Interim Pension and Other Postretirement Benefits (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Pension Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost		$ 4,575	$ 5,217	$ 9,135	$ 10,433
Interest Cost		6,433	6,297	12,863	12,594
Expected return on assets		(6,916)	(6,994)	(13,833)	(13,988)
Amortization of prior service (credit)/cost		(58)	(58)	(116)	(116)
Amortization of actuarial (gain) loss		3,085	4,249	6,174	8,498
Settlements		2,415	0	2,415	0
Net periodic pension cost		$ 9,534	$ 8,711	$ 16,638	$ 17,421
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate		3.89%	3.73%	3.89%	3.73%
Rate of compensation increase		3.50%	3.50%	3.50%	3.50%
Expected return on plan assets		6.75%	7.00%	6.75%	7.00%
Supplemental Employee Retirement Plan [Member]
Components of net periodic pension cost [Abstract]
Settlements		$ (2,400)
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate	4.12%	4.12%	3.73%	4.12%	3.73%
Rate of compensation increase		3.50%	3.50%	3.50%	3.50%
Current Year Benefit Plan Contributions [Abstract]
Change in Net Periodic Cost, Remainder of Year		$ 100
Other Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost		3,019	$ 3,109	$ 6,039	$ 6,218
Interest Cost		2,727	2,670	5,454	5,340
Expected return on assets		(2,001)	(1,797)	(4,003)	(3,593)
Amortization of prior service (credit)/cost		3	(411)	6	(822)
Amortization of actuarial (gain) loss		(1,619)	(707)	(3,237)	(1,414)
Settlements		0	0	0	0
Net periodic pension cost		$ 2,129	$ 2,864	$ 4,259	$ 5,729
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate		3.89%	3.73%	3.89%	3.73%
Expected return on plan assets		4.29%	4.45%	4.29%	4.45%
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual				$ 7,500
Other Benefits [Member] | Minimum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year		$ 10,000		10,000
Other Benefits [Member] | Maximum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year		$ 20,000		$ 20,000