Segment Information - Disclosure by Reportable Segment and Reconciliation of Total Operating Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 27, 2021	Mar. 28, 2020	Mar. 27, 2021	Mar. 28, 2020	Sep. 26, 2020
Revenues [Abstract]
Total revenues	$ 537,238	$ 401,055	$ 842,429	$ 734,933
Operating income (loss):
Total operating income	147,157	97,625	204,843	157,479
Reconciliation to net income:
Loss on debt extinguishment	0	109	0	109
Interest expense, net	18,092	19,176	36,227	38,248
Other, net	1,582	979	2,660	1,957
Provision for (benefit from) income taxes	267	0	763	(359)
Net income	127,216	77,361	165,193	117,524
Depreciation and amortization [Abstract]
Total depreciation and amortization	27,346	29,288	55,363	58,562
Assets [Abstract]
Total assets	2,128,734		2,128,734		$ 2,047,253
Operating/Reportable Segments [Member] | Propane [Member]
Revenues [Abstract]
Total revenues	481,328	347,686	749,952	633,111
Operating income (loss):
Total operating income	172,090	115,143	255,695	201,265
Depreciation and amortization [Abstract]
Total depreciation and amortization	24,988	26,871	50,679	53,851
Assets [Abstract]
Total assets	1,999,457		1,999,457		1,934,960
Operating/Reportable Segments [Member] | Fuel Oil and Refined Fuels [Member]
Revenues [Abstract]
Total revenues	32,011	31,502	47,761	57,393
Operating income (loss):
Total operating income	7,608	6,391	10,233	9,119
Depreciation and amortization [Abstract]
Total depreciation and amortization	396	468	796	975
Assets [Abstract]
Total assets	52,698		52,698		47,063
Operating/Reportable Segments [Member] | Natural Gas and Electricity [Member]
Revenues [Abstract]
Total revenues	10,750	10,198	17,626	18,919
Operating income (loss):
Total operating income	3,404	2,778	5,363	5,007
Depreciation and amortization [Abstract]
Total depreciation and amortization	6	6	12	6
Assets [Abstract]
Total assets	12,157		12,157		10,594
Operating/Reportable Segments [Member] | All Other [Member]
Revenues [Abstract]
Total revenues	13,149	11,669	27,090	25,510
Operating income (loss):
Total operating income	(4,232)	(4,846)	(9,293)	(10,233)
Depreciation and amortization [Abstract]
Total depreciation and amortization	47	48	94	95
Assets [Abstract]
Total assets	18,367		18,367		18,733
Operating/Reportable Segments [Member] | Corporate [Member]
Operating income (loss):
Total operating income	(31,713)	(21,841)	(57,155)	(47,679)
Depreciation and amortization [Abstract]
Total depreciation and amortization	1,909	$ 1,895	3,782	$ 3,635
Assets [Abstract]
Total assets	$ 46,055		$ 46,055		$ 35,903