Reportable Segments (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 30, 2012	Sep. 30, 2012	Jul. 01, 2012	Apr. 01, 2012	Jan. 01, 2012	Sep. 29, 2013 item	Sep. 30, 2012 item	Oct. 02, 2011
Reportable Segments
Number of clients exceeding threshold									0	0
Revenue by client sector
Threshold percentage for disclosure of revenue from a single client									10.00%
Revenue	$ 698,376	$ 614,835	$ 641,999	$ 658,545	$ 719,405	$ 684,698	$ 624,345	$ 682,627	$ 2,613,755	$ 2,711,075	$ 2,573,144
International
Revenue by client sector
Revenue									697,975	664,375	596,692
U.S. commercial
Revenue by client sector
Revenue									693,677	718,457	577,782
U.S. federal government
Revenue by client sector
Revenue									829,790	1,008,424	1,115,729
U.S. state and local government
Revenue by client sector
Revenue									$ 392,313	$ 319,819	$ 282,941