Segment Information - Schedule of Operating Information for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Net interest income:
Net interest income	$ 462,358	$ 401,448	$ 1,367,890	$ 1,038,546
Net interest income, change in contribution	$ 60,910		$ 329,344
Net interest income, percent change in contribution	15.00%		32.00%
Provision for credit losses:
Provision for credit losses	$ 19,923	6,420	$ 71,482	30,943
Provision for credit losses, change in contribution	13,503		40,539
Non-interest income:
Non-interest income	112,478	101,482	333,277	367,214
Non-interest income, change in contribution	$ 10,996		$ (33,937)
Non-interest income, percent change in contribution	11.00%		(9.00%)
Net revenue:
Net revenue	$ 574,836	502,930	$ 1,701,167	1,405,760
Net revenue, change in contribution	$ 71,906		$ 295,407
Net revenue, percent change in contribution	14.00%		21.00%
Segment profit:
Segment profit	$ 164,198	142,961	$ 499,146	364,865
Segment profit, change in contribution	$ 21,237		$ 134,281
Segment profit, percent change in contribution	15.00%		37.00%
Segment assets:
Segment assets	$ 55,555,246	52,382,939	$ 55,555,246	52,382,939	$ 52,949,649
Segment assets, change in contribution	$ 3,172,307
Segment assets, percent change in contribution	6.00%
Community banking
Segment profit:
Segment profit	$ 115,156	104,668	351,905	249,414
Segment profit, change in contribution	$ 10,488		$ 102,491
Segment profit, percent change in contribution	10.00%		41.00%
Segment assets:
Segment assets	$ 43,801,560	41,193,521	$ 43,801,560	41,193,521
Segment assets, change in contribution	$ 2,608,039
Segment assets, percent change in contribution	6.00%
Specialty finance
Segment profit:
Segment profit	$ 40,548	27,187	123,687	87,349
Segment profit, change in contribution	$ 13,361		$ 36,338
Segment profit, percent change in contribution	49.00%		42.00%
Segment assets:
Segment assets	$ 10,521,547	9,450,977	$ 10,521,547	9,450,977
Segment assets, change in contribution	$ 1,070,570
Segment assets, percent change in contribution	11.00%
Wealth management
Segment profit:
Segment profit	$ 8,494	11,106	23,554	28,102
Segment profit, change in contribution	$ (2,612)		$ (4,548)
Segment profit, percent change in contribution	(24.00%)		(16.00%)
Segment assets:
Segment assets	$ 1,232,139	1,738,441	$ 1,232,139	1,738,441
Segment assets, change in contribution	$ (506,302)
Segment assets, percent change in contribution	(29.00%)
Operating Segments
Net interest income:
Net interest income	$ 453,999	393,636	1,341,782	1,015,975
Net interest income, change in contribution	$ 60,363		$ 325,807
Net interest income, percent change in contribution	15.00%		32.00%
Provision for credit losses:
Provision for credit losses	$ 19,923	6,420	$ 71,482	30,943
Provision for credit losses, change in contribution	13,503		40,539
Non-interest income:
Non-interest income	128,641	116,851	386,719	411,371
Non-interest income, change in contribution	$ 11,790		$ (24,652)
Non-interest income, percent change in contribution	10.00%		(6.00%)
Net revenue:
Net revenue	$ 582,640	510,487	$ 1,728,501	1,427,346
Net revenue, change in contribution	$ 72,153		$ 301,155
Net revenue, percent change in contribution	14.00%		21.00%
Operating Segments | Community banking
Net interest income:
Net interest income	$ 360,575	319,929	$ 1,076,655	810,270
Net interest income, change in contribution	$ 40,646		$ 266,385
Net interest income, percent change in contribution	13.00%		33.00%
Provision for credit losses:
Provision for credit losses	$ 16,742	3,608	$ 64,554	27,951
Provision for credit losses, change in contribution	13,134		36,603
Non-interest income:
Non-interest income	70,536	60,615	207,399	245,217
Non-interest income, change in contribution	$ 9,921		$ (37,818)
Non-interest income, percent change in contribution	16.00%		(15.00%)
Net revenue:
Net revenue	$ 431,111	380,544	$ 1,284,054	1,055,487
Net revenue, change in contribution	$ 50,567		$ 228,567
Net revenue, percent change in contribution	13.00%		22.00%
Operating Segments | Specialty finance
Net interest income:
Net interest income	$ 85,427	64,122	$ 240,771	178,210
Net interest income, change in contribution	$ 21,305		$ 62,561
Net interest income, percent change in contribution	33.00%		35.00%
Provision for credit losses:
Provision for credit losses	$ 3,181	2,812	$ 6,928	2,992
Provision for credit losses, change in contribution	$ 369		3,936
Provision for credit losses, percent change in contribution	13.00%
Non-interest income:
Non-interest income	$ 20,793	23,784	78,320	72,898
Non-interest income, change in contribution	$ (2,991)		$ 5,422
Non-interest income, percent change in contribution	(13.00%)		7.00%
Net revenue:
Net revenue	$ 106,220	87,906	$ 319,091	251,108
Net revenue, change in contribution	$ 18,314		$ 67,983
Net revenue, percent change in contribution	21.00%		27.00%
Operating Segments | Wealth management
Net interest income:
Net interest income	$ 7,997	9,585	$ 24,356	27,495
Net interest income, change in contribution	$ (1,588)		$ (3,139)
Net interest income, percent change in contribution	(17.00%)		(11.00%)
Provision for credit losses:
Provision for credit losses	$ 0	0	$ 0	0
Provision for credit losses, change in contribution	$ 0		$ 0
Provision for credit losses, percent change in contribution	0.00%		0.00%
Non-interest income:
Non-interest income	$ 37,312	32,452	$ 101,000	93,256
Non-interest income, change in contribution	$ 4,860		$ 7,744
Non-interest income, percent change in contribution	15.00%		8.00%
Net revenue:
Net revenue	$ 45,309	42,037	$ 125,356	120,751
Net revenue, change in contribution	$ 3,272		$ 4,605
Net revenue, percent change in contribution	8.00%		4.00%
Intersegment Eliminations
Net interest income:
Net interest income	$ 8,359	7,812	$ 26,108	22,571
Net interest income, change in contribution	$ 547		$ 3,537
Net interest income, percent change in contribution	7.00%		16.00%
Provision for credit losses:
Provision for credit losses	$ 0	0	$ 0	0
Provision for credit losses, change in contribution	$ 0		$ 0
Provision for credit losses, percent change in contribution	0.00%		0.00%
Non-interest income:
Non-interest income	$ (16,163)	(15,369)	$ (53,442)	(44,157)
Non-interest income, change in contribution	$ (794)		$ (9,285)
Non-interest income, percent change in contribution	5.00%		21.00%
Net revenue:
Net revenue	$ (7,804)	$ (7,557)	$ (27,334)	$ (21,586)
Net revenue, change in contribution	$ (247)		$ (5,748)
Net revenue, percent change in contribution	3.00%		27.00%