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
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