CONDENSED CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL (unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Unitholders [Member]	Accumulated Other Comprehensive (Loss) [Member]
Balance, beginning of period at Sep. 29, 2018	$ 493,824	$ 518,494	$ (24,670)
Balance (in units) at Sep. 29, 2018		61,405
Net (loss) income	119,694	$ 119,694
Amortization of net actuarial losses and prior service credits into earnings	1,656		1,656
Partnership distributions	(110,841)	(110,841)
Common Units issued under Restricted Unit Plans	(1,349)	$ (1,349)
Common Units issued under Restricted Unit Plans (in units)		261
Recognition in earnings of net actuarial loss for pension settlement	0
Common Units issued for acquisition of business	1,600	$ 1,600
Common Units issued for acquisition of business (in units)		69
Compensation costs recognized under Restricted Unit Plans	8,855	$ 8,855
Balance, end of period at Jun. 29, 2019	513,439	$ 536,453	(23,014)
Balance (in units) at Jun. 29, 2019		61,735
Balance, beginning of period at Mar. 29, 2019	575,048	$ 598,614	(23,566)
Balance (in units) at Mar. 29, 2019		61,664
Net (loss) income	(29,041)	$ (29,041)
Amortization of net actuarial losses and prior service credits into earnings	552		552
Partnership distributions	(37,000)	(37,000)
Common Units issued under Restricted Unit Plans	0	$ 0
Common Units issued under Restricted Unit Plans (in units)		2
Recognition in earnings of net actuarial loss for pension settlement	0
Common Units issued for acquisition of business	1,600	$ 1,600
Common Units issued for acquisition of business (in units)		69
Compensation costs recognized under Restricted Unit Plans	2,280	$ 2,280
Balance, end of period at Jun. 29, 2019	513,439	$ 536,453	(23,014)
Balance (in units) at Jun. 29, 2019		61,735
Balance, beginning of period at Sep. 28, 2019	423,830
Balance, beginning of period (Including Cumulative Effect Adjustment of Lease Operation on Retained Earnings [Member]) at Sep. 28, 2019	423,938	$ 450,124	(26,186)
Balance (in units) (Including Cumulative Effect Adjustment of Lease Operation on Retained Earnings [Member]) at Sep. 28, 2019		61,735
Net (loss) income	101,946	$ 101,946
Amortization of net actuarial losses and prior service credits into earnings	1,623		1,623
Partnership distributions	(111,562)	(111,562)
Common Units issued under Restricted Unit Plans	(1,761)	$ (1,761)
Common Units issued under Restricted Unit Plans (in units)		398
Recognition in earnings of net actuarial loss for pension settlement	900		900
Compensation costs recognized under Restricted Unit Plans	7,084	$ 7,084
Balance, end of period at Jun. 27, 2020	422,168	$ 445,831	(23,663)
Balance (in units) at Jun. 27, 2020		62,133
Balance, beginning of period at Mar. 28, 2020	471,322	$ 496,426	(25,104)
Balance (in units) at Mar. 28, 2020		62,073
Net (loss) income	(15,578)	$ (15,578)
Amortization of net actuarial losses and prior service credits into earnings	541		541
Partnership distributions	(37,279)	(37,279)
Common Units issued under Restricted Unit Plans	0	$ 0
Common Units issued under Restricted Unit Plans (in units)		60
Recognition in earnings of net actuarial loss for pension settlement	900		900
Compensation costs recognized under Restricted Unit Plans	2,262	$ 2,262
Balance, end of period at Jun. 27, 2020	$ 422,168	$ 445,831	$ (23,663)
Balance (in units) at Jun. 27, 2020		62,133