Disaggregation of Revenue - Schedule of Revenue Disaggregation for Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 26, 2022	Mar. 27, 2021	Mar. 26, 2022	Mar. 27, 2021
Disaggregation Of Revenue [Line Items]
Total revenues	$ 588,095	$ 537,238	$ 963,502	$ 842,429
Retail [Member] | Residential [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	342,560	310,930	540,565	485,641
Retail [Member] | Commercial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	151,833	128,886	262,785	208,326
Retail [Member] | Industrial [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	41,376	35,447	75,570	61,242
Retail [Member] | Agricultural [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	15,916	13,571	29,719	24,709
Retail [Member] | Government [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	28,281	23,572	44,265	35,472
Wholesale [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 8,129	$ 24,832	$ 10,598	$ 27,039