Defined Benefit Pension and Other Postretirement Plans - Narrative (Details) - USD ($)	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure
Contribution made to Pension Plan	$ 0	$ 3,359,000
Expected contribution to pensions plans in the remainder of current fiscal year	11,500,000
VEBA
Defined Benefit Plan Disclosure
Contribution made to Pension Plan	$ 0	$ 0