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	Dec. 26, 2015	Sep. 26, 2015
Derivatives, Fair Value [Line Items]
Fair value - assets	$ 6,849	$ 13,803
Fair value - liabilities	4,468	10,184
Commodity-Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	6,004	13,063
Fair value - liabilities	2,821	8,132
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	845	740
Fair value - liabilities	1,647	2,052
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	3,992	7,498
Fair value - liabilities	809	2,567
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	3,992	7,013
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	0	485
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	809	0
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	0	2,567
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	802	1,312
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	792	1,112
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	$ 10	$ 200