Loans and Allowance for Credit Losses for Loans - Internal Loan Classification Risk by Loan Portfolio Class by Origination Year (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 49,272,823		$ 49,272,823		$ 48,799,711
Gross loan charge-offs
Total	16,566	$ 48,221	102,656	$ 111,460
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,153,556		1,153,556		1,824,953
Year two, fiscal year before current fiscal year	1,506,596		1,506,596		854,030
Year three, two years before current fiscal year	758,822		758,822		772,815
Year four, three years before current fiscal year	626,916		626,916		492,961
Year five, four years before current fiscal year	375,660		375,660		250,075
More than five years before current fiscal year	696,633		696,633		524,794
Revolving Loans Amortized Cost Basis	5,602,741		5,602,741		5,155,993
Revolving Loans Converted to Term Loans	36,933		36,933		55,779
Total	10,757,857		10,757,857		9,931,400
Gross loan charge-offs
Total	2,745	7,501	56,390	36,515
Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,152,491		1,152,491		1,769,585
Year two, fiscal year before current fiscal year	1,458,777		1,458,777		828,087
Year three, two years before current fiscal year	720,721		720,721		703,962
Year four, three years before current fiscal year	555,773		555,773		476,091
Year five, four years before current fiscal year	352,012		352,012		246,992
More than five years before current fiscal year	577,220		577,220		392,834
Revolving Loans Amortized Cost Basis	5,242,931		5,242,931		4,804,095
Revolving Loans Converted to Term Loans	9,715		9,715		6,006
Total	10,069,640		10,069,640		9,227,652
Commercial and industrial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,065		1,065		30,755
Year two, fiscal year before current fiscal year	25,208		25,208		3,553
Year three, two years before current fiscal year	5,127		5,127		59,434
Year four, three years before current fiscal year	8,122		8,122		11,646
Year five, four years before current fiscal year	10,176		10,176		270
More than five years before current fiscal year	6,908		6,908		72,514
Revolving Loans Amortized Cost Basis	161,230		161,230		147,254
Revolving Loans Converted to Term Loans	7,425		7,425		10,762
Total	225,261		225,261		336,188
Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		24,613
Year two, fiscal year before current fiscal year	22,611		22,611		13,479
Year three, two years before current fiscal year	27,522		27,522		9,415
Year four, three years before current fiscal year	63,018		63,018		4,296
Year five, four years before current fiscal year	13,150		13,150		2,813
More than five years before current fiscal year	63,455		63,455		7,382
Revolving Loans Amortized Cost Basis	196,303		196,303		201,053
Revolving Loans Converted to Term Loans	19,793		19,793		39,011
Total	405,852		405,852		302,062
Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	0		0		8,911
Year three, two years before current fiscal year	5,452		5,452		4
Year four, three years before current fiscal year	3		3		928
Year five, four years before current fiscal year	322		322		0
More than five years before current fiscal year	49,050		49,050		52,064
Revolving Loans Amortized Cost Basis	2,277		2,277		3,591
Revolving Loans Converted to Term Loans	0		0		0
Total	57,104		57,104		65,498
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	28,683,374		28,683,374		29,644,958
Gross loan charge-offs
Total	12,317	$ 38,123	40,363	$ 69,277
Commercial real estate | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,611,922		1,611,922		2,338,118
Year two, fiscal year before current fiscal year	2,204,674		2,204,674		3,433,126
Year three, two years before current fiscal year	3,072,646		3,072,646		5,988,114
Year four, three years before current fiscal year	5,580,392		5,580,392		4,400,609
Year five, four years before current fiscal year	4,062,069		4,062,069		2,604,959
More than five years before current fiscal year	8,804,581		8,804,581		6,937,081
Revolving Loans Amortized Cost Basis	777,632		777,632		749,597
Revolving Loans Converted to Term Loans	52,200		52,200		78,621
Total	26,166,116		26,166,116		26,530,225
Commercial real estate | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,609,537		1,609,537		2,097,314
Year two, fiscal year before current fiscal year	1,964,384		1,964,384		2,941,270
Year three, two years before current fiscal year	2,605,451		2,605,451		5,310,807
Year four, three years before current fiscal year	4,947,176		4,947,176		3,883,333
Year five, four years before current fiscal year	3,511,719		3,511,719		2,302,480
More than five years before current fiscal year	7,671,234		7,671,234		6,086,608
Revolving Loans Amortized Cost Basis	527,891		527,891		597,266
Revolving Loans Converted to Term Loans	52,134		52,134		78,621
Total	22,889,526		22,889,526		23,297,699
Commercial real estate | Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	2,385		2,385		156,394
Year two, fiscal year before current fiscal year	150,587		150,587		380,852
