v3.26.1
Shareholder Report
 6 Months Ended
Apr. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name NEUBERGER BERMAN ALTERNATIVE FUNDS
Entity Central Index Key 0001317474
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2026
C000108852  
Shareholder Report [Line Items]  
Fund Name Long Short Fund
Class Name Institutional Class
Trading Symbol NLSIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Fund for the period of November 1, 2025 to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at neuberger.com/longshort-documents. You can also request this information by contacting your financial intermediary or investment provider or at 800.366.6264 or issdl@nb.com.
Additional Information Phone Number 800.366.6264
Additional Information Email issdl@nb.com
Additional Information Website neuberger.com/longshort-documents
Expenses [Text Block]

What were the Fund's costs for the past six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference*
Institutional Class
$53
1.07%
FootnoteDescription
Footnote*
Annualized.
Expenses Paid, Amount $ 53
Expense Ratio, Percent 1.07%
AssetsNet $ 8,253,035,902
Holdings Count | Holding 207
InvestmentCompanyPortfolioTurnover 39.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets
$8,253,035,902
Number of Portfolio Holdings
207
Portfolio Turnover Rate
39%
Holdings [Text Block]

Top Ten Short Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Lamar Advertising Co. Class A
(0.7)%
Consolidated Edison, Inc.
(0.5)%
Omnicom Group, Inc.
(0.5)%
Public Service Enterprise Group, Inc.
(0.4)%
Allstate Corp.
(0.4)%
Exelon Corp.
(0.4)%
Brookfield Renewable Corp.
(0.4)%
HP, Inc.
(0.4)%
Cheesecake Factory, Inc.
(0.4)%
Nexstar Media Group, Inc.
(0.3)%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.

Portfolio by Investment Type

(as a % of Total Net Assets)

Table Summary
Name
Long
Short
Common Stocks
88.7%
(13.1)%
Master Limited Partnerships and Limited Partnerships
3.1%
-%
Preferred Stocks
1.3%
-%
Loan Assignments
0.2%
-%
Purchased Option Contracts
0.0%Footnote Reference*
-%
Corporate Bonds
0.0%Footnote Reference*
-%
Short-Term Investments
4.5%
-%
Other Assets Less Liabilities
15.3%Footnote Reference**
-%
Total
113.1%
(13.1)%
FootnoteDescription
Footnote*
Represents less than 0.05% of net assets of the Fund.
Footnote**
Includes the impact of the Fund's open positions in derivatives (other than options purchased), if any.
Largest Holdings [Text Block]

Top Ten Long Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Alphabet, Inc. Class A
8.1%
Amazon.com, Inc.
7.1%
NVIDIA Corp.
6.5%
Microsoft Corp.
5.5%
Apple, Inc.
5.4%
State Street Institutional U.S. Government Money Market Fund Premier Class
5.0%
Meta Platforms, Inc. Class A
3.3%
Broadcom, Inc.
2.6%
Fanatics Holdings, Inc. Class A
2.1%
Brookfield Infrastructure Partners LP
2.0%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.
C000108850  
Shareholder Report [Line Items]  
Fund Name Long Short Fund
Class Name Class A
Trading Symbol NLSAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Fund for the period of November 1, 2025 to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at neuberger.com/longshort-documents. You can also request this information by contacting your financial intermediary or investment provider or at 800.877.9700 or fundinfo@nb.com.
Additional Information Phone Number 800.877.9700
Additional Information Email fundinfo@nb.com
Additional Information Website neuberger.com/longshort-documents
Expenses [Text Block]

What were the Fund's costs for the past six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference*
Class A
$71
1.43%
FootnoteDescription
Footnote*
Annualized.
Expenses Paid, Amount $ 71
Expense Ratio, Percent 1.43%
AssetsNet $ 8,253,035,902
Holdings Count | Holding 207
InvestmentCompanyPortfolioTurnover 39.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets
$8,253,035,902
Number of Portfolio Holdings
207
Portfolio Turnover Rate
39%
Holdings [Text Block]

Top Ten Short Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Lamar Advertising Co. Class A
(0.7)%
Consolidated Edison, Inc.
(0.5)%
Omnicom Group, Inc.
(0.5)%
Public Service Enterprise Group, Inc.
(0.4)%
Allstate Corp.
(0.4)%
Exelon Corp.
(0.4)%
Brookfield Renewable Corp.
(0.4)%
HP, Inc.
(0.4)%
Cheesecake Factory, Inc.
(0.4)%
Nexstar Media Group, Inc.
(0.3)%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.

