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Reportable Segments - Revenue By Client Sector (Details) - USD ($) $ in Thousands | 3 Months Ended
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Dec. 31, 2017 | Jan. 01, 2017
Revenue by client sector |  |
Threshold percentage for disclosure of revenue from a single client | 10.00% | 10.00%
Revenue | $ 759,749 | $ 668,851
U.S. federal government |  |
Revenue by client sector |  |
Revenue | 236,249 | 222,634
International |  |
Revenue by client sector |  |
Revenue | 164,960 | 172,457
U.S. state and local government |  |
Revenue by client sector |  |
Revenue | 151,754 | 83,494
U.S. commercial |  |
Revenue by client sector |  |
Revenue | $ 206,786 | $ 190,266

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts. + References Reference 1: 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=63488584&loc=d3e20235-122688 + Details
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- Details
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- Details
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