Loans and Leases - Credit Quality Indicators (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Financing Receivable
Loans and leases	$ 53,671,959		$ 53,671,959		$ 52,505,168
Current period gross write-offs
Total	41,238	$ 34,774	97,856	$ 74,565
Consumer portfolio
Financing Receivable
Total financing receivable, Current fiscal year	805,747		805,747		1,298,754
Total financing receivable, Fiscal year before current fiscal year	1,437,747		1,437,747		763,519
Total financing receivable, Two years before current fiscal year	715,124		715,124		1,924,258
Total financing receivable, Three years before current fiscal year	1,875,637		1,875,637		2,156,856
Total financing receivable, Four years before current fiscal year	2,090,850		2,090,850		811,965
Total financing receivable, More than five years before current fiscal year	3,068,757		3,068,757		2,420,593
Revolving Loans Amortized Cost Basis	1,026,219		1,026,219		1,061,222
Loans and leases	11,020,081		11,020,081		10,437,167
Current period gross write-offs
Current fiscal year			1,198		3,467
Fiscal year before current fiscal year			951		17
Two years before current fiscal year			8		34
Three years before current fiscal year			4		20
Four years before current fiscal year			8		115
More than five years before current fiscal year			71		784
Revolving Loans Amortized Cost Basis			258		573
Total	1,446	$ 1,418	2,498	$ 2,748	5,010
Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	696,779		696,779		1,151,655
Total financing receivable, Fiscal year before current fiscal year	1,232,744		1,232,744		697,121
Total financing receivable, Two years before current fiscal year	653,986		653,986		1,862,151
Total financing receivable, Three years before current fiscal year	1,817,633		1,817,633		2,082,332
Total financing receivable, Four years before current fiscal year	2,020,737		2,020,737		770,546
Total financing receivable, More than five years before current fiscal year	2,910,534		2,910,534		2,289,864
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	9,332,413		9,332,413		8,853,669
Current period gross write-offs
Current fiscal year			0		0
Fiscal year before current fiscal year			0		0
Two years before current fiscal year			0		0
Three years before current fiscal year			0		0
Four years before current fiscal year			0		0
More than five years before current fiscal year			15		147
Revolving Loans Amortized Cost Basis			0		0
Total			15		147
Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	19,741		19,741		37,780
Total financing receivable, Fiscal year before current fiscal year	35,971		35,971		64,724
Total financing receivable, Two years before current fiscal year	59,777		59,777		61,048
Total financing receivable, Three years before current fiscal year	57,225		57,225		72,184
Total financing receivable, Four years before current fiscal year	68,018		68,018		40,991
Total financing receivable, More than five years before current fiscal year	157,550		157,550		129,910
Revolving Loans Amortized Cost Basis	987,464		987,464		1,021,055
Loans and leases	1,385,746		1,385,746		1,427,692
Current period gross write-offs
Current fiscal year			0		0
Fiscal year before current fiscal year			50		0
Two years before current fiscal year			0		0
Three years before current fiscal year			0		0
Four years before current fiscal year			0		2
More than five years before current fiscal year			29		444
Revolving Loans Amortized Cost Basis			161		351
Total			240		797
Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	89,227		89,227		109,319
Total financing receivable, Fiscal year before current fiscal year	169,032		169,032		1,674
Total financing receivable, Two years before current fiscal year	1,361		1,361		1,059
Total financing receivable, Three years before current fiscal year	779		779		2,340
Total financing receivable, Four years before current fiscal year	2,095		2,095		428
Total financing receivable, More than five years before current fiscal year	673		673		819
Revolving Loans Amortized Cost Basis	38,755		38,755		40,167
Loans and leases	301,922		301,922		155,806
Current period gross write-offs
Current fiscal year			1,198		3,467
Fiscal year before current fiscal year			901		17
Two years before current fiscal year			8		34
Three years before current fiscal year			4		20
Four years before current fiscal year			8		113
More than five years before current fiscal year			27		193
Revolving Loans Amortized Cost Basis			97		222
Total			2,243		4,066
800+ | Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	191,796		191,796		312,771
Total financing receivable, Fiscal year before current fiscal year	501,827		501,827		299,006
