Business Segments - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Average interest earning assets (unaudited)	$ 38,227,815	$ 37,010,933	$ 30,575,530
Interest income	1,334,226	1,383,719	1,321,000
Interest expense	124,325	264,815	422,952
Net Interest Income	1,209,901	1,118,904	898,048
(Credit) provision for credit losses	32,633	125,722	24,218
Net Interest Income After Provision for Credit Losses	1,177,268	993,182	873,830
Non-interest income	155,013	183,032	214,520
Non-interest expense	691,542	646,148	631,555
Internal transfer expense (income)	0	0	0
Income Before Income Taxes	$ 640,739	$ 530,066	$ 456,795
Return on average interest earning assets (pre-tax) (unaudited)	1.68%	1.43%	1.49%
Consumer Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets (unaudited)	$ 7,262,808	$ 7,160,793	$ 6,891,462
Interest income	238,715	257,196	272,773
Interest expense	19,117	47,712	91,798
Net Interest Income	219,598	209,484	180,975
(Credit) provision for credit losses	(6,807)	11,502	6,688
Net Interest Income After Provision for Credit Losses	226,405	197,982	174,287
Non-interest income	72,063	81,499	57,981
Non-interest expense	78,853	77,582	76,046
Internal transfer expense (income)	81,423	77,835	78,743
Income Before Income Taxes	$ 138,192	$ 124,064	$ 77,479
Return on average interest earning assets (pre-tax) (unaudited)	1.90%	1.73%	1.12%
Commercial Lending | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets (unaudited)	$ 25,554,177	$ 24,625,066	$ 19,343,791
Interest income	1,018,674	1,027,796	926,328
Interest expense	67,265	164,075	257,670
Net Interest Income	951,409	863,721	668,658
(Credit) provision for credit losses	39,703	113,585	17,530
Net Interest Income After Provision for Credit Losses	911,706	750,136	651,128
Non-interest income	35,600	64,783	41,157
Non-interest expense	108,577	98,710	101,924
Internal transfer expense (income)	286,335	267,588	221,113
Income Before Income Taxes	$ 552,394	$ 448,621	$ 369,248
Return on average interest earning assets (pre-tax) (unaudited)	2.16%	1.82%	1.91%
Investment Management | Operating Segments
Segment Reporting Information [Line Items]
Average interest earning assets (unaudited)	$ 5,410,830	$ 5,225,074	$ 4,340,277
Interest income	80,051	102,883	126,723
Interest expense	14,243	34,814	57,815
Net Interest Income	65,808	68,069	68,908
(Credit) provision for credit losses	(263)	635	0
Net Interest Income After Provision for Credit Losses	66,071	67,434	68,908
Non-interest income	10,575	10,083	8,818
Non-interest expense	3,632	1,136	1,034
Internal transfer expense (income)	60,573	56,788	49,670
Income Before Income Taxes	$ 12,441	$ 19,593	$ 27,022
Return on average interest earning assets (pre-tax) (unaudited)	0.23%	0.37%	0.62%
Corporate and Other Adjustments | Corporate and Other Adjustments
Segment Reporting Information [Line Items]
Average interest earning assets (unaudited)	$ 0	$ 0	$ 0
Interest income	(3,214)	(4,156)	(4,824)
Interest expense	23,700	18,214	15,669
Net Interest Income	(26,914)	(22,370)	(20,493)
(Credit) provision for credit losses	0	0	0
Net Interest Income After Provision for Credit Losses	(26,914)	(22,370)	(20,493)
Non-interest income	36,775	26,667	106,564
Non-interest expense	500,480	468,720	452,551
Internal transfer expense (income)	(428,331)	(402,211)	(349,526)
Income Before Income Taxes	$ (62,288)	$ (62,212)	$ (16,954)