Segment Information - Disclosure by Reportable Segment and Reconciliation of Total Operating Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 30, 2017	Dec. 24, 2016	Sep. 30, 2017
Revenues [Abstract]
Total revenues		$ 373,277	$ 317,307
Operating income (loss):
Total operating income		55,748	53,485
Reconciliation to net income:
Interest expense, net		19,514	18,831
(Benefit from) provision for income taxes		(934)	165
Net income		37,168	34,489
Depreciation and amortization [Abstract]
Total depreciation and amortization		31,131	31,261
Assets [Abstract]
Total assets		2,236,372		$ 2,171,283
Operating/Reportable Segments [Member] | Propane [Member]
Revenues [Abstract]
Total revenues		322,130	269,459
Operating income (loss):
Total operating income	[1]	74,551	74,663
Depreciation and amortization [Abstract]
Total depreciation and amortization		27,781	27,384
Assets [Abstract]
Total assets		2,110,715		2,066,997
Operating/Reportable Segments [Member] | Fuel Oil and Refined Fuels [Member]
Revenues [Abstract]
Total revenues		25,315	22,096
Operating income (loss):
Total operating income		3,824	2,848
Depreciation and amortization [Abstract]
Total depreciation and amortization		579	631
Assets [Abstract]
Total assets		54,943		49,863
Operating/Reportable Segments [Member] | Natural Gas and Electricity [Member]
Revenues [Abstract]
Total revenues		13,147	13,067
Operating income (loss):
Total operating income		3,485	3,120
Depreciation and amortization [Abstract]
Total depreciation and amortization		0	0
Assets [Abstract]
Total assets		15,816		12,455
Operating/Reportable Segments [Member] | All Other [Member]
Revenues [Abstract]
Total revenues		12,685	12,685
Operating income (loss):
Total operating income		(5,233)	(5,206)
Depreciation and amortization [Abstract]
Total depreciation and amortization		50	70
Assets [Abstract]
Total assets		3,753		2,147
Operating/Reportable Segments [Member] | Corporate [Member]
Operating income (loss):
Total operating income		(20,879)	(21,940)
Depreciation and amortization [Abstract]
Total depreciation and amortization		2,721	$ 3,176
Assets [Abstract]
Total assets		$ 51,145		$ 39,821

[1] Includes the loss on sale of business of $4,823 for the three months ended December 30, 2017 (see Note 3).