The expense example can help you compare costs among mutual funds. The example assumes that you invested $10,000 for the periods shown, that you redeemed all of your shares at the end of those periods, that the Fund earned a hypothetical 5% total return each year, and that the Fund’s expenses were those in the table. Actual performance and expenses may be higher or lower.

Strategy Narrative [Text Block]

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To pursue its goal, the Fund normally invests at least 80% of its net assets in common stocks of mid-capitalization companies, which it defines as those with a market capitalization within the market capitalization range of the Russell Midcap^® Index at the time of initial purchase. Although the Fund invests primarily in domestic securities, it may also invest in securities of foreign companies.

The Fund’s strategy utilizes a qualitative, bottom-up research driven approach to identify companies that the Portfolio Managers believe have catalysts for growth which are underappreciated by the market. The Portfolio Managers seek to invest in underappreciated companies with the following characteristics: durable and potentially unique business models and/or proficient management capable of advancing the development of and/or strengthening of sustainable and consistent revenue growth, cash flow growth, earnings growth and/or overall balance sheet strength. Such catalysts may include a new technology, product or service, a regulatory update, market share gains, cyclical inflections (e.g. companies whose returns are driven by macro-economic factors), corporate restructurings or self-help initiatives (e.g. internal operating efforts to increase company efficiencies). The Portfolio Managers may also invest in anticipation of a catalyst.

In analyzing catalysts, the Portfolio Managers evaluate each catalyst’s uniqueness, timing, growth potential and sustainability, as well as assessing execution risks, competitive barriers and threats. The Portfolio Managers are also attempting to exploit market inefficiencies that potentially may exist within the small-to-mid-capitalization market, due to the number of companies that comprise the investable universe and the limited amount of available research that exists for some of those companies. Investable

companies emerging from the Portfolio Manager’s bottom-up fundamental, qualitative and valuation analysis fall into the following investment classifications:

Core investments: are typically more mature companies, engaged with, and participating in, compelling secular growth trends, that the Portfolio Managers believe offer a demonstrated history of consistent execution and results. These tend to represent multi-year holdings of the strategy.

Turn investments: represent holdings in a wide range of corporate development and maturity stages and are generally driven by what the Portfolio Managers believe to be a distinct developing catalyst, such as a new product or service, market share gains or internal corporate self-help opportunities to improve operating efficiencies.

Tactical investments: represent holdings with a shorter-term investment horizon due to catalysts the Portfolio Managers believe are typically associated with cyclical trends and opportunities, a disconnect with market expectations providing an opportunity on valuation or a new product, or financial or regulatory developments that could have a material impact on the company.

Tactical investments have the potential to grow into Turn investments, while compelling Turn investments will ideally develop into Core investments.

The Fund seeks to reduce risk by diversifying among many companies, sectors and industries. At times, the Portfolio Managers may emphasize certain sectors that they believe will benefit from market or economic trends.

The Portfolio Managers constantly monitor their holdings and are focused on maintaining what they believe is an appropriate and attractive risk/reward balance with a disciplined sell process that acts quickly and dispassionately to address both positive and negative outcomes. A position is typically trimmed or exited for the following reasons: to harvest gains from significant short-term price appreciation, the positive realization of a catalyst, the achievement of a price target or elevated valuations, identification of a better idea, to minimize potential risks, to address an absence of near-term drivers or catalysts, a significant deterioration of fundamentals, a change in management or operating strategy or the failure of a catalyst to develop.

The Fund will not change its strategy of normally investing at least 80% of its net assets in mid-capitalization companies, without providing shareholders at least 60 days’ notice. This test is applied at the time the Fund invests; later percentage changes caused by a change in Fund assets, market values or company circumstances will not require the Fund to dispose of a holding.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

PERFORMANCE

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart shows how the Fund’s performance has varied from year to year. The table below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of one or more broad-based market indices.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-877-9700

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance is not a prediction of future results.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Best quarter:	Q2 2020 29.89%
	Worst quarter:	Q2 2022 -20.61%

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

reflects no deduction for fees, expenses or taxes

1 Year

rr_AverageAnnualReturnYear01

25.87%

10 Years

rr_AverageAnnualReturnYear10

10.57%

Prospectus [Line Items]

rr_ProspectusLineItems

5 Years

rr_AverageAnnualReturnYear05

12.68%

Shareholder Fee, Other

rr_ShareholderFeeOther

none

Distribution and Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Expenses (as a percentage of Assets)

rr_ExpensesOverAssets

0.93%

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

296

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,143

Annual Return 2015

rr_AnnualReturn2015

1.28%

Annual Return 2017

rr_AnnualReturn2017

25.29%

Annual Return 2019

rr_AnnualReturn2019

32.75%

Annual Return 2021

rr_AnnualReturn2021

12.99%

Annual Return 2023

rr_AnnualReturn2023

18.15%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.61%)

5 Years

rr_AverageAnnualReturnYear05

12.07%

Risk Caption

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The Fund is a mutual fund, not a bank deposit, and is not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency.

Prospectus [Line Items]

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Risk [Text Block]

rr_RiskTextBlock

Most of the Fund’s performance depends on what happens in the stock market, the Portfolio Managers’ evaluation of those developments, and the success of the Portfolio Managers in implementing the Fund’s investment strategies. The market’s behavior can be difficult to predict, particularly in the short term. There can be no guarantee that the Fund will achieve its goal. The Fund may take temporary defensive and cash management positions; to the extent it does, it will not be pursuing its principal investment strategies.

The actual risk exposure taken by the Fund in its investment program will vary over time, depending on various factors including the Portfolio Managers’ evaluation of issuer, political, regulatory, market, or economic developments. There can be no guarantee that the Portfolio Managers will be successful in their attempts to manage the risk exposure of the Fund or will appropriately evaluate or weigh the multiple factors involved in investment decisions, including issuer, market and/or instrument-specific analysis and valuation.

