Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2012

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

Schedule of Accounts Receivable

Net accounts receivable consisted of the following (in thousands):

	September 30, 2012			December 31, 2011
Trade accounts receivable	$	170,963		$	142,166
Unbilled accounts	71,047			73,325
Gross accounts receivable	242,010			215,491
Allowance for doubtful accounts	(1,791		)	(1,627		)
Reserve for cash-basis customers	(3,987		)	(2,928		)
Total accounts receivable reserves	(5,778		)	(4,555		)
Accounts receivable, net	$	236,232		$	210,936