Employee Benefit Plans (Effect of a 1% Change in Health Care Cost Trend Rate Assumptions) (Details) $ in Thousands	12 Months Ended
Sep. 30, 2020 USD ($)
1% Increase
Effect on total service and interest cost components	$ 132
Effect on accumulated postretirement benefit obligation	3,042
1% Decrease
Effect on total service and interest cost components	(105)
Effect on accumulated postretirement benefit obligation	$ (2,454)

Defined Benefit Plan, Effect of One-Percentage Point Decrease in Assumed Health Care Cost Trend Rates [Abstract]

No definition available.

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- Definition

Defined Benefit Plan, Effect of One-Percentage Point Increase in Assumed Health Care Cost Trend Rates [Abstract]

+ References

No definition available.

+ Details

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- Definition

Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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- Definition

Amount of decrease in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point decrease in assumed health care cost trend rate.

+ References

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- Definition

Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate.

+ References

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- Definition

Amount of increase in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point increase in assumed health care cost trend rate.

+ References

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