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	Sep. 30, 2021	Dec. 31, 2020
Credit Quality Information [Abstract]
Current fiscal year	$ 799,252	$ 1,085,080
Fiscal year before current fiscal year	911,425	558,953
Two years before current fiscal year	624,971	386,847
Three years before current fiscal year	397,185	300,829
Four years before current fiscal year	241,548	247,242
Prior	929,680	517,313
Revolving Loans	43,708	42,155
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	3,947,769	3,138,419
Pass
Credit Quality Information [Abstract]
Current fiscal year	775,322	1,052,257
Fiscal year before current fiscal year	907,023	511,427
Two years before current fiscal year	604,031	367,652
Three years before current fiscal year	387,870	279,274
Four years before current fiscal year	218,694	230,730
Prior	884,824	459,453
Revolving Loans	42,664	40,363
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	3,820,428	2,941,156
Special Mention
Credit Quality Information [Abstract]
Current fiscal year	20,819	29,692
Fiscal year before current fiscal year	2,350	44,049
Two years before current fiscal year	12,071	8,731
Three years before current fiscal year	3,073	15,165
Four years before current fiscal year	14,318	9,344
Prior	23,535	30,525
Revolving Loans	56	293
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	76,222	137,799
Substandard
Credit Quality Information [Abstract]
Current fiscal year	3,111	3,131
Fiscal year before current fiscal year	2,052	3,477
Two years before current fiscal year	8,869	10,464
Three years before current fiscal year	6,242	6,390
Four years before current fiscal year	8,536	7,168
Prior	21,321	27,335
Revolving Loans	988	1,499
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	51,119	59,464
Agricultural Loans
Credit Quality Information [Abstract]
Current fiscal year	90,743	104,515
Fiscal year before current fiscal year	20,384	20,401
Two years before current fiscal year	8,539	6,697
Three years before current fiscal year	3,808	2,062
Four years before current fiscal year	1,234	783
Prior	1,826	2,894
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	126,534	137,352
Agricultural Loans | Pass
Credit Quality Information [Abstract]
Current fiscal year	75,148	83,377
Fiscal year before current fiscal year	19,930	15,680
Two years before current fiscal year	5,582	5,978
Three years before current fiscal year	3,653	1,838
Four years before current fiscal year	1,074	635
Prior	1,480	2,856
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	106,867	110,364
Agricultural Loans | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	15,568	21,070
Fiscal year before current fiscal year	436	4,483
Two years before current fiscal year	2,957	694
Three years before current fiscal year	155	224
Four years before current fiscal year	160	148
Prior	65	38
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	19,341	26,657
Agricultural Loans | Substandard
Credit Quality Information [Abstract]
Current fiscal year	27	68
Fiscal year before current fiscal year	18	238
Two years before current fiscal year	0	25
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	281	0
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	326	331
Consumer Loans
Credit Quality Information [Abstract]
Current fiscal year	20,973	31,624
Fiscal year before current fiscal year	21,642	21,424
Two years before current fiscal year	27,447	12,219
Three years before current fiscal year	6,694	8,375
Four years before current fiscal year	2,670	3,218
Prior	638	1,142
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	80,064	78,002
Consumer Loans | Pass
Credit Quality Information [Abstract]
Current fiscal year	20,854	31,609
Fiscal year before current fiscal year	21,547	21,384
Two years before current fiscal year	27,317	12,084
Three years before current fiscal year	6,633	8,279
Four years before current fiscal year	2,640	3,150
Prior	492	1,022
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	79,483	77,528
Consumer Loans | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	21	0
Fiscal year before current fiscal year	78	24
Two years before current fiscal year	55	24
Three years before current fiscal year	10	1
Four years before current fiscal year	0	1
Prior	0	0
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	164	50
Consumer Loans | Substandard
Credit Quality Information [Abstract]
Current fiscal year	98	15
Fiscal year before current fiscal year	17	16
Two years before current fiscal year	75	111
Three years before current fiscal year	51	95
Four years before current fiscal year	30	67
Prior	146	120
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	417	424
Commercial and Industrial Loans
Credit Quality Information [Abstract]
Current fiscal year	154,001	376,688
Fiscal year before current fiscal year	186,054	166,638
Two years before current fiscal year	168,726	71,878
Three years before current fiscal year	79,480	81,068
Four years before current fiscal year	3,889	43,676
Prior	387,441	116,603
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	979,591	856,551
Commercial and Industrial Loans | Pass
Credit Quality Information [Abstract]
Current fiscal year	152,729	371,683
Fiscal year before current fiscal year	184,801	132,148
Two years before current fiscal year	166,553	70,497
Three years before current fiscal year	77,324	78,890
Four years before current fiscal year	3,402	42,439
Prior	384,318	114,904
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	969,127	810,561
Commercial and Industrial Loans | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	844	4,116
Fiscal year before current fiscal year	542	32,130
Two years before current fiscal year	1,725	849
Three years before current fiscal year	568	489
Four years before current fiscal year	416	1,101
Prior	1,155	730
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	5,250	39,415
Commercial and Industrial Loans | Substandard
Credit Quality Information [Abstract]
Current fiscal year	428	889
Fiscal year before current fiscal year	711	2,360
Two years before current fiscal year	448	532
Three years before current fiscal year	1,588	1,689
Four years before current fiscal year	71	136
Prior	1,968	969
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	5,214	6,575
Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,761,580	2,066,514
