Interim Pension and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost	$ 4,698	$ 5,051
Interest Cost	7,095	6,699
Expected return on assets	(6,881)	(6,436)
Amortization of transition (asset)/obligation	0	0
Amortization of prior service (credit)/cost	(57)	(49)
Amortization of actuarial (gain) loss	3,320	3,917
Net periodic pension cost	$ 8,175	$ 9,182
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate	4.55%	4.43%
Rate of compensation increase	3.50%	3.50%
Expected return on plan assets	7.00%	7.25%
Other Benefits [Member]
Components of net periodic pension cost [Abstract]
Service Cost	$ 2,706	$ 3,896
Interest Cost	3,106	3,596
Expected return on assets	(1,566)	(1,608)
Amortization of transition (asset)/obligation	21	68
Amortization of prior service (credit)/cost	(411)	(411)
Amortization of actuarial (gain) loss	(542)	0
Net periodic pension cost	$ 3,314	$ 5,541
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate	4.55%	4.43%
Expected return on plan assets	4.45%	4.60%
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual	$ 5,500
Other Benefits [Member] | Minimum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year	15,000
Other Benefits [Member] | Maximum [Member]
Current Year Benefit Plan Contributions [Abstract]
Defined Benefit Plan, Expected Contributions in Current Fiscal Year	$ 25,000