Disaggregation of Revenue - Schedule of Revenue Disaggregation for Customer Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 24, 2022	Sep. 25, 2021
Disaggregation Of Revenue [Line Items]
Total revenues	$ 1,429,194	$ 1,501,465	$ 1,288,755
Retail [Member] | Residential [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	771,783	798,784	703,263
Retail [Member] | Commercial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	393,482	435,015	353,365
Retail [Member] | Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	130,656	136,257	111,723
Retail [Member] | Government [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	65,489	66,035	51,917
Retail [Member] | Agricultural [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	40,971	45,259	37,873
Wholesale [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 26,813	$ 20,115	$ 30,614