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Loans - Risk Category of Loans at Amortized Cost, by Portfolio Segment Based on Year of Origination (Detail) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Grand Total | $ 2,624,947 | $ 2,560,795
Consumer Real Estate [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 28,019 | 40,400
2024 | 35,619 | 64,555
2023 | 56,713 | 80,069
2022 | 75,541 | 91,137
2021 | 87,874 | 75,461
Prior | 168,553 | 107,166
Term Total | 452,319 | 458,788
Revolving Loans Amortized Cost Basis | 71,382 | 61,352
Revolving Loans Converted to Term | 505 | 252
Grand Total | 524,206 | 520,392
Gross charge-offs - Prior |  | 13
Gross charge-offs - Term Total |  | 13
Gross charge-offs - Grand Total |  | 13
Consumer Real Estate [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 28,019 | 40,257
2024 | 35,476 | 64,316
2023 | 56,179 | 79,503
2022 | 74,924 | 89,800
2021 | 86,557 | 74,996
Prior | 166,676 | 106,007
Term Total | 447,831 | 454,879
Revolving Loans Amortized Cost Basis | 71,216 | 61,097
Revolving Loans Converted to Term | 499 | 237
Grand Total | 519,546 | 516,213
Consumer Real Estate [Member] | Special Mention [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2023 |  | 37
2022 | 35 | 551
2021 | 133 |
Prior | 115 | 119
Term Total | 283 | 707
Revolving Loans Amortized Cost Basis | 19 | 19
Grand Total | 302 | 726
Consumer Real Estate [Member] | Substandard [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 |  | 143
2024 | 143 | 239
2023 | 534 | 529
2022 | 582 | 786
2021 | 1,184 | 465
Prior | 1,762 | 1,040
Term Total | 4,205 | 3,202
Revolving Loans Amortized Cost Basis | 147 | 236
Revolving Loans Converted to Term | 6 | 15
Grand Total | 4,358 | 3,453
Agricultural Real Estate [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 16,486 | 29,513
2024 | 27,767 | 28,088
2023 | 26,433 | 34,840
2022 | 33,191 | 22,983
2021 | 22,189 | 23,639
Prior | 94,606 | 76,982
Term Total | 220,672 | 216,045
Revolving Loans Amortized Cost Basis | 88 | 92
Grand Total | 220,760 | 216,137
Agricultural Real Estate [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 16,486 | 23,817
2024 | 22,099 | 28,088
2023 | 26,433 | 34,469
2022 | 32,788 | 22,983
2021 | 21,107 | 23,639
Prior | 94,504 | 76,964
Term Total | 213,417 | 209,960
Revolving Loans Amortized Cost Basis | 88 | 92
Grand Total | 213,505 | 210,052
Agricultural Real Estate [Member] | Special Mention [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2022 | 32 |
Prior | 12 | 13
Term Total | 44 | 13
Grand Total | 44 | 13
Agricultural Real Estate [Member] | Substandard [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 |  | 5,696
2024 | 5,668 |
2023 |  | 371
2022 | 371 |
2021 | 1,082 |
Prior | 90 | 5
Term Total | 7,211 | 6,072
Grand Total | 7,211 | 6,072
Agricultural [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 12,842 | 14,915
2024 | 10,268 | 10,534
2023 | 8,303 | 14,381
2022 | 10,641 | 5,624
2021 | 4,319 | 3,233
Prior | 5,860 | 3,911
Term Total | 52,233 | 52,598
Revolving Loans Amortized Cost Basis | 106,008 | 99,783
Grand Total | 158,241 | 152,381
Agricultural [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 12,542 | 14,915
2024 | 10,268 | 10,500
2023 | 8,193 | 14,381
2022 | 10,336 | 5,616
2021 | 4,296 | 3,204
Prior | 5,860 | 3,911
Term Total | 51,495 | 52,527
Revolving Loans Amortized Cost Basis | 104,031 | 98,283
Grand Total | 155,526 | 150,810
Agricultural [Member] | Special Mention [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 57 |
2024 |  | 13
2022 | 305 | 8
2021 | 23 |
Term Total | 385 | 21
Revolving Loans Amortized Cost Basis | 336 | 30
Grand Total | 721 | 51
Agricultural [Member] | Substandard [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 243 |
2024 |  | 21
2023 | 110 |
2021 |  | 29
Term Total | 353 | 50
Revolving Loans Amortized Cost Basis | 1,641 | 1,470
Grand Total | 1,994 | 1,520
Commercial Real Estate [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 106,326 | 128,608
2024 | 145,106 | 234,491
2023 | 239,745 | 425,696
2022 | 410,632 | 218,309
2021 | 212,264 | 111,787
Prior | 229,497 | 189,570
Term Total | 1,343,570 | 1,308,461
Grand Total | 1,343,570 | 1,308,461
Gross charge-offs - Prior |  | 15
Gross charge-offs - Term Total |  | 15
