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	Dec. 31, 2020	Dec. 31, 2019
Credit Quality Information [Abstract]
2020	$ 1,085,080
2019	558,953
2018	386,847
2017	300,829
2016	247,242
Prior	517,313
Revolving Loans	42,155
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	3,138,419	$ 2,695,347
Pass
Credit Quality Information [Abstract]
2020	1,052,257
2019	511,427
2018	367,652
2017	279,274
2016	230,730
Prior	459,453
Revolving Loans	40,363
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,941,156	2,558,157
Special Mention
Credit Quality Information [Abstract]
2020	29,692
2019	44,049
2018	8,731
2017	15,165
2016	9,344
Prior	30,525
Revolving Loans	293
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	137,799	71,611
Substandard
Credit Quality Information [Abstract]
2020	3,131
2019	3,477
2018	10,464
2017	6,390
2016	7,168
Prior	27,335
Revolving Loans	1,499
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	59,464	65,579
Agricultural Loans
Credit Quality Information [Abstract]
2020	104,515
2019	20,401
2018	6,697
2017	2,062
2016	783
Prior	2,894
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	137,352	136,124
Agricultural Loans | Pass
Credit Quality Information [Abstract]
2020	83,377
2019	15,680
2018	5,978
2017	1,838
2016	635
Prior	2,856
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	110,364	129,811
Agricultural Loans | Special Mention
Credit Quality Information [Abstract]
2020	21,070
2019	4,483
2018	694
2017	224
2016	148
Prior	38
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	26,657	3,862
Agricultural Loans | Substandard
Credit Quality Information [Abstract]
2020	68
2019	238
2018	25
2017	0
2016	0
Prior	0
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	331	2,451
Commercial and Industrial Loans
Credit Quality Information [Abstract]
2020	376,688
2019	166,638
2018	71,878
2017	81,068
2016	43,676
Prior	116,603
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	856,551	655,580
Commercial and Industrial Loans | Pass
Credit Quality Information [Abstract]
2020	371,683
2019	132,148
2018	70,497
2017	78,890
2016	42,439
Prior	114,904
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	810,561	603,047
Commercial and Industrial Loans | Special Mention
Credit Quality Information [Abstract]
2020	4,116
2019	32,130
2018	849
2017	489
2016	1,101
Prior	730
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	39,415	40,395
Commercial and Industrial Loans | Substandard
Credit Quality Information [Abstract]
2020	889
2019	2,360
2018	532
2017	1,689
2016	136
Prior	969
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	6,575	12,138
Consumer Loans
Credit Quality Information [Abstract]
2020	31,624
2019	21,424
2018	12,219
2017	8,375
2016	3,218
Prior	1,142
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	78,002	83,183
Consumer Loans | Pass
Credit Quality Information [Abstract]
2020	31,609
2019	21,384
2018	12,084
2017	8,279
2016	3,150
Prior	1,022
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	77,528	82,117
Consumer Loans | Special Mention
Credit Quality Information [Abstract]
2020	0
2019	24
2018	24
2017	1
2016	1
Prior	0
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	50	140
Consumer Loans | Substandard
Credit Quality Information [Abstract]
2020	15
2019	16
2018	111
2017	95
2016	67
Prior	120
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	424	926
Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,066,514	1,820,460
Real Estate Loan | Pass
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable		1,743,182
Real Estate Loan | Special Mention
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable		27,214
Real Estate Loan | Substandard
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable		50,064
Real Estate Loan | Construction and Land Development
Credit Quality Information [Abstract]
2020	41,842
2019	41,117
2018	31,500
2017	3,277
2016	871
Prior	3,872
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	122,479	94,142
Real Estate Loan | Construction and Land Development | Pass
Credit Quality Information [Abstract]
2020	41,842
2019	40,989
2018	31,500
2017	2,760
2016	871
Prior	3,822
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	121,784	93,413
Real Estate Loan | Construction and Land Development | Special Mention
Credit Quality Information [Abstract]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	413
Real Estate Loan | Construction and Land Development | Substandard
Credit Quality Information [Abstract]
2020	0
2019	128
2018	0
2017	517
2016	0
Prior	50
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	695	316
Real Estate Loan | Agricultural
Credit Quality Information [Abstract]
2020	75,475
2019	38,382
2018	39,172
2017	16,815
2016	14,729
Prior	69,768
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	254,341	240,241
Real Estate Loan | Agricultural | Pass
Credit Quality Information [Abstract]
2020	73,630
2019	34,412
2018	37,839
2017	16,138
2016	13,559
Prior	58,291
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	233,869	231,227
Real Estate Loan | Agricultural | Special Mention
Credit Quality Information [Abstract]
2020	1,845
2019	3,970
2018	533
2017	469
2016	1,106
Prior	11,232
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	19,155	6,902
Real Estate Loan | Agricultural | Substandard
Credit Quality Information [Abstract]
2020	0
2019	0
2018	800
2017	208
2016	64
Prior	245
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,317	2,112
Real Estate Loan | Commercial
Credit Quality Information [Abstract]
2020	373,082
2019	238,459
2018	184,780
2017	161,567
2016	155,046
Prior	250,998
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,363,932	1,149,650
Real Estate Loan | Commercial | Pass
Credit Quality Information [Abstract]
2020	368,750
2019	237,119
2018	171,591
2017	148,283
2016	143,400
Prior	215,616
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,284,759	1,103,543
Real Estate Loan | Commercial | Special Mention
Credit Quality Information [Abstract]
2020	2,469
2019	1,300
2018	6,108
2017	11,262
2016	6,741
Prior	16,947
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	44,827	14,156
Real Estate Loan | Commercial | Substandard
Credit Quality Information [Abstract]
2020	1,863
2019	40
2018	7,081
2017	2,022
2016	4,905
Prior	18,435
Revolving Loans	0
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	34,346	31,951
1-4 Family | Real Estate Loan | Residential Properties
Credit Quality Information [Abstract]
2020	81,854
2019	32,532
2018	40,601
2017	27,665
2016	28,919
Prior	72,036
Revolving Loans	42,155
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	325,762	336,427
1-4 Family | Real Estate Loan | Residential Properties | Pass
Credit Quality Information [Abstract]
2020	81,366
2019	29,695
2018	38,163
2017	23,086
2016	26,676
Prior	62,942
Revolving Loans	40,363
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	302,291	314,999
1-4 Family | Real Estate Loan | Residential Properties | Special Mention
Credit Quality Information [Abstract]
2020	192
2019	2,142
2018	523
2017	2,720
2016	247
Prior	1,578
Revolving Loans	293
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	7,695	5,743
1-4 Family | Real Estate Loan | Residential Properties | Substandard
Credit Quality Information [Abstract]
2020	296
2019	695
2018	1,915
2017	1,859
2016	1,996
Prior	7,516
Revolving Loans	1,499
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	$ 15,776	$ 15,685