Segment Information - Information about Reclassified Segment Information on Comparable Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 5,821,956	$ 3,824,778	$ 3,866,317
Provision for credit losses	517,000	(75,000)	800,000
Other noninterest expense	4,616,293	3,287,415	3,064,952
Net income (loss)	1,991,663	1,858,746	1,353,152
All Other [Member]
Segment Reporting Information [Line Items]
Net interest income	831,073	105,876	121,808
Provision for credit losses	349,759	(313,145)	482,202
Other noninterest expense	1,522,006	1,022,786	873,367
Net income (loss)	(165,052)	19,684	(459,112)
Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	712,207	518,940	462,614
Provision for credit losses	17,154	10,928	25,928
Other noninterest expense	421,052	350,265	329,323
Net income (loss)	312,627	207,148	154,455
Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	1,338,552	832,659	827,640
Provision for credit losses	72,200	58,064	68,232
Other noninterest expense	667,282	391,568	382,822
Net income (loss)	729,817	499,002	475,673
Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	736,791	665,020	710,403
Provision for credit losses	(5,621)	110,401	112,077
Other noninterest expense	343,205	289,026	268,527
Net income (loss)	445,983	353,642	400,453
Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	163,695	483,624	486,831
Provision for credit losses	5,156	3,622	1,508
Other noninterest expense	77,996	66,490	62,855
Net income (loss)	16,536	287,009	321,001
Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	41,137	92,706	52,712
Provision for credit losses	(1,569)	(562)	1,785
Other noninterest expense	343,947	338,398	338,389
Net income (loss)	20,928	168,668	128,952
Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	1,998,501	1,125,953	1,204,309
Provision for credit losses	79,921	55,692	108,268
Other noninterest expense	1,240,805	828,882	809,669
Net income (loss)	$ 630,824	323,593	331,730
Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		3,824,778	3,866,317
Provision for credit losses		(75,000)	800,000
Other noninterest expense		3,287,415	3,064,952
Net income (loss)		1,858,746	1,353,152
Previously Reported [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Net interest income		105,876	121,808
Provision for credit losses		(313,145)	482,202
Other noninterest expense		1,082,993	959,258
Net income (loss)		(23,979)	(522,572)
Previously Reported [Member] | Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		518,940	462,614
Provision for credit losses		10,928	25,928
Other noninterest expense		341,751	322,868
Net income (loss)		213,464	159,220
Previously Reported [Member] | Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		854,264	864,149
Provision for credit losses		101,060	73,099
Other noninterest expense		384,505	375,769
Net income (loss)		493,723	508,472
Previously Reported [Member] | Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		643,415	673,894
Provision for credit losses		67,405	107,210
Other noninterest expense		276,791	256,428
Net income (loss)		372,326	381,828
Previously Reported [Member] | Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		483,624	486,831
Provision for credit losses		3,622	1,508
Other noninterest expense		64,122	54,339
Net income (loss)		288,766	327,291
Previously Reported [Member] | Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		92,706	52,712
Provision for credit losses		(562)	1,785
Other noninterest expense		332,491	332,028
Net income (loss)		172,960	133,652
Previously Reported [Member] | Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		1,125,953	1,204,309
Provision for credit losses		55,692	108,268
Other noninterest expense		804,762	764,262
Net income (loss)		341,486	365,261
Impact of Changes [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Other noninterest expense		(60,207)	(85,891)
Net income (loss)		43,663	63,460
Impact of Changes [Member] | Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Other noninterest expense		8,514	6,455
Net income (loss)		(6,316)	(4,765)
Impact of Changes [Member] | Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		(21,605)	(36,509)
Provision for credit losses		(42,996)	(4,867)
Other noninterest expense		7,063	7,053
Net income (loss)		5,279	(32,799)
Impact of Changes [Member] | Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		21,605	36,509
Provision for credit losses		42,996	4,867
Other noninterest expense		12,235	12,099
Net income (loss)		(18,684)	18,625
Impact of Changes [Member] | Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Other noninterest expense		2,368	8,516
Net income (loss)		(1,757)	(6,290)
Impact of Changes [Member] | Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Other noninterest expense		5,907	6,361
Net income (loss)		(4,292)	(4,700)
Impact of Changes [Member] | Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Other noninterest expense		24,120	45,407
Net income (loss)		(17,893)	(33,531)
Reclassified [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		3,824,778	3,866,317
Provision for credit losses		(75,000)	800,000
Other noninterest expense		3,287,415	3,064,952
Net income (loss)		1,858,746	1,353,152
Reclassified [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Net interest income		105,876	121,808
Provision for credit losses		(313,145)	482,202
Other noninterest expense		1,022,786	873,367
Net income (loss)		19,684	(459,112)
Reclassified [Member] | Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		518,940	462,614
Provision for credit losses		10,928	25,928
Other noninterest expense		350,265	329,323
Net income (loss)		207,148	154,455
Reclassified [Member] | Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		832,659	827,640
Provision for credit losses		58,064	68,232
Other noninterest expense		391,568	382,822
Net income (loss)		499,002	475,673
Reclassified [Member] | Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		665,020	710,403
Provision for credit losses		110,401	112,077
Other noninterest expense		289,026	268,527
Net income (loss)		353,642	400,453
Reclassified [Member] | Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		483,624	486,831
Provision for credit losses		3,622	1,508
Other noninterest expense		66,490	62,855
Net income (loss)		287,009	321,001
Reclassified [Member] | Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		92,706	52,712
Provision for credit losses		(562)	1,785
Other noninterest expense		338,398	338,389
Net income (loss)		168,668	128,952
Reclassified [Member] | Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income		1,125,953	1,204,309
Provision for credit losses		55,692	108,268
Other noninterest expense		828,882	809,669
Net income (loss)		$ 323,593	$ 331,730