Accounts receivable, net	$	256,453		$	218,777