Accounts Receivable, Net

12 Months Ended

Dec. 31, 2012

Accounts Receivable, Net [Abstract]

Accounts Receivable, Net

2. Accounts Receivable, Net

Accounts receivable, net balances at December 31, 2012 and 2011 were as follows (in thousands):

	2012			2011
Trade accounts receivable	$	125,787		$	113,143
Unbilled revenue, at net realizable value		41,005			33,150
Total accounts receivable		166,792			146,293
Allowance for doubtful accounts		(11,819	)		(9,220	)
Accounts receivable, net	$	154,973		$	137,073