Employee Benefit Plans - Schedule of Measurement of Partnership's Pension Plan Assets by Category (Details) - Pension Benefits [Member] - USD ($) $ in Thousands		Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Deferred Compensation Arrangement With Individual Postretirement Benefits [Line Items]
Fair value of plan assets		$ 80,001	$ 80,913	$ 78,032
Short-term investments [Member]
Deferred Compensation Arrangement With Individual Postretirement Benefits [Line Items]
Fair value of plan assets	[1]	1,485	1,502
Domestic equity securities [Member]
Deferred Compensation Arrangement With Individual Postretirement Benefits [Line Items]
Fair value of plan assets	[1],[2]	4,138	4,314
International equity securities [Member]
Deferred Compensation Arrangement With Individual Postretirement Benefits [Line Items]
Fair value of plan assets	[1],[2]	7,117	7,393
Fixed income securities [Member]
Deferred Compensation Arrangement With Individual Postretirement Benefits [Line Items]
Fair value of plan assets	[1],[3]	$ 67,261	$ 67,704

[1] Includes funds which are not publicly traded and are valued at the net asset value of the units provided by the fund issuer.

[2] Includes funds which invest primarily in a diversified portfolio of publicly traded U.S. and Non-U.S. common stock.

[3] Includes funds which invest primarily in publicly traded and non-publicly traded, investment grade corporate bonds, U.S. government bonds and asset-backed securities.