Reportable Segments (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 01, 2012	Apr. 03, 2011	Apr. 01, 2012	Apr. 03, 2011
Revenue by client sector
Revenue	$ 624,345	$ 612,566	$ 1,306,972	$ 1,223,690
International
Revenue by client sector
Revenue	154,781	150,024	314,713	276,581
U.S. commercial
Revenue by client sector
Revenue	142,438	112,072	319,868	247,207
U.S. federal government
Revenue by client sector
Threshold percentage for disclosure of revenue from a single client	10.00%
Revenue	252,709	284,510	524,116	568,030
U.S. state and local government
Revenue by client sector
Revenue	$ 74,417	$ 65,960	$ 148,275	$ 131,872