Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of long-term debt and lease obligation, classified as current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_ThreePointSevenTwoPercentUnsecuredSeniorNotesDueMarchTwentySevenTwoThousandTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_UnsecuredSeniorNotesSixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_A2510YearNoteDue2031Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_VariableRateCommittedUnsecuredTermLoanDueOctoberTwentyEightTwoThousandTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_A2127YearNoteDue2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_UnsecuredSeniorNotesFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_VariableRateGuaranteedSeniorNoteDueMayTwentyTwoThousandTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_VariableRateGuaranteedSeniorNoteDueJulyFifteenTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dci_VariableRateCommittedRevolvingCreditFacilityDueMayTwentyFirstTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Short-Term Borrowings and Long-Term Debt (Schedule of Long-term Debt) (Details)	Jul. 31, 2022 USD ($)	Jul. 31, 2022 EUR (€)	Jul. 31, 2022 JPY (¥)	Jul. 31, 2021 USD ($)	Jul. 31, 2021 JPY (¥)
Debt Instrument
Debt issuance costs, net	$ (2,400,000)			$ (2,300,000)
Subtotal	644,300,000			461,000,000.0
Less current maturities	0			0
Long-term debt	644,300,000			$ 461,000,000.0
Unsecured notes \| 3.72% fixed rate unsecured senior notes maturing 2024
Debt Instrument
Principal amount	$ 125,000,000
Debt instrument interest rate (percent)	3.72%	3.72%	3.72%	3.72%	3.72%
Long-term debt, gross	$ 125,000,000.0			$ 125,000,000.0
Unsecured notes \| 3.18% fixed rate unsecured senior notes maturing 2030
Debt Instrument
Principal amount	$ 125,000,000
Debt instrument interest rate (percent)	3.18%	3.18%	3.18%	3.18%	3.18%
Long-term debt, gross	$ 125,000,000.0			$ 125,000,000.0
Unsecured notes \| 2.50% fixed rate unsecured senior notes maturing 2031
Debt Instrument
Principal amount	$ 100,000,000
Debt instrument interest rate (percent)	2.50%	2.50%	2.50%	2.50%	2.50%
Long-term debt, gross	$ 100,000,000.0			$ 0
Unsecured notes \| .70% variable rate unsecured senior notes maturing 2024
Debt Instrument
Principal amount \| €		€ 80,000,000
Debt instrument interest rate (percent)	0.91%	0.91%	0.91%	0.70%	0.70%
Long-term debt, gross	$ 81,700,000			$ 95,100,000
Unsecured notes \| 2.12% fixed rate unsecured senior notes maturing 2028
Debt Instrument
Principal amount	$ 50,000,000
Debt instrument interest rate (percent)	2.12%	2.12%	2.12%	2.12%	2.12%
Long-term debt, gross	$ 50,000,000.0			$ 0
Unsecured notes \| 2.93% fixed rate unsecured senior notes maturing 2025
Debt Instrument
Principal amount	$ 25,000,000
Debt instrument interest rate (percent)	2.93%	2.93%	2.93%	2.93%	2.93%
Long-term debt, gross	$ 25,000,000.0			$ 25,000,000.0
Unsecured notes \| .42% variable rate unsecured term loan maturing 2024
Debt Instrument
Principal amount \| ¥			¥ 1,000,000,000
Debt instrument interest rate (percent)	0.41%	0.41%	0.41%	0.42%	0.42%
Long-term debt, gross \| ¥			¥ 7,500,000		¥ 9,100,000
Unsecured notes \| .47% variable rate unsecured term loan 2026
Debt Instrument
Principal amount \| ¥			¥ 1,000,000,000
Debt instrument interest rate (percent)	0.49%	0.49%	0.49%	0.47%	0.47%
Long-term debt, gross \| ¥			¥ 7,500,000		¥ 9,100,000
Unsecured revolving credit facility \| Unsecured notes \| 1.29 % Variable rate unsecured credit facility maturing 2026
Debt Instrument
Principal amount	$ 500,000,000.0
Debt instrument interest rate (percent)	2.88%	2.88%	2.88%	1.10%	1.10%
Long-term debt, gross	$ 125,000,000.0			$ 75,000,000.0