Reportable Operating Segments - Selected Business Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Selected business segment financial information
Net interest income (expense)	$ 154,427	$ 167,247
Benefit (provision) for credit losses	(6,300)	(8,800)
Net interest income (expense) after (provision) benefit for credit losses	148,127	158,447
Noninterest income	51,371	49,023
Noninterest expense	(128,813)	(118,567)
Income before provision for income taxes	70,685	88,903
(Provision) benefit for income taxes	(16,465)	(22,085)
Net income	54,220	66,818
Retail Banking
Selected business segment financial information
Net interest income (expense)	128,057	108,920
Benefit (provision) for credit losses	(3,379)	(2,563)
Net interest income (expense) after (provision) benefit for credit losses	124,678	106,357
Noninterest income	26,035	24,267
Noninterest expense	(76,640)	(75,843)
Income before provision for income taxes	74,073	54,781
(Provision) benefit for income taxes	(17,928)	(13,266)
Net income	56,145	41,515
Commercial Banking
Selected business segment financial information
Net interest income (expense)	45,381	40,939
Benefit (provision) for credit losses	(3,713)	(3,873)
Net interest income (expense) after (provision) benefit for credit losses	41,668	37,066
Noninterest income	17,958	17,888
Noninterest expense	(25,685)	(27,770)
Income before provision for income taxes	33,941	27,184
(Provision) benefit for income taxes	(7,273)	(6,330)
Net income	26,668	20,854
Treasury and Other
Selected business segment financial information
Net interest income (expense)	(19,011)	17,388
Benefit (provision) for credit losses	792	(2,364)
Net interest income (expense) after (provision) benefit for credit losses	(18,219)	15,024
Noninterest income	7,378	6,868
Noninterest expense	(26,488)	(14,954)
Income before provision for income taxes	(37,329)	6,938
(Provision) benefit for income taxes	8,736	(2,489)
Net income	$ (28,593)	$ 4,449