Goodwill and Other Intangible Assets - Carrying Values of Goodwill Assigned to Partnership's Operating Segments (Details) - USD ($) $ in Thousands		6 Months Ended
		Mar. 26, 2016	Sep. 26, 2015
Goodwill [Line Items]
Goodwill		$ 1,108,601	$ 1,093,891
Accumulated adjustments		(6,462)	(6,462)
Goodwill, net		1,102,139	1,087,429
Goodwill acquired during fiscal 2016	[1]	14,710
Propane [Member]
Goodwill [Line Items]
Goodwill		1,089,801	1,075,091
Accumulated adjustments		0	0
Goodwill, net		1,089,801	1,075,091
Goodwill acquired during fiscal 2016	[1]	14,710
Fuel Oil and Refined Fuels [Member]
Goodwill [Line Items]
Goodwill		10,900	10,900
Accumulated adjustments		(6,462)	(6,462)
Goodwill, net		4,438	4,438
Goodwill acquired during fiscal 2016	[1]	0
Natural Gas and Electricity [Member]
Goodwill [Line Items]
Goodwill		7,900	7,900
Accumulated adjustments		0	0
Goodwill, net		7,900	$ 7,900
Goodwill acquired during fiscal 2016	[1]	$ 0

[1] Increases reflect the Propane USA acquisition (Note 3)