Investments in Marketable Securities - Additional Information (Detail) - USD ($) |
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2025 |
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| Schedule Of Available For Sale Securities [Line Items] | |||
| Net unrealized gains (losses) on marketable equity securities recognized in investment income | $ 1,700,000 | $ (900,000) | |
| Allowance for credit losses | 0 | $ 0 | |
| Truck, Parts and Other | |||
| Schedule Of Available For Sale Securities [Line Items] | |||
| Gross realized gains from sales of marketable debt securities | 2,300,000 | 2,700,000 | |
| Gross realized loss from sales of marketable debt securities | $ 1,900,000 | $ 1,800,000 | |
| X | ||||||||||
- Definition Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Details
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