Loans and Loans Held for Sale - Nonperforming Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Nonperforming Assets
Nonaccrual loans	$ 102,430	$ 117,485
Nonaccrual TDRs	29,983	29,289
Total Nonperforming Loans	132,413	146,774	$ 54,057
OREO	1,620	2,155
Total Nonperforming Assets	134,033	148,929
Financing receivable, nonaccrual, including held-for-sale	135,200
Commercial | Commercial and industrial
Nonperforming Assets
Total Nonperforming Loans	12,416	$ 16,985	$ 10,911
Financing receivable, nonaccrual, held-for-sale	$ 2,800