Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 30, 2017	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Current [Abstract]
Federal		$ 67	$ 7	$ 13
State and local		790	473	446
Total current taxes		857	480	459
Deferred [Abstract]
Deferred	$ (1,086)	0	(1,086)	0
Provision for income taxes - current and deferred		$ 857	$ (606)	$ 459