Loans and Allowance for Credit Losses - Schedule of Risk Category of Loans by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Commercial Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	$ 92,952	$ 212,570
Year 2	217,292	381,734
Year 3	359,553	257,437
Year 4	220,045	180,191
Year 5	170,652	76,935
Prior	239,943	188,808
Revolving Loans Amortized Cost	492,174	461,427
Revolving Loans Converted to Term	933	753
Total	1,793,544	1,759,855
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	92,952	212,229
Year 2	217,209	379,233
Year 3	357,362	253,837
Year 4	216,129	179,935
Year 5	170,417	75,472
Prior	235,221	186,073
Revolving Loans Amortized Cost	491,548	461,346
Revolving Loans Converted to Term	896	753
Total	1,781,734	1,748,878
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1		257
Year 3		119
Year 4	116
Prior	380	399
Revolving Loans Amortized Cost	143
Total	639	775
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1		84
Year 2	83	2,501
Year 3	2,191	3,481
Year 4	3,800	256
Year 5	235	1,463
Prior	4,342	2,336
Revolving Loans Amortized Cost	483	81
Revolving Loans Converted to Term	37
Total	11,171	10,202
Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	52,170	129,915
Year 2	97,001	111,285
Year 3	91,498	54,661
Year 4	44,165	52,479
Year 5	70,615	30,168
Prior	36,076	10,456
Revolving Loans Amortized Cost	270,401	207,583
Revolving Loans Converted to Term	1,792	1,780
Total	663,718	598,327
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	50,622	128,598
Year 2	95,651	110,817
Year 3	90,877	54,416
Year 4	43,813	49,557
Year 5	67,128	29,931
Prior	32,781	7,293
Revolving Loans Amortized Cost	261,926	204,237
Revolving Loans Converted to Term	1,792	1,780
Total	644,590	586,629
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Year 3	136	15
Year 5	807
Prior	1,041	992
Revolving Loans Amortized Cost	1,202
Total	3,186	1,007
Commercial and Industrial [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	1,548	1,317
Year 2	1,350	468
Year 3	485	230
Year 4	352	2,922
Year 5	2,680	237
Prior	2,175	2,171
Revolving Loans Amortized Cost	7,273	3,346
Total	15,863	10,691
Commercial and Industrial [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Prior	79
Total	79
Residential Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	12,433	35,040
Year 2	35,235	29,979
Year 3	36,717	277,798
Year 4	271,567	5,205
Year 5	8,190	12,662
Prior	147,078	132,104
Revolving Loans Amortized Cost	60,516	62,409
Revolving Loans Converted to Term	787	1,131
Total	572,523	556,328
Residential Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	12,433	35,040
Year 2	35,081	29,766
Year 3	36,426	277,611
Year 4	271,236	5,183
Year 5	8,170	12,506
Prior	143,137	130,144
Revolving Loans Amortized Cost	59,664	57,699
Revolving Loans Converted to Term	726	1,065
Total	566,873	549,014
Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Prior	346
Total	418
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 2	154	213
Year 3	291	187
Year 4	331	22
Year 5	20	156
Prior	3,595	1,960
Revolving Loans Amortized Cost	780	4,710
Revolving Loans Converted to Term	61	66
Total	5,232	7,314
Agricultural Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	13,214	23,311
Year 2	22,831	26,920
Year 3	29,255	18,011
Year 4	17,748	18,551
Year 5	20,063	10,754
Prior	42,719	23,626
Revolving Loans Amortized Cost	73,109	74,652
Revolving Loans Converted to Term	287	289
Total	219,226	196,114
Agricultural Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	11,476	22,368
Year 2	20,602	26,762
Year 3	29,089	17,987
Year 4	17,708	18,551
Year 5	20,063	10,653
Prior	39,164	20,039
Revolving Loans Amortized Cost	72,318	74,010
Revolving Loans Converted to Term	287	289
Total	210,707	190,659
Agricultural Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	1,695	903
Year 2		158
Year 3	150
Prior		164
Revolving Loans Amortized Cost	711	605
Total	2,556	1,830
Agricultural Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	43	40
Year 2	2,229
Year 3	16	24
Year 4	40
Year 5		101
Prior	3,555	3,423
Revolving Loans Amortized Cost	80	37
Total	5,963	3,625
Agricultural [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	10,359	12,463
Year 2	5,658	7,373
Year 3	6,315	5,279
Year 4	4,065	7,777
Year 5	7,890	3,246
Prior	3,066	3,894
Revolving Loans Amortized Cost	66,915	78,500
Revolving Loans Converted to Term	74	55
Total	104,342	118,587
Agricultural [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	10,325	12,424
Year 2	5,530	7,363
Year 3	6,180	4,815
Year 4	3,620	7,148
Year 5	7,483	1,385
Prior	2,996	3,809
Revolving Loans Amortized Cost	66,187	78,285
Revolving Loans Converted to Term	74	55
Total	102,395	115,284
Agricultural [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Year 3	1
Prior	33	33
Revolving Loans Amortized Cost		9
Total	34	42
Agricultural [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	34	39
Year 2	128	10
Year 3	134	464
Year 4	445	629
Year 5	407	1,861
Prior	37	52
Revolving Loans Amortized Cost	728	206
Total	1,913	3,261
Consumer [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	31,145	47,069
Year 2	22,327	24,861
Year 3	19,161	10,547
Year 4	8,128	4,939
Year 5	3,683	1,330
Prior	3,291	2,908
Revolving Loans Amortized Cost	13,319	12,035
Revolving Loans Converted to Term	0	1
Total	101,054	103,690
Consumer [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	31,145	47,019
Year 2	22,235	24,620
Year 3	18,835	10,384
Year 4	7,862	4,841
Year 5	3,619	1,281
Prior	3,237	2,885
Revolving Loans Amortized Cost	13,318	12,035
Revolving Loans Converted to Term		1
Total	100,251	103,066
Consumer [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	0	50
Year 2	92	241
Year 3	326	163
Year 4	266	98
Year 5	64	49
Prior	54	23
Revolving Loans Amortized Cost	1
Total	803	624
Total Loans Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	212,273	460,368
Year 2	400,344	582,152
Year 3	542,499	623,733
Year 4	565,718	269,142
Year 5	281,093	135,095
Prior	472,173	361,796
Revolving Loans Amortized Cost	976,434	896,606
Revolving Loans Converted to Term	3,873	4,009
Total	3,454,407	3,332,901
Total Loans Portfolio Segment [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	208,953	457,678
Year 2	396,308	578,561
Year 3	538,769	619,050
Year 4	560,368	265,215
Year 5	276,880	131,228
Prior	456,536	350,243
Revolving Loans Amortized Cost	964,961	887,612
Revolving Loans Converted to Term	3,775	3,943
Total	3,406,550	3,293,530
Total Loans Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	1,695	1,160
Year 2		158
Year 3	287	134
Year 4	116
Year 5	807
Prior	1,800	1,588
Revolving Loans Amortized Cost	2,128	614
Total	6,833	3,654
Total Loans Portfolio Segment [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Year 1	1,625	1,530
Year 2	4,036	3,433
Year 3	3,443	4,549
Year 4	5,234	3,927
Year 5	3,406	3,867
Prior	13,758	9,965
Revolving Loans Amortized Cost	9,345	8,380
Revolving Loans Converted to Term	98	66
Total	40,945	$ 35,717
Total Loans Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Prior	79
Total	$ 79