Summary of Significant Accounting Policies - Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Accounting Policies [Abstract]
Due from the FRB	$ 1,756,245		$ 4,981,723
Cash and due from banks	360,242	$ 413,821	469,883
Cash and cash equivalents at end of period	$ 2,116,487		$ 5,451,606