Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2011

Accounts Receivable [Abstract]

Unbilled accounts receivable

Unbilled accounts receivable consisted of the following:

	December 31,
	2011			2010
	(in thousands)
Accrued worksite employee payroll cost	$	130,317		$	109,697
Unbilled revenues		38,564			32,613
Customer prepayments		(10,373	)		(8,123	)
Unbilled accounts receivable	$	158,508		$	134,187