Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Income Statement Data Abstract
Net interest income	$ 1,039,573	$ 957,321	$ 725,855
Net intersegment interest income (expense)	0	0	0
Segment net interest income	1,039,573	957,321	725,855
Noninterest income	63,182	282,370	332,364
Total revenue	1,102,756	1,239,691	1,058,219
Provision for credit losses	83,021	32,998	(88,011)
Noninterest expense	813,682	747,063	709,924
Income before income taxes	206,052	459,630	436,307
Income tax expense	23,097	93,508	85,313
Net income	182,956	366,122	350,994
Goodwill	1,104,992	1,104,992	1,104,992
Operating Segments | Corporate and Commercial Specialty [Member]
Segment Income Statement Data Abstract
Net interest income	958,046	566,566	361,634
Net intersegment interest income (expense)	(391,276)	(103,360)	18,001
Segment net interest income	566,769	463,205	379,636
Noninterest income	136,995	145,751	165,345
Total revenue	703,764	608,956	544,980
Provision for credit losses	55,801	49,543	60,311
Noninterest expense	248,926	234,234	219,655
Income before income taxes	399,037	325,179	265,015
Income tax expense	71,766	59,000	46,906
Net income	327,271	266,179	218,109
Goodwill	525,836	525,836	525,836
Operating Segments | Community, Consumer and Business [Member]
Segment Income Statement Data Abstract
Net interest income	285,175	322,725	289,075
Net intersegment interest income (expense)	447,100	176,164	62,376
Segment net interest income	732,276	498,889	351,451
Noninterest income	108,858	118,848	151,474
Total revenue	841,133	617,737	502,925
Provision for credit losses	28,258	20,755	20,622
Noninterest expense	435,986	417,042	401,206
Income before income taxes	376,889	179,939	81,097
Income tax expense	79,147	37,787	17,030
Net income	297,742	142,152	64,067
Goodwill	579,156	579,156	579,156
Operating Segments | Risk Management and Shared Services [Member]
Segment Income Statement Data Abstract
Net interest income	(203,647)	68,031	75,146
Net intersegment interest income (expense)	(55,824)	(72,803)	(80,378)
Segment net interest income	(259,471)	(4,772)	(5,232)
Noninterest income	(182,671)	17,772	15,546
Total revenue	(442,142)	12,999	10,314
Provision for credit losses	(1,038)	(37,300)	(168,944)
Noninterest expense	128,770	95,787	89,063
Income before income taxes	(569,873)	(45,488)	90,195
Income tax expense	(127,816)	(3,279)	21,377
Net income	(442,057)	(42,209)	68,818
Goodwill	$ 0	$ 0	$ 0