Pension Plans and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 30, 2019	Sep. 29, 2018
Components of net periodic benefit costs included in operating expenses [Abstract]
Contribution to defined pension benefit plan	$ 4,335	$ 3,839
Estimated obligation due to full withdrawal multi employer pension plans			$ 21,710	$ 22,509
Defined Benefit Pension Plan [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Defined benefit plan expected future benefit payments	5,350
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	4,335
Post-Retirement Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Defined benefit plan expected future benefit payments	1,129
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	$ 718