Form N-CSR Cover
| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | T. ROWE PRICE NEW HORIZONS FUND, INC. |
| Entity Central Index Key | 0000080248 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
Shareholder Report
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | T. ROWE PRICE NEW HORIZONS FUND, INC. |
| Entity Central Index Key | 0000080248 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| C000005478 | |
| Shareholder Report [Line Items] | |
| Fund Name | New Horizons Fund |
| Class Name | Investor Class |
| Trading Symbol | PRNHX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about New Horizons Fund (the "fund") for the period of January 1, 2024 to June 30, 2024. You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Material Fund Change Notice [Text Block] | |
| Additional Information Phone Number | 1‑800‑638‑5660 |
| Additional Information Email | info@troweprice.com</span>" id="sjs-B20"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">info@troweprice.com</span> |
| Additional Information Website | www.troweprice.com/prospectus</span>" id="sjs-B21"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 700; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/prospectus</span> |
| Expenses [Text Block] | What were the fund costs for the last six months? Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment New Horizons Fund - Investor Class $39 0.79% |
| Expenses Paid, Amount | $ 39 |
| Expense Ratio, Percent | 0.79% |
| Updated Performance Information Location [Text Block] | If you invest directly with T. Rowe Price, you can elect to receive future shareholder reports or other important documents through electronic delivery by enrolling at www.troweprice.com/paperless |
| AssetsNet | $ 21,664,894,000 |
| Holdings Count | Holding | 232 |
| InvestmentCompanyPortfolioTurnover | 12.30% |
| Additional Fund Statistics [Text Block] | What are some fund statistics? Fund Statistics Total Net Assets (000s) $21,664,894 Number of Portfolio Holdings 232 |
| Additional Fund Statistics Significance or Limits [Text Block] | Portfolio Turnover Rate 12.3% |
| Holdings [Text Block] | Sector Allocation Industrials & Business Services 28.4 % Health Care 28.2 Information Technology 24.3 Consumer Discretionary 6.3 Energy 5.2 Financials 3.6 Materials 1.2 Consumer Staples 0.5 Communication Services 0.0 Other 2.3 |
| Largest Holdings [Text Block] | Top Ten Holdings Weatherford International 2.6 % Saia 2.6 Toast 2.5 Booz Allen Hamilton Holding 2.4 Dayforce 2.4 Teledyne Technologies 2.4 Globant 2.4 IDEX 2.4 Paylocity Holding 2.3 TechnipFMC 2.2 |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | www.troweprice.com/paperless</span>" id="sjs-B34"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 13.8667px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/paperless</span> |
| C000159684 | |
| Shareholder Report [Line Items] | |
| Fund Name | New Horizons Fund |
| Class Name | I Class |
| Trading Symbol | PRJIX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about New Horizons Fund (the "fund") for the period of January 1, 2024 to June 30, 2024. You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Material Fund Change Notice [Text Block] | |
| Additional Information Phone Number | 1‑800‑638‑5660 |
| Additional Information Email | info@troweprice.com</span>" id="sjs-B45"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">info@troweprice.com</span> |
| Additional Information Website | www.troweprice.com/prospectus</span>" id="sjs-B46"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 700; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/prospectus</span> |
| Expenses [Text Block] | What were the fund costs for the last six months? Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment New Horizons Fund - I Class $32 0.65% |
| Expenses Paid, Amount | $ 32 |
| Expense Ratio, Percent | 0.65% |
| Updated Performance Information Location [Text Block] | If you invest directly with T. Rowe Price, you can elect to receive future shareholder reports or other important documents through electronic delivery by enrolling at www.troweprice.com/paperless |
| AssetsNet | $ 21,664,894,000 |
| Holdings Count | Holding | 232 |
| InvestmentCompanyPortfolioTurnover | 12.30% |
| Additional Fund Statistics [Text Block] | What are some fund statistics? Fund Statistics Total Net Assets (000s) $21,664,894 Number of Portfolio Holdings 232 |
| Additional Fund Statistics Significance or Limits [Text Block] | Portfolio Turnover Rate 12.3% |
| Holdings [Text Block] | Sector Allocation Industrials & Business Services 28.4 % Health Care 28.2 Information Technology 24.3 Consumer Discretionary 6.3 Energy 5.2 Financials 3.6 Materials 1.2 Consumer Staples 0.5 Communication Services 0.0 Other 2.3 |
| Largest Holdings [Text Block] | Top Ten Holdings Weatherford International 2.6 % Saia 2.6 Toast 2.5 Booz Allen Hamilton Holding 2.4 Dayforce 2.4 Teledyne Technologies 2.4 Globant 2.4 IDEX 2.4 Paylocity Holding 2.3 TechnipFMC 2.2 |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | www.troweprice.com/paperless</span>" id="sjs-B59"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 13.8667px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/paperless</span> |
| C000219323 | |
| Shareholder Report [Line Items] | |
| Fund Name | New Horizons Fund |
| Class Name | Z Class |
| Trading Symbol | TRUZX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about New Horizons Fund (the "fund") for the period of January 1, 2024 to June 30, 2024. You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| Additional Information [Text Block] | You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information at www.troweprice.com/prospectus info troweprice.com |
| Material Fund Change Notice [Text Block] | |
| Additional Information Phone Number | 1‑800‑638‑5660 |
| Additional Information Email | info@troweprice.com</span>" id="sjs-B70"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">info@troweprice.com</span> |
