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 table and Example below. Additional fees and expenses will be applied at the variable contract level. Those fees and expenses are described in your variable contract prospectus. If the information below were to reflect the deduction of variable contract charges, fees and expenses would be higher.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

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 may indicate higher transaction costs. These costs, which are not reflected in the annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 67% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

67.00%

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

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 does not reflect expenses and charges which are, or may be, imposed under your variable contract. If the examples were to reflect the deduction of such charges, the costs shown would be greater. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem or hold all of your 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 and returns might be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategy

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is managed using a value oriented approach. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in a diversified portfolio of equity investments in small‑cap issuers with public stock market capitalizations (measured at the time of purchase) within the range of the market capitalization of companies constituting the Russell 2000^® Value Index at the time of investment (as of March 31, 2022, and as provided by the Sub‑Adviser, this range was between $12.14 million and $14.75 billion). If the market capitalization of a company held by the Fund moves outside this range, the Fund may, but is not required to, sell the securities. Because the Fund’s definition of small‑cap issuers is dynamic, the lower and upper limits on market capitalization will change with the markets. The Fund’s investments in small capitalization companies may include micro-capitalization companies and “unseasoned companies,” which are companies that (together with their predecessors) have operated for less than three years. The Russell 2000^® Value Index measures the performance of those Russell 2000 companies with lower price to book ratio and lower forecasted growth values. Under normal circumstances, the Fund’s investment horizons for ownership of stocks will be two to three years.

The Sub‑Adviser on behalf of the Fund employs an equity investment process that involves: (1) using multiple industry-specific valuation metrics to identify real economic value and company potential in stocks, screened by valuation, profitability and business characteristics; (2) conducting in‑depth company research and assessing overall business quality; (3) considering a wide range of factors as part of the fundamental investment process, which may include integrating environmental, social and governance (“ESG”) factors with traditional fundamental factors; and (4) buying those securities that a sector portfolio manager recommends, taking into account feedback from the rest of the portfolio management team. No one factor or consideration is determinative in the stock selection process. The Sub‑Adviser may decide to sell a position for various reasons, including valuation and price considerations, readjustment of the Sub‑Adviser’s outlook based on subsequent events, the Sub‑Adviser’s ongoing assessment of the quality and effectiveness of management, if new investment ideas offer the potential for better risk/reward profiles than existing holdings, or for risk management purpose.

Although the Fund will invest primarily in publicly traded U.S. securities, including real estate investment trusts (“REITs”), it may invest up to 25% of its net assets in foreign securities, including securities of issuers in emerging countries and securities quoted in foreign currencies. The Fund may, but is not required to, undertake hedging activities and may invest in certain instruments, such as forward currency exchange contracts, and may use certain techniques to hedge currency risks associated with the purchase of individual securities denominated in a foreign currency. The Fund may invest in the aggregate up to 20% of its net assets in companies with public stock market capitalizations outside the range of companies constituting the Russell 2000^® Value Index at the time of investment and in fixed income securities, such as government, corporate, and bank debt obligations. While the Fund’s sector and industry exposure is expected to vary over time, as of February 28, 2022, the Fund had significant exposure to the Financials Sector, Industrials Sector, and Real Estate Sector as each sector is defined by the Global Industry Classification Standard.

Risk [Heading]

rr_RiskHeading

Principal Risks of Investing

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

As with all mutual funds, an investor is subject to the risk that his or her investment could lose money. In addition to this risk, the Fund is subject to the principal risks described below.

Small- and Mid‑Cap Securities Risk. The possibility that the Fund’s investments in small- and mid‑cap securities may be subject to greater risk and higher volatility than are customarily associated with investing in larger more established companies. Securities issued by small- and mid‑sized companies, which can include start‑up companies, tend to be more vulnerable than larger and more established companies to adverse business and economic developments. Such companies generally have narrower product lines, more limited financial resources and more limited markets for their stock as compared with larger companies. As a result, the value of such securities also may be more volatile than the securities of larger companies, and the Fund’s portfolio may experience difficulty in purchasing or selling such securities at the desired time and price or in the desired amount.

