Shareholder Report |
6 Months Ended |
|---|---|
|
Jun. 30, 2026
USD ($)
Holding
| |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | T. ROWE PRICE INDEX TRUST, INC. |
| Entity Central Index Key | 0000858581 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2026 |
| Shareholder Report Annual or Semi-Annual | Semi-Annual Shareholder Report |
| C000005458 | |
| Shareholder Report [Line Items] | |
| Fund Name | Extended Equity Market Index Fund |
| Trading Symbol | PEXMX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about Extended Equity Market Index Fund (the "fund") for the period of January 1, 2026 to June 30, 2026. |
| 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 atwww.troweprice.com/prospectus. You can also request this information without charge by contacting T. Rowe Price at 1‑800‑638‑5660 or info@troweprice.com or contacting your intermediary. |
| Material Fund Change Notice [Text Block] | |
| Additional Information Phone Number | 1‑800‑638‑5660 |
| Additional Information Email | <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; text-align-last: left; white-space-collapse: preserve-breaks;">info@troweprice.com</span> |
| Additional Information Website | www.troweprice.com/prospectus |
| Expenses [Text Block] | |
| Expenses Paid, Amount | $ 12 |
| Expense Ratio, Percent | 0.23% |
| 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. If you invest through a financial intermediary such as an investment advisor, a bank, retirement plan sponsor or a brokerage firm, please contact that organization and ask if it can provide electronic delivery. Visit www.troweprice.com/en/us/market-data-disclosures for additional legal notices & disclaimers. |
| AssetsNet | $ 1,193,359,000 |
| Holdings Count | Holding | 1,581 |
| InvestmentCompanyPortfolioTurnover | 4.30% |
| Additional Fund Statistics [Text Block] | |
| Additional Fund Statistics Significance or Limits [Text Block] | |
| Holdings [Text Block] | |
| Largest Holdings [Text Block] | |
| Material Fund Change [Text Block] | |
| Updated Prospectus Web Address | www.troweprice.com/paperless |