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Fair Value Measurements - Summary of Companies Unrealized and Realized Gains and Losses on Investments (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Gain (Loss) on Securities [Line Items] |  |  |  |
Unrealized gains/(losses) | $ (529) | $ 1,674 | $ 1,829 | $ 2,935
Realized gains/(losses) | 1,161 | 32 | 1,255 | (343)
Securities sold, not yet purchased gross unrealized gains | 0 | (44) | 0 | 0
Securities sold, not yet purchased gross realized gains | 0 | 174 | 0 | 174
Corporate Debt [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Unrealized gains/(losses) | 124 | 324 | 626 | 233
Realized gains/(losses) | 0 | 2 | 0 | 4
U.S. Treasuries [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Unrealized gains/(losses) | (166) | 845 | 1,113 | 852
Mutual Funds Held In Rabbi Trust [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Unrealized gains/(losses) | (487) | 505 | 90 | 1,850
Realized gains/(losses) | $ 1,161 | $ 30 | $ 1,255 | $ (347)

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