Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Net interest income from external sources	$ 1,327,344	$ 1,210,758	$ 1,272,180
Net interest income (expense) from internal sources	0	0	0
Net interest income	1,327,344	1,210,758	1,272,180
Provision for credit losses	2,000	18,000	46,000
Net interest income after provision for credit losses	1,325,344	1,192,758	1,226,180
Other operating revenue	848,130	839,641	789,949
Personnel	877,969	811,239	766,610
Non-personnel expense	554,887	554,516	566,271
Total other operating expense	1,432,856	1,365,755	1,332,881
Corporate allocations	0	0	0
Net income before taxes	740,618	666,644	683,248
Assets, Average Outstanding	51,706,906	50,749,498	48,244,154
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income from external sources	1,073,396	1,115,402	1,268,488
Net interest income (expense) from internal sources	48,138	88,969	(9,051)
Net interest income	1,121,534	1,204,371	1,259,437
Provision for credit losses	8,582	14,493	19,074
Net interest income after provision for credit losses	1,112,952	1,189,878	1,240,363
Other operating revenue	846,745	825,268	859,241
Personnel	587,053	553,751	533,598
Non-personnel expense	372,401	359,364	348,364
Total other operating expense	959,454	913,115	881,962
Corporate allocations	186,855	181,780	178,003
Net income before taxes	813,388	920,251	1,039,639
Assets, Average Outstanding	41,307,300	40,635,585	38,927,333
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest income from external sources	948,465	1,078,190	1,178,506
Net interest income (expense) from internal sources	(234,944)	(263,094)	(305,107)
Net interest income	713,521	815,096	873,399
Provision for credit losses	3,715	8,850	13,967
Net interest income after provision for credit losses	709,806	806,246	859,432
Other operating revenue	269,195	222,584	247,001
Personnel	204,213	191,398	193,455
Non-personnel expense	120,476	117,216	124,926
Total other operating expense	324,689	308,614	318,381
Corporate allocations	70,106	68,970	75,037
Net income before taxes	584,206	651,246	713,015
Assets, Average Outstanding	21,616,765	21,751,103	21,003,551
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest income from external sources	55,150	25,946	59,962
Net interest income (expense) from internal sources	175,830	234,101	207,058
Net interest income	230,980	260,047	267,020
Provision for credit losses	4,892	5,827	5,157
Net interest income after provision for credit losses	226,088	254,220	261,863
Other operating revenue	149,938	140,005	105,793
Personnel	102,226	98,667	89,472
Non-personnel expense	139,296	127,597	122,642
Total other operating expense	241,522	226,264	212,114
Corporate allocations	58,092	55,737	48,565
Net income before taxes	76,412	112,224	106,977
Assets, Average Outstanding	8,321,005	8,112,293	8,040,602
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income from external sources	69,781	11,266	30,020
Net interest income (expense) from internal sources	107,252	117,962	88,998
Net interest income	177,033	129,228	119,018
Provision for credit losses	(25)	(184)	(50)
Net interest income after provision for credit losses	177,058	129,412	119,068
Other operating revenue	427,612	462,679	506,447
Personnel	280,614	263,686	250,671
Non-personnel expense	112,629	114,551	100,796
Total other operating expense	393,243	378,237	351,467
Corporate allocations	58,657	57,073	54,401
Net income before taxes	152,770	156,781	219,647
Assets, Average Outstanding	11,369,530	10,772,189	9,883,180
Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest income from external sources	253,948	95,356	3,692
Net interest income (expense) from internal sources	(48,138)	(88,969)	9,051
Net interest income	205,810	6,387	12,743
Provision for credit losses	(6,582)	3,507	26,926
Net interest income after provision for credit losses	212,392	2,880	(14,183)
Other operating revenue	1,385	14,373	(69,292)
Personnel	290,916	257,488	233,012
Non-personnel expense	182,486	195,152	217,907
Total other operating expense	473,402	452,640	450,919
Corporate allocations	(186,855)	(181,780)	(178,003)
Net income before taxes	(72,770)	(253,607)	(356,391)
Assets, Average Outstanding	$ 10,399,606	$ 10,113,913	$ 9,316,821