Loans Held-for-Investment and Allowance for Credit Losses - Changes in Allowance for Loan Losses (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 101,080,000	$ 89,562,000	$ 98,325,000	$ 88,734,000
Provision for loan losses	2,432,000	5,910,000	5,423,000	7,166,000
Recoveries	469,000	400,000	1,179,000	822,000
Charge-offs	(1,189,000)	(702,000)	(2,135,000)	(1,552,000)
Ending balance	102,792,000	95,170,000	102,792,000	95,170,000
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	15,592,000	16,106,000	15,436,000	15,698,000
Provision for loan losses	2,502,000	(790,000)	2,656,000	(289,000)
Recoveries	100,000	177,000	193,000	288,000
Charge-offs	(320,000)	(242,000)	(411,000)	(446,000)
Ending balance	17,874,000	15,251,000	17,874,000	15,251,000
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	360,000	195,000	200,000	195,000
Provision for loan losses	1,000	44,000	161,000	44,000
Recoveries	0	0	0	0
Charge-offs	0	0	0	0
Ending balance	361,000	239,000	361,000	239,000
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,564,000	3,243,000	1,653,000	1,281,000
Provision for loan losses	(665,000)	(1,359,000)	(790,000)	658,000
Recoveries	38,000	46,000	74,000	51,000
Charge-offs	0	1,000	0	(59,000)
Ending balance	937,000	1,931,000	937,000	1,931,000
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	19,717,000	24,811,000	19,861,000	28,553,000
Provision for loan losses	2,368,000	(1,300,000)	2,224,000	(5,009,000)
Recoveries	2,000	0	2,000	0
Charge-offs	(40,000)	(0)	(40,000)	(33,000)
Ending balance	22,047,000	23,511,000	22,047,000	23,511,000
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,919,000	2,517,000	2,871,000	2,914,000
Provision for loan losses	(135,000)	385,000	(88,000)	(12,000)
Recoveries	0	0	1,000	0
Charge-offs	0	0	0	0
Ending balance	2,784,000	2,902,000	2,784,000	2,902,000
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	15,709,000	14,968,000	14,664,000	13,425,000
Provision for loan losses	(1,456,000)	(1,951,000)	(414,000)	(415,000)
Recoveries	5,000	24,000	8,000	31,000
Charge-offs	(250,000)	(13,000)	(250,000)	(13,000)
Ending balance	14,008,000	13,028,000	14,008,000	13,028,000
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	21,492,000	12,756,000	21,413,000	13,813,000
Provision for loan losses	(239,000)	8,260,000	(287,000)	7,161,000
Recoveries	5,000	38,000	307,000	80,000
Charge-offs	0	0	(175,000)	0
Ending balance	21,258,000	21,054,000	21,258,000	21,054,000
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	21,739,000	13,565,000	20,488,000	11,654,000
Provision for loan losses	(130,000)	2,112,000	1,368,000	3,925,000
Recoveries	22,000	2,000	25,000	100,000
Charge-offs	(154,000)	(11,000)	(404,000)	(11,000)
Ending balance	21,477,000	15,668,000	21,477,000	15,668,000
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,495,000	907,000	1,186,000	810,000
Provision for loan losses	199,000	406,000	649,000	790,000
Recoveries	129,000	89,000	327,000	201,000
Charge-offs	(277,000)	(329,000)	(616,000)	(728,000)
Ending balance	1,546,000	1,073,000	1,546,000	1,073,000
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	493,000	494,000	553,000	391,000
Provision for loan losses	(13,000)	103,000	(56,000)	313,000
Recoveries	168,000	24,000	242,000	71,000
Charge-offs	(148,000)	(108,000)	(239,000)	(262,000)
Ending balance	$ 500,000	$ 513,000	$ 500,000	$ 513,000