“Value” Investing Risk. The possibility that the Fund’s investments in securities believed by the Sub‑Adviser to be undervalued may not realize their perceived value for extended periods of time or may never realize their perceived value. The securities in which the Fund invests may respond differently to market and other developments than other types of securities, and may underperform growth stocks and/or the market as a whole, particularly if the Fund’s investment style shifts out of favor.

Equity Securities Risk. In general, prices of equity securities are more volatile than those of fixed income securities. The prices of equity securities fluctuate, and sometimes widely fluctuate, in response to activities specific to the issuer of the security as well as factors unrelated to the fundamental condition of the issuer, including general market, economic and political conditions.

Market Risk. The possibility that the values of, and/or the income generated by, securities held by the Fund may decline, sometimes unpredictably, due to general market conditions or other factors, including those directly involving the issuers of such securities. Security markets are volatile and may decline significantly in response to adverse issuer, regulatory, political, or economic developments. Different sectors of the market and different security types may react differently to such developments.

Management Risk. The possibility that the investment decisions, techniques, analyses or models implemented by the Fund’s Sub‑Adviser in seeking to achieve the Fund’s investment objective may not produce the returns expected, may cause the Fund’s shares to lose value or may cause the Fund to underperform relevant benchmarks or other funds with similar investment objectives.

Liquidity Risk. The possibility that the market for certain of the Fund’s investments may become illiquid under adverse or volatile market or economic conditions, making those investments difficult to sell at an advantageous price, particularly in times of market turmoil. The market price of certain investments may fall dramatically if there is no liquid trading market for the investments. Illiquid securities may also be more difficult to value. If the Fund is forced to sell an illiquid security to fund redemptions or for other cash needs, it may be forced to sell the security at a loss.

Sector Risk. The possibility that the Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector, including adverse market conditions, legislative or regulatory changes, and/or increased competition affecting that sector, than funds that invest more broadly. While the Fund’s sector and industry exposure is expected to vary over time, as of February 28, 2022, the Fund had significant exposure to the Financials Sector, Industrials Sector, and Real Estate Sector. In addition to these general risks, the sectors specified are also subject to the risks described below.

Financials Sector Risk. The Financials Sector includes companies involved in banking, thrifts and mortgage finance, specialized finance, consumer finance, asset management and custody banks, investment banking and brokerage and insurance. It also includes the Financial Exchanges & Data and Mortgage Real Estate Investment Trusts (“REITs”) sub‑industries. Certain financial sector companies serve as counterparties with which the Fund may enter into derivatives agreements or other similar contractual arrangements. Companies operating in the Financials Sector are subject to extensive government regulation, which may limit the financial commitments they can make and the interest rates and fees they can charge. Profitability is largely dependent on the availability and cost of capital funds, and can fluctuate significantly when interest rates change or due to increased competition.

Industrials Sector Risk. The Industrials Sector includes manufacturers and distributors of capital goods such as aerospace and defense, building projects, electrical equipment and machinery and companies that offer construction and engineering services. It also includes providers of commercial and professional services including printing, environmental and facilities services, office services and supplies, security and alarm services, human resource and employment services, research and consulting services. It also includes companies that provide transportation services. The prices of the securities of companies operating in the Industrials Sector may fluctuate due to the level and volatility of commodity prices, the exchange value of the dollar, import controls, worldwide competition, liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control devices.

Real Estate Sector Risk. The Real Estate Sector contains companies operating in real estate development and operation. It also includes companies offering real estate related services and REITs. The performance of companies operating in the Real Estate Sector has historically been cyclical and particularly sensitive to the overall economy and market changes, including declines in the value of real estate or, conversely, saturation of the real estate market, economic downturns and defaults by borrowers or tenants during such periods, increases in competition, possible lack of mortgage funds or other limits to accessing the credit or capital markets, and changes in interest rates.

