Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Sep. 30, 2017	Dec. 24, 2016
Liabilities:
Total liabilities	$ 9,058	$ 9,343	$ 4,253
Liability for contingent consideration
Liabilities:
Total liabilities	9,058	9,343	4,253
Level 1
Liabilities:
Total liabilities	0	0	0
Level 1 | Liability for contingent consideration
Liabilities:
Total liabilities	0	0	0
Level 2
Liabilities:
Total liabilities	0	0	0
Level 2 | Liability for contingent consideration
Liabilities:
Total liabilities	0	0	0
Level 3
Liabilities:
Total liabilities	9,058	9,343	4,253
Level 3 | Liability for contingent consideration
Liabilities:
Total liabilities	$ 9,058	$ 9,343	$ 4,253