Loans and Allowance for Loan Losses - Loans Restructured as TDRs, Excluding Loans Acquired, Segregated by Class of Loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	8	16
Balance Prior to TDR	$ 3,006	$ 11,001
Balance	2,999	10,905
Financial Impact on Date of Restructure	$ 402	$ 33
Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	33	40
Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 2,999	$ 10,866
Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 39
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	1
Balance Prior to TDR	$ 91
Balance	91
Financial Impact on Date of Restructure	0
Consumer | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	91
Consumer | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	1
Balance Prior to TDR	$ 91
Balance	91
Financial Impact on Date of Restructure	0
Consumer | Other consumer | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	91
Consumer | Other consumer | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	4	5
Balance Prior to TDR	$ 552	$ 8,310
Balance	550	8,301
Financial Impact on Date of Restructure	$ 212	$ 33
Real Estate | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	23	29
Real Estate | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 550	$ 8,301
Real Estate | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 0
Real Estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	1	1
Balance Prior to TDR	$ 99	$ 456
Balance	98	456
Financial Impact on Date of Restructure	$ 0	$ 0
Real Estate | Construction | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	3	1
Real Estate | Construction | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 98	$ 456
Real Estate | Construction | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 0
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	1	1
Balance Prior to TDR	$ 61	$ 139
Balance	62	130
Financial Impact on Date of Restructure	$ 0	$ 0
Real Estate | Single family residential | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	16	19
Real Estate | Single family residential | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 62	$ 130
Real Estate | Single family residential | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 0
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	2	3
Balance Prior to TDR	$ 392	$ 7,715
Balance	390	7,715
Financial Impact on Date of Restructure	$ 212	$ 33
Real Estate | Other commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	4	9
Real Estate | Other commercial | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 390	$ 7,715
Real Estate | Other commercial | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 0
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	3	11
Balance Prior to TDR	$ 2,363	$ 2,691
Balance	2,358	2,604
Financial Impact on Date of Restructure	$ 190	$ 0
Commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	10	11
Commercial | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 2,358	$ 2,565
Commercial | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 39
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	3	11
Balance Prior to TDR	$ 2,363	$ 2,691
Balance	2,358	2,604
Financial Impact on Date of Restructure	$ 190	$ 0
Commercial | Commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan	10	11
Commercial | Commercial | Change in Maturity Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 2,358	$ 2,565
Commercial | Commercial | Change in Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 0	$ 39