| Additional Information Website | www.troweprice.com/prospectus</span>" id="sjs-B71"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 700; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/prospectus</span> |
| Expenses [Text Block] | What were the fund costs for the last six months? Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment New Horizons Fund - Z Class $0 0.00% |
| Expenses Paid, Amount | $ 0 |
| Expense Ratio, Percent | 0% |
| Updated Performance Information Location [Text Block] | If you invest directly with T. Rowe Price, you can elect to receive future shareholder reports or other important documents through electronic delivery by enrolling at www.troweprice.com/paperless |
| AssetsNet | $ 21,664,894,000 |
| Holdings Count | Holding | 232 |
| InvestmentCompanyPortfolioTurnover | 12.30% |
| Additional Fund Statistics [Text Block] | What are some fund statistics? Fund Statistics Total Net Assets (000s) $21,664,894 Number of Portfolio Holdings 232 |
| Additional Fund Statistics Significance or Limits [Text Block] | Portfolio Turnover Rate 12.3% |
| Holdings [Text Block] | Sector Allocation Industrials & Business Services 28.4 % Health Care 28.2 Information Technology 24.3 Consumer Discretionary 6.3 Energy 5.2 Financials 3.6 Materials 1.2 Consumer Staples 0.5 Communication Services 0.0 Other 2.3 |
| Largest Holdings [Text Block] | Top Ten Holdings Weatherford International 2.6 % Saia 2.6 Toast 2.5 Booz Allen Hamilton Holding 2.4 Dayforce 2.4 Teledyne Technologies 2.4 Globant 2.4 IDEX 2.4 Paylocity Holding 2.3 TechnipFMC 2.2 |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | www.troweprice.com/paperless</span>" id="sjs-B84"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 13.8667px; margin: 0px; overflow: visible; text-align: justify;">www.troweprice.com/paperless</span> |
Shareholder Report, Holdings (D
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| C000005478 | Weatherford International | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000005478 | Saia | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000005478 | Toast | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000005478 | Booz Allen Hamilton Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000005478 | Dayforce | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000005478 | Teledyne Technologies | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000005478 | Globant | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000005478 | IDEX | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000005478 | Paylocity Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000005478 | TechnipFMC | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000005478 | Industrials & Business Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.40% |
| C000005478 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.20% |
| C000005478 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.30% |
| C000005478 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000005478 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.20% |
| C000005478 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000005478 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000005478 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| C000005478 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000159684 | Weatherford International | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000159684 | Saia | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000159684 | Toast | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000159684 | Booz Allen Hamilton Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000159684 | Dayforce | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000159684 | Teledyne Technologies | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000159684 | Globant | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000159684 | IDEX | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000159684 | Paylocity Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000159684 | TechnipFMC | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000159684 | Industrials & Business Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.40% |
| C000159684 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.20% |
| C000159684 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.30% |
| C000159684 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000159684 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.20% |
| C000159684 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000159684 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000159684 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| C000159684 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| C000219323 | Weatherford International | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000219323 | Saia | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000219323 | Toast | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000219323 | Booz Allen Hamilton Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000219323 | Dayforce | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000219323 | Teledyne Technologies | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000219323 | Globant | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000219323 | IDEX | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000219323 | Paylocity Holding | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000219323 | TechnipFMC | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000219323 | Industrials & Business Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.40% |
| C000219323 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 28.20% |
| C000219323 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.30% |
| C000219323 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000219323 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.20% |
| C000219323 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000219323 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000219323 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| C000219323 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |