Financial Instruments and Risk Management - Fair Value of the Partnership's Derivative Instruments and their Location in the Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 26, 2015	Sep. 27, 2014
Derivatives, Fair Value [Line Items]
Fair value - assets	$ 13,803	$ 11,672
Fair value - liabilities	10,184	10,806
Commodity-Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	13,063	9,533
Fair value - liabilities	8,132	7,127
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	740	2,139
Fair value - liabilities	2,052	3,679
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	7,498	3,986
Fair value - liabilities	2,567	1,580
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	7,013	3,924
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	485	62
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	0	1,527
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	2,567	53
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	1,312	1,540
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	1,112	1,257
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	$ 200	$ 283