Condensed Financial Information - Parent Company Only - Schedule of Condensed Income Statement (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statements of Income
Interest expense	$ 201,185,000	$ 151,733,000	$ 33,896,000
Income before income taxes	95,300,000	88,689,000	97,210,000
Income tax expense	19,369,000	17,585,000	19,090,000
Equity in undistributed income of subsidiaries:
Net income	75,931,000	71,104,000	78,120,000
Parent Company [Member]
Statements of Income
Dividends from Bank	56,283,000	18,386,000	23,303,000
Dividends from non-bank	0	0	0
Other income	24,754,000	25,000,000	28,630,000
Total operating income	81,037,000	43,386,000	51,933,000
Interest expense	9,125,000	9,125,000	5,798,000
Operating expenses	28,266,000	27,627,000	30,297,000
Income before income taxes	43,646,000	6,634,000	15,838,000
Income tax expense	(2,733,000)	(2,751,000)	(1,983,000)
Income before equity in undistributed income of subsidiaries	46,379,000	9,385,000	17,821,000
Equity in undistributed income of subsidiaries:
Bank	29,552,000	61,719,000	60,299,000
Non-banks	0	0	0
Net income	$ 75,931,000	$ 71,104,000	$ 78,120,000