Gross charge-offs - Grand Total |  | 15
Commercial Real Estate [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 103,232 | 128,608
2024 | 145,106 | 200,192
2023 | 190,276 | 413,106
2022 | 392,326 | 218,309
2021 | 208,429 | 110,435
Prior | 225,400 | 188,239
Term Total | 1,264,769 | 1,258,889
Grand Total | 1,264,769 | 1,258,889
Commercial Real Estate [Member] | Special Mention [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 1,350 |
2023 | 15,380 | 12,590
2022 | 18,306 |
2021 | 3,835 | 1,352
Prior | 1,924 | 753
Term Total | 40,795 | 14,695
Grand Total | 40,795 | 14,695
Commercial Real Estate [Member] | Substandard [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 1,744 |
2024 |  | 34,299
2023 | 34,089 |
Prior | 2,173 | 578
Term Total | 38,006 | 34,877
Grand Total | 38,006 | 34,877
Commercial Real Estate [Member] | Doubtful [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Term Total | 0 |
Commercial & Industrial [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 22,324 | 31,972
2024 | 27,387 | 55,066
2023 | 44,871 | 39,694
2022 | 33,460 | 15,235
2021 | 13,010 | 13,506
Prior | 10,017 | 1,738
Term Total | 151,069 | 157,211
Revolving Loans Amortized Cost Basis | 142,397 | 117,386
Revolving Loans Converted to Term | 78 | 222
Grand Total | 293,544 | 274,819
Gross charge-offs - fiscal year 2022 | 25 |
Gross charge-offs - fiscal year 2021 |  | 101
Gross charge-offs - Term Total | 25 | 101
Gross charge-offs - Revolving Loans Converted to Term |  | 5
Gross charge-offs - Grand Total | 25 | 106
Commercial & Industrial [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 22,324 | 31,933
2024 | 27,351 | 54,581
2023 | 44,450 | 39,665
2022 | 33,460 | 15,047
2021 | 12,801 | 13,480
Prior | 9,655 | 1,294
Term Total | 150,041 | 156,000
Revolving Loans Amortized Cost Basis | 138,301 | 113,446
Revolving Loans Converted to Term | 78 | 222
Grand Total | 288,420 | 269,668
Commercial & Industrial [Member] | Special Mention [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 |  | 137
2023 | 117 |
2022 |  | 188
2021 | 177 | 26
Prior | 362 | 416
Term Total | 656 | 767
Revolving Loans Amortized Cost Basis | 550 | 459
Grand Total | 1,206 | 1,226
Commercial & Industrial [Member] | Substandard [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 |  | 39
2024 | 36 | 348
2023 | 304 | 29
2021 | 32 |
Prior |  | 28
Term Total | 372 | 444
Revolving Loans Amortized Cost Basis | 3,546 | 3,481
Grand Total | 3,918 | 3,925
Consumer [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Grand Total | 59,973 | 63,627
Consumer [Member] | Payment Performance [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 12,148 | 13,477
2024 | 10,836 | 13,521
2023 | 10,390 | 27,304
2022 | 20,659 | 5,952
2021 | 4,085 | 2,314
Prior | 1,589 | 582
Term Total | 59,707 | 63,150
Revolving Loans Amortized Cost Basis | 266 | 477
Grand Total | 59,973 | 63,627
Gross charge-offs - fiscal year 2025 | 88 | 201
Gross charge-offs - fiscal year 2024 | 45 | 69
Gross charge-offs - fiscal year 2023 | 95 | 62
Gross charge-offs - fiscal year 2022 | 162 | 14
Gross charge-offs - fiscal year 2021 | 52 |
Gross charge-offs - Term Total | 442 | 346
Gross charge-offs - Grand Total | 442 | 346
Consumer [Member] | Performing [Member] | Payment Performance [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 12,148 | 13,437
2024 | 10,836 | 13,521
2023 | 10,385 | 27,264
2022 | 20,640 | 5,917
2021 | 4,077 | 2,310
Prior | 1,586 | 582
Term Total | 59,672 | 63,031
Revolving Loans Amortized Cost Basis | 266 | 477
Grand Total | 59,938 | 63,508
Consumer [Member] | Nonperforming [Member] | Payment Performance [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 |  | 40
2023 | 5 | 40
2022 | 19 | 35
2021 | 8 | 4
Prior | 3 |
Term Total | 35 | 119
Grand Total | 35 | 119
Other Loan [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 600 |
2022 |  | 15,829
2021 | 15,666 | 5,068
Prior | 8,387 | 4,081
Term Total | 24,653 | 24,978
Grand Total | 24,653 | 24,978
Other Loan [Member] | Pass [Member] |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2025 | 600 |
2022 |  | 15,829
2021 | 15,666 | 5,068
Prior | 8,387 | 4,081
Term Total | 24,653 | 24,978
Grand Total | $ 24,653 | $ 24,978

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