Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	TRANSAMERICA FUNDS
Prospectus Date	rr_ProspectusDate	Mar. 01, 2022
Class I2 | Transamerica Mid Cap Value
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Times New Roman;font-size:11pt;font-weight:bold;">Transamerica Mid Cap Value</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">Investment Objective:</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Seeks growth from capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Fees and Expenses:</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;font-weight:bold;margin-left:0%;">Shareholder Fees (fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;font-weight:bold;">Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Portfolio Turnover:</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the fund’s performance.During the most recent fiscal year, the portfolio turnover rate for the fund was 25% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	25.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Example:</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds.The Example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Investment Strategies:</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The fund’s sub-adviser, J.P. Morgan Investment Management Inc. (the “sub-adviser”), seeks to achieve the fund’s objective by investing, under normal circumstances, at least 80% of the fund’s net assets (plus the amount of borrowings, if any, for investment purposes) in equity securities of mid cap companies. Mid cap companies are companies with market capitalizations equal to those within the universe of the Russell Midcap®Value Index1 and/or between $1 billion and $20 billion at the time of purchase. As of the current reconstitution of the Russell Midcap® Value Index on June 30, 2021, the market capitalizations of the companies in the index ranged from $5.2 billion to $46.4 billion. The fund will normally only purchase securities that are traded on registered exchanges or the over-the-counter market in the United States. The fund may invest in other equity securities, which include preferred stocks, convertible securities and foreign securities, which may take the form of depositary receipts. Maximum weightings in any sector are double that of the benchmark or 25%, whichever is greater. Value stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “growth” stocks.The sub-adviser may use derivatives, including futures contracts, covered call options, options on futures contracts and stock index futures and options, for the purpose of remaining fully invested, equitizing cash, reducing transaction costs or managing interest rate risk.As part of its investment process, alongside traditional fundamental financial analysis, the sub-adviser also evaluates whether environmental, social and governance (“ESG”) factors could, in the sub-adviser’s view, have a material negative or positive impact on the cash flows or risk profiles of many companies in the universe in which the fund may invest. The sub-adviser seeks to identify material ESG risks and opportunities for each company and the potential for financial impacts. These assessments of ESG factors are subjective and may not be conclusive. The sub-adviser may purchase or retain securities of companies that it believes may be negatively impacted by ESG factors while it may divest or not invest in securities of issuers that it believes may be positively impacted by such factors.1 “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Risks:</span>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Risk is inherent in all investing. Many factors and risks affect the fund's performance, including those described below. The value of your investment in the fund, as well as the amount of return you receive on your investment, may fluctuate significantly day to day and over time. You may lose part or all of your investment in the fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks (in alphabetical order after certain key risks) of investing in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.You may lose money if you invest in this fund.Market – The market prices of the fund’s securities or other assets may go up or down, sometimes rapidly or unpredictably, due to general market conditions, overall economic trends or events, inflation, changes in interest rates, governmental actions or interventions, actions taken by the U.S. Federal Reserve or foreign central banks, market disruptions caused by tariffs, trade disputes or other factors, political developments, investor sentiment, the global and domestic effects of a pandemic, and other factors that may or may not be related to the issuer of the security or other asset. If the market prices of the fund’s securities and assets fall, the value of your investment will go down.Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or political events, trading and tariff arrangements, public health events (such as the spread of infectious disease), wars, terrorism, cybersecurity events,technology and data interruptions, natural disasters, and other circumstances in one or more countries or regions could be highly disruptive to, and have profound impacts on, global economies or markets. As a result, whether or not the fund invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the fund’s investments may go down.The pandemic of the novel coronavirus respiratory disease designated COVID-19 has resulted in extreme volatility in the financial markets, a domestic and global economic downturn, severe losses, particularly to some sectors of the economy and individual issuers, and reduced liquidity of many instruments.There also have been significant disruptions to business operations, including business closures; strained healthcare systems; disruptions to supply chains and employee availability; large fluctuations in consumer demand; and widespread uncertainty regarding the duration and long-term effects of the pandemic. The domestic and global economic downturn may be prolonged. The pandemic may result in domestic and foreign political and social instability, damage to diplomatic and international trade relations, and continued volatility and/or decreased liquidity in the securities markets. Developing or emerging market countries may be more impactedby the pandemic.The U.S. government and the Federal Reserve, as well as certain foreign governments and central banks, have taken extraordinary actions to support local and global economies and the financial markets in response to the COVID-19 pandemic, including by pushing interest rates to very low levels. This and other government intervention into the economy and financial markets to address the pandemic may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Government actions to mitigate the economic impact of the pandemic have resulted in large expansion of government deficits and debt, the long-term consequences of which are not known. Rates of inflation have recently risen, which could adversely affect economies and markets.The COVID-19 pandemic could continue to adversely affect the value and liquidity of the fund’s investments, impair the fund’s ability to satisfy redemption requests, and negatively impact the fund’s performance. In addition, the pandemic, and measures taken to mitigate its effects, could result in disruptions to the services provided to the fund by its service providers.Equity Securities – Equity securities generally have greater risk of loss than debt securities. Stock markets are volatile and the value of equity securities may go up or down, sometimes rapidly and unpredictably. The value of equity securities fluctuates based on real or perceived changes in a company’s financial condition, factors affecting a particular industry or industries, and overall market, economic and political conditions. If the market prices of the equity securities owned by the fund fall, the value of your investment in the fund will decline. The fund may lose its entire investment in the equity securities of an issuer. A change in financial condition or other event affecting a single issuer may adversely impact securities markets as a whole.Medium Capitalization Companies – The fund will be exposed to additional risks as a result of its investments in the securities of medium capitalization companies. Investing in medium capitalization companies involves greater risk than is customarily associated with more established companies. The prices of securities of medium capitalization companies generally are more volatile and are more likely to be adversely affected by changes in earnings results and investor expectations or poor economic or market conditions. Securities of medium capitalization companies may underperform larger capitalization companies, may be harder to sell at times and at prices the portfolio managers believe appropriate and may offer greater potential for losses.Value Investing – The prices of securities the sub-adviser believes are undervalued may not appreciate as anticipated or may go down. The value approach to investing involves the risk that stocks may remain undervalued, undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Value stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “growth” stocks.Focused Investing – To the extent the fund invests in a limited number of countries, regions, sectors, industries or market segments, in a limited number of issuers, or in issuers in related businesses or that are subject to related operating risks, the fund will be more susceptible to negative events affecting those countries, regions, sectors, industries, segments or issuers, and the value of its shares may be more volatile than if it invested more widely.Management – The value of your investment may go down if the investment manager’s or sub-adviser's judgments and decisions are incorrect or otherwise do not produce the desired results, or if the investment strategy does not work as intended. You may also suffer losses if there are imperfections, errors or limitations in the quantitative, analytic or other tools, resources, information and data used, investment techniques applied, or the analyses employed or relied on, by the investment manager or sub-adviser, if such tools, resources, information or data are used incorrectly or otherwise do not work as intended, or if the investment manager’s or sub-adviser's investment style is out of favor or otherwise fails to produce the desired results. Any of these things could cause the fund to lose value or its results to lag relevant benchmarks or other funds with similar