Loans and Allowances for Credit Losses, Activity in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for loan losses [Roll Forward]
Beginning balance	$ 235,704	$ 256,421	$ 388,640
Provision for loan losses	59,518	428	(95,202)
Loans charged off	(27,316)	(28,746)	(51,351)
Recoveries of loans previously charged off	9,217	7,601	14,334
Ending balance	277,123	235,704	256,421
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning Balance	60,919	32,977	36,921
Provision for off-balance sheet credit risk	(11,942)	27,942	(3,944)
Ending Balance	48,977	60,919	32,977
Provision Details [Abstract]
Total provision for credit losses	46,000	30,000	(100,000)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	23,759,499	22,435,353
Individually measured for impairment, recorded investment	145,469	121,797
Total	23,904,968	22,557,150
Related allowance [Abstract]
Collectively measured for impairment, related allowance	274,431	230,134
Individually measured for impairment, related allowance	2,692	5,570
Total	277,123	235,704
Commercial [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	131,586	162,056	254,934
Provision for loan losses	19,308	(12,782)	(59,326)
Loans charged off	(12,898)	(22,382)	(43,956)
Recoveries of loans previously charged off	3,236	4,694	10,404
Ending balance	141,232	131,586	162,056
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning Balance	18,246	13,812	14,422
Provision for off-balance sheet credit risk	1,516	4,434	(610)
Ending Balance	19,762	18,246	13,812
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	14,693,638	14,152,202
Individually measured for impairment, recorded investment	110,131	60,297
Total	14,803,769	14,212,499
Related allowance [Abstract]
Collectively measured for impairment, related allowance	138,540	127,566
Individually measured for impairment, related allowance	2,692	4,020
Total	141,232	131,586
Commercial real estate [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	57,648	58,553	86,558
Provision for loan losses	42,151	(813)	(26,522)
Loans charged off	(8,446)	(269)	(2,485)
Recoveries of loans previously charged off	3,365	177	1,002
Ending balance	94,718	57,648	58,553
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning Balance	40,490	17,442	20,571
Provision for off-balance sheet credit risk	(13,051)	23,048	(3,129)
Ending Balance	27,439	40,490	17,442
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	5,330,327	4,590,207
Individually measured for impairment, recorded investment	7,320	16,570
Total	5,337,647	4,606,777
Related allowance [Abstract]
Collectively measured for impairment, related allowance	94,718	56,098
Individually measured for impairment, related allowance	0	1,550
Total	94,718	57,648
Loans to individuals [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	46,470	35,812	47,148
Provision for loan losses	(1,941)	14,023	(9,354)
Loans charged off	(5,972)	(6,095)	(4,910)
Recoveries of loans previously charged off	2,616	2,730	2,928
Ending balance	41,173	46,470	35,812
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning Balance	2,183	1,723	1,928
Provision for off-balance sheet credit risk	(407)	460	(205)
Ending Balance	1,776	2,183	$ 1,723
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	3,735,534	3,692,944
Individually measured for impairment, recorded investment	28,018	44,930
Total	3,763,552	3,737,874
Related allowance [Abstract]
Collectively measured for impairment, related allowance	41,173	46,470
Individually measured for impairment, related allowance	0	0
Total	$ 41,173	$ 46,470