Employee Benefit Plans (Details) $ in Millions	3 Months Ended
Oct. 31, 2018 USD ($) plan
Defined Benefit Plan Disclosure [Line Items]
Number of U.S. plans \| plan	2
Annual company retirement contribution in addition to 401 (k) match, percent	3.00%
Pension Plan \| United States
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 1.0
Estimated future contributions to pension plans	3.1
Pension Plan \| Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Company contributions	0.3
Additional future contribution towards pension plans for the remainder of Fiscal 2018	$ 1.0

Additional contributions to pension plans.

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

Defined contribution plan, annual retirement contributions, percent.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of U.S. Plans.

+ References

No definition available.

+ Details

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Namespace Prefix:	dci_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

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Balance Type:	debit
Period Type:	duration

- 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.

+ Details

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Period Type:	duration

- Definition

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

+ References

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- Details

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