objectives.Active Trading – The fund may purchase and sell securities without regard to the length of time held. Active trading may be more pronounced during periods of market volatility, may have a negative impact on performance and may generate greater amounts of short-term capital gains.Convertible Securities – Convertible securities are subject to risks associated with both fixed-income and equity securities. For example, if market interest rates rise, the value of a convertible security typically falls. In addition, a convertible security is subject to the risk that the issuer will not be able to pay interest or dividends when due, and the market value of the security may change based on the issuer’s actual or perceived creditworthiness. Since the convertible security derives a portion of its value from the underlying common stock, the security is also subject to the same types of market and issuer-specific risks that apply to the underlying common stock. Convertible securities generally offer lower interest or dividend yields than non-convertible securities of similar quality.Counterparty – The fund could lose money if the counterparties to derivatives, repurchase agreements and other financial contracts entered into for the fund do not fulfill their contractual obligations. In addition, the fund may incur costs and may be hindered or delayed in enforcing its rights against a counterparty.Credit – If an issuer or other obligor (such as a party providing insurance or other credit enhancement) of a security held by the fund or a counterparty to a financial contract with the fund is unable or unwilling to meet its financial obligations, or is downgraded or perceived to be less creditworthy (whether by market participants or otherwise), or if the value of any underlying assets declines, the value of your investment will typically decline. A decline may be significant, particularly in certain market environments. In addition, the fund may incur costs and may be hindered or delayed in enforcing its rights against an issuer, obligor or counterparty.Currency – The value of a fund’s investments in securities denominated in foreign currencies increases or decreases as the rates of exchange between those currencies and the U.S. dollar change. U.S. dollar-denominated securities of foreign issuers may also be affected by currency risk. Currency exchange rates can be volatile and may fluctuate significantly over short periods of time. Currency conversion costs and currency fluctuations could reduce or eliminate investment gains or add to investment losses. A fund may be unable or may choose not to hedge its foreign currency exposure.Depositary Receipts – Depositary receipts are generally subject to the same risks as are the foreign securities that they evidence or into which they may be converted, and they may be less liquid than the underlying shares in their primary trading market. Holders of depositary receipts may have limited voting rights, and investment restrictions in certain countries may adversely impact the value of depositary receipts because such restrictions may limit the ability to convert equity shares into depositary receipts and vice versa.Derivatives – The use of derivatives involves a variety of risks, which may be different from, or greater than, the risks associated with investing in traditional securities, such as stocks and bonds.Risks of derivatives include leverage risk, liquidity risk, valuation risk, market risk, counterparty risk, credit risk, operational risk and legal risk. Use of derivatives can increase fund losses, increase costs, reduce opportunities for gains, increase fund volatility, and not produce the result intended. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Even a small investment in derivatives can have a disproportionate impact on the fund. Derivatives may be difficult or impossible to sell, unwind or value, and the counterparty (including, if applicable, the fund’s clearing broker, the derivatives exchange or the clearinghouse) may default on its obligations to the fund. In certain cases, the fund may incur costs and may be hindered or delayed in enforcing its rights against or closing out derivatives instruments with a counterparty, which may result in additional losses. Derivatives are also generally subject to the risks applicable to the assets, rates, indices or other indicators underlying the derivative, including market risk, credit risk, liquidity risk, management and valuation risk. Also, suitable derivative transactions may not be available in all circumstances or at reasonable prices. The value of a derivative may fluctuate more or less than, or otherwise not correlate well with, the underlying assets, rates, indices or other indicators to which it relates. The fund may, under the current asset segregation and coverage regulatory framework, be required to segregate or earmark liquid assets or otherwise cover its obligations under derivatives transactions and may have to liquidate positions before it is desirable in order to meet these segregation and coverage requirements. The SEC has adopted new Rule 18f-4 under the 1940 Act, which provides a comprehensive regulatory framework for the use of derivatives by registered investment companies and set limits on a fund’s investments in derivatives. Compliance