Purchased Loans - Purchased With Deteriorated Credit (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	$ 9,637,476	$ 9,034,103
Purchased | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	172,264	222,254
Purchased | Receivables Acquired with Deteriorated Credit Quality | Commercial, financial, agricultural
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	29,538	29,143
Purchased | Receivables Acquired with Deteriorated Credit Quality | Lease financing
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	0	0
Purchased | Receivables Acquired with Deteriorated Credit Quality | Real estate – construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	863	0
Purchased | Receivables Acquired with Deteriorated Credit Quality | Real estate – 1-4 family mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	35,543	48,243
Purchased | Receivables Acquired with Deteriorated Credit Quality | Real estate – commercial mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	103,133	140,438
Purchased | Receivables Acquired with Deteriorated Credit Quality | Installment loans to individuals
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Purchased Credit Deteriorated Loans	$ 3,187	$ 4,430