Income Taxes - Gross Unrecognized Tax Benefits (Details) $ in Thousands	9 Months Ended
Jul. 04, 2020 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of the beginning of the year	$ 58,111
Increases related to acquisitions	0
Tax positions related to current year:
Additions	1,238
Reductions	0
Unrecognized Tax Benefits, Prior Period Tax Positions [Abstract]
Additions	0
Reductions	0
Lapses in statutes of limitations	(681)
Decrease in unrecognized tax benefits based on tax audit results	(19,463)
Foreign currency revaluation adjustment	247
Balance as of end of period	$ 39,452

Unrecognized Tax Benefits, Current Period Tax Positions [Abstract]

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Unrecognized Tax Benefits, Prior Period Tax Positions [Abstract]

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Amount of unrecognized tax benefits.

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