Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Accumulated other comprehensive income, deferred tax (benefit) expense	$ 11,100	$ (68,200)	$ (8,300)
Accumulated other comprehensive income, deferred tax (benefit) expense	(3,900)	6,200	3,100
Accumulated other comprehensive income, a deferred tax expense (benefit)	884	$ (517)	$ 1,400
Retained earnings amount for which no provision for income tax has been made	51,800
Unrecognized tax liability	14,000
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, limitations on use	197
Beacon Trust
Operating Loss Carryforwards [Line Items]
Unused capital loss carryforwards	$ 760