Segment Information (Details 2) (Customer Concentration Risk [Member])	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Well Point [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	29.50%	29.20%	6.00%
Department of Defense [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	20.90%	19.70%	5.40%
Other [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	6.30%	6.30%	12.30%
Five Top Clients [Member]
Segment information percentage of revenue by top clients
Revenue percentage represented by largest clients	56.70%	55.20%	23.70%