The Fund is a mutual fund, not a bank deposit, and is not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency. The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund.

Each of the following risks, which are described in alphabetical order and not in order of any presumed importance, can significantly affect the Fund’s performance. The relative importance of, or potential exposure as a result of, each of these risks will vary based on market and other investment-specific considerations.

Prospectus [Line Items]

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Risk [Text Block]

rr_RiskTextBlock

Foreign Risk. Foreign securities involve risks in addition to those associated with comparable U.S. securities. Additional risks include exposure to less developed or less efficient trading markets; social, political, diplomatic, or economic instability; trade barriers and other protectionist trade policies (including those of the U.S.); imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals; significant government involvement in an economy and/or market structure; fluctuations in foreign currencies or currency redenomination; potential for default on sovereign debt; nationalization or expropriation of assets; settlement, custodial or other operational risks; higher transaction costs; confiscatory withholding or other taxes; and less stringent auditing and accounting, corporate disclosure, governance, and legal standards. As a result, foreign securities may fluctuate more widely in price, and may also be less liquid, than comparable U.S. securities. World markets, or those in a particular region, may all react in similar fashion to important economic or political developments. In addition, foreign markets may perform differently than the U.S. markets. The effect of economic instability on specific foreign markets or issuers may be difficult to predict or evaluate. Regardless of where a company is organized or its stock is traded, its performance may be affected significantly by events in regions from which it derives its profits or in which it conducts significant operations.

Securities of issuers traded on foreign exchanges may be suspended, either by the issuers themselves, by an exchange, or by governmental authorities. Trading suspensions may be applied from time to time to the securities of individual issuers for reasons specific to that issuer, or may be applied broadly by exchanges or governmental authorities in response to market events. In the event that the Fund holds material positions in such suspended securities or instruments, the Fund’s ability to liquidate its positions or provide liquidity to investors may be compromised and the Fund could incur significant losses.

Prospectus [Line Items]

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Risk [Text Block]

rr_RiskTextBlock

Growth Stock Risk. Because the prices of most growth stocks are based on future expectations, these stocks tend to be more sensitive than value stocks to bad economic news and negative earnings surprises. When these expectations are not met or decrease, the prices of these stocks may decline, sometimes sharply, even if earnings showed an absolute increase. Bad economic news or changing investor perceptions may adversely affect growth stocks across several sectors and industries simultaneously.

Prospectus [Line Items]

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Risk [Text Block]

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Market Volatility Risk. Markets may be volatile and values of individual securities and other investments, including those of a particular type, may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Geopolitical and other risks, including environmental and public health risks may add to instability in world economies and markets generally. Changes in value may be temporary or may last for extended periods. If the Fund sells a portfolio position before it reaches its market peak, it may miss out on opportunities for better performance.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing or changing, which may impact such economies and markets in ways that cannot be foreseen at this time.

Although interest rates were unusually low in recent years in the U.S. and abroad, recently, the Federal Reserve and certain foreign central banks raised interest rates as part of their efforts to address rising inflation. It is difficult to accurately predict the pace at which interest rates might increase or start decreasing, the timing, frequency or magnitude of any such changes in interest rates, or when such changes might stop or reverse course. Additionally, various economic and political factors could cause the Federal Reserve or other foreign central banks to change their approach in the future and such actions may result in an economic slowdown both in the U.S. and abroad. Unexpected changes in interest rates could lead to significant market volatility or reduce liquidity in certain sectors of the market. Deteriorating economic fundamentals may, in turn, increase the risk of default or

insolvency of particular issuers, negatively impact market value, cause credit spreads to widen, and reduce bank balance sheets. Any of these could cause an increase in market volatility, or reduce liquidity across various markets or decrease confidence in the markets.

Some countries, including the U.S., have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the United Kingdom and the European Union, and the risks associated with trade negotiations between the U.S. and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, if the U.S. dollar continues to be strong, it may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries.

Regulators in the U.S. have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance.

Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted.

High public debt in the U.S. and other countries creates ongoing systemic and market risks and policymaking uncertainty. There is no assurance that the U.S. Congress will act to raise the nation’s debt ceiling; a failure to do so could cause market turmoil and substantial investment risks that cannot now be fully predicted. Unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy.

There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Sector Risk. From time to time, based on market or economic conditions, the Fund may have significant positions in one or more sectors of the market. To the extent the Fund invests more heavily in particular sectors, its performance will be especially sensitive to developments that significantly affect those sectors. Individual sectors or sub-sectors may be more volatile, and may perform differently, than the broader market. The industries that constitute a sector may all react in the same way to economic, political or regulatory events.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Risk of Increase in Expenses. A decline in the Fund’s average net assets during the current fiscal year due to market volatility or other factors could cause the Fund’s expenses for the current fiscal year to be higher than the expense information presented in “Fees and Expenses.”

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Risk Management. Risk is an essential part of investing. No risk management program can eliminate the Fund’s exposure to adverse events; at best, it may only reduce the possibility that the Fund will be affected by such events, and especially those risks that are not intrinsic to the Fund’s investment program. The Fund could experience losses if judgments about risk prove to be incorrect.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk/Return [Heading]

rr_RiskReturnHeading

Mid Cap Intrinsic Value Portfolio Class I

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks growth of capital.

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

These tables describe the fees and expenses that you may pay if you buy, hold or sell shares of the Fund. These tables do not reflect any fees and expenses charged by your insurance company under your variable contract or by your qualified plan. If the tables did reflect such fees and expenses, the overall expenses would be higher than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

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. These costs, which are not reflected in annual operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 20% of the average value of its portfolio.

