Purchased Loans Purchased Loans - Loans Purchased with Deteriorated Credit Quality (Details) - Purchased with deteriorated credit quality - Purchased loans $ in Thousands	Dec. 31, 2019 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	$ 172,264
Commercial, financial, agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	29,538
Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	863
Real estate – 1-4 family mortgage:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	35,543
Real estate – commercial mortgage:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	103,133
Installment loans to individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance of restructured loans	$ 3,187