Comprehensive Income (Loss) - Schedule of Components of Other Comprehensive Income or Loss and Related Tax Effects Allocated to Each Component (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Before Tax
Net unrealized (losses) gains arising during the period	$ (11,355)	$ (692)	$ 86
Credit losses charged to income	0	0	611
Call and repayment gains charged to investment income	0	(36)	(374)
Reclassification adjustment for net realized losses (gains)	429	(687)	(1,163)
Total other comprehensive loss	(10,926)	(1,415)	(840)
Income Tax Effect
Net unrealized (losses) gains	(263)	(170)	21
Credit losses on investments			150
Call and repayment gains charged to investment income		(9)	(92)
Reclassification adjustment for net realized losses (gains)	109	(168)	(285)
Total other comprehensive loss	(154)	(347)	(206)
Net of Tax
Net unrealized (losses) gains	(11,092)	(522)	65
Credit losses on investments			461
Call and repayment gains charged to investment income		(27)	(282)
Reclassification adjustment for net realized losses (gains)	320	(519)	(878)
Total other comprehensive loss, net of income taxes	$ (10,772)	$ (1,068)	$ (634)