Expense Example [Heading]

rr_ExpenseExampleHeading

Expense Example

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Risk [Heading]

rr_RiskHeading

PRINCIPAL INVESTMENT RISKS

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide an 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 below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of one or more broad-based market indices. The indices, which are described in “Descriptions of Indices” in the prospectus, have characteristics relevant to the Fund’s investment strategy. The performance information does not reflect variable contract or qualified plan fees and expenses. If such fees and expenses were reflected, returns would be less than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Returns would have been lower if Neuberger Berman Investment Advisers LLC had not reimbursed certain expenses and/or waived a portion of the investment management fees during certain of the periods shown.

Past performance is not a prediction of future results. Visit www.nb.com or call 800-877-9700 for updated performance information.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The table below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of one or more broad-based market indices.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.nb.com

Bar Chart [Heading]

rr_BarChartHeading

year-by-year % Returns as of 12/31 each year

Performance Table Heading

rr_PerformanceTableHeading

average annual total % returns as of 12/31/23

Average Annual Return, Caption

rr_AverageAnnualReturnCaption

Mid Cap Intrinsic Value Portfolio

Prospectus [Line Items]

rr_ProspectusLineItems

5 Years

rr_AverageAnnualReturnYear05

11.16%

1 Year

rr_AverageAnnualReturnYear01

17.23%

10 Years

rr_AverageAnnualReturnYear10

9.42%

Prospectus [Line Items]

rr_ProspectusLineItems

Management Fees (as a percentage of Assets)

rr_ManagementFeesOverAssets

0.85%

Other Expenses (as a percentage of Assets):

rr_OtherExpensesOverAssets

0.17%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 104

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

563

Annual Return 2014

rr_AnnualReturn2014

13.84%

Annual Return 2016

rr_AnnualReturn2016

16.17%

Annual Return 2018

rr_AnnualReturn2018

(15.28%)

Annual Return 2020

rr_AnnualReturn2020

(2.62%)

Annual Return 2022

rr_AnnualReturn2022

(9.75%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

26.65%

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

1 Year

rr_AverageAnnualReturnYear01

11.00%

10 Years

rr_AverageAnnualReturnYear10

6.13%

Prospectus [Line Items]

rr_ProspectusLineItems

Risk Caption

rr_RiskCaption

The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Catalyst Risk. Investing in companies in anticipation of a catalyst carries the risk that the catalyst may not happen as anticipated, or the market may react to the catalyst differently than expected.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Issuer-Specific Risk. An individual security may be more volatile, and may perform differently, than the market as a whole.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Mid-Cap Companies Risk. At times, mid-cap companies may be out of favor with investors. Compared to larger companies, mid-cap companies may depend on a more limited management group, may have a shorter history of operations, less publicly available information, less stable earnings, and limited product lines, markets or financial resources. The securities of mid-cap

companies are often more volatile, which at times can be rapid and unpredictable, and less liquid than the securities of larger companies and may be more affected than other types of securities by the underperformance of a sector, during market downturns, or by adverse publicity and investor perceptions.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Redemption Risk. The Fund may experience periods of large or frequent redemptions that could cause the Fund to sell assets at inopportune times, which could have a negative impact on the Fund’s overall liquidity, or at a loss or depressed value. Redemption risk is greater to the extent that one or more investors or intermediaries control a large percentage of investments in the Fund and the risk is heightened during periods of declining or illiquid markets. Large redemptions could hurt the Fund’s performance, increase transaction costs, and create adverse tax consequences.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Risk of Increase in Expenses. A decline in the Fund’s average net assets during the current fiscal year due to market volatility or other factors could cause the Fund’s expenses for the current fiscal year to be higher than the expense information presented in “Fees and Expenses.”

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Risk Management. Risk is an essential part of investing. No risk management program can eliminate the Fund’s exposure to adverse events; at best, it may only reduce the possibility that the Fund will be affected by such events, and especially those risks that are not intrinsic to the Fund’s investment program. The Fund could experience losses if judgments about risk prove to be incorrect.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Currency Risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar. To the extent that the Fund invests in securities or other instruments denominated in or indexed to foreign currencies, changes in currency exchange rates could adversely impact investment gains or add to investment losses. Currency exchange rates may fluctuate significantly over short periods of time and can be affected unpredictably by various factors, including investor perception and changes in interest rates; intervention, or failure to intervene, by U.S. or foreign governments, central banks, or supranational entities; or by currency controls or political developments in the U.S. or abroad.

Prospectus [Line Items]

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Risk [Text Block]

rr_RiskTextBlock

Private Placements and Other Restricted Securities Risk. Private placements and other restricted securities, including securities for which Fund management has material non-public information, are securities that are subject to legal and/or contractual restrictions on their sales. These securities may not be sold to the public unless certain conditions are met, which may include registration under the applicable securities laws. As a result of the absence of a public trading market, the prices of these securities may be more difficult to determine than publicly traded securities and these securities may involve heightened risk as compared to investments in securities of publicly traded companies. Private placements and other restricted securities may be illiquid, and it frequently can be difficult to sell them at a time when it may otherwise be desirable to do so or the Fund may be able to sell them only at prices that are less than what the Fund regards as their fair market value. Transaction costs may be higher for these securities. In addition, the Fund may get only limited information about the issuer of a private placement or other restricted security.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Value Stock Risk. Value stocks may remain undervalued for extended periods of time, may decrease in value during a given period, may not ever realize what the portfolio management team believes to be their full value or intrinsic value, or the portfolio management team’s assumptions about intrinsic value or potential for appreciation may be incorrect. This may happen, among other reasons, because of a failure to anticipate which stocks or industries would benefit from changing market or economic conditions or investor preferences.

