Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Income Statement Data Abstract
Net interest income	$ 257,858	$ 274,010
Net intersegment interest (expense)	0	0
Segment net interest income	257,858	274,010
Noninterest income	64,985	62,073
Total revenue	322,842	336,083
Provision for credit losses	24,001	17,971
Noninterest expense	197,657	187,412
Income before income taxes	101,185	130,700
Income tax expense (benefit)	20,016	27,340
Net income	81,169	103,360
Segment Balance Sheet Data
Allocated goodwill	1,104,992	1,104,992
Operating Segments | Corporate and Commercial Specialty
Segment Income Statement Data Abstract
Net interest income	242,931	219,123
Net intersegment interest (expense)	(93,736)	(80,980)
Segment net interest income	149,195	138,143
Noninterest income	34,422	32,717
Total revenue	183,617	170,860
Provision for credit losses	15,428	13,782
Noninterest expense	66,350	62,119
Income before income taxes	101,839	94,960
Income tax expense (benefit)	21,081	17,726
Net income	80,758	77,234
Segment Balance Sheet Data
Allocated goodwill	525,836	525,836
Operating Segments | Community, Consumer, and Business
Segment Income Statement Data Abstract
Net interest income	58,192	80,284
Net intersegment interest (expense)	130,159	88,079
Segment net interest income	188,351	168,363
Noninterest income	24,494	25,947
Total revenue	212,845	194,310
Provision for credit losses	6,825	6,758
Noninterest expense	110,490	111,735
Income before income taxes	95,530	75,817
Income tax expense (benefit)	20,062	15,922
Net income	75,468	59,895
Segment Balance Sheet Data
Allocated goodwill	579,156	579,156
Operating Segments | Risk Management and Shared Services
Segment Income Statement Data Abstract
Net interest income	(43,266)	(25,397)
Net intersegment interest (expense)	(36,422)	(7,099)
Segment net interest income	(79,688)	(32,496)
Noninterest income	6,068	3,409
Total revenue	(73,620)	(29,087)
Provision for credit losses	1,747	(2,568)
Noninterest expense	20,817	13,558
Income before income taxes	(96,184)	(40,077)
Income tax expense (benefit)	(21,127)	(6,307)
Net income	(75,058)	(33,770)
Segment Balance Sheet Data
Allocated goodwill	$ 0	$ 0