Loans and Allowance for Credit Losses - Schedule of Nonaccrual Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	$ 126,987	$ 132,431
Nonaccrual With No Related Allowance	20,355
Past Due 90 Days or More and Accruing	658
Interest Income Recognized on Nonaccrual	0
Commercial
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	39,893	40,103
Nonaccrual With No Related Allowance	7,040
Past Due 90 Days or More and Accruing	3
Interest Income Recognized on Nonaccrual	0
Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	51,355	58,350
Nonaccrual With No Related Allowance	13,281
Past Due 90 Days or More and Accruing	165
Interest Income Recognized on Nonaccrual	0
BBCC
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	3,869	4,530
Nonaccrual With No Related Allowance	0
Past Due 90 Days or More and Accruing	0
Interest Income Recognized on Nonaccrual	0
Residential real estate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	23,567	20,970
Nonaccrual With No Related Allowance	0
Past Due 90 Days or More and Accruing	112
Interest Income Recognized on Nonaccrual	0
Indirect
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	2,885	3,318
Nonaccrual With No Related Allowance	0
Past Due 90 Days or More and Accruing	81
Interest Income Recognized on Nonaccrual	0
Direct
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	1,195	1,303
Nonaccrual With No Related Allowance	0
Past Due 90 Days or More and Accruing	102
Interest Income Recognized on Nonaccrual	0
Home equity
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	4,223	$ 3,857
Nonaccrual With No Related Allowance	34
Past Due 90 Days or More and Accruing	195
Interest Income Recognized on Nonaccrual	$ 0

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