Loans, Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2018 USD ($) contract	Jun. 30, 2018 USD ($) contract loan	Dec. 31, 2017 USD ($) contract loan
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	$ 1,080	$ 1,080	$ 530
Summary of information for TDR loans [Abstract]
Number of contracts | contract		56	54
Recorded investment	$ 13,237	$ 13,237	$ 12,094
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	3	11
Pre-modification recorded investment	$ 4,105	$ 6,306
Post-modification recorded investment	4,105	6,306
Commitments to lend additional borrowings			530
TDR loans default payment		$ 520	$ 0
Number of TDR loans default payment | loan		1	0
Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	1,002	$ 1,002	$ 321
Summary of information for TDR loans [Abstract]
Number of contracts | contract		5	9
Recorded investment	$ 1,369	$ 1,369	$ 3,628
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Commercial and Financial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	78	$ 78	$ 169
Summary of information for TDR loans [Abstract]
Number of contracts | contract		13	14
Recorded investment	$ 2,318	$ 2,318	$ 2,575
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	2	2
Pre-modification recorded investment	$ 461	$ 461
Post-modification recorded investment	461	461
Real Estate: Construction, 1 to 4 family residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 16
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Construction, land development and commercial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		2	2
Recorded investment	$ 333	$ 333	$ 339
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		8	7
Recorded investment	$ 5,641	$ 5,641	$ 2,761
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	1	2
Pre-modification recorded investment	$ 3,644	$ 4,944
Post-modification recorded investment	3,644	4,944
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		18	13
Recorded investment	$ 2,019	$ 2,019	$ 1,442
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	6
Pre-modification recorded investment	$ 0	$ 627
Post-modification recorded investment	0	627
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 24
Summary of information for TDR loans [Abstract]
Number of contracts | contract		1	1
Recorded investment	$ 25	$ 25	$ 25
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, multi-family [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, commercial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		9	8
Recorded investment	$ 1,532	$ 1,532	$ 1,324
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	1
Pre-modification recorded investment	$ 0	$ 274
Post-modification recorded investment	0	274
Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0