Real Estate Loan | Construction and Land Development
Credit Quality Information [Abstract]
Current fiscal year	33,652	41,842
Fiscal year before current fiscal year	68,429	41,117
Two years before current fiscal year	26,623	31,500
Three years before current fiscal year	35,654	3,277
Four years before current fiscal year	3,841	871
Prior	11,862	3,872
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	180,061	122,479
Real Estate Loan | Construction and Land Development | Pass
Credit Quality Information [Abstract]
Current fiscal year	33,540	41,842
Fiscal year before current fiscal year	68,429	40,989
Two years before current fiscal year	26,623	31,500
Three years before current fiscal year	34,739	2,760
Four years before current fiscal year	3,841	871
Prior	11,328	3,822
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	178,500	121,784
Real Estate Loan | Construction and Land Development | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	112	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	112	0
Real Estate Loan | Construction and Land Development | Substandard
Credit Quality Information [Abstract]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	128
Two years before current fiscal year	0	0
Three years before current fiscal year	915	517
Four years before current fiscal year	0	0
Prior	534	50
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,449	695
Real Estate Loan | Agricultural
Credit Quality Information [Abstract]
Current fiscal year	63,167	75,475
Fiscal year before current fiscal year	66,079	38,382
Two years before current fiscal year	34,752	39,172
Three years before current fiscal year	37,429	16,815
Four years before current fiscal year	13,540	14,729
Prior	63,821	69,768
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	278,788	254,341
Real Estate Loan | Agricultural | Pass
Credit Quality Information [Abstract]
Current fiscal year	62,342	73,630
Fiscal year before current fiscal year	65,820	34,412
Two years before current fiscal year	30,303	37,839
Three years before current fiscal year	36,823	16,138
Four years before current fiscal year	13,095	13,559
Prior	57,580	58,291
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	265,963	233,869
Real Estate Loan | Agricultural | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	825	1,845
Fiscal year before current fiscal year	259	3,970
Two years before current fiscal year	4,184	533
Three years before current fiscal year	417	469
Four years before current fiscal year	388	1,106
Prior	6,010	11,232
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	12,083	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	265	800
Three years before current fiscal year	189	208
Four years before current fiscal year	57	64
Prior	231	245
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	742	1,317
Real Estate Loan | Commercial
Credit Quality Information [Abstract]
Current fiscal year	363,034	373,082
Fiscal year before current fiscal year	446,957	238,459
Two years before current fiscal year	318,548	184,780
Three years before current fiscal year	183,271	161,567
Four years before current fiscal year	177,071	155,046
Prior	401,285	250,998
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,890,166	1,363,932
Real Estate Loan | Commercial | Pass
Credit Quality Information [Abstract]
Current fiscal year	357,285	368,750
Fiscal year before current fiscal year	445,335	237,119
Two years before current fiscal year	310,825	171,591
Three years before current fiscal year	180,042	148,283
Four years before current fiscal year	161,629	143,400
Prior	376,631	215,616
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,831,747	1,284,759
Real Estate Loan | Commercial | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	3,369	2,469
Fiscal year before current fiscal year	886	1,300
Two years before current fiscal year	1,198	6,108
Three years before current fiscal year	1,418	11,262
Four years before current fiscal year	10,726	6,741
Prior	15,251	16,947
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	32,848	44,827
Real Estate Loan | Commercial | Substandard
Credit Quality Information [Abstract]
Current fiscal year	2,380	1,863
Fiscal year before current fiscal year	736	40
Two years before current fiscal year	6,525	7,081
Three years before current fiscal year	1,811	2,022
Four years before current fiscal year	4,716	4,905
Prior	9,403	18,435
Revolving Loans	0	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	25,571	34,346
1-4 Family | Real Estate Loan | Residential Properties
Credit Quality Information [Abstract]
Current fiscal year	73,682	81,854
Fiscal year before current fiscal year	101,880	32,532
Two years before current fiscal year	40,336	40,601
Three years before current fiscal year	50,849	27,665
Four years before current fiscal year	39,303	28,919
Prior	62,807	72,036
Revolving Loans	43,708	42,155
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	412,565	325,762
1-4 Family | Real Estate Loan | Residential Properties | Pass
Credit Quality Information [Abstract]
Current fiscal year	73,424	81,366
Fiscal year before current fiscal year	101,161	29,695
Two years before current fiscal year	36,828	38,163
Three years before current fiscal year	48,656	23,086
Four years before current fiscal year	33,013	26,676
Prior	52,995	62,942
Revolving Loans	42,664	40,363
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	388,741	302,291
1-4 Family | Real Estate Loan | Residential Properties | Special Mention
Credit Quality Information [Abstract]
Current fiscal year	80	192
Fiscal year before current fiscal year	149	2,142
Two years before current fiscal year	1,952	523
Three years before current fiscal year	505	2,720
Four years before current fiscal year	2,628	247
Prior	1,054	1,578
Revolving Loans	56	293
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	6,424	7,695
1-4 Family | Real Estate Loan | Residential Properties | Substandard
Credit Quality Information [Abstract]
Current fiscal year	178	296
Fiscal year before current fiscal year	570	695
Two years before current fiscal year	1,556	1,915
Three years before current fiscal year	1,688	1,859
Four years before current fiscal year	3,662	1,996
Prior	8,758	7,516
Revolving Loans	988	1,499
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	$ 17,400	$ 15,776