Deposits - Interest-bearing or Noninterest-bearing (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
U.S.:
Interest-bearing	$ 10,393,449	$ 10,800,140
Noninterest-bearing	5,368,729	5,494,803
Foreign:
Interest-bearing	748,678	685,129
Noninterest-bearing	639,212	632,050
Total deposits	$ 17,150,068	$ 17,612,122