Segment Information - Disclosure by Reportable Segment and Reconciliation of Total Operating Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 25, 2017	Mar. 26, 2016	Mar. 25, 2017	Mar. 26, 2016	Sep. 24, 2016
Revenues [Abstract]
Total revenues	$ 450,578	$ 404,140	$ 767,885	$ 679,997
Operating income [Abstract]:
Total operating income	102,857	111,213	156,342	142,557
Reconciliation to net income:
Loss on debt extinguishment	1,567	292	1,567	292
Interest expense, net	17,487	18,852	36,318	37,745
Provision for income tax (benefit) expense	(9)	58	156	243
Net income	83,812	92,011	118,301	104,277
Depreciation and amortization [Abstract]
Total depreciation and amortization	32,670	33,150	63,931	64,788
Assets [Abstract]
Total assets	2,283,885		2,283,885		$ 2,282,299
Operating/Reportable Segments [Member] | Propane [Member]
Revenues [Abstract]
Total revenues	385,654	348,216	655,113	579,691
Operating income [Abstract]:
Total operating income	115,346	129,277	190,009	184,860
Depreciation and amortization [Abstract]
Total depreciation and amortization	28,072	27,518	55,456	54,625
Assets [Abstract]
Total assets	2,157,744		2,157,744		2,141,108
Operating/Reportable Segments [Member] | Fuel Oil and Refined Fuels [Member]
Revenues [Abstract]
Total revenues	34,630	28,814	56,726	49,502
Operating income [Abstract]:
Total operating income	6,828	6,470	9,676	8,439
Depreciation and amortization [Abstract]
Total depreciation and amortization	667	686	1,298	1,382
Assets [Abstract]
Total assets	57,488		57,488		53,266
Operating/Reportable Segments [Member] | Natural Gas and Electricity [Member]
Revenues [Abstract]
Total revenues	19,239	15,962	32,306	27,636
Operating income [Abstract]:
Total operating income	5,535	4,444	8,655	6,696
Depreciation and amortization [Abstract]
Total depreciation and amortization	0	1	0	3
Assets [Abstract]
Total assets	15,208		15,208		13,415
Operating/Reportable Segments [Member] | All Other [Member]
Revenues [Abstract]
Total revenues	11,055	11,148	23,740	23,168
Operating income [Abstract]:
Total operating income	(5,186)	(5,812)	(10,392)	(12,868)
Depreciation and amortization [Abstract]
Total depreciation and amortization	76	79	146	161
Assets [Abstract]
Total assets	1,990		1,990		2,185
Operating/Reportable Segments [Member] | Corporate [Member]
Operating income [Abstract]:
Total operating income	(19,666)	(23,166)	(41,606)	(44,570)
Depreciation and amortization [Abstract]
Total depreciation and amortization	3,855	$ 4,866	7,031	$ 8,617
Assets [Abstract]
Total assets	$ 51,455		$ 51,455		$ 72,325