Parent Company Only Condensed Financial Information - Schedule of Condensed Statements of Cash Flows (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net income	$ 31,683,000	$ 42,964,000	$ 39,427,000
Adjustment to reconcile net income to net cash from operating activities:
Net cash provided by operating activities	48,246,000	62,698,000	25,183,000
Cash flows used for investing activities:
Acquisition and additional capitalization of subsidiary, net of cash acquired			(51,643,000)
Net cash used in investing activities	(258,801,000)	(311,784,000)	(410,364,000)
Cash flows from financing activities:
Net cash provided by financing activities	213,304,000	266,131,000	164,303,000
Increase (decrease) in cash and due from financial institutions	2,749,000	17,045,000	(220,878,000)
CBI[Member]
Operating activities:
Net income	31,683,000	42,964,000	39,427,000
Adjustment to reconcile net income to net cash from operating activities:
Change in other assets and other liabilities	(5,546,000)	(12,836,000)	4,587,000
Equity in undistributed net earnings of subsidiaries	(15,362,000)	(18,382,000)	(16,662,000)
Net cash provided by operating activities	10,775,000	11,746,000	27,352,000
Cash flows used for investing activities:
Acquisition and additional capitalization of subsidiary, net of cash acquired		(14,000,000)	(25,960,000)
Net cash used in investing activities		(14,000,000)	(25,960,000)
Cash flows from financing activities:
Purchase of treasury stock	(164,000)	(1,628,000)	(16,887,000)
Cash dividends paid	(10,063,000)	(9,599,000)	(8,493,000)
Net cash provided by financing activities	(10,227,000)	(11,227,000)	(25,380,000)
Increase (decrease) in cash and due from financial institutions	548,000	(13,481,000)	(23,988,000)
Cash and cash equivalents at beginning of year	8,331,000	21,812,000	45,800,000
Cash and cash equivalents at end of year	$ 8,879,000	$ 8,331,000	$ 21,812,000