Loans and Allowance - Summary of Troubled Debt Restructurings by Modification Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	$ 184	$ 205	$ 433	$ 606
Term Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	0		0	77
Rate Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	0	112	88	290
Combination
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	184	93	345	239
Residential
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	184	140	433	447
Residential | Term Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification			0
Residential | Rate Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	0	47	88	208
Residential | Combination
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification	$ 184	93	$ 345	239
Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification		65		153
Home equity | Term Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification				77
Home equity | Rate Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification		65		76
Home equity | Combination
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification		$ 0		0
Individuals' loans for household and other personal expenditures
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification				6
Individuals' loans for household and other personal expenditures | Term Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification				0
Individuals' loans for household and other personal expenditures | Rate Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification				6
Individuals' loans for household and other personal expenditures | Combination
Financing Receivable, Troubled Debt Restructuring [Line Items]
Modification				$ 0