Regulatory Capital - Adjusted Transition Amounts (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2020
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	$ 4,107,980		$ 3,624,859
Allowance for credit losses	1,269,652	$ 1,350,058	1,339,772	$ 1,364,716	$ 1,479,306	$ 1,357,075
Liability for unfunded commitments	49,479	$ 32,034	112,962	$ 62,600	$ 32,720	124,924
Adjusted Phase-In Amounts Remaining
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	209,087						$ 836,351
Allowance for credit losses	259,537						1,038,145
Liability for unfunded commitments	26,094						104,377
Deferred tax asset	76,544						$ 306,171
Adjustments
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	(209,088)		(209,088)			(209,088)		$ 953,000
Allowance for credit losses	(259,536)		(259,536)			(259,536)		1,100,000
Liability for unfunded commitments	(26,095)		(26,094)			(26,094)		116,000
Deferred tax asset	$ (76,543)		$ (76,542)			$ (76,542)		$ 306,000