Loans and Allowance for Credit Losses - Schedule of Nonaccrual Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	$ 128,268	$ 147,339
Nonaccrual With No Related Allowance	31,754	25,618
Past Due 90 Days or More and Accruing	9	167
Commercial
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	29,535	34,895
Nonaccrual With No Related Allowance	1,630	3,394
Past Due 90 Days or More and Accruing	0	122
Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	66,711	76,138
Nonaccrual With No Related Allowance	30,124	22,152
Past Due 90 Days or More and Accruing	0	20
BBCC
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	4,067	3,551
Nonaccrual With No Related Allowance	0	0
Past Due 90 Days or More and Accruing	0	0
Residential real estate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	19,156	24,794
Nonaccrual With No Related Allowance	0	0
Past Due 90 Days or More and Accruing	0	0
Indirect
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	2,814	2,529
Nonaccrual With No Related Allowance	0	0
Past Due 90 Days or More and Accruing	0	12
Direct
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	1,279	1,178
Nonaccrual With No Related Allowance	0	27
Past Due 90 Days or More and Accruing	9	13
Home equity
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Amortized Cost	4,706	4,254
Nonaccrual With No Related Allowance	0	45
Past Due 90 Days or More and Accruing	$ 0	$ 0