Pension Plans and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 26, 2021	Mar. 27, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020	Jun. 27, 2020	Sep. 26, 2020
Components of net periodic benefit costs included in operating expenses [Abstract]
Contribution to defined pension benefit plan				$ 5,255	$ 2,030
Pension settlement charge				712	$ 900
Estimated obligation due to full withdrawal multi employer pension plans	$ 19,607			19,607			$ 20,396
Defined Benefit Pension Plan [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Defined benefit plan expected future benefit payments	6,250			6,250
Settlement threshold amount	2,135	$ 2,135
Pension settlement charge	142	$ 570	$ 900	712		$ 900
Defined Benefit Pension Plan [Member] | Other, Net [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Contribution to defined pension benefit plan				5,255
Post-Retirement Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Defined benefit plan expected future benefit payments	$ 843			843
Post-Retirement Benefits [Member] | Other, Net [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Employer contribution for postretirement health care and life insurance				$ 525