Label	Element	Value
Virtus Vontobel Emerging Markets Opportunities Fund
Risk/Return:	rr_RiskReturnAbstract
Supplement to Prospectus [Text Block]	rr_SupplementToProspectusTextBlock	Virtus Opportunities Trust Supplement dated December 18, 2020 to the Summary Prospectuses and Statutory Prospectus, each dated January 28, 2020, as supplemented Important Notice to Investors Effective February 1, 2021, certain changes relating to sales charges and compensation to dealers will be made. These changes include lowered Sales Charges for Class A Shares of certain funds and dealers will no longer need to have an aggregate value of $50,000 or more per fund CUSIP to qualify for payment of 12b-1 fees. In addition, a maximum purchase amount will be applied to purchases of Class C Shares. Please see below for details about these changes. Summary Prospectus Changes
Risk/Return [Heading]	rr_RiskReturnHeading	Virtus Vontobel Emerging Markets Opportunities Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	Beginning on February 1, 2021, for the Virtus Duff & Phelps Global Infrastructure Fund, Virtus Duff & Phelps Global Real Estate Securities Fund, Virtus Duff & Phelps International Real Estate Securities Fund, Virtus Duff & Phelps Real Estate Securities Fund, Virtus KAR Emerging Markets Small-Cap Fund, Virtus KAR International Small-Cap Fund, Virtus KAR International Small-Mid Cap Fund, Virtus Vontobel Emerging Markets Opportunities Fund, Virtus Vontobel Foreign Opportunities Fund, Virtus Vontobel Global Opportunities Fund and Virtus Vontobel Greater European Opportunities Fund, in the “Shareholder Fees” table of the “Fees and Expenses” section of the summary prospectus, the Class A Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) will be 5.50%. Prior to February 1, 2021, the Class A Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price) will remain 5.75%
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	In addition, for the same funds listed above, the “Performance Information” section of the summary prospectuses reflects the higher sales charge before it will be lowered. Therefore, if you purchase Class A Shares with the new sales charges effective February 1, 2021, the Performance Information section of the summary prospectuses may be different than what is stated in the current prospectuses.
Performance Table Closing [Text Block]	rr_PerformanceTableClosingTextBlock	Investors should retain this supplement with the Prospectuses for future reference.

This table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 3
-Subsection instructions
-Paragraph 1
-Subparagraph b

+ Details

Name:	rr_ExpenseNarrativeTextBlock
Namespace Prefix:	rr_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

- Definition

Risk/Return Bar Chart and Table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 4
-Subsection b
-Paragraph 2

+ Details

Name:	rr_PerformanceNarrativeTextBlock
Namespace Prefix:	rr_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

- Definition

If the Fund has annual returns for at least one calendar year, provide a table showing the Fund's (A) average annual total return; (B) average annual total return (after taxes on distributions); and (C) average annual total return (after taxes on distributions and redemption). A Money Market Fund should show only the returns described in clause (A) of the preceding sentence. All returns should be shown for 1-, 5-, and 10- calendar year periods ending on the date of the most recently completed calendar year (or for the life of the Fund, if shorter), but only for periods subsequent to the effective date of the Fund's registration statement. The table also should show the returns of an appropriate broad-based securities market index as defined in Instruction 5 to Item 22(b)(7) for the same periods. A Fund that has been in existence for more than 10 years also may include returns for the life of the Fund. A Money Market Fund may provide the Fund's 7-day yield ending on the date of the most recent calendar year or disclose a toll-free (or collect) telephone number that investors can use to obtain the Fund's current 7-day yield. For a Fund (other than a Money Market Fund or a Fund described in General Instruction C.3.(d)(iii)), provide the information in the following table with the specified captions AVERAGE ANNUAL TOTAL RETURNS (For the periods ended December 31, _____)

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 4
-Subsection b
-Paragraph 2
-Subparagraph iii

+ Details

Name:	rr_PerformanceTableClosingTextBlock
Namespace Prefix:	rr_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	rr_RiskReturnAbstract
Namespace Prefix:	rr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Risk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicated

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 2

+ Details

Name:	rr_RiskReturnHeading
Namespace Prefix:	rr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element contains the text of a prospectus supplement (submission type 497) not already contained in an element containing amended text or other data from a previous submission.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A

+ Details

Name:	rr_SupplementToProspectusTextBlock
Namespace Prefix:	rr_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=ck0001005020_S000055178Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: