Loans and Allowance for Loan Losses - Loan Portfolio Aging Analysis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Loans Receivable Aging Analysis [Abstract]
Total Past Due	$ 17,789	$ 27,593
Current	3,218,458	2,667,754
Total Loans Receivable	3,236,247	2,695,347
Total Loans> 90 Days &Accruing	0	0
Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	10,944	18,575
Current	2,068,799	1,801,885
Total Loans Receivable	2,079,743	1,820,460
Total Loans> 90 Days &Accruing	0	0
Construction and Land Development | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	128	235
Current	167,387	93,907
Total Loans Receivable	167,515	94,142
Total Loans> 90 Days &Accruing	0	0
Agricultural | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	1,399	1,642
Current	254,831	238,599
Total Loans Receivable	256,230	240,241
Total Loans> 90 Days &Accruing	0	0
Residential Properties | Real Estate Loan | 1-4 Family
Loans Receivable Aging Analysis [Abstract]
Total Past Due	4,922	10,835
Current	334,250	325,592
Total Loans Receivable	339,172	336,427
Total Loans> 90 Days &Accruing	0	0
Residential Properties | Real Estate Loan | Multifamily
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	2,525
Current	139,255	151,423
Total Loans Receivable	139,255	153,948
Total Loans> 90 Days &Accruing	0	0
Commercial | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	4,495	3,338
Current	1,173,076	992,364
Total Loans Receivable	1,177,571	995,702
Total Loans> 90 Days &Accruing	0	0
Agricultural Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	4,024	607
Current	137,050	135,517
Total Loans Receivable	141,074	136,124
Total Loans> 90 Days &Accruing	0	0
Commercial and Industrial Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	2,455	7,611
Current	805,213	521,362
Total Loans Receivable	807,668	528,973
Total Loans> 90 Days &Accruing	0	0
Consumer Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	366	800
Current	79,982	82,383
Total Loans Receivable	80,348	83,183
Total Loans> 90 Days &Accruing	0	0
All Other Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	0
Current	127,414	126,607
Total Loans Receivable	127,414	126,607
Total Loans> 90 Days &Accruing	0	0
Financial Asset, 30 to 59 Days Past Due
Loans Receivable Aging Analysis [Abstract]
Total Past Due	6,361	9,135
Financial Asset, 30 to 59 Days Past Due | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	3,932	7,614
Financial Asset, 30 to 59 Days Past Due | Construction and Land Development | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	235
Financial Asset, 30 to 59 Days Past Due | Agricultural | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	1,196	1,595
Financial Asset, 30 to 59 Days Past Due | Residential Properties | Real Estate Loan | 1-4 Family
Loans Receivable Aging Analysis [Abstract]
Total Past Due	2,299	3,834
Financial Asset, 30 to 59 Days Past Due | Residential Properties | Real Estate Loan | Multifamily
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	1,348
Financial Asset, 30 to 59 Days Past Due | Commercial | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	437	602
Financial Asset, 30 to 59 Days Past Due | Agricultural Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	2,212	300
Financial Asset, 30 to 59 Days Past Due | Commercial and Industrial Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	79	767
Financial Asset, 30 to 59 Days Past Due | Consumer Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	138	454
Financial Asset, 30 to 59 Days Past Due | All Other Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due
Loans Receivable Aging Analysis [Abstract]
Total Past Due	3,274	3,880
Financial Asset, 60 to 89 Days Past Due | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	1,770	2,829
Financial Asset, 60 to 89 Days Past Due | Construction and Land Development | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due | Agricultural | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	203	0
Financial Asset, 60 to 89 Days Past Due | Residential Properties | Real Estate Loan | 1-4 Family
Loans Receivable Aging Analysis [Abstract]
Total Past Due	584	2,288
Financial Asset, 60 to 89 Days Past Due | Residential Properties | Real Estate Loan | Multifamily
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	46
Financial Asset, 60 to 89 Days Past Due | Commercial | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	983	495
Financial Asset, 60 to 89 Days Past Due | Agricultural Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	1,284	0
Financial Asset, 60 to 89 Days Past Due | Commercial and Industrial Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	145	855
Financial Asset, 60 to 89 Days Past Due | Consumer Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	75	196
Financial Asset, 60 to 89 Days Past Due | All Other Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due
Loans Receivable Aging Analysis [Abstract]
Total Past Due	8,154	14,578
Financial Asset, Equal to or Greater than 90 Days Past Due | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	5,242	8,132
Financial Asset, Equal to or Greater than 90 Days Past Due | Construction and Land Development | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	128	0
Financial Asset, Equal to or Greater than 90 Days Past Due | Agricultural | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	47
Financial Asset, Equal to or Greater than 90 Days Past Due | Residential Properties | Real Estate Loan | 1-4 Family
Loans Receivable Aging Analysis [Abstract]
Total Past Due	2,039	4,713
Financial Asset, Equal to or Greater than 90 Days Past Due | Residential Properties | Real Estate Loan | Multifamily
Loans Receivable Aging Analysis [Abstract]
Total Past Due	0	1,131
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial | Real Estate Loan
Loans Receivable Aging Analysis [Abstract]
Total Past Due	3,075	2,241
Financial Asset, Equal to or Greater than 90 Days Past Due | Agricultural Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	528	307
Financial Asset, Equal to or Greater than 90 Days Past Due | Commercial and Industrial Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	2,231	5,989
Financial Asset, Equal to or Greater than 90 Days Past Due | Consumer Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	153	150
Financial Asset, Equal to or Greater than 90 Days Past Due | All Other Loans
Loans Receivable Aging Analysis [Abstract]
Total Past Due	$ 0	$ 0