A summary of the Fund’s additional principal investment risks is as follows:

Prospectus [Line Items]

rr_ProspectusLineItems

Objective [Heading]

rr_ObjectiveHeading

GOAL

Objective, Secondary [Text Block]

rr_ObjectiveSecondaryTextBlock

total return is a secondary goal.

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

These tables describe the fees and expenses that you may pay if you buy, hold or sell shares of the Fund. These tables do not reflect any fees and expenses charged by your insurance company under your variable contract or by your qualified plan. If the tables did reflect such fees and expenses, the overall expenses would be higher than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

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. These costs, which are not reflected in annual operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.

Expense Example [Heading]

rr_ExpenseExampleHeading

Expense Example

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Risk [Heading]

rr_RiskHeading

PRINCIPAL INVESTMENT RISKS

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table provide an 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 below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of a broad-based market index. The index, which is described in “Description of Index” in the prospectus, has characteristics relevant to the Fund’s investment strategy. The performance information does not reflect variable contract or qualified plan fees and expenses. If such fees and expenses were reflected, returns would be less than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Returns would have been lower if Neuberger Berman Investment Advisers LLC had not reimbursed certain expenses and/or waived a portion of the investment management fees during certain of the periods shown.

Past performance is not a prediction of future results. Visit www.nb.com or call 800-877-9700 for updated performance information.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800-877-9700

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance is not a prediction of future results.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

	Best quarter:	Q2 2020 5.25%
	Worst quarter:	Q1 2020 -4.54%

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

reflects no deduction for fees, expenses or taxes

1 Year

rr_AverageAnnualReturnYear01

4.61%

10 Years

rr_AverageAnnualReturnYear10

1.27%

Prospectus [Line Items]

rr_ProspectusLineItems

Management Fees (as a percentage of Assets)

rr_ManagementFeesOverAssets

0.57%

Other Expenses (as a percentage of Assets):

rr_OtherExpensesOverAssets

0.29%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 88

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

477

Annual Return 2014

rr_AnnualReturn2014

0.61%

Annual Return 2016

rr_AnnualReturn2016

1.22%

Annual Return 2018

rr_AnnualReturn2018

1.02%

Annual Return 2020

rr_AnnualReturn2020

3.46%

Annual Return 2022

rr_AnnualReturn2022

(5.19%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

5.25%

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

1 Year

rr_AverageAnnualReturnYear01

5.90%

10 Years

rr_AverageAnnualReturnYear10

1.21%

Prospectus [Line Items]

rr_ProspectusLineItems

Risk Caption

rr_RiskCaption

The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund. While this Fund may have a shorter duration than many other income funds, this Fund is not intended to operate like a money market fund.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Issuer-Specific Risk. An individual security may be more volatile, and may perform differently, than the market as a whole.

Prospectus [Line Items]

rr_ProspectusLineItems

Risk [Text Block]

rr_RiskTextBlock

Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing or changing, which may impact such economies and markets in ways that cannot be foreseen at this time.

Although interest rates were unusually low in recent years in the U.S. and abroad, recently, the Federal Reserve and certain foreign central banks raised interest rates as part of their efforts to address rising inflation. It is difficult to accurately predict the pace at which interest rates might increase or start decreasing, the timing, frequency or magnitude of any such changes in interest rates, or when such changes might stop or reverse course. Additionally, various economic and political factors could cause the Federal Reserve or other foreign central banks to change their approach in the future and such actions may result in an economic slowdown both in the U.S. and abroad. Unexpected changes in interest rates could lead to significant market volatility or reduce liquidity in certain sectors of the market. Deteriorating economic fundamentals may, in turn, increase the risk of default or insolvency of particular issuers, negatively impact market value, cause credit spreads to widen, and reduce bank balance sheets. Any of these could cause an increase in market volatility, or reduce liquidity across various markets or decrease confidence in the markets.

Some countries, including the U.S., have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the United Kingdom and the European Union, and the risks associated with trade negotiations between the U.S. and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, if the U.S. dollar continues to be strong, it may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries.

Regulators in the U.S. have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance.

Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted.

High public debt in the U.S. and other countries creates ongoing systemic and market risks and policymaking uncertainty. There is no assurance that the U.S. Congress will act to raise the nation’s debt ceiling; a failure to do so could cause market turmoil and substantial investment risks that cannot now be fully predicted. Unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy.

There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries.

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Sector Risk. From time to time, based on market or economic conditions, the Fund may have significant positions in one or more sectors of the market. To the extent the Fund invests more heavily in particular sectors, its performance will be especially sensitive to developments that significantly affect those sectors. Individual sectors or sub-sectors may be more volatile, and may perform differently, than the broader market. The industries that constitute a sector may all react in the same way to economic, political or regulatory events.

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Operational and Cybersecurity Risk. The Fund and its service providers, and your ability to transact with the Fund, may be negatively impacted due to operational matters arising from, among other problems, human errors, systems and technology disruptions or failures, or cybersecurity incidents. Cybersecurity incidents may allow an unauthorized party to gain access to fund assets, customer data, or proprietary information, or cause the Fund or its service providers, as well as the securities trading venues and their service providers, to suffer data corruption or lose operational functionality. Cybersecurity incidents can result from deliberate attacks or unintentional events. It is not possible for the Manager or the other Fund service providers to identify all of the cybersecurity or other operational risks that may affect the Fund or to develop processes and controls to completely eliminate or mitigate their occurrence or effects. Most issuers in which the Fund invests are heavily dependent on computers for data storage and operations, and require ready access to the internet to conduct their business. Thus, cybersecurity incidents could also affect issuers of securities in which the Fund invests, leading to significant loss of value.

