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Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2017 | Sep. 24, 2016 | Sep. 26, 2015
Investment/Profit Sharing Plan [Member] |  |  |
Postemployment and Postretirement Benefit Plans [Line Items] |  |  |
Operating and administrative expenses | $ 2,400 | $ 1,800 | $ 1,600
Nonqualified Investment Plan [Member] |  |  |
Postemployment and Postretirement Benefit Plans [Line Items] |  |  |
Operating and administrative expenses | 159 | 110 | 99
Cash Bonuses [Member] |  |  |
Postemployment and Postretirement Benefit Plans [Line Items] |  |  |
Operating and administrative expenses | $ 10,600 | $ 10,600 | $ 10,100

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- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
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