REITs Risk. The possibility that the Fund’s investments in REITs will subject the Fund to the risks associated with the direct ownership of real estate, including fluctuations in the value of underlying properties, changes in interest rates and risks related to general or local economic conditions. REITs are dependent upon management skills and generally may not be diversified. REITs are also subject to heavy cash flow dependency, defaults by borrowers or tenants and self-liquidation.

Micro‑Cap Securities Risk. The possibility that the return on the Fund’s investments in micro‑cap companies may be less than the return on investments in stocks of larger companies or the stock market as a whole. Stock prices of micro‑cap companies may be based in substantial part on future expectations rather than current achievements and may move sharply, especially during market upturns and downturns. Micro‑cap companies are followed by relatively few securities analysts, and there tends to be less publicly available information about these companies. Micro‑cap companies are more likely to be newly formed or in the early stages of development, depend on a few key employees, and have relatively limited product lines, markets or financial resources compared to larger capitalization companies.

Foreign Investment Risk. The possibility that the Fund’s investments in foreign securities may be adversely affected by political, social, and economic conditions affecting foreign issuers or decreases in foreign currency values relative to the U.S. dollar. Investments in foreign markets may be subject to greater market volatility, decreased market liquidity, and higher transaction and custody costs. Foreign issuers also may be subject to less government and exchange regulation and there may be less reliable financial information available for such issuers and their securities.

Emerging Markets Risk. The possibility that the stocks of companies located in emerging markets may be more volatile, and less liquid, than the stocks of companies located in the U.S. and developed foreign markets due to political, economic, or regulatory conditions within emerging market countries. In addition, emerging market countries may experience more volatile interest and currency exchange rates, higher levels of inflation and less efficient trading and settlement systems.

Currency Risk. The possibility that the value of the Fund’s assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and restrictions or prohibitions on the repatriation of foreign currencies.

Unseasoned Company Risk. The possibility that the Fund’s investment in relatively new or unseasoned companies that are in their early stages of development may expose the Fund to greater risks than investments in more established companies with more extensive financial histories and greater liquidity. Unseasoned companies do not have proven track records and may lack substantial capital reserves.

Derivatives Risk. The possibility that the Fund’s use of derivatives, such as futures, options and swap agreements, may lead to losses, including those magnified by leverage, particularly when derivatives are used to enhance return rather than mitigate risk. Certain derivative instruments may be difficult to sell when the Sub‑Adviser believes it would be appropriate to do so, difficult to value if the instrument becomes illiquid, or the other party to a derivative contract may be unwilling or unable to fulfill its contractual obligations.

Credit Risk. The possibility that an issuer of a debt security, or the counterparty to a derivatives contract, held by the Fund defaults on its payment obligations.

Interest Rate Risk. The possibility that the prices of the Fund’s fixed income investments will decline due to rising interest rates.

An investment in the Fund may be appropriate for investors who are willing to accept the risks and uncertainties of investing in small‑cap stocks in the hope of earning above-average capital appreciation.

Risk Lose Money [Text]

rr_RiskLoseMoney

As with all mutual funds, an investor is subject to the risk that his or her investment could lose money.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below show the performance of the Fund both year‑by‑year and as an average over different periods of time. The bar chart and table demonstrate the variability of performance over time and provide an indication of the risks and volatility of an investment in the Fund by showing how the Fund’s average annual total returns for various periods compare with those of a broad-based securities market index. Past performance does not necessarily indicate how the Fund will perform in the future. This performance information does not include the impact of any charges deducted under your variable contract. If it did, returns would be lower.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart and table demonstrate the variability of performance over time and provide an indication of the risks and volatility of an investment in the Fund by showing how the Fund’s average annual total returns for various periods compare with those of a broad-based securities market index.

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance does not necessarily indicate how the Fund will perform in the future.

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

This performance information does not include the impact of any charges deducted under your variable contract. If it did, returns would be lower.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock