Financial Instruments and Risk Management - Fair Value of the Partnership's Derivative Instruments and their Location in the Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 25, 2017	Sep. 24, 2016
Derivatives, Fair Value [Line Items]
Fair value - assets	$ 6,282	$ 7,072
Fair value - liabilities	6,131	4,780
Commodity-Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	6,282	6,842
Fair value - liabilities	6,131	4,345
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	0	230
Fair value - liabilities	0	435
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	1,604	4,852
Fair value - liabilities	1,453	2,355
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	1,418	3,306
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	186	1,546
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	1,453	1,002
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	0	1,353
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	$ 0	$ 205