Loans and Allowance for Credit Losses - Amortized cost basis of collateral-dependent loans (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	$ 7,166,998	$ 7,650,633
Business or Other Assets
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	10,643	14,519
Business or Other Assets | Commercial
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	7,450	11,326
Business or Other Assets | Income producing - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	3,193	3,193
Business or Other Assets | Owner occupied - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	0	0
Business or Other Assets | Real estate mortgage - residential
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	0	0
Business or Other Assets | Construction - commercial and residential
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	0	0
Business or Other Assets | Home equity
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	0	0
Business or Other Assets | Other consumer
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	0	0
Real Estate
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	49,081	46,424
Real Estate | Commercial
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	8,520	4,026
Real Estate | Income producing - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	27,342	15,686
Real Estate | Owner occupied - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	7,058	23,159
Real Estate | Real estate mortgage - residential
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	1,938	2,932
Real Estate | Construction - commercial and residential
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	3,659	206
Real Estate | Home equity
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	564	415
Real Estate | Other consumer
Loans and Leases Receivable Disclosure [Line Items]
PPP loans, net	$ 0	$ 0