Employee Benefit Plans (Unfunded Commitments and Redemption Restrictions) (Details) - U.S. Plan - Pension Plan - USD ($) $ in Millions	12 Months Ended
Jul. 31, 2023	Jul. 31, 2022
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Unfunded Commitments	$ 6.0	$ 6.0
NAV
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
NAV	46.2	50.7
Global equity securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Unfunded Commitments	$ 1.8	1.8
Global equity securities \| Minimum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Redemption Notice (Days)	0 days
Global equity securities \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Redemption Notice (Days)	5 days
Global equity securities \| NAV
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
NAV	$ 33.6	37.0
Fixed income securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Unfunded Commitments	$ 0.0	0.0
Fixed income securities \| Minimum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Redemption Notice (Days)	0 days
Fixed income securities \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Redemption Notice (Days)	60 days
Fixed income securities \| NAV
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
NAV	$ 9.5	10.8
Real asset funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
Unfunded Commitments	4.2	4.2
Real asset funds \| NAV
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share
NAV	$ 3.1	$ 2.9

Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets

No definition available.

Name:	dci_DefinedBenefitPlanAlternativeInvestmentsFairValueOfPlanAssets
Namespace Prefix:	dci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Notice period the entity is required to deliver before it can redeem an investment calculated using net asset value per share, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, investments calculated by per unit, per membership interest, other equity or ownership interest and alternative investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A

+ Details

Name:	us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareInvestmentRedemptionNoticePeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

Name:	us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A

+ Details

Name:	us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: