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)

Financial instruments sold not yet purchased gross realized gains1.

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Financial instruments sold not yet purchased gross unrealized gains1.

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Amount of realized gain (loss) on investment.

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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.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Amount of unrealized gain (loss) on investment.

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