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Valuation Risk. The Fund may not be able to sell an investment at the price at which the Fund has valued the investment. Such differences could be significant, particularly for illiquid securities and securities that trade in relatively thin markets and/or markets that experience extreme volatility. If market or other conditions make it difficult to value an investment, the Fund may be required to value such investments using more subjective methods, known as fair value methodologies. Using fair value methodologies to price investments may result in a value that is different from an investment’s most recent price and from the prices used by other funds to calculate their NAVs. The Fund uses pricing services to provide values for certain securities and there is no assurance that the Fund will be able to sell an investment at the price established by such pricing services. The Fund’s ability to value its investments in an accurate and timely manner may be impacted by technological issues and/or errors by third party service providers, such as pricing services or accounting agents.

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Liquidity Risk. From time to time, the trading market for a particular investment in which the Fund invests, or a particular type of instrument in which the Fund is invested, may become less liquid or even illiquid. Illiquid investments frequently can be more difficult to purchase or sell at an advantageous price or time, and there is a greater risk that the investments may not be sold for the price at which the Fund is carrying them. Certain investments that were liquid when the Fund purchased them may become illiquid, sometimes abruptly. Additionally, market closures due to holidays or other factors may render a security or group of securities (e.g., securities tied to a particular country or geographic region) illiquid for a period of time. An inability to sell a portfolio position can adversely affect the Fund’s value or prevent the Fund from being able to take advantage of other investment opportunities. Market prices for such securities or other investments may be volatile. During periods of substantial market volatility, an investment or even an entire market segment may become illiquid, sometimes abruptly, which can adversely affect the Fund’s ability to limit losses.

Unexpected episodes of illiquidity, including due to market or political factors, instrument or issuer-specific factors and/or unanticipated outflows or other factors, may limit the Fund’s ability to pay redemption proceeds within the allowable time period. To meet redemption requests during periods of illiquidity, the Fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions.

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Credit Risk. Credit risk is the risk that issuers, guarantors, or insurers may fail, or become less able or unwilling, to pay interest and/or principal when due. Changes in the actual or perceived creditworthiness of an issuer or a downgrade or default affecting any of the Fund’s securities could affect the Fund’s performance by affecting the credit quality or value of the Fund’s securities. Generally, the longer the maturity and the lower the credit quality of a security, the more sensitive it is to credit risk.

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Interest Rate Risk.The Fund’s yield and share price will fluctuate in response to changes in interest rates. In general, the value of investments with interest rate risk, such as debt securities, will move in the direction opposite to movements in interest rates. If interest rates rise, the value of such securities may decline. Typically, the longer the maturity or duration of a debt security, the greater the effect a change in interest rates could have on the security’s price. Thus, the sensitivity of the Fund’s debt securities to interest rate risk will increase with any increase in the duration of those securities.

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Call Risk. Upon the issuer’s desire to call a security, or under other circumstances where a security is called, including when interest rates are low and issuers opt to repay the obligation underlying a “callable security” early, the Fund may have to reinvest the proceeds in an investment offering a lower yield and may not benefit from any increase in value that might otherwise result from declining interest rates.

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Derivatives Risk. Use of derivatives is a highly specialized activity that can involve investment techniques and risks different from, and in some respects greater than, those associated with investing in more traditional investments, such as stocks and bonds. Derivatives can be highly complex and highly volatile and may perform in unanticipated ways. Derivatives can create leverage, and the Fund could lose more than the amount it invests; some derivatives can have the potential for unlimited losses. Derivatives may at times be highly illiquid, and the Fund may not be able to close out or sell a derivative at a particular time or at an anticipated price. Derivatives can be difficult to value and valuation may be more difficult in times of market turmoil. The value of a derivative instrument depends largely on (and is derived from) the value of the reference instrument underlying the derivative. There may be imperfect correlation between the behavior of a derivative and that of the reference instrument underlying the derivative. An abrupt change in the price of a reference instrument could render a derivative worthless. Derivatives may involve risks different from, and possibly greater than, the risks associated with investing directly in the reference instrument. Suitable derivatives may not be available in all circumstances, and there can be no assurance that the Fund will use derivatives to reduce exposure to other risks when that might have been beneficial. Derivatives involve counterparty risk, which is the risk that the other party to the derivative will fail to make required payments or otherwise comply with the terms of the derivative. That risk is generally thought to be greater with over-the-counter (OTC) derivatives than with derivatives that are exchange traded or centrally cleared. When the Fund uses derivatives, it will likely be required to provide margin or collateral; these practices are intended to satisfy contractual undertakings and regulatory requirements and will not prevent the Fund from incurring losses on derivatives. The need to provide margin or collateral could limit the Fund’s ability to pursue other opportunities as they arise. Ongoing changes to regulation of the derivatives markets and actual and potential changes in the regulation of funds using derivative

instruments could limit the Fund’s ability to pursue its investment strategies. New regulation of derivatives may make them more costly, or may otherwise adversely affect their liquidity, value or performance.

Additional risks associated with certain types of derivatives are discussed below:

Forward Contracts. There are no limitations on daily price movements of forward contracts. Changes in foreign exchange regulations by governmental authorities might limit the trading of forward contracts on currencies.

Futures. Futures contracts are subject to the risk that an exchange may impose price fluctuation limits, which may make it difficult or impossible for a fund to close out a position when desired. In the absence of such limits, the liquidity of the futures market depends on participants entering into offsetting transactions rather than taking or making delivery. To the extent a Fund enters into futures contracts requiring physical delivery (e.g., certain commodities contracts), the inability of the Fund to take or make physical delivery can negatively impact performance.

Swaps. The risk of loss with respect to swaps generally is limited to the net amount of payments that the Fund is contractually obligated to make or, in the case of the other party to a swap defaulting, the net amount of payments that the Fund is contractually entitled to receive. If the Fund sells a credit default swap, however, the risk of loss may be the entire notional amount of the swap.

Some swaps are now executed through an organized exchange or regulated facility and cleared through a regulated clearing organization. The absence of an organized exchange or market for swap transactions may result in difficulties in trading and valuation, especially in the event of market disruptions. The use of an organized exchange or market for swap transactions is expected to result in swaps being easier to trade or value, but this may not always be the case.

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Leverage Risk. Leverage amplifies changes in the Fund’s net asset value and may make the Fund more volatile. Derivatives and when-issued and forward-settling securities may create leverage and can result in losses to the Fund that exceed the amount originally invested and may accelerate the rate of losses or magnify the risks of other portfolio investments. There can be no assurance that the Fund’s use of any leverage will be successful and the Fund may need to dispose of some of its holdings at unfavorable times or prices. The Fund’s investment exposure can exceed its net assets, sometimes by a significant amount.

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Other Investment Company Risk. To the extent the Fund invests in other investment companies, including money market funds and exchange-traded funds (ETFs), its performance will be affected by the performance of those other investment companies. Investments in other investment companies are subject to the risks of the other investment companies’ investments, as well as to the other investment companies’ expenses.

An ETF may trade in the secondary market at a price below the value of its underlying portfolio, may not be liquid and may be halted by the listing exchange. An actively managed ETF’s performance will reflect its adviser’s ability to make investment decisions that are suited to achieving the ETF’s investment objectives. A passively managed ETF may not replicate the performance of the index it intends to track.

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Sovereign Debt Risk. Sovereign debt securities are subject to the risk that a governmental entity may delay or refuse to pay interest or principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the size of the governmental entity’s debt position in relation to the economy, its policy toward international lenders or the failure to put in place economic reforms required by multilateral agencies. If a governmental entity defaults, it may ask for more time in which to pay or for further loans. There may be no legal process for collecting sovereign debt that a government does not pay nor are there bankruptcy proceedings through which all or part of the sovereign debt that a governmental entity has not repaid may be collected. Sovereign debt risk is increased for emerging market issuers.

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Variable and Floating Rate Instruments Risk. The market prices of instruments with variable and floating interest rates are generally less sensitive to interest rate changes than are the market prices of instruments with fixed interest rates. Variable and floating rate instruments may decline in value if market interest rates or interest rates paid by such instruments do not move as expected. Certain types of floating rate instruments, such as interests in bank loans, may be subject to greater liquidity risk than other debt securities, may have restrictions on resale and may lack an active market.

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Risk/Return [Heading]

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Sustainable Equity Portfolio Class I

Objective, Primary [Text Block]

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The Fund seeks long-term growth of capital by investing primarily in securities of companies that meet the Fund’s environmental, social and governance (ESG) criteria.

Expense Narrative [Text Block]

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These tables describe the fees and expenses that you may pay if you buy, hold or sell shares of the Fund. These tables do not reflect any fees and expenses charged by your insurance company under your variable contract or by your qualified plan. If the tables did reflect such fees and expenses, the overall expenses would be higher than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Operating Expenses Caption [Text]

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

Portfolio Turnover [Text Block]

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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. These costs, which are not reflected in annual operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 15% of the average value of its portfolio.

Expense Example [Heading]

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Expense Example

Strategy [Heading]

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Principal Investment Strategies

Risk [Heading]

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PRINCIPAL INVESTMENT RISKS

Performance Narrative [Text Block]

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The following bar chart and table provide an 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 below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of a broad-based market index. The index, which is described in “Description of Index” in the prospectus, has characteristics relevant to the Fund’s investment strategy. The performance information does not reflect variable contract or qualified plan fees and expenses. If such fees and expenses were reflected, returns would be less than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Returns would have been lower if Neuberger Berman Investment Advisers LLC had not reimbursed certain expenses and/or waived a portion of the investment management fees during certain of the periods shown.

Past performance is not a prediction of future results. Visit www.nb.com or call 800-877-9700 for updated performance information.

Performance Availability Phone [Text]

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800-877-9700

Performance Past Does Not Indicate Future [Text]

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Past performance is not a prediction of future results.

Bar Chart Closing [Text Block]

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	Best quarter:	Q2 2020 19.21%
	Worst quarter:	Q1 2020 -21.38%

Index No Deduction for Fees, Expenses, Taxes [Text]

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reflects no deduction for fees, expenses or taxes

1 Year

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26.29%

10 Years

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12.03%

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Management Fees (as a percentage of Assets)

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0.83%

Other Expenses (as a percentage of Assets):

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0.07%

Expense Example, with Redemption, 1 Year

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$ 92

Expense Example, with Redemption, 5 Years

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498

Annual Return 2014

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10.38%

Annual Return 2016

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9.86%

Annual Return 2018

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(5.73%)

Annual Return 2020

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19.56%

Annual Return 2022

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(18.45%)

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return

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19.21%

Lowest Quarterly Return, Date

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Mar. 31, 2020

1 Year

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26.90%

10 Years

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9.99%

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Risk Caption

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The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund.

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Most of the Fund’s performance depends on what happens in the stock market, the Portfolio Manager’s evaluation of those developments, and the success of the Portfolio Manager in implementing the Fund’s investment strategies. The market’s behavior can be difficult to predict, particularly in the short term. There can be no guarantee that the Fund will achieve its goal. The Fund may take temporary defensive and cash management positions; to the extent it does, it will not be pursuing its principal investment strategies.

The actual risk exposure taken by the Fund in its investment program will vary over time, depending on various factors including the Portfolio Manager’s evaluation of issuer, political, regulatory, market, or economic developments. There can be no guarantee that the Portfolio Manager will be successful in his attempts to manage the risk exposure of the Fund or will appropriately evaluate or weigh the multiple factors involved in investment decisions, including issuer, market and/or instrument-specific analysis and valuation.

The Fund is a mutual fund, not a bank deposit, and is not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency. The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund.

Each of the following risks, which are described in alphabetical order and not in order of any presumed importance, can significantly affect the Fund’s performance. The relative importance of, or potential exposure as a result of, each of these risks will vary based on market and other investment-specific considerations.

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Issuer-Specific Risk. An individual security may be more volatile, and may perform differently, than the market as a whole.

The Fund’s portfolio may contain fewer securities than the portfolios of other funds, which increases the risk that the value of the Fund could go down because of the poor performance of one or a few investments.

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Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might

adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing or changing, which may impact such economies and markets in ways that cannot be foreseen at this time.

Although interest rates were unusually low in recent years in the U.S. and abroad, recently, the Federal Reserve and certain foreign central banks raised interest rates as part of their efforts to address rising inflation. It is difficult to accurately predict the pace at which interest rates might increase or start decreasing, the timing, frequency or magnitude of any such changes in interest rates, or when such changes might stop or reverse course. Additionally, various economic and political factors could cause the Federal Reserve or other foreign central banks to change their approach in the future and such actions may result in an economic slowdown both in the U.S. and abroad. Unexpected changes in interest rates could lead to significant market volatility or reduce liquidity in certain sectors of the market. Deteriorating economic fundamentals may, in turn, increase the risk of default or insolvency of particular issuers, negatively impact market value, cause credit spreads to widen, and reduce bank balance sheets. Any of these could cause an increase in market volatility, or reduce liquidity across various markets or decrease confidence in the markets.

Some countries, including the U.S., have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the United Kingdom and the European Union, and the risks associated with trade negotiations between the U.S. and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, if the U.S. dollar continues to be strong, it may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries.

Regulators in the U.S. have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance.

Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted.

High public debt in the U.S. and other countries creates ongoing systemic and market risks and policymaking uncertainty. There is no assurance that the U.S. Congress will act to raise the nation’s debt ceiling; a failure to do so could cause market turmoil and substantial investment risks that cannot now be fully predicted. Unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy.

There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries.

Prospectus [Line Items]

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Risk [Text Block]

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Sector Risk. From time to time, based on market or economic conditions, the Fund may have significant positions in one or more sectors of the market. To the extent the Fund invests more heavily in particular sectors, its performance will be especially sensitive to developments that significantly affect those sectors. Individual sectors or sub-sectors may be more volatile, and may perform differently, than the broader market. The industries that constitute a sector may all react in the same way to economic, political or regulatory events.

Prospectus [Line Items]

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Risk [Text Block]

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Operational and Cybersecurity Risk. The Fund and its service providers, and your ability to transact with the Fund, may be negatively impacted due to operational matters arising from, among other problems, human errors, systems and technology disruptions or failures, or cybersecurity incidents. Cybersecurity incidents may allow an unauthorized party to gain access to fund assets, customer data, or proprietary information, or cause the Fund or its service providers, as well as the securities trading venues and their service providers, to suffer data corruption or lose operational functionality. Cybersecurity incidents can result from deliberate attacks or unintentional events. It is not possible for the Manager or the other Fund service providers to identify all of the cybersecurity or other operational risks that may affect the Fund or to develop processes and controls to completely eliminate or mitigate their occurrence or effects. Most issuers in which the Fund invests are heavily dependent on computers for data storage and operations, and require ready access to the internet to conduct their business. Thus, cybersecurity incidents could also affect issuers of securities in which the Fund invests, leading to significant loss of value.

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Risk [Text Block]

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Valuation Risk. The Fund may not be able to sell an investment at the price at which the Fund has valued the investment. Such differences could be significant, particularly for illiquid securities and securities that trade in relatively thin markets and/or markets that experience extreme volatility. If market or other conditions make it difficult to value an investment, the Fund may be required to value such investments using more subjective methods, known as fair value methodologies. Using fair value methodologies to price investments may result in a value that is different from an investment’s most recent price and from the prices used by other funds to calculate their NAVs. The Fund uses pricing services to provide values for certain securities and there is no assurance that the Fund will be able to sell an investment at the price established by such pricing services. The Fund’s ability to value its investments in an accurate and timely manner may be impacted by technological issues and/or errors by third party service providers, such as pricing services or accounting agents.

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Risk [Text Block]

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Value Stock Risk. Value stocks may remain undervalued for extended periods of time, may decrease in value during a given period, may not ever realize what the portfolio management team believes to be their full value, or the portfolio management team’s assumptions about intrinsic value or potential for appreciation may be incorrect. This may happen, among other reasons, because of a failure to anticipate which stocks or industries would benefit from changing market or economic conditions or investor preferences.

A summary of the Fund’s additional principal investment risks is as follows:

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Risk [Text Block]

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ESG Criteria Risk. The Fund’s application of ESG criteria is designed and utilized to help identify companies that demonstrate the potential to create economic value or reduce risk; however, as with the use of any investment criteria in selecting a portfolio, there is no guarantee that the criteria used by the Fund will result in the selection of issuers that will outperform other issuers, or help reduce risk in the portfolio. Investing based on ESG criteria is qualitative and subjective by nature and there is no guarantee that the criteria used by the Fund will reflect the beliefs or values of any particular investor. The use of the Fund’s ESG criteria could also affect the Fund’s exposure to certain issuers, sectors or industries, and could impact the Fund’s investment performance depending on whether the ESG criteria used are ultimately reflected in the market. Information used to evaluate the Fund’s application of ESG criteria, like other information used to identify companies in which to invest, may not be readily available, complete, or accurate, which could negatively impact the Fund’s performance or create additional risk in the portfolio.

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Risk/Return [Heading]

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Mid Cap Growth Portfolio Class S

Objective, Primary [Text Block]

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The Fund seeks growth of capital.

Expense Narrative [Text Block]

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These tables describe the fees and expenses that you may pay if you buy, hold or sell shares of the Fund. These tables do not reflect any fees and expenses charged by your insurance company under your variable contract or by your qualified plan. If the tables did reflect such fees and expenses, the overall expenses would be higher than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Operating Expenses Caption [Text]

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

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover, Rate

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105.00%

Expense Example Narrative [Text Block]

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The expense example can help you compare costs among mutual funds. The example assumes that you invested $10,000 for the periods shown, that you redeemed all of your shares at the end of those periods, that the Fund earned a hypothetical 5% total return each year, and that the Fund’s expenses were those in the table. Actual performance and expenses may be higher or lower.

Strategy Narrative [Text Block]

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To pursue its goal, the Fund normally invests at least 80% of its net assets in common stocks of mid-capitalization companies, which it defines as those with a market capitalization within the market capitalization range of the Russell Midcap^® Index at the time of initial purchase. Although the Fund invests primarily in domestic securities, it may also invest in securities of foreign companies.

The Fund’s strategy utilizes a qualitative, bottom-up research driven approach to identify companies that the Portfolio Managers believe have catalysts for growth which are underappreciated by the market. The Portfolio Managers seek to invest in underappreciated companies with the following characteristics: durable and potentially unique business models and/or proficient management capable of advancing the development of and/or strengthening of sustainable and consistent revenue growth, cash flow growth, earnings growth and/or overall balance sheet strength. Such catalysts may include a new technology, product or

service, a regulatory update, market share gains, cyclical inflections (e.g. companies whose returns are driven by macro-economic factors), corporate restructurings or self-help initiatives (e.g. internal operating efforts to increase company efficiencies). The Portfolio Managers may also invest in anticipation of a catalyst.

In analyzing catalysts, the Portfolio Managers evaluate each catalyst’s uniqueness, timing, growth potential and sustainability, as well as assessing execution risks, competitive barriers and threats. The Portfolio Managers are also attempting to exploit market inefficiencies that potentially may exist within the small-to-mid-capitalization market, due to the number of companies that comprise the investable universe and the limited amount of available research that exists for some of those companies. Investable companies emerging from the Portfolio Manager’s bottom-up fundamental, qualitative and valuation analysis fall into the following investment classifications:

Core investments: are typically more mature companies, engaged with, and participating in, compelling secular growth trends, that the Portfolio Managers believe offer a demonstrated history of consistent execution and results. These tend to represent multi-year holdings of the strategy.

Turn investments: represent holdings in a wide range of corporate development and maturity stages and are generally driven by what the Portfolio Managers believe to be a distinct developing catalyst, such as a new product or service, market share gains or internal corporate self-help opportunities to improve operating efficiencies.

Tactical investments: represent holdings with a shorter-term investment horizon due to catalysts the Portfolio Managers believe are typically associated with cyclical trends and opportunities, a disconnect with market expectations providing an opportunity on valuation or a new product, or financial or regulatory developments that could have a material impact on the company.

Tactical investments have the potential to grow into Turn investments, while compelling Turn investments will ideally develop into Core investments.

The Fund seeks to reduce risk by diversifying among many companies, sectors and industries. At times, the Portfolio Managers may emphasize certain sectors that they believe will benefit from market or economic trends.

The Portfolio Managers constantly monitor their holdings and are focused on maintaining what they believe is an appropriate and attractive risk/reward balance with a disciplined sell process that acts quickly and dispassionately to address both positive and negative outcomes. A position is typically trimmed or exited for the following reasons: to harvest gains from significant short-term price appreciation, the positive realization of a catalyst, the achievement of a price target or elevated valuations, identification of a better idea, to minimize potential risks, to address an absence of near-term drivers or catalysts, a significant deterioration of fundamentals, a change in management or operating strategy or the failure of a catalyst to develop.

The Fund will not change its strategy of normally investing at least 80% of its net assets in mid-capitalization companies, without providing shareholders at least 60 days’ notice. This test is applied at the time the Fund invests; later percentage changes caused by a change in Fund assets, market values or company circumstances will not require the Fund to dispose of a holding.

Bar Chart and Performance Table [Heading]

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PERFORMANCE

Performance Information Illustrates Variability of Returns [Text]

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The bar chart shows how the Fund’s performance has varied from year to year. The table below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of one or more broad-based market indices.

Performance Availability Phone [Text]

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800-877-9700

Performance Past Does Not Indicate Future [Text]

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Past performance is not a prediction of future results.

Bar Chart Closing [Text Block]

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	Best quarter:	Q2 2020 29.83%
	Worst quarter:	Q2 2022 -20.65%

Index No Deduction for Fees, Expenses, Taxes [Text]

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reflects no deduction for fees, expenses or taxes

1 Year

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25.87%

10 Years

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10.57%

Prospectus [Line Items]

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5 Years

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12.68%

Shareholder Fee, Other

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none

Distribution and Service (12b-1) Fees

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0.25%

Expenses (as a percentage of Assets)

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1.18%

Net Expenses (as a percentage of Assets)

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1.11%

^[1]

Expense Example, with Redemption, 3 Years

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353

Expense Example, with Redemption, 10 Years

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$ 1,412

Annual Return 2015

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1.00%

Annual Return 2017

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24.56%

Annual Return 2019

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32.48%

Annual Return 2021

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12.72%

Annual Return 2023

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17.96%

Highest Quarterly Return, Date

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Jun. 30, 2020

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return

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(20.65%)

5 Years

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11.86%