Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Income Statement Data Abstract
Net interest income	$ 957,321	$ 725,855	$ 762,957
Net intersegment interest income (expense)	0	0	0
Segment net interest income	957,321	725,855	762,957
Noninterest income	282,370	332,364	514,056
Total revenue	1,239,691	1,058,219	1,277,012
Provision for credit losses	32,998	(88,011)	174,006
Noninterest expense	747,063	709,924	776,034
Income before income taxes	459,630	436,307	326,972
Income tax expense	93,508	85,313	20,200
Net income	366,122	350,994	306,771
Goodwill	1,104,992	1,104,992	1,109,300
Operating Segments | Corporate and Commercial Specialty [Member]
Segment Income Statement Data Abstract
Net interest income	566,566	361,634	382,570
Net intersegment interest income (expense)	(103,360)	18,001	3,477
Segment net interest income	463,205	379,636	386,047
Noninterest income	145,751	165,345	144,274
Total revenue	608,956	544,980	530,321
Provision for credit losses	49,543	60,311	56,409
Noninterest expense	234,234	219,655	200,856
Income before income taxes	325,179	265,015	273,056
Income tax expense	59,000	46,906	50,537
Net income	266,179	218,109	222,519
Goodwill	525,836	525,836	530,144
Operating Segments | Community, Consumer and Business [Member]
Segment Income Statement Data Abstract
Net interest income	322,725	289,075	307,862
Net intersegment interest income (expense)	176,164	62,376	61,126
Segment net interest income	498,889	351,451	368,988
Noninterest income	118,848	151,474	190,808
Total revenue	617,737	502,925	559,796
Provision for credit losses	20,755	20,622	25,233
Noninterest expense	416,742	401,053	441,527
Income before income taxes	180,240	81,251	93,035
Income tax expense	37,850	17,063	19,537
Net income	142,389	64,188	73,498
Goodwill	579,156	579,156	579,156
Operating Segments | Risk Management and Shared Services [Member]
Segment Income Statement Data Abstract
Net interest income	68,031	75,146	72,525
Net intersegment interest income (expense)	(72,803)	(80,378)	(64,603)
Segment net interest income	(4,772)	(5,232)	7,922
Noninterest income	17,772	15,546	178,974
Total revenue	12,999	10,314	186,896
Provision for credit losses	(37,300)	(168,944)	92,365
Noninterest expense	96,088	89,216	133,651
Income before income taxes	(45,788)	90,042	(39,120)
Income tax expense	(3,342)	21,345	(49,874)
Net income	(42,447)	68,697	10,754
Goodwill	$ 0	$ 0	$ 0