Loans and Allowance for Loan Losses - Loans Restructured as TDRs, Excluding Loans Acquired, Segregated by Class of Loans (Details)	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan		2
Balance Prior to TDR		$ 152,000
Balance		153,000
Financial Impact on Date of Restructure	$ 0
Change in Maturity Date
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		153,000
Change in Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		$ 0
Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan		1
Balance Prior to TDR		$ 91,000
Balance		91,000
Financial Impact on Date of Restructure		0
Consumer | Change in Maturity Date
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		91,000
Consumer | Change in Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		$ 0
Consumer | Other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan		1
Balance Prior to TDR		$ 91,000
Balance		91,000
Financial Impact on Date of Restructure		0
Consumer | Other consumer | Change in Maturity Date
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		91,000
Consumer | Other consumer | Change in Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		$ 0
Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan		1
Balance Prior to TDR		$ 61,000
Balance		62,000
Financial Impact on Date of Restructure		0
Real Estate | Change in Maturity Date
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		62,000
Real Estate | Change in Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		$ 0
Real Estate | Single family residential
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan		1
Balance Prior to TDR		$ 61,000
Balance		62,000
Financial Impact on Date of Restructure		0
Real Estate | Single family residential | Change in Maturity Date
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		62,000
Real Estate | Single family residential | Change in Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance		$ 0