Retirement and Post-Retirement Employee Benefit Plans - Schedule of Expected Benefit Payments Post Retirement Benefit Plan (Details) - Postretirement Plans $ in Thousands	Sep. 30, 2020 USD ($)
Company Payments
2021	$ 22,632
2022	16,263
2023	16,590
2024	17,517
2025	18,353
2026-2030	101,158
Retiree Payments
2021	4,368
2022	4,772
2023	5,144
2024	5,651
2025	6,104
2026-2030	35,039
Subsidy Payments
2021	0
2022	0
2023	0
2024	0
2025	0
2026-2030	0
Total Postretirement Benefits
2021	27,000
2022	21,035
2023	21,734
2024	23,168
2025	24,457
2026-2030	$ 136,197

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

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Postretirement Benefits [Abstract]

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Retiree Payments [Abstract]

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Subsidy Payments [Abstract]

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

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

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

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

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

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

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Amount of prescription drug subsidy receipt expected after fifth fiscal year following current fiscal year.

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