Defined Benefit Pension and Other Postretirement Plans - Narrative (Details) - USD ($)	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans
Contribution made to Pension and Post-retirement Plans	$ 2,800,000	$ 2,500,000
Expected contribution to pension plan during remainder of fiscal year	8,500,000
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans
Contribution made to Pension and Post-retirement Plans	$ 0	$ 0