Loans and Allowance - Summary of Troubled Debt Restructurings by Modification Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Modifications [Line Items]
Modification	$ 125	$ 638	$ 416	$ 993
Term Modification
Financing Receivable, Modifications [Line Items]
Modification		41	97	41
Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	91	385	180	505
Combination
Financing Receivable, Modifications [Line Items]
Modification	34	212	139	447
Commercial and industrial loans
Financing Receivable, Modifications [Line Items]
Modification		169		169
Commercial and industrial loans | Term Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and industrial loans | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and industrial loans | Combination
Financing Receivable, Modifications [Line Items]
Modification		169		169
Real estate loans - Commercial and farmland
Financing Receivable, Modifications [Line Items]
Modification		195		430
Real estate loans - Commercial and farmland | Term Modification
Financing Receivable, Modifications [Line Items]
Modification		41		41
Real estate loans - Commercial and farmland | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification		154		154
Real estate loans - Commercial and farmland | Combination
Financing Receivable, Modifications [Line Items]
Modification				235
Real estate loans - Residential
Financing Receivable, Modifications [Line Items]
Modification	125	274	339	394
Real estate loans - Residential | Term Modification
Financing Receivable, Modifications [Line Items]
Modification			37
Real estate loans - Residential | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	91	231	163	351
Real estate loans - Residential | Combination
Financing Receivable, Modifications [Line Items]
Modification	$ 34	$ 43	139	$ 43
Real estate loans - Home equity
Financing Receivable, Modifications [Line Items]
Modification			70
Real estate loans - Home equity | Term Modification
Financing Receivable, Modifications [Line Items]
Modification			60
Real estate loans - Home equity | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification			10
Real estate loans - Home equity | Combination
Financing Receivable, Modifications [Line Items]
Modification
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Modification			7
Individuals' loans for household and other personal expenditures | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification			7
Individuals' loans for household and other personal expenditures | Combination
Financing Receivable, Modifications [Line Items]
Modification