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Commitments and Contingencies - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Sep. 27, 2019
Sep. 27, 2019
Sep. 28, 2018
Sep. 29, 2017
Commitments and Contingencies Disclosure [Abstract]        
Rent expense   $ 9.7 $ 9.5 $ 10.9
Asset retirement obligation $ 1.8 $ 1.8 $ 1.8  
Long-term purchase commitment $ 40.6