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Loans and Allowance for Credit Losses - Credit Risk Profile of Loan Portfolio on Amortized Cost Basis Based on Risk Rating Category (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020
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Credit Quality Information [Abstract] |  |
Current fiscal year | $ 581,544 | $ 1,085,080
Fiscal year before current fiscal year | 957,368 | 558,953
Two years before current fiscal year | 628,303 | 386,847
Three years before current fiscal year | 427,432 | 300,829
Four years before current fiscal year | 277,891 | 247,242
Prior | 893,738 | 517,313
Revolving Loans | 30,028 | 42,155
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 3,796,304 | 3,138,419
Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 560,678 | 1,052,257
Fiscal year before current fiscal year | 946,430 | 511,427
Two years before current fiscal year | 605,180 | 367,652
Three years before current fiscal year | 414,893 | 279,274
Four years before current fiscal year | 255,940 | 230,730
Prior | 840,846 | 459,453
Revolving Loans | 29,035 | 40,363
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 3,653,002 | 2,941,156
Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 17,963 | 29,692
Fiscal year before current fiscal year | 5,165 | 44,049
Two years before current fiscal year | 12,670 | 8,731
Three years before current fiscal year | 4,620 | 15,165
Four years before current fiscal year | 14,791 | 9,344
Prior | 31,650 | 30,525
Revolving Loans | 56 | 293
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 86,915 | 137,799
Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 2,903 | 3,131
Fiscal year before current fiscal year | 5,773 | 3,477
Two years before current fiscal year | 10,453 | 10,464
Three years before current fiscal year | 7,919 | 6,390
Four years before current fiscal year | 7,160 | 7,168
Prior | 21,242 | 27,335
Revolving Loans | 937 | 1,499
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 56,387 | 59,464
Agricultural Loans |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 73,401 | 104,515
Fiscal year before current fiscal year | 33,058 | 20,401
Two years before current fiscal year | 10,069 | 6,697
Three years before current fiscal year | 3,801 | 2,062
Four years before current fiscal year | 1,565 | 783
Prior | 1,207 | 2,894
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 123,101 | 137,352
Agricultural Loans | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 57,984 | 83,377
Fiscal year before current fiscal year | 31,547 | 15,680
Two years before current fiscal year | 6,957 | 5,978
Three years before current fiscal year | 3,625 | 1,838
Four years before current fiscal year | 1,405 | 635
Prior | 999 | 2,856
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 102,517 | 110,364
Agricultural Loans | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 15,373 | 21,070
Fiscal year before current fiscal year | 1,393 | 4,483
Two years before current fiscal year | 3,087 | 694
Three years before current fiscal year | 176 | 224
Four years before current fiscal year | 160 | 148
Prior | 155 | 38
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 20,344 | 26,657
Agricultural Loans | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 44 | 68
Fiscal year before current fiscal year | 118 | 238
Two years before current fiscal year | 25 | 25
Three years before current fiscal year | 0 | 0
Four years before current fiscal year | 0 | 0
Prior | 53 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 240 | 331
Consumer Loans |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 15,001 | 31,624
Fiscal year before current fiscal year | 27,076 | 21,424
Two years before current fiscal year | 20,095 | 12,219
Three years before current fiscal year | 9,840 | 8,375
Four years before current fiscal year | 5,841 | 3,218
Prior | 6,688 | 1,142
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 84,541 | 78,002
Consumer Loans | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 14,552 | 31,609
Fiscal year before current fiscal year | 24,756 | 21,384
Two years before current fiscal year | 19,516 | 12,084
Three years before current fiscal year | 8,138 | 8,279
Four years before current fiscal year | 5,688 | 3,150
Prior | 5,239 | 1,022
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 77,889 | 77,528
Consumer Loans | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 7 | 0
Fiscal year before current fiscal year | 0 | 24
Two years before current fiscal year | 20 | 24
Three years before current fiscal year | 13 | 1
Four years before current fiscal year | 0 | 1
Prior | 0 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 40 | 50
Consumer Loans | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 442 | 15
Fiscal year before current fiscal year | 2,320 | 16
Two years before current fiscal year | 559 | 111
Three years before current fiscal year | 1,689 | 95
Four years before current fiscal year | 153 | 67
Prior | 1,449 | 120
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 6,612 | 424
Commercial and Industrial Loans |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 194,601 | 376,688
Fiscal year before current fiscal year | 251,684 | 166,638
Two years before current fiscal year | 199,175 | 71,878
Three years before current fiscal year | 95,301 | 81,068
Four years before current fiscal year | 52,429 | 43,676
Prior | 226,532 | 116,603
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,019,722 | 856,551
Commercial and Industrial Loans | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 193,441 | 371,683
Fiscal year before current fiscal year | 248,712 | 132,148
Two years before current fiscal year | 197,188 | 70,497
Three years before current fiscal year | 92,963 | 78,890
Four years before current fiscal year | 51,719 | 42,439
Prior | 223,906 | 114,904
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,007,929 | 810,561
Commercial and Industrial Loans | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 817 | 4,116
Fiscal year before current fiscal year | 670 | 32,130
Two years before current fiscal year | 1,540 | 849
Three years before current fiscal year | 751 | 489
Four years before current fiscal year | 610 | 1,101
Prior | 1,318 | 730
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 5,706 | 39,415
Commercial and Industrial Loans | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 343 | 889
Fiscal year before current fiscal year | 2,302 | 2,360
Two years before current fiscal year | 447 | 532
Three years before current fiscal year | 1,587 | 1,689
Four years before current fiscal year | 100 | 136
Prior | 1,308 | 969
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 6,087 | 6,575
Real Estate Loan |  |
