Loans and Allowance for Credit Losses - Non-TDR Loan Modifications due to COVID-19 (Details) - CARES Act Modification $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) loan
Financing Receivable, Modification [Line Items]
Number | loan	4,162
Booked Amount | $	$ 1,303,544
Booked % of Portfolio	11.00%
Commercial
Financing Receivable, Modification [Line Items]
Number | loan	1,474
Booked Amount | $	$ 713,619
Booked % of Portfolio	25.00%
Commercial real estate
Financing Receivable, Modification [Line Items]
Number | loan	194
Booked Amount | $	$ 456,500
Booked % of Portfolio	8.00%
Residential real estate
Financing Receivable, Modification [Line Items]
Number | loan	335
Booked Amount | $	$ 78,639
Booked % of Portfolio	3.00%
Consumer
Financing Receivable, Modification [Line Items]
Number | loan	2,159
Booked Amount | $	$ 54,786
Booked % of Portfolio	3.00%