Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Jun. 27, 2020	Sep. 28, 2019	Jun. 29, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration (a)	$ 1,246	$ 7,369	$ 7,824
Total liabilities	1,246	7,369	7,824
Short term investments (b)			119
Total assets			119
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration (a)	0	0	0
Total liabilities	0	0	0
Short term investments (b)			119
Total assets			119
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration (a)	0	0	0
Total liabilities	0	0	0
Short term investments (b)			0
Total assets			0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration (a)	1,246	7,369	7,824
Total liabilities	1,246	$ 7,369	7,824
Short term investments (b)			0
Total assets			$ 0
Segrest, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration (a)	$ 6,000