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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Gain (Loss) on Securities [Line Items]
Unrealized gains/(losses)	$ 1,674	$ (376)	$ 2,935	$ 160
Realized gains/(losses)	32	(79)	(343)	(155)
Liabilities, Fair Value Disclosure [Abstract]
Securities sold, not yet purchased gross unrealized losses	(44)	0	0	0
Securities sold, not yet purchased gross realized gains	174		174
Securities sold, not yet purchased gross realized losses		0		0
Corporate Debt [Member]
Gain (Loss) on Securities [Line Items]
Unrealized gains/(losses)	324	(22)	233	(245)
Realized gains/(losses)	2	0	4	(17)
U.S. Treasuries [Member]
Gain (Loss) on Securities [Line Items]
Unrealized gains/(losses)	845	(154)	852	(500)
Mutual Funds Held In Rabbi Trust [Member]
Gain (Loss) on Securities [Line Items]
Unrealized gains/(losses)	505	(200)	1,850	905
Realized gains/(losses)	$ 30	$ (79)	$ (347)	$ (138)