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	Sep. 29, 2018	Sep. 30, 2017
Derivatives, Fair Value [Line Items]
Fair value - assets	$ 23,181	$ 16,378
Fair value - liabilities	14,582	6,853
Commodity-Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	23,181	16,378
Fair value - liabilities	14,582	6,853
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	14,888	11,935
Fair value - liabilities	6,289	2,410
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	14,875	11,164
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	13	771
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	6,122	1,978
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	$ 167	$ 432