with Rule 18f-4 is not required until August 2022, but the rule may impact the fund’s use of derivatives before that date. Rule 18f-4 could have an adverse impact on the fund’s performance and its ability to implement its investment strategies as it has historically.Foreign Investments – Investing in securities of foreign issuers or issuers with significant exposure to foreign markets involves additional risks. Foreign markets can be less liquid, less regulated, less transparent and more volatile than U.S. markets. The value of the fund’s foreign investments may decline, sometimes rapidly or unpredictably, because of factors affecting the particular issuer as well as foreign markets and issuers generally, such as unfavorable or unsuccessful government actions, reduction of government or central bank support, tariffs and trade disruptions, sanctions, political or financial instability, social unrest or other adverse economic or political developments. Foreign investments may also be subject to different accounting practices and different regulatory, legal, auditing, financial reporting and recordkeeping standards and practices, and may be more difficult to value than investments in U.S. issuers.Large Shareholder – A significant portion of the fund’s shares may be owned by other funds sponsored by Transamerica. Transactions by these funds may be disruptive to the management of the fund. For example, the fund may experience large redemptions and could be required to sell securities at a time when it may not otherwise desire to do so. Such transactions may increase the fund’s brokerage and/or other transaction costs. These transactions may also accelerate the realization of taxable income to shareholders if such sales of investments resulted in gains. In addition, sizeable redemptions could cause the fund’s total expenses to increase.Preferred Stock – Preferred stock’s right to dividends and liquidation proceeds is junior to the rights of a company’s debt securities. The value of preferred stock may be subject to factors that affect fixed-income and equity securities. The value of preferred stock tends to vary more with fluctuations in the underlying common stock and less with fluctuations in interest rates and tends to exhibit greater volatility.REITs – Investing in real estate investment trusts (“REITs”) involves unique risks. When the fund invests in REITs, it is subject to risks generally associated with investing in real estate. A REIT’s performance depends on the types and locations of the properties it owns, how well it manages those properties and cash flow. REITs may have limited financial resources, may trade less frequently and in limited volume, may engage in dilutive offerings, and may be subject to more abrupt or erratic price movements than the overall securities markets. In addition to its own expenses, the fund will indirectly bear its proportionate share of any management and other expenses paid by REITs in which it invests. U.S. REITs are subject to a number of highly technical tax-related rules and requirements; and a U.S. REIT’s failure to qualify for the favorable U.S. federal income tax treatment generally available to U.S. REITs could result in corporate-level taxation, significantly reducing the return on an investment to the fund.Sustainability and Environmental, Social and Governance (“ESG”) Considerations – Applying sustainability and/or ESG factors as part of the fund’s security selection process may impact the sub-adviser’s investment decisions. Sustainability and ESG factors are not uniformly defined and applying such factors involves subjective assessments. Sustainability and ESG ratings and assessments of issuers can vary across investment advisers (including sub-advisers) and third party data providers and may change over time. Sustainability and ESG factors can be difficult to apply consistently across issuers, regions, countries, industries or sectors. The application of these factors could negatively impact the fund’s performance. Sustainability and ESG information from issuers and from third party data providers may be incomplete, inaccurate or unavailable, which could lead to an incorrect assessment of a company’s sustainability or ESG characteristics.Valuation – The sales price the fund could receive for any particular portfolio investment may differ from the fund's valuation of the investment, particularly for securities that trade in thin or volatile markets, that are priced based upon valuations provided by third party pricing services that use matrix or evaluated pricing systems, or that are valued using a fair value methodology. These differences may increase significantly and affect fund investments more broadly during periods of market volatility. Investors who purchase or redeem fund shares on days when the fund is holding fair-valued securities may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the fund had not fair-valued securities or had used a different valuation methodology. The fund’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;">You may lose money if you invest in this fund.</span>
