v3.26.1
Stock-Based Compensation - Schedule of Weighted Average Assumptions (Details) - Unvested performance stock units
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance period (in years) 3 years 3 years
Risk-free interest rate 3.52% 4.26%
Expected volatility of Magnite 66.00% 78.00%
Expected volatility of selected peer companies 54.00% 56.00%
Expected correlation coefficients of Magnite 48.00% 57.00%
Expected correlation coefficients of selected peer companies 45.00% 47.00%
Dividend yield 0.00% 0.00%