Segment Information - Schedule of Operating Information for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Net interest income:
Net interest income	$ 502,583	$ 462,358	$ 1,437,387	$ 1,367,890
Net interest income, change in contribution	$ 40,225		$ 69,497
Net interest income, percent change in contribution	9.00%		5.00%
Provision for credit losses:
Provision for credit losses	$ 22,334	19,923	$ 84,068	71,482
Provision for credit losses, change in contribution	$ 2,411		$ 12,586
Provision for credit losses, percent change in contribution	12.00%		18.00%
Non-interest income:
Non-interest income	$ 113,147	112,478	$ 374,874	333,277
Non-interest income, change in contribution	$ 669		$ 41,597
Non-interest income, percent change in contribution	1.00%		12.00%
Net revenue:
Net revenue	$ 615,730	574,836	$ 1,812,261	1,701,167
Net revenue, change in contribution	$ 40,894		$ 111,094
Net revenue, percent change in contribution	7.00%		7.00%
Segment profit:
Segment profit	$ 170,001	164,198	$ 509,683	499,146
Segment profit, change in contribution	$ 5,803		$ 10,537
Segment profit, percent change in contribution	4.00%		15.00%
Segment assets:
Segment assets	$ 63,788,424	55,555,246	$ 63,788,424	55,555,246	$ 56,259,934
Segment assets, change in contribution	$ 8,233,178
Segment assets, percent change in contribution	15.00%
Community banking
Segment profit:
Segment profit	$ 115,213	115,156	326,495	351,905
Segment profit, change in contribution	$ 57		$ (25,410)
Segment profit, percent change in contribution	0.00%		18.00%
Segment assets:
Segment assets	$ 51,598,626	43,801,560	$ 51,598,626	43,801,560
Segment assets, change in contribution	$ 7,797,066
Segment assets, percent change in contribution	18.00%
Specialty finance
Segment profit:
Segment profit	$ 46,803	40,548	142,417	123,687
Segment profit, change in contribution	$ 6,255		$ 18,730
Segment profit, percent change in contribution	15.00%		5.00%
Segment assets:
Segment assets	$ 11,047,585	10,521,547	$ 11,047,585	10,521,547
Segment assets, change in contribution	$ 526,038
Segment assets, percent change in contribution	5.00%
Wealth management
Segment profit:
Segment profit	$ 7,985	8,494	40,771	23,554
Segment profit, change in contribution	$ (509)		$ 17,217
Segment profit, percent change in contribution	(6.00%)		(7.00%)
Segment assets:
Segment assets	$ 1,142,213	1,232,139	$ 1,142,213	1,232,139
Segment assets, change in contribution	$ (89,926)
Segment assets, percent change in contribution	(7.00%)
Operating Segments
Net interest income:
Net interest income	$ 492,274	453,999	1,407,950	1,341,782
Net interest income, change in contribution	$ 38,275		$ 66,168
Net interest income, percent change in contribution	8.00%		5.00%
Provision for credit losses:
Provision for credit losses	$ 22,334	19,923	$ 84,068	71,482
Provision for credit losses, change in contribution	$ 2,411		$ 12,586
Provision for credit losses, percent change in contribution	12.00%		18.00%
Non-interest income:
Non-interest income	$ 133,341	128,641	$ 433,320	386,719
Non-interest income, change in contribution	$ 4,700		$ 46,601
Non-interest income, percent change in contribution	4.00%		12.00%
Net revenue:
Net revenue	$ 625,615	582,640	$ 1,841,270	1,728,501
Net revenue, change in contribution	$ 42,975		$ 112,769
Net revenue, percent change in contribution	7.00%		7.00%
Operating Segments | Community banking
Net interest income:
Net interest income	$ 396,894	360,575	$ 1,119,411	1,076,655
Net interest income, change in contribution	$ 36,319		$ 42,756
Net interest income, percent change in contribution	10.00%		4.00%
Provision for credit losses:
Provision for credit losses	$ 20,475	16,742	$ 77,192	64,554
Provision for credit losses, change in contribution	$ 3,733		$ 12,638
Provision for credit losses, percent change in contribution	22.00%		20.00%
Non-interest income:
Non-interest income	$ 66,323	70,536	$ 212,578	207,399
Non-interest income, change in contribution	$ (4,213)		$ 5,179
Non-interest income, percent change in contribution	(6.00%)		2.00%
Net revenue:
Net revenue	$ 463,217	431,111	$ 1,331,989	1,284,054
Net revenue, change in contribution	$ 32,106		$ 47,935
Net revenue, percent change in contribution	7.00%		4.00%
Operating Segments | Specialty finance
Net interest income:
Net interest income	$ 88,448	85,427	$ 265,921	240,771
Net interest income, change in contribution	$ 3,021		$ 25,150
Net interest income, percent change in contribution	4.00%		10.00%
Provision for credit losses:
Provision for credit losses	$ 1,859	3,181	$ 6,876	6,928
Provision for credit losses, change in contribution	$ (1,322)		$ (52)
Provision for credit losses, percent change in contribution	(42.00%)		(1.00%)
Non-interest income:
Non-interest income	$ 29,587	20,793	$ 89,221	78,320
Non-interest income, change in contribution	$ 8,794		$ 10,901
Non-interest income, percent change in contribution	42.00%		14.00%
Net revenue:
Net revenue	$ 118,035	106,220	$ 355,142	319,091
Net revenue, change in contribution	$ 11,815		$ 36,051
Net revenue, percent change in contribution	11.00%		11.00%
Operating Segments | Wealth management
Net interest income:
Net interest income	$ 6,932	7,997	$ 22,618	24,356
Net interest income, change in contribution	$ (1,065)		$ (1,738)
Net interest income, percent change in contribution	(13.00%)		(7.00%)
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	$ 37,431	37,312	$ 131,521	101,000
Non-interest income, change in contribution	$ 119		$ 30,521
Non-interest income, percent change in contribution	0.00%		30.00%
Net revenue:
Net revenue	$ 44,363	45,309	$ 154,139	125,356
Net revenue, change in contribution	$ (946)		$ 28,783
Net revenue, percent change in contribution	(2.00%)		23.00%
Intersegment Eliminations
Net interest income:
Net interest income	$ 10,309	8,359	$ 29,437	26,108
Net interest income, change in contribution	$ 1,950		$ 3,329
Net interest income, percent change in contribution	23.00%		13.00%
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	$ (20,194)	(16,163)	$ (58,446)	(53,442)
Non-interest income, change in contribution	$ (4,031)		$ (5,004)
Non-interest income, percent change in contribution	25.00%		9.00%
Net revenue:
Net revenue	$ (9,885)	$ (7,804)	$ (29,009)	$ (27,334)
Net revenue, change in contribution	$ (2,081)		$ (1,675)
Net revenue, percent change in contribution	27.00%		6.00%