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. 26, 2016	Sep. 26, 2015
Derivatives, Fair Value [Line Items]
Fair value - assets	$ 5,752	$ 13,803
Fair value - liabilities	5,261	10,184
Commodity-Related Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	5,163	13,063
Fair value - liabilities	4,012	8,132
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	589	740
Fair value - liabilities	1,249	2,052
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	3,233	7,498
Fair value - liabilities	2,082	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	2,399	7,013
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value - assets	834	485
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	1,882	0
Derivatives Not Designated as Hedging Instruments [Member] | Commodity-Related Derivatives [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	200	2,567
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	660	1,312
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	660	1,112
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value - liabilities	$ 0	$ 200