Investments - Summary of Unrealized Gains and Losses in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Gain (Loss) on Securities [Line Items]
Net unrealized investment gains (losses)	$ 3,215	$ (7,153)	$ 1,363
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net (losses) gains recognized	2,282	(8,149)	5,486
Exclude: Net realized (losses) gains recognized for securities sold	$ (933)	$ (996)	$ 4,123