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;">An investment in the fund is </span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;">not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:bold;margin-left:0%;">Performance:</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and the table below provide some indication of the risks of investing in the fund. The bar chart shows how the fund’s performance has varied from year to year. The table shows how the fund’s average annual total returns for different periods compare to the returns of a broad measure of market performance.As with all mutual funds, past performance (before and after taxes) is not a prediction of future results. Updated performance information is available on our website at www.transamerica.com/investments-fund-center or by calling 1-888-233-4339.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> The bar chart and the table below provide some indication of the risks of investing in the fund. The bar chart shows how the fund’s performance has varied from year to year. The table shows how the fund’s average annual total returns for different periods compare to the returns of a broad measure of market performance.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="font-family:Times New Roman;font-size:10pt;">1-888-233-4339</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Times New Roman;font-size:10pt;">www.transamerica.com/investments</span><span style="font-family:Times New Roman;font-size:10pt;">-fund-center</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="font-family:Times New Roman;font-size:10pt;margin-left:0%;">As with all mutual funds, past performance (before and after taxes) </span><span style="font-family:Times New Roman;font-size:10pt;">is not a prediction of future results.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;margin-left:0%;">Annual Total Returns (calendar years ended December 31) - Class I2</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Quarter EndedReturnBest Quarter:12/31/202019.31%Worst Quarter:3/31/2020-31.84%
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;margin-left:0%;">Average Annual Total Returns (periods ended December 31, </span><span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;line-height:11pt;"> </span><span style="font-family:Times New Roman;font-size:8.5pt;font-weight:bold;">2021)</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;margin-left:0%;">The after-tax returns are calculated using the historic highest individual</span><span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> federal marginal income tax rates and do not reflect the impact of state and local taxes.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Times New Roman;font-size:10pt;"> Actual after-tax returns may depend on the investor’s individual tax situation and may differ from those shown. After-tax returns may not be relevant if the investment is made through a tax-exempt or tax-deferred account, such as a 401(k) plan.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns are calculated using the historic highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns may depend on the investor’s individual tax situation and may differ from those shown. After-tax returns may not be relevant if the investment is made through a tax-exempt or tax-deferred account, such as a 401(k) plan.
Class I2 | Transamerica Mid Cap Value | I2
Risk Return Abstract	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) (as a percentage of purchase price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther	none
Management fees	rr_ManagementFeesOverAssets	0.87%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.07%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.94%
1 year	rr_ExpenseExampleYear01	$ 96
3 years	rr_ExpenseExampleYear03	300
5 years	rr_ExpenseExampleYear05	520
10 years	rr_ExpenseExampleYear10	$ 1,155
2012	rr_AnnualReturn2012	20.76%
2013	rr_AnnualReturn2013	32.59%
2014	rr_AnnualReturn2014	15.32%
2015	rr_AnnualReturn2015	(2.71%)
2016	rr_AnnualReturn2016	14.70%
2017	rr_AnnualReturn2017	13.81%
2018	rr_AnnualReturn2018	(11.77%)
2019	rr_AnnualReturn2019	26.57%
2020	rr_AnnualReturn2020	0.18%
2021	rr_AnnualReturn2021	29.23%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;margin-left:0.0pt;">Best Quarter:</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	19.31%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="color:#000000;font-family:Times New Roman;font-size:9pt;margin-left:0.0pt;">Worst Quarter:</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(31.84%)
1 Year	rr_AverageAnnualReturnYear01	29.23%
5 Years	rr_AverageAnnualReturnYear05	10.47%
10 Years	rr_AverageAnnualReturnYear10	12.99%
Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 15, 2005
Class I2 | Transamerica Mid Cap Value | Return After Taxes on Distributions | I2
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	23.86%
5 Years	rr_AverageAnnualReturnYear05	6.45%
10 Years	rr_AverageAnnualReturnYear10	9.97%
Class I2 | Transamerica Mid Cap Value | Return After Taxes on Distributions and Sale of Fund Shares | I2
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.43%
5 Years	rr_AverageAnnualReturnYear05	7.49%
10 Years	rr_AverageAnnualReturnYear10	10.10%
Class I2 | Transamerica Mid Cap Value | Russell Midcap® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	28.34%	[1]
5 Years	rr_AverageAnnualReturnYear05	11.22%	[1]
10 Years	rr_AverageAnnualReturnYear10	13.44%	[1]

[1] “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.