Segment Information (Details 2)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Well Point [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	29.90%	29.40%	29.70%	28.70%
DoD [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	21.30%	19.80%	21.20%	19.20%
Other [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	6.20%	6.30%	6.20%	6.40%
Five Top Clients [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	57.40%	55.50%	57.10%	54.30%