Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 28, 2019	Sep. 25, 2021	Sep. 26, 2020	Sep. 28, 2019
Income Tax Disclosure [Abstract]
Discrete deferred tax benefit	$ 496	$ (102)	$ 496	$ 0