Segment Information - Information about Company's Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Net Income (Loss)	$ 867,034	$ 217,522	$ 1,568,658	$ 579,696
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	2,602,300	1,982,817	5,007,697	3,427,878
Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		1,982,817		3,427,878
Net Income (Loss)		217,522		579,696
Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		1,982,817		3,427,878
Net Income (Loss)		217,522		579,696
Business Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	116,163	67,583	229,414	107,115
Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	277,181	203,630	550,732	344,976
Business Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	1,047	726	1,924	1,