Accounts Receivable

12 Months Ended

Dec. 31, 2011

Accounts Receivable

Note 2: Accounts Receivable

Accounts receivable, net consists of the following:

December 31,	2011			2010
(in thousands)
Trade receivables:
Billed	$	367,718		$	216,201
Unbilled		99,913			84,977
Other receivables		1,734			1,519
Total		469,365			302,697
Less: allowance for doubtful accounts		(8,093	)		(8,695	)
Accounts receivable, net	$	461,272		$	294,002

Trade receivables relate to sale of our services and products, for which credit is extended based on our evaluation of the customer’s credit worthiness.  Unbilled receivables represent revenues earned but not billed to the customer until future dates, usually within one month.  Other receivables consist primarily of amounts due from purchasers of Company property and rebates from suppliers.

Changes in the Company’s allowance for doubtful accounts are as follows:

Years Ended December 31,	2011			2010
(in thousands)
Beginning balance	$	8,695		$	3,210
Bad debt expense		2,868			4,812
Accounts written-off		(3,820	)		(730	)
Recoveries		350			1,403
Ending balance	$	8,093		$	8,695