Total financing receivable, Two years before current fiscal year	298,943		298,943		909,109
Total financing receivable, Three years before current fiscal year	919,014		919,014		1,097,807
Total financing receivable, Four years before current fiscal year	1,087,229		1,087,229		433,950
Total financing receivable, More than five years before current fiscal year	1,311,324		1,311,324		956,478
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	4,310,133		4,310,133		4,009,121
800+ | Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	5,930		5,930		12,313
Total financing receivable, Fiscal year before current fiscal year	11,151		11,151		25,226
Total financing receivable, Two years before current fiscal year	25,589		25,589		23,512
Total financing receivable, Three years before current fiscal year	25,595		25,595		32,695
Total financing receivable, Four years before current fiscal year	30,833		30,833		22,705
Total financing receivable, More than five years before current fiscal year	70,449		70,449		53,844
Revolving Loans Amortized Cost Basis	349,518		349,518		365,741
Loans and leases	519,065		519,065		536,036
800+ | Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	3,318		3,318		4,920
Total financing receivable, Fiscal year before current fiscal year	7,264		7,264		312
Total financing receivable, Two years before current fiscal year	317		317		218
Total financing receivable, Three years before current fiscal year	141		141		1,765
Total financing receivable, Four years before current fiscal year	1,725		1,725		50
Total financing receivable, More than five years before current fiscal year	148		148		284
Revolving Loans Amortized Cost Basis	14,477		14,477		31,549
Loans and leases	27,390		27,390		39,098
740-799 | Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	401,252		401,252		649,118
Total financing receivable, Fiscal year before current fiscal year	546,890		546,890		258,699
Total financing receivable, Two years before current fiscal year	227,983		227,983		567,545
Total financing receivable, Three years before current fiscal year	531,523		531,523		656,599
Total financing receivable, Four years before current fiscal year	629,765		629,765		235,749
Total financing receivable, More than five years before current fiscal year	812,135		812,135		623,989
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	3,149,548		3,149,548		2,991,699
740-799 | Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	7,838		7,838		12,238
Total financing receivable, Fiscal year before current fiscal year	12,907		12,907		21,831
Total financing receivable, Two years before current fiscal year	18,702		18,702		20,718
Total financing receivable, Three years before current fiscal year	16,799		16,799		23,517
Total financing receivable, Four years before current fiscal year	22,594		22,594		10,861
Total financing receivable, More than five years before current fiscal year	40,189		40,189		33,703
Revolving Loans Amortized Cost Basis	317,213		317,213		330,691
Loans and leases	436,242		436,242		453,559
740-799 | Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	34,320		34,320		45,001
Total financing receivable, Fiscal year before current fiscal year	66,461		66,461		721
Total financing receivable, Two years before current fiscal year	466		466		301
Total financing receivable, Three years before current fiscal year	241		241		165
Total financing receivable, Four years before current fiscal year	214		214		124
Total financing receivable, More than five years before current fiscal year	231		231		266
Revolving Loans Amortized Cost Basis	4,287		4,287		3,550
Loans and leases	106,220		106,220		50,128
670-739 | Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	97,051		97,051		172,886
Total financing receivable, Fiscal year before current fiscal year	162,365		162,365		123,354
Total financing receivable, Two years before current fiscal year	100,743		100,743		317,373
Total financing receivable, Three years before current fiscal year	297,619		297,619		271,247
Total financing receivable, Four years before current fiscal year	237,615		237,615		80,318
Total financing receivable, More than five years before current fiscal year	625,265		625,265		550,252
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	1,520,658		1,520,658		1,515,430
670-739 | Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	5,352		5,352		11,416
Total financing receivable, Fiscal year before current fiscal year	10,143		10,143		14,298
Total financing receivable, Two years before current fiscal year	12,131		12,131		12,732
Total financing receivable, Three years before current fiscal year	9,648		9,648		13,074
