Document and Entity Information	Total
Prospectus:
Document Type	497
Document Period End Date	Sep. 30, 2020
Entity Registrant Name	HARRIS ASSOCIATES INVESTMENT TRUST
Entity Central Index Key	0000872323
Entity Inv Company Type	N-1A
Amendment Flag	false
Document Creation Date	Apr. 30, 2021
Document Effective Date	Apr. 30, 2021
Prospectus Date	Dec. 15, 2020
Oakmark Bond Fund \| R6 Class
Prospectus:
Trading Symbol	OAZCX
Oakmark Bond Fund \| Advisor Class
Prospectus:
Trading Symbol	OAYCX
Oakmark Bond Fund \| Institutional Class
Prospectus:
Trading Symbol	OANCX

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The date the document was made available and submitted, in CCYY-MM-DD format. The date of submission, date of acceptance by the recipient, and the document effective date are all potentially different.

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The date when a document, upon receipt and acceptance, becomes officially effective, in CCYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.

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No definition available.

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The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
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-Section 12
-Subsection b-2

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One of: N-1A (Mutual Fund), N-1 (Open-End Separate Account with No Variable Annuities), N-2 (Closed-End Investment Company), N-3 (Separate Account Registered as Open-End Management Investment Company), N-4 (Variable Annuity UIT Separate Account), N-5 (Small Business Investment Company), N-6 (Variable Life UIT Separate Account), S-1 or S-3 (Face Amount Certificate Company), S-6 (UIT, Non-Insurance Product).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Trading symbol of an instrument as listed on an exchange.

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The date of the prospectus.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Prospectus Table.

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