Retirement Plans (Components Of Net Periodic Benefit Cost) (Details) $ in Thousands		4 Months Ended
		Jan. 20, 2019 USD ($) defined_benefit_plan healthcare_plan	Jan. 21, 2018 USD ($)
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Number of sponsored defined benefit pension plans | defined_benefit_plan		2
Number of postretirement health care plans | healthcare_plan		2
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		6.20%
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost		$ 7,048	$ 6,879
Service cost		0	151
Expected return on plan assets	[1]	(8,104)	(8,144)
Actuarial gain (2)	[2]	1,219	1,498
Amortization of unrecognized prior service cost	[2]	35	45
Net periodic benefit cost		198	429
Postretirement Healthcare Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost		307	294
Actuarial gain (2)	[2]	(49)	(8)
Net periodic benefit cost		$ 258	$ 286

[1] Determined as of the beginning of the year based on a return on asset assumption of 6.2%.

[2] Amounts were reclassified from accumulated OCI into net earnings as a component of “Other pension and post-retirement expenses, net