Reportable Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Dec. 30, 2012	Jan. 01, 2012
Revenue by client sector
Revenue	$ 658,545	$ 682,627
International
Revenue by client sector
Revenue	167,518	159,931
U.S. commercial
Revenue by client sector
Revenue	173,141	177,430
U.S. federal government
Revenue by client sector
Threshold percentage for disclosure of revenue from a single client	10.00%
Revenue	227,390	271,408
U.S. state and local government
Revenue by client sector
Revenue	$ 90,496	$ 73,858

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueServicesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration