Loans Acquired - Nonaccrual Acquired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	$ 70,836	$ 34,201
Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	22,494	21,640
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	1,760	2,455
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	1,378	2,159
Consumer | Other consumer | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	327	140
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	32,001	20,413
Real Estate | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	17,565	7,884
Real Estate | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	4,538	1,269
Real Estate | Construction and development | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	751	114
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	18,102	11,939
Real Estate | Single family residential | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	9,593	6,603
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	9,361	7,205
Real Estate | Other commercial | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	7,221	1,167
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	37,075	11,333
Commercial | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	4,602	13,616
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	36,575	10,049
Commercial | Commercial | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	4,349	13,578
Commercial | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	500	1,284
Commercial | Agricultural | Loans acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in nonaccrual status	$ 253	$ 38