Unit-Based Compensation Arrangements - Summary of Activity In the Restricted Units Plans (Details) - 2009 Restricted Unit Plan [Member] - $ / shares		12 Months Ended
		Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Units [Rollforward]
Outstanding, beginning of period (in units)		988,339	696,131	621,045
Awarded (in units)		471,111	618,268	424,431
Forfeited (in units)		(9,975)	(5,904)	(14,092)
Vested (in units)	[1]	(487,659)	(320,156)	(335,253)
Outstanding, end of period (in units)		961,816	988,339	696,131
Weighted Average Grant Date Fair Value Per Unit [Abstract]
Outstanding, beginning of period (in dollars per unit)		$ 18.12	$ 19.47	$ 22.10
Awarded (in dollars per unit)		18.19	18.13	19.52
Forfeited (in dollars per unit)		(18.01)	(18.34)	(19.70)
Vested (in dollars per unit)	[1]	(19.22)	(21.08)	(24.39)
Outstanding, end of period (in dollars per unit)		$ 17.60	$ 18.12	$ 19.47

[1] During fiscal 2020, 2019 and 2018, the Partnership withheld 76,453, 59,227 and 34,388 Common Units, respectively, from participants for income tax withholding purposes for those executive officers of the Partnership whose shares of restricted units vested during the period.