Reportable Segments (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2012	Jul. 01, 2012	Apr. 01, 2012	Jan. 01, 2012	Oct. 02, 2011	Jul. 03, 2011	Apr. 03, 2011	Jan. 02, 2011	Sep. 30, 2012	Oct. 02, 2011	Oct. 03, 2010
Revenue by client sector
Revenue	$ 719,405	$ 684,698	$ 624,345	$ 682,627	$ 675,662	$ 673,792	$ 612,566	$ 611,124	$ 2,711,075	$ 2,573,144	$ 2,201,232
International
Revenue by client sector
Revenue									664,375	596,692	209,474
U.S. commercial
Revenue by client sector
Revenue									718,457	577,782	523,723
U.S. federal government
Revenue by client sector
Threshold percentage for disclosure of revenue from a single client									10.00%
Revenue									1,008,424	1,115,729	1,142,082
U.S. state and local government
Revenue by client sector
Revenue									$ 319,819	$ 282,941	$ 325,953