Loans, Impaired Financing Receivables Activity (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Recorded Investment
With no related allowance recorded	$ 15,794	$ 15,794	$ 15,201
With an allowance recorded	4,057	4,057	12,784
Total impaired loans	19,851	19,851	27,985
Unpaid Principal Balance
With no related allowance recorded	20,866	20,866	19,515
With an allowance recorded	4,404	4,404	13,023
Total	25,270	25,270	32,538
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1,383	1,383	2,114
Total	1,383	1,383	$ 2,114
Average Recorded Investment
With no related allowance recorded	16,560	16,292
With an allowance recorded	4,741	4,475
Total	21,301	20,767
Interest Income Recognized
With no related allowance recorded	77	153
With an allowance recorded	45	85
Total	$ 122	238
Decrease in impaired loans		$ 8,130
Percentages of impaired loans to loans held for investment (in hundredths)	0.75%	0.75%	1.06%
Decrease in TDR loans		$ 340
Decrease in nonaccrual loans		40
Increase (Decrease) accruing loans past days or more financing receivable unpaid principal balance		$ 440
Prior period within which impairment is being measured		1 year
Number of period within which average appraisals obtained		1 month
Agricultural and Farmland Real Estate [Member]
Interest Income Recognized
Decrease in impaired loans		$ 8,170
Agricultural [Member]
Recorded Investment
With no related allowance recorded	$ 1,680	1,680	$ 1,395
With an allowance recorded	250	250	1,065
Total impaired loans	1,930	1,930	2,460
Unpaid Principal Balance
With no related allowance recorded	2,168	2,168	1,663
With an allowance recorded	250	250	1,229
Total	2,418	2,418	2,892
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	213	213	479
Total	213	213	479
Average Recorded Investment
With no related allowance recorded	1,777	1,757
With an allowance recorded	287	269
Total	2,064	2,026
Interest Income Recognized
With no related allowance recorded	1	3
With an allowance recorded	4	7
Total	5	10
Commercial and Financial [Member]
Recorded Investment
With no related allowance recorded	1,655	1,655	1,650
With an allowance recorded	2,558	2,558	2,512
Total impaired loans	4,213	4,213	4,162
Unpaid Principal Balance
With no related allowance recorded	2,565	2,565	2,503
With an allowance recorded	2,856	2,856	2,512
Total	5,421	5,421	5,015
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1,059	1,059	1,189
Total	1,059	1,059	1,189
Average Recorded Investment
With no related allowance recorded	1,844	1,773
With an allowance recorded	3,125	2,918
Total	4,969	4,691
Interest Income Recognized
With no related allowance recorded	15	29
With an allowance recorded	29	56
Total	44	85
Real Estate: Construction, 1 to 4 family residential [Member]
Recorded Investment
With no related allowance recorded	101	101	111
With an allowance recorded	0	0	698
Total impaired loans	101	101	809
Unpaid Principal Balance
With no related allowance recorded	144	144	148
With an allowance recorded	0	0	698
Total	144	144	846
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	4
Total	0	0	4
Average Recorded Investment
With no related allowance recorded	111	106
With an allowance recorded	0	0
Total	111	106
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	0	0
Total	0	0
Real Estate: Construction, land development and commercial [Member]
Recorded Investment
With no related allowance recorded	357	357	328
With an allowance recorded	0	0	0
Total impaired loans	357	357	328
Unpaid Principal Balance
With no related allowance recorded	381	381	344
With an allowance recorded	0	0	0
Total	381	381	344
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	0
Total	0	0	0
Average Recorded Investment
With no related allowance recorded	364	363
With an allowance recorded	0	0
Total	364	363
Interest Income Recognized
With no related allowance recorded	4	9
With an allowance recorded	0	0
Total	4	9
Real Estate: Mortgage, farmland [Member]
Recorded Investment
With no related allowance recorded	4,170	4,170	3,612
With an allowance recorded	0	0	0
Total impaired loans	4,170	4,170	3,612
Unpaid Principal Balance
With no related allowance recorded	4,648	4,648	4,071
With an allowance recorded	0	0	0
Total	4,648	4,648	4,071
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	0
Total	0	0	0
Average Recorded Investment
With no related allowance recorded	4,198	4,189
With an allowance recorded	0	0
Total	4,198	4,189
Interest Income Recognized
With no related allowance recorded	39	78
With an allowance recorded	0	0
Total	39	78
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Recorded Investment
With no related allowance recorded	5,820	5,820	6,089
With an allowance recorded	1,112	1,112	899
Total impaired loans	6,932	6,932	6,988
Unpaid Principal Balance
With no related allowance recorded	7,759	7,759	7,819
With an allowance recorded	1,161	1,161	974
Total	8,920	8,920	8,793
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	69	69	70
Total	69	69	70
Average Recorded Investment
With no related allowance recorded	6,054	5,982
With an allowance recorded	1,175	1,143
Total	7,229	7,125
Interest Income Recognized
With no related allowance recorded	8	15
With an allowance recorded	9	16
Total	17	31
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Recorded Investment
With no related allowance recorded	0	0	0
With an allowance recorded	24	24	24
Total impaired loans	24	24	24
Unpaid Principal Balance
With no related allowance recorded	250	250	254
With an allowance recorded	24	24	24
Total	274	274	278
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1	1	2
Total	1	1	2
Average Recorded Investment
With no related allowance recorded	0	0
With an allowance recorded	24	24
Total	24	24
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	0	1
Total	0	1
Real Estate: Mortgage, multi-family [Member]
Recorded Investment
With no related allowance recorded	105	105	145
With an allowance recorded	0	0	7,447
Total impaired loans	105	105	7,592
Unpaid Principal Balance
With no related allowance recorded	213	213	213
With an allowance recorded	0	0	7,447
Total	213	213	7,660
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	305
Total	0	0	305
Average Recorded Investment
With no related allowance recorded	144	125
With an allowance recorded	0	0
Total	144	125
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	0	0
Total	0	0
Real Estate: Mortgage, commercial [Member]
Recorded Investment
With no related allowance recorded	1,906	1,906	1,871
With an allowance recorded	73	73	75
Total impaired loans	1,979	1,979	1,946
Unpaid Principal Balance
With no related allowance recorded	2,724	2,724	2,486
With an allowance recorded	73	73	75
Total	2,797	2,797	2,561
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1	1	1
Total	1	1	1
Average Recorded Investment
With no related allowance recorded	2,068	1,997
With an allowance recorded	74	74
Total	2,142	2,071
Interest Income Recognized
With no related allowance recorded	10	19
With an allowance recorded	1	2
Total	11	21
Loans to individuals [Member]
Recorded Investment
With no related allowance recorded	0	0	0
With an allowance recorded	40	40	64
Total impaired loans	40	40	64
Unpaid Principal Balance
With no related allowance recorded	14	14	14
With an allowance recorded	40	40	64
Total	54	54	78
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	40	40	64
Total	40	40	$ 64
Average Recorded Investment
With no related allowance recorded	0	0
With an allowance recorded	56	47
Total	56	47
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	2	3
Total	$ 2	$ 3