Pension and Other Postretirement Benefits Narrative (Details)	3 Months Ended	6 Months Ended
Jan. 31, 2020 USD ($)	Jan. 31, 2020 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension Plan Obligation Decrease for Curtailment		$ 6,632,000
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax		1,592,000
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Voluntary contributions	$ 5,000,000
Estimated contributions in remainder of current fiscal year	$ 0	$ 0
Postretirement Health Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Medical Cost Trend Assumption	7.35%	7.35%
Ultimate Health Care Cost Trend Rate	4.50%	4.50%
Year that Rate Reaches Ultimate Trend Rate		2038
Supplemental Executive Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		$ 1,296,000

Defined Benefit Plan Voluntary Contribution

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- Definition

Amount of (increase) decrease in benefit obligation of defined benefit plan from event reducing expected years of future service of present employees or eliminating accrual of benefits for some or all future services of present employees.

+ References

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Amount of contributions expected to be received by defined benefit plan from employer in fiscal year. Excludes contributions paid by employer in current fiscal year.

+ References

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Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

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Ultimate trend rate for health care cost for defined benefit postretirement plan.

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- Definition

Year ultimate health care cost trend rate is expected to be reached, in CCYY format.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of tax expense (benefit) for increase (decrease) to other comprehensive income from settlement and curtailment gain (loss) of defined benefit plan.

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Amount, before tax, of increase (decrease) to other comprehensive income from settlement and curtailment gain (loss) of defined benefit plan.

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