Deposits - Interest-bearing or Noninterest-bearing (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
U.S.:
Interest-bearing	$ 10,928,712	$ 9,782,957
Noninterest-bearing	6,674,352	5,188,696
Foreign:
Interest-bearing	776,897	781,965
Noninterest-bearing	847,762	691,376
Total deposits	$ 19,227,723	$ 16,444,994