Retirement and Post-Retirement Employee Benefit Plans - Schedule of Expected Benefit Payments Post Retirement Benefit Plan (Details) - Postretirement Plans $ in Thousands	Sep. 30, 2018 USD ($)
Company Payments
2019	$ 14,407
2020	13,363
2021	13,572
2022	14,503
2023	15,405
2024-2028	88,120
Retiree Payments
2019	3,532
2020	3,742
2021	3,975
2022	4,412
2023	4,832
2024-2028	29,514
Subsidy Payments
2019	0
2020	0
2021	0
2022	0
2023	0
2024-2028	0
Total Postretirement Benefits
2019	17,939
2020	17,105
2021	17,547
2022	18,915
2023	20,237
2024-2028	$ 117,634

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The amount of the aggregate postretirement benefits estimated to be paid in the five fiscal years thereafter (the aggregate amount of postretirement benefits estimated to be paid in years 6 through 10 after the date of the latest statement of financial position) by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 5 by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 4 by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 1 by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 3 by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 2 by the Company.

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The amount of the postretirement benefits estimated to be paid in Year 5 by the retirees.

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The amount of the postretirement benefits estimated to be paid in Year 4 by the retirees.

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The amount of the postretirement benefits estimated to be paid in Year 1 by the retirees.

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The amount of the postretirement benefits estimated to be paid in Year 3 by the retirees.

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Postretirement Benefits [Abstract]

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Retiree Payments [Abstract]

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Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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Amount of prescription drug subsidy receipts expected after fifth fiscal year following latest fiscal year.

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