Deposits - Summary of Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits
Non-interest bearing	$ 11,009,911	$ 7,948,637
Interest bearing	7,222,275	5,966,178
Total checking	18,232,186	13,914,815
Savings	9,523,073	8,521,093
Certificates of deposit	5,524,381	7,455,556
Money market	5,576,679	4,576,999
Total deposits	$ 38,856,319	$ 34,468,463
Year-to-Date Weighted-average Rate
Interest bearing checking	0.18%	0.36%
Total checking	0.07%	0.15%
Savings	0.31%	0.72%
Certificates of deposit	1.32%	2.01%
Money market	0.69%	1.38%
Total deposits	0.44%	0.88%