Loans and Allowances for Credit Losses, Activity in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 281,623	$ 249,460	$ 277,123	$ 235,704	$ 235,704
Provision for loan losses	13,148	19,957	23,108	34,482
Loans charged off	(7,940)	(8,049)	(15,000)	(11,716)
Recoveries of loans previously charged off	995	1,346	2,595	4,244
Ending balance	287,826	262,714	287,826	262,714	277,123
Provision Details [Abstract]
Provision for credit losses	8,000	17,000	16,000	33,000
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance	47,319	62,943	48,977	60,919	60,919
Provision for off-balance sheet credit risk	(4,983)	(3,003)	(6,641)	(979)
Ending balance	42,336	59,940	42,336	59,940	48,977
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	24,462,898		24,462,898		23,759,499
Individually measured for impairment, recorded investment	90,683		90,683		145,469
Total	24,553,581		24,553,581		23,904,968
Related allowance [Abstract]
Collectively measured for impairment, related allowance	285,612		285,612		274,431
Individually measured for impairment, related allowance	2,214		2,214		2,692
Total	287,826		287,826		277,123
Commercial [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	146,267	139,898	141,232	131,586	131,586
Provision for loan losses	10,441	5,420	18,752	11,750
Loans charged off	(6,391)	(2,797)	(10,631)	(2,809)
Recoveries of loans previously charged off	420	748	1,384	2,742
Ending balance	150,737	143,269	150,737	143,269	141,232
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance	17,790	20,608	19,762	18,246	18,246
Provision for off-balance sheet credit risk	(474)	(314)	(2,446)	2,048
Ending balance	17,316	20,294	17,316	20,294	19,762
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	15,564,975		15,564,975		14,693,638
Individually measured for impairment, recorded investment	58,434		58,434		110,131
Total	15,623,409		15,623,409		14,803,769
Related allowance [Abstract]
Collectively measured for impairment, related allowance	148,523		148,523		138,540
Individually measured for impairment, related allowance	2,214		2,214		2,692
Total	150,737		150,737		141,232
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	97,479	66,003	94,718	57,648	57,648
Provision for loan losses	(1,042)	14,300	2,953	24,726
Loans charged off	(205)	(4,000)	(1,455)	(6,208)	(8,446)
Recoveries of loans previously charged off	24	44	40	181
Ending balance	96,256	76,347	96,256	76,347	94,718
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance	27,865	40,211	27,439	40,490	40,490
Provision for off-balance sheet credit risk	(4,551)	(2,530)	(4,125)	(2,809)
Ending balance	23,314	37,681	23,314	37,681	27,439
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	5,070,692		5,070,692		5,330,327
Individually measured for impairment, recorded investment	12,883		12,883		7,320
Total	5,083,575		5,083,575		5,337,647
Related allowance [Abstract]
Collectively measured for impairment, related allowance	96,256		96,256		94,718
Individually measured for impairment, related allowance	0		0		0
Total	96,256		96,256		94,718
Loans to individuals [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	37,877	43,559	41,173	46,470	46,470
Provision for loan losses	3,749	237	1,403	(1,994)
Loans charged off	(1,344)	(1,252)	(2,914)	(2,699)
Recoveries of loans previously charged off	551	554	1,171	1,321
Ending balance	40,833	43,098	40,833	43,098	41,173
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance	1,664	2,124	1,776	2,183	2,183
Provision for off-balance sheet credit risk	42	(159)	(70)	(218)
Ending balance	1,706	$ 1,965	1,706	$ 1,965	1,776
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment	3,827,231		3,827,231		3,735,534
Individually measured for impairment, recorded investment	19,366		19,366		28,018
Total	3,846,597		3,846,597		3,763,552
Related allowance [Abstract]
Collectively measured for impairment, related allowance	40,833		40,833		41,173
Individually measured for impairment, related allowance	0		0		0
Total	$ 40,833		$ 40,833		$ 41,173