Investment Securities - Expected Maturities of Investment Securities Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Available-for-sale, Amortized Cost
Within one year	$ 378,992
One to five years	1,875,152
Five to ten years	3,944,940
Beyond ten years	1,485,805
Amortized Cost	7,684,889	$ 7,772,603
Available-for-sale, Fair Value
Within one year	375,976
One to five years	1,736,452
Five to ten years	3,408,082
Beyond ten years	1,192,545
Total	$ 6,713,055	6,773,712
Available-for-sale, Weighted Average Yield
Within one year	4.37%
One to five years	3.14%
Five to ten years	2.39%
Beyond ten years	2.60%
Total	2.71%
Held-to-Maturity, Amortized Cost
One to five years	$ 161,440
Five to ten years	1,183,893
Beyond ten years	1,668,160
Total held-to-maturity securities	3,013,493	3,089,147
Held-to-Maturity, Fair Value
One to five years	134,333
Five to ten years	1,040,925
Beyond ten years	1,425,930
Total	$ 2,601,188	$ 2,643,682
Held-to-Maturity, Weighted Average Yield
One to five years	2.65%
Five to ten years	2.66%
Beyond ten years	2.72%
Total	2.69%