Total financing receivable, Four years before current fiscal year	11,091		11,091		6,242
Total financing receivable, More than five years before current fiscal year	32,121		32,121		28,638
Revolving Loans Amortized Cost Basis	228,224		228,224		224,449
Loans and leases	308,710		308,710		310,849
670-739 | Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	50,326		50,326		57,952
Total financing receivable, Fiscal year before current fiscal year	93,010		93,010		432
Total financing receivable, Two years before current fiscal year	408		408		372
Total financing receivable, Three years before current fiscal year	236		236		313
Total financing receivable, Four years before current fiscal year	97		97		220
Total financing receivable, More than five years before current fiscal year	162		162		188
Revolving Loans Amortized Cost Basis	18,444		18,444		3,349
Loans and leases	162,683		162,683		62,826
580-669 | Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	6,680		6,680		16,643
Total financing receivable, Fiscal year before current fiscal year	20,747		20,747		13,382
Total financing receivable, Two years before current fiscal year	22,924		22,924		55,507
Total financing receivable, Three years before current fiscal year	53,824		53,824		35,292
Total financing receivable, Four years before current fiscal year	43,214		43,214		16,738
Total financing receivable, More than five years before current fiscal year	111,958		111,958		109,240
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	259,347		259,347		246,802
580-669 | Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	469		469		1,755
Total financing receivable, Fiscal year before current fiscal year	1,555		1,555		2,570
Total financing receivable, Two years before current fiscal year	1,898		1,898		1,685
Total financing receivable, Three years before current fiscal year	2,864		2,864		2,172
Total financing receivable, Four years before current fiscal year	2,927		2,927		754
Total financing receivable, More than five years before current fiscal year	9,883		9,883		9,471
Revolving Loans Amortized Cost Basis	60,667		60,667		67,745
Loans and leases	80,263		80,263		86,152
580-669 | Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	1,261		1,261		1,417
Total financing receivable, Fiscal year before current fiscal year	2,242		2,242		116
Total financing receivable, Two years before current fiscal year	93		93		105
Total financing receivable, Three years before current fiscal year	115		115		69
Total financing receivable, Four years before current fiscal year	31		31		25
Total financing receivable, More than five years before current fiscal year	96		96		81
Revolving Loans Amortized Cost Basis	1,093		1,093		1,150
Loans and leases	4,931		4,931		2,963
579 and below | Consumer portfolio | Residential
Financing Receivable
Total financing receivable, Current fiscal year	0		0		237
Total financing receivable, Fiscal year before current fiscal year	915		915		2,680
Total financing receivable, Two years before current fiscal year	3,393		3,393		12,617
Total financing receivable, Three years before current fiscal year	15,653		15,653		21,387
Total financing receivable, Four years before current fiscal year	22,914		22,914		3,791
Total financing receivable, More than five years before current fiscal year	49,852		49,852		49,905
Revolving Loans Amortized Cost Basis	0		0		0
Loans and leases	92,727		92,727		90,617
579 and below | Consumer portfolio | Home equity
Financing Receivable
Total financing receivable, Current fiscal year	152		152		58
Total financing receivable, Fiscal year before current fiscal year	215		215		799
Total financing receivable, Two years before current fiscal year	1,457		1,457		2,401
Total financing receivable, Three years before current fiscal year	2,319		2,319		726
Total financing receivable, Four years before current fiscal year	573		573		429
Total financing receivable, More than five years before current fiscal year	4,908		4,908		4,254
Revolving Loans Amortized Cost Basis	31,842		31,842		32,429
Loans and leases	41,466		41,466		41,096
579 and below | Consumer portfolio | Other consumer
Financing Receivable
Total financing receivable, Current fiscal year	2		2		29
Total financing receivable, Fiscal year before current fiscal year	55		55		93
Total financing receivable, Two years before current fiscal year	77		77		63
Total financing receivable, Three years before current fiscal year	46		46		28
Total financing receivable, Four years before current fiscal year	28		28		9
Total financing receivable, More than five years before current fiscal year	36		36		0
Revolving Loans Amortized Cost Basis	454		454		569
Loans and leases	$ 698		$ 698		$ 791