Deposits - Interest-bearing or Noninterest-bearing (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
U.S.:
Interest-bearing	$ 11,393,789	$ 10,928,712
Noninterest-bearing	7,718,714	6,674,352
Foreign:
Interest-bearing	851,404	776,897
Noninterest-bearing	871,208	847,762
Total deposits	$ 20,835,115	$ 19,227,723