Accumulated Other Comprehensive Income - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Realized gains on sales of investment securities	$ 8,500	$ 200	$ 3,100
Amount reclassified from accumulated other comprehensive income	(2,100)	0	700
Amount reclassified from accumulated other comprehensive income	$ 6,400	$ 200	2,400
Income Tax Expense [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income			$ (700)