Loans and Allowance for Loan Losses - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	$ 27,145	$ 27,028	$ 28,388	$ 29,873
Interest Income Recognized	70	91	209	267
Real Estate Loan
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	20,450	18,999	20,756	20,412
Interest Income Recognized	68	86	204	257
Construction and Land Development | Real Estate Loan
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	708	755	715	765
Interest Income Recognized	8	8	23	24
Agricultural | Real Estate Loan
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	830	932	831	935
Interest Income Recognized	0	0	0	0
Residential Properties | Real Estate Loan | 1-4 Family
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	9,138	9,521	9,339	9,629
Interest Income Recognized	18	21	55	63
Residential Properties | Real Estate Loan | Multifamily
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	2,321	1,559	2,344	1,561
Interest Income Recognized	0	14	0	42
Commercial | Real Estate Loan
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	7,453	6,232	7,527	7,522
Interest Income Recognized	42	43	126	128
Agricultural Loans
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	1,453	852	1,692	800
Interest Income Recognized	1	1	1	2
Commercial and Industrial Loans
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	4,846	6,479	5,501	7,897
Interest Income Recognized	1	4	4	7
Consumer Loans
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	396	698	439	764
Interest Income Recognized	0	0	0	1
All Other Loans
Average recorded investment and interest income recognized [Abstract]
Average Investment in Impaired Loans	0	0	0	0
Interest Income Recognized	$ 0	$ 0	$ 0	$ 0