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Reportable Segments - Revenue By Client Sector (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Apr. 01, 2018 | Apr. 02, 2017 | Apr. 01, 2018 | Apr. 02, 2017
Revenue by client sector |  |  |  |
Threshold percentage for disclosure of revenue from a single client | 10.00% | 10.00% | 10.00% | 10.00%
Revenue | $ 700,262 | $ 663,781 | $ 1,460,010 | $ 1,332,632
U.S. federal government |  |  |  |
Revenue by client sector |  |  |  |
Revenue | 236,951 | 218,110 | 473,199 | 440,744
International |  |  |  |
Revenue by client sector |  |  |  |
Revenue | 178,008 | 197,114 | 342,968 | 369,571
U.S. state and local government |  |  |  |
Revenue by client sector |  |  |  |
Revenue | 104,905 | 83,181 | 256,659 | 166,676
U.S. commercial |  |  |  |
Revenue by client sector |  |  |  |
Revenue | $ 180,398 | $ 165,376 | $ 387,184 | $ 355,641

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