Reportable Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013 item	Jul. 01, 2012	Sep. 30, 2012 item
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	$ 614,835	$ 684,698	$ 1,915,379	$ 1,991,670
International
Revenue by client sector
Revenue	158,579	170,055	522,921	484,767
U.S. commercial
Revenue by client sector
Revenue	167,280	183,601	488,722	503,469
U.S. federal government
Revenue by client sector
Revenue	187,983	245,050	621,677	769,167
U.S. state and local government
Revenue by client sector
Revenue	$ 100,993	$ 85,992	$ 282,059	$ 234,267