Year three, two years before current fiscal year	247,472		247,472		289,669
Year four, three years before current fiscal year	263,298		263,298		192,614
Year five, four years before current fiscal year	142,029		142,029		55,739
More than five years before current fiscal year	291,848		291,848		327,732
Revolving Loans Amortized Cost Basis	126,364		126,364		141,164
Revolving Loans Converted to Term Loans	0		0		0
Total	1,223,983		1,223,983		1,544,164
Commercial real estate | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		84,410
Year two, fiscal year before current fiscal year	89,703		89,703		107,944
Year three, two years before current fiscal year	216,663		216,663		387,638
Year four, three years before current fiscal year	369,918		369,918		288,906
Year five, four years before current fiscal year	379,021		379,021		236,927
More than five years before current fiscal year	830,924		830,924		520,858
Revolving Loans Amortized Cost Basis	123,377		123,377		11,167
Revolving Loans Converted to Term Loans	66		66		0
Total	2,009,672		2,009,672		1,637,850
Commercial real estate | Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	0		0		3,060
Year three, two years before current fiscal year	3,060		3,060		0
Year four, three years before current fiscal year	0		0		35,756
Year five, four years before current fiscal year	29,300		29,300		9,813
More than five years before current fiscal year	10,575		10,575		1,883
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	42,935		42,935		50,512
Commercial real estate | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	449,213		449,213		568,710
Year two, fiscal year before current fiscal year	567,570		567,570		680,260
Year three, two years before current fiscal year	285,280		285,280		346,587
Year four, three years before current fiscal year	325,728		325,728		102,776
Year five, four years before current fiscal year	87,760		87,760		25,228
More than five years before current fiscal year	60,913		60,913		47,665
Revolving Loans Amortized Cost Basis	683,253		683,253		1,284,863
Revolving Loans Converted to Term Loans	57,541		57,541		58,644
Total	2,517,258		2,517,258		3,114,733
Commercial real estate | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	447,477		447,477		545,597
Year two, fiscal year before current fiscal year	536,548		536,548		680,260
Year three, two years before current fiscal year	230,253		230,253		334,899
Year four, three years before current fiscal year	315,070		315,070		92,765
Year five, four years before current fiscal year	59,043		59,043		17,955
More than five years before current fiscal year	52,380		52,380		45,161
Revolving Loans Amortized Cost Basis	551,588		551,588		1,224,698
Revolving Loans Converted to Term Loans	17,574		17,574		58,644
Total	2,209,933		2,209,933		2,999,979
Commercial real estate | Construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,736		1,736		13,278
Year two, fiscal year before current fiscal year	10,864		10,864		0
Year three, two years before current fiscal year	21,494		21,494		664
Year four, three years before current fiscal year	1,711		1,711		5,069
Year five, four years before current fiscal year	23,029		23,029		0
More than five years before current fiscal year	0		0		2,504
Revolving Loans Amortized Cost Basis	79,161		79,161		16,691
Revolving Loans Converted to Term Loans	7,011		7,011		0
Total	145,006		145,006		38,206
Commercial real estate | Construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		9,835
Year two, fiscal year before current fiscal year	20,158		20,158		0
Year three, two years before current fiscal year	33,533		33,533		8,950
Year four, three years before current fiscal year	8,947		8,947		4,942
Year five, four years before current fiscal year	5,688		5,688		0
More than five years before current fiscal year	8,533		8,533		0
Revolving Loans Amortized Cost Basis	52,504		52,504		43,474
Revolving Loans Converted to Term Loans	32,956		32,956		0
Total	$ 162,319		162,319		67,201
Commercial real estate | Construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year					0
Year two, fiscal year before current fiscal year					0
Year three, two years before current fiscal year					2,074
Year four, three years before current fiscal year					0
Year five, four years before current fiscal year					7,273
More than five years before current fiscal year					0
Revolving Loans Amortized Cost Basis					0
Revolving Loans Converted to Term Loans					0
Total					9,347
Commercial and Industrial and Commercial Real Estate
Gross loan charge-offs
Year one, gross loan charge-offs			0		706
Year two, gross loan charge-offs			6,848		31,809
Year three, gross loan charge-offs			3,679		7,523
Year four, gross loan charge-offs			9,746		44,610
Year five, gross loan charge-offs			14,812		66,632
More than five years gross loan charge-offs			22,627		49,436
Revolving Loans Amortized Cost Basis			23,450		3,930
Revolving Loans Converted to Term Loans			15,591		2,148
Total			$ 96,753		$ 206,794