Loans and Allowance for Loan Losses - Troubled Debt Restructurings, Excluding Loans Acquired, Segregated by Class of Loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	4	8
Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	30	33
Total TDR loans | $	$ 5,313	$ 9,215
Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	12	12
Total TDR loans | $	$ 4,411	$ 6,369
Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	18	21
Total TDR loans | $	$ 902	$ 2,846
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	4	4
Real Estate | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	23	23
Total TDR loans | $	$ 2,450	$ 5,664
Real Estate | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	8	8
Total TDR loans | $	$ 1,627	$ 3,536
Real Estate | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	15	15
Total TDR loans | $	$ 823	$ 2,128
Real Estate | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans		1
Real Estate | Construction and development | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	1	3
Total TDR loans | $	$ 72	$ 485
Real Estate | Construction and development | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	0	0
Total TDR loans | $	$ 0	$ 0
Real Estate | Construction and development | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	1	3
Total TDR loans | $	$ 72	$ 485
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	4	1
Real Estate | Single family residential | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	19	16
Total TDR loans | $	$ 1,822	$ 846
Real Estate | Single family residential | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	7	6
Total TDR loans | $	$ 1,151	$ 230
Real Estate | Single family residential | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	12	10
Total TDR loans | $	$ 671	$ 616
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans		2
Real Estate | Other commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	3	4
Total TDR loans | $	$ 556	$ 4,333
Real Estate | Other commercial | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	1	2
Total TDR loans | $	$ 476	$ 3,306
Real Estate | Other commercial | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	2	2
Total TDR loans | $	$ 80	$ 1,027
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans		3
Commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	7	10
Total TDR loans | $	$ 2,863	$ 3,551
Commercial | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	4	4
Total TDR loans | $	$ 2,784	$ 2,833
Commercial | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	3	6
Total TDR loans | $	$ 79	$ 718
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans		3
Commercial | Commercial | Loans, Excluding Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	7	10
Total TDR loans | $	$ 2,863	$ 3,551
Commercial | Commercial | Loans, Excluding Acquired Loans | Accruing TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	4	4
Total TDR loans | $	$ 2,784	$ 2,833
Commercial | Commercial | Loans, Excluding Acquired Loans | Nonaccrual TDR Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans	3	6
Total TDR loans | $	$ 79	$ 718