Form N-1A Supplement |
Oct. 31, 2025 |
|---|---|
| Old Westbury All Cap Core Fund | Old Westbury All Cap Core Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Large Cap Strategies Fund | Old Westbury Large Cap Strategies Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Small & Mid Cap Strategies Fund | Old Westbury Small & Mid Cap Strategies Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Total Equity Fund | Old Westbury Total Equity Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Credit Income Fund | Old Westbury Credit Income Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Fixed Income Fund | Old Westbury Fixed Income Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Short-Term Bond Fund | Old Westbury Short-Term Bond Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury Municipal Bond Fund | Old Westbury Municipal Bond Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury California Municipal Bond Fund | Old Westbury California Municipal Bond Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |
| Old Westbury New York Municipal Bond Fund | Old Westbury New York Municipal Bond Fund | |
| Prospectus [Line Items] | |
| Supplement to Prospectus [Text Block] | Old Westbury All Cap Core Fund Old Westbury Large Cap Strategies Fund Old Westbury Small & Mid Cap Strategies Fund Old Westbury Total Equity Fund Old Westbury Credit Income Fund Old Westbury Fixed Income Fund Old Westbury Short-Term Bond Fund Old Westbury Municipal Bond Fund Old Westbury California Municipal Bond Fund Old Westbury New York Municipal Bond Fund
Supplement dated October 1, 2026 to the |