Repayment Date Of Long Term Debt

Name:	dci_RepaymentDateOfLongTermDebt
Namespace Prefix:	dci
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Interest rate stated in the contractual debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 7
-Section 03
-Paragraph 16

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer plus capital lease obligations due to be paid more than one year after the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section H

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Obligation related to long-term debt (excluding convertible debt) and capital leases, the portion which is due in one year or less in the future.

+ References

+ Details

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

Long-Term Debt (Schedule Of Long-Term Debt) (Details) In Thousands, unless otherwise specified			12 Months Ended																12 Months Ended				12 Months Ended
	Jul. 31, 2011 USD ($)	Jul. 31, 2010 USD ($)	Jul. 31, 2011 6.39% Unsecured Senior Notes Due August 15, 2010 [Member]	Jul. 31, 2010 6.39% Unsecured Senior Notes Due August 15, 2010 [Member] USD ($)	Jul. 31, 2011 4.85% Unsecured Senior Notes Due December 17, 2011 [Member] USD ($)	Jul. 31, 2010 4.85% Unsecured Senior Notes Due December 17, 2011 [Member] USD ($)	Jul. 31, 2011 6.59% Unsecured Senior Notes Due November 14, 2013 [Member] USD ($)	Jul. 31, 2010 6.59% Unsecured Senior Notes Due November 14, 2013 [Member] USD ($)	Jul. 31, 2011 5.48% Unsecured Senior Notes Due June 1, 2017 [Member] USD ($)	Jul. 31, 2010 5.48% Unsecured Senior Notes Due June 1, 2017 [Member] USD ($)	Jul. 31, 2011 5.48% Unsecured Senior Notes Due September 28, 2017 [Member] USD ($)	Jul. 31, 2010 5.48% Unsecured Senior Notes Due September 28, 2017 [Member] USD ($)	Jul. 31, 2011 5.48% Unsecured Senior Notes Due November 30, 2017 [Member] USD ($)	Jul. 31, 2010 5.48% Unsecured Senior Notes Due November 30, 2017 [Member] USD ($)	Jul. 31, 2011 1.418% Guaranteed Senior Notes Due January 31, 2012 [Member] JPY (¥)	Jul. 31, 2010 1.418% Guaranteed Senior Notes Due January 31, 2012 [Member] JPY (¥)	Jul. 31, 2011 1.418% Guaranteed Senior Notes Due January 31, 2012 [Member] USD ($)	Jul. 31, 2010 1.418% Guaranteed Senior Notes Due January 31, 2012 [Member] USD ($)	Jul. 31, 2011 2.019% Guaranteed Senior Note Due May 18, 2014 [Member] JPY (¥)	Jul. 31, 2010 2.019% Guaranteed Senior Note Due May 18, 2014 [Member] JPY (¥)	Jul. 31, 2011 2.019% Guaranteed Senior Note Due May 18, 2014 [Member] USD ($)	Jul. 31, 2010 2.019% Guaranteed Senior Note Due May 18, 2014 [Member] USD ($)	Jul. 31, 2011 Variable Rate Industrial Development Revenue Bonds Due September 1, 2024 Interest Rate of 0.40% [Member] USD ($)	Jul. 31, 2010 Variable Rate Industrial Development Revenue Bonds Due September 1, 2024 Interest Rate of 0.40% [Member] USD ($)	Jul. 31, 2011 Capitalized Lease Obligations And Other, With Various Maturity Dates And Interest Rates [Member] USD ($)	Jul. 31, 2010 Capitalized Lease Obligations And Other, With Various Maturity Dates And Interest Rates [Member] USD ($)	Jul. 31, 2011 Terminated Interest Rate Swap Contract [Member] USD ($)	Jul. 31, 2010 Terminated Interest Rate Swap Contract [Member] USD ($)
Total	$ 253,619	$ 261,728		$ 4,999	$ 30,000	$ 30,000	$ 80,000	$ 80,000	$ 50,000	$ 50,000	$ 25,000	$ 25,000	$ 25,000	$ 25,000			$ 15,595	$ 13,884			$ 21,442	$ 19,091		$ 7,755	$ 796	$ 890	$ 5,786	$ 5,109
Less current maturities	47,871	5,536
Total long-term debt	205,748	256,192
Interest rate percentage			6.39%	6.39%	4.85%	4.85%	6.59%	6.59%	5.48%	5.48%	5.48%	5.48%	5.48%	5.48%			1.418%	1.418%			2.019%	2.019%
Interest rate percentage, at period end																							0.40%	0.40%
Senior unsecured notes, due date			Aug. 15, 2010	Aug. 15, 2010	Dec. 17, 2011	Dec. 17, 2011	Nov. 14, 2013	Nov. 14, 2013	Jun. 01, 2017	Jun. 01, 2017	Sep. 28, 2017	Sep. 28, 2017	Nov. 30, 2017	Nov. 30, 2017	Jan. 31, 2012	Jan. 31, 2012			May 18, 2014	May 18, 2014			Sep. 01, 2024	Sep. 01, 2024
Long-term debt, principal payment					$ 30,000	$ 30,000	$ 80,000	$ 80,000	$ 50,000	$ 50,000	$ 25,000	$ 25,000	$ 25,000	$ 25,000	¥ 1,200,000	¥ 1,200,000			¥ 1,650,000	¥ 1,650,000			$ 7,755	$ 7,755
Long-term debt, repayment date			Aug. 16, 2010	Aug. 16, 2010