Deposits - Summary of Deposits by Type (Detail) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Non-interest-bearing:
Demand	$ 10,139,131	$ 10,316,501
Interest-bearing:
Health savings accounts	9,180,889	8,951,031
Checking	9,741,569	9,834,790
Money market	21,517,733	20,433,250
Savings	7,473,515	6,982,554
Time deposits	7,522,392	8,234,954
Total interest-bearing	55,436,098	54,436,579
Total deposits	65,575,229	64,753,080
Time deposits, money market, and interest-bearing checking obtained through brokers	2,311,841	3,181,298
Aggregate amount of time deposit accounts that exceeded the FDIC limit	1,436,038	1,407,077
Deposit overdrafts reclassified as loan balances	4,486	7,146
Money market sweep deposits received	8,000,000	7,300,000
Time deposit accounts at FDIC limit	$ 25,000	$ 16,800