Disaggregation of Revenue - Schedule of Revenue Disaggregation for Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 25, 2021	Dec. 26, 2020
Disaggregation Of Revenue [Line Items]
Total revenues	$ 375,407	$ 305,191
Retail [Member] | Residential [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	198,005	174,711
Retail [Member] | Commercial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	110,952	79,440
Retail [Member] | Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	34,194	25,795
Retail [Member] | Agricultural [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	13,803	11,138
Retail [Member] | Government [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	15,984	11,900
Wholesale [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 2,469	$ 2,207