Investment Securities (Investment Securities, At Fair Value) (Details) - USD ($) $ in Thousands		Mar. 31, 2026	Dec. 31, 2025
Investment Securities [Abstract]
Available for sale debt securities		$ 8,646,127	$ 9,095,513
Trading debt securities		44,329	40,080
Equity securities with a readily determinable fair value		46,193	47,551
Equity Securities without Readily Determinable Fair Value, Amount		10,000	9,803
Federal Reserve Bank Stock		54,434	35,918
Federal Home Loan Bank Stock		10,141	10,198
Private equity investments		183,764	184,343
Total investment securities	[1]	8,994,988	9,423,406
Interest Receivable, Current		$ 36,400	$ 42,000

[1] (1)Accrued interest receivable totaled $36.4 million and $42.0 million at March 31, 2026 and December 31, 2025, respectively, and was included within other assets on the consolidated balance sheets.