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 2,568,940 | 2,066,514
Real Estate Loan | Construction and Land Development |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 15,090 | 41,842
Fiscal year before current fiscal year | 34,847 | 41,117
Two years before current fiscal year | 36,595 | 31,500
Three years before current fiscal year | 35,416 | 3,277
Four years before current fiscal year | 7,483 | 871
Prior | 12,137 | 3,872
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 141,568 | 122,479
Real Estate Loan | Construction and Land Development | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 15,090 | 41,842
Fiscal year before current fiscal year | 34,719 | 40,989
Two years before current fiscal year | 36,595 | 31,500
Three years before current fiscal year | 34,908 | 2,760
Four years before current fiscal year | 7,483 | 871
Prior | 12,089 | 3,822
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 140,884 | 121,784
Real Estate Loan | Construction and Land Development | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 0
Two years before current fiscal year | 0 | 0
Three years before current fiscal year | 0 | 0
Four years before current fiscal year | 0 | 0
Prior | 0 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 0 | 0
Real Estate Loan | Construction and Land Development | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 128 | 128
Two years before current fiscal year | 0 | 0
Three years before current fiscal year | 508 | 517
Four years before current fiscal year | 0 | 0
Prior | 48 | 50
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 684 | 695
Real Estate Loan | Agricultural |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 53,653 | 75,475
Fiscal year before current fiscal year | 67,463 | 38,382
Two years before current fiscal year | 35,377 | 39,172
Three years before current fiscal year | 38,899 | 16,815
Four years before current fiscal year | 14,365 | 14,729
Prior | 67,605 | 69,768
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 277,362 | 254,341
Real Estate Loan | Agricultural | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 52,827 | 73,630
Fiscal year before current fiscal year | 67,204 | 34,412
Two years before current fiscal year | 30,337 | 37,839
Three years before current fiscal year | 38,280 | 16,138
Four years before current fiscal year | 13,913 | 13,559
Prior | 61,057 | 58,291
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 263,618 | 233,869
Real Estate Loan | Agricultural | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 826 | 1,845
Fiscal year before current fiscal year | 259 | 3,970
Two years before current fiscal year | 4,333 | 533
Three years before current fiscal year | 417 | 469
Four years before current fiscal year | 390 | 1,106
Prior | 6,313 | 11,232
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 12,538 | 19,155
Real Estate Loan | Agricultural | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 0
Two years before current fiscal year | 707 | 800
Three years before current fiscal year | 202 | 208
Four years before current fiscal year | 62 | 64
Prior | 235 | 245
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,206 | 1,317
Real Estate Loan | Commercial |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 185,050 | 373,082
Fiscal year before current fiscal year | 454,916 | 238,459
Two years before current fiscal year | 295,228 | 184,780
Three years before current fiscal year | 206,380 | 161,567
Four years before current fiscal year | 175,280 | 155,046
Prior | 438,254 | 250,998
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,755,108 | 1,363,932
Real Estate Loan | Commercial | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 182,328 | 368,750
Fiscal year before current fiscal year | 452,220 | 237,119
Two years before current fiscal year | 286,760 | 171,591
Three years before current fiscal year | 201,624 | 148,283
Four years before current fiscal year | 159,414 | 143,400
Prior | 404,899 | 215,616
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,687,245 | 1,284,759
Real Estate Loan | Commercial | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 940 | 2,469
Fiscal year before current fiscal year | 2,659 | 1,300
Two years before current fiscal year | 1,567 | 6,108
Three years before current fiscal year | 2,752 | 11,262
Four years before current fiscal year | 10,978 | 6,741
Prior | 22,786 | 16,947
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 41,682 | 44,827
Real Estate Loan | Commercial | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 1,782 | 1,863
Fiscal year before current fiscal year | 37 | 40
Two years before current fiscal year | 6,901 | 7,081
Three years before current fiscal year | 2,004 | 2,022
Four years before current fiscal year | 4,888 | 4,905
Prior | 10,569 | 18,435
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 26,181 | 34,346
1-4 Family | Real Estate Loan | Residential Properties |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 44,748 | 81,854
Fiscal year before current fiscal year | 88,324 | 32,532
Two years before current fiscal year | 31,764 | 40,601
Three years before current fiscal year | 37,795 | 27,665
Four years before current fiscal year | 20,928 | 28,919
Prior | 141,315 | 72,036
Revolving Loans | 30,028 | 42,155
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 394,902 | 325,762
1-4 Family | Real Estate Loan | Residential Properties | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 44,456 | 81,366
Fiscal year before current fiscal year | 87,272 | 29,695
Two years before current fiscal year | 27,827 | 38,163
Three years before current fiscal year | 35,355 | 23,086
Four years before current fiscal year | 16,318 | 26,676
Prior | 132,657 | 62,942
Revolving Loans | 29,035 | 40,363
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 372,920 | 302,291
1-4 Family | Real Estate Loan | Residential Properties | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 192
Fiscal year before current fiscal year | 184 | 2,142
Two years before current fiscal year | 2,123 | 523
Three years before current fiscal year | 511 | 2,720
Four years before current fiscal year | 2,653 | 247
Prior | 1,078 | 1,578
Revolving Loans | 56 | 293
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 6,605 | 7,695
1-4 Family | Real Estate Loan | Residential Properties | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 292 | 296
Fiscal year before current fiscal year | 868 | 695
Two years before current fiscal year | 1,814 | 1,915
Three years before current fiscal year | 1,929 | 1,859
Four years before current fiscal year | 1,957 | 1,996
Prior | 7,580 | 7,516
Revolving Loans | 937 | 1,499
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | $ 15,377 | $ 15,776

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