Portfolio by Investment Type

(as a % of Total Net Assets)

Table Summary
Name
Long
Short
Common Stocks
88.7%
(13.1)%
Master Limited Partnerships and Limited Partnerships
3.1%
-%
Preferred Stocks
1.3%
-%
Loan Assignments
0.2%
-%
Purchased Option Contracts
0.0%Footnote Reference*
-%
Corporate Bonds
0.0%Footnote Reference*
-%
Short-Term Investments
4.5%
-%
Other Assets Less Liabilities
15.3%Footnote Reference**
-%
Total
113.1%
(13.1)%
FootnoteDescription
Footnote*
Represents less than 0.05% of net assets of the Fund.
Footnote**
Includes the impact of the Fund's open positions in derivatives (other than options purchased), if any.
Largest Holdings [Text Block]

Top Ten Long Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Alphabet, Inc. Class A
8.1%
Amazon.com, Inc.
7.1%
NVIDIA Corp.
6.5%
Microsoft Corp.
5.5%
Apple, Inc.
5.4%
State Street Institutional U.S. Government Money Market Fund Premier Class
5.0%
Meta Platforms, Inc. Class A
3.3%
Broadcom, Inc.
2.6%
Fanatics Holdings, Inc. Class A
2.1%
Brookfield Infrastructure Partners LP
2.0%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.
C000108851  
Shareholder Report [Line Items]  
Fund Name Long Short Fund
Class Name Class C
Trading Symbol NLSCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Fund for the period of November 1, 2025 to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at neuberger.com/longshort-documents. You can also request this information by contacting your financial intermediary or investment provider or at 800.877.9700 or fundinfo@nb.com.
Additional Information Phone Number 800.877.9700
Additional Information Email fundinfo@nb.com
Additional Information Website neuberger.com/longshort-documents
Expenses [Text Block]

What were the Fund's costs for the past six months?

(based on a hypothetical $10,000 investment)

Table Summary
Class Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investmentFootnote Reference*
Class C
$108
2.18%
FootnoteDescription
Footnote*
Annualized.
Expenses Paid, Amount $ 108
Expense Ratio, Percent 2.18%
AssetsNet $ 8,253,035,902
Holdings Count | Holding 207
InvestmentCompanyPortfolioTurnover 39.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics

Table Summary
Net Assets
$8,253,035,902
Number of Portfolio Holdings
207
Portfolio Turnover Rate
39%
Holdings [Text Block]

Top Ten Short Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Lamar Advertising Co. Class A
(0.7)%
Consolidated Edison, Inc.
(0.5)%
Omnicom Group, Inc.
(0.5)%
Public Service Enterprise Group, Inc.
(0.4)%
Allstate Corp.
(0.4)%
Exelon Corp.
(0.4)%
Brookfield Renewable Corp.
(0.4)%
HP, Inc.
(0.4)%
Cheesecake Factory, Inc.
(0.4)%
Nexstar Media Group, Inc.
(0.3)%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.

Portfolio by Investment Type

(as a % of Total Net Assets)

Table Summary
Name
Long
Short
Common Stocks
88.7%
(13.1)%
Master Limited Partnerships and Limited Partnerships
3.1%
-%
Preferred Stocks
1.3%
-%
Loan Assignments
0.2%
-%
Purchased Option Contracts
0.0%Footnote Reference*
-%
Corporate Bonds
0.0%Footnote Reference*
-%
Short-Term Investments
4.5%
-%
Other Assets Less Liabilities
15.3%Footnote Reference**
-%
Total
113.1%
(13.1)%
FootnoteDescription
Footnote*
Represents less than 0.05% of net assets of the Fund.
Footnote**
Includes the impact of the Fund's open positions in derivatives (other than options purchased), if any.
Largest Holdings [Text Block]

Top Ten Long Securities

(as a % of Total InvestmentsFootnote Reference*)

Table Summary
Alphabet, Inc. Class A
8.1%
Amazon.com, Inc.
7.1%
NVIDIA Corp.
6.5%
Microsoft Corp.
5.5%
Apple, Inc.
5.4%
State Street Institutional U.S. Government Money Market Fund Premier Class
5.0%
Meta Platforms, Inc. Class A
3.3%
Broadcom, Inc.
2.6%
Fanatics Holdings, Inc. Class A
2.1%
Brookfield Infrastructure Partners LP
2.0%
FootnoteDescription
Footnote*
Derivatives (other than options purchased), if any, are excluded from this calculation.