Loans and Allowance - Summary of Troubled Debt Restructurings by Modification Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Modifications [Line Items]
Modification	$ 90	$ 251
Term Modification
Financing Receivable, Modifications [Line Items]
Modification	0	54
Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	90	91
Combination
Financing Receivable, Modifications [Line Items]
Modification	0	106
Residential
Financing Receivable, Modifications [Line Items]
Modification	90	218
Residential | Term Modification
Financing Receivable, Modifications [Line Items]
Modification		38
Residential | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	$ 90	74
Residential | Combination
Financing Receivable, Modifications [Line Items]
Modification		106
Home equity
Financing Receivable, Modifications [Line Items]
Modification		26
Home equity | Term Modification
Financing Receivable, Modifications [Line Items]
Modification		16
Home equity | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification		10
Home equity | Combination
Financing Receivable, Modifications [Line Items]
Modification		0
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Modification		7
Individuals' loans for household and other personal expenditures | Term Modification
Financing Receivable, Modifications [Line Items]
Modification		0
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		$ 0