Pension Plans and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 25, 2017	Mar. 26, 2016	Sep. 24, 2016
Components of net periodic benefit costs included in operating expenses [Abstract]
Contribution to defined pension benefit plan	$ 2,792	$ 0
Estimated obligation due to withdrawal multi employer pension plans	23,176		$ 24,205
Defined Benefit Pension Plan [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Defined pension benefit plan expected contribution to be paid for the remainder of fiscal year	9,527
Contribution to defined pension benefit plan	2,792
Post-Retirement Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Projected annual contribution requirements related to the Partnership's postretirement health care and life insurance benefit plan for fiscal year	922
Employer contribution for postretirement health care and life insurance	$ 553