Regulatory Capital - Adjusted Transition Amounts (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Jan. 01, 2020
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	$ 3,485,575		$ 3,163,640
Allowance for credit losses	1,416,048	$ 1,364,716	1,357,075	$ 1,194,238	$ 1,081,066	$ 1,165,335
Liability for unfunded commitments	113,847	$ 62,600	124,924	$ 107,794	$ 113,525	72,713
Adjusted Phase-In Amounts Remaining
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	418,175					836,351
Allowance for credit losses	519,073					1,038,145
Liability for unfunded commitments	52,189					104,377
Deferred tax asset	153,087					$ 306,171
Adjustments
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	(209,088)		(209,088)				$ 953,000
Allowance for credit losses	(259,536)		(259,536)				1,100,000
Liability for unfunded commitments	(26,094)		(26,094)				116,000
Deferred tax asset	$ (76,542)		$ (76,542)				$ 306,000