Loans and Allowance for Loan Losses - Net (Charge-Offs)/Recoveries, Excluding Loans Acquired, Segregated by Class of Loans (Details) - Loans, Excluding Acquired Loans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	$ (29,575)	$ (19,918)	$ (19,145)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(6,101)	(9,126)
Consumer | Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(3,564)	(3,046)	(2,884)
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(2,537)	(6,080)
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(1,823)	(4,914)	(6,999)
Real Estate | Construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(375)	(1,775)
Real Estate | Single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(703)	(494)
Real Estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(745)	(2,645)
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(21,651)	(5,878)	$ (7,734)
Commercial | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	(21,651)	(5,878)
Commercial | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries	$ 0	$ 0