Accounts Receivable (Tables)

3 Months Ended

Mar. 31, 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):

	March 31, 2012			December 31, 2011
Trade accounts receivable	$	151,235		$	142,166
Unbilled accounts	70,065			73,325
Gross accounts receivable	221,300			215,491
Allowance for doubtful accounts	(2,017		)	(1,627		)
Reserve for cash-basis customers	(3,428		)	(2,928		)
Total accounts receivable reserves	(5,445		)	(4,555		)
Accounts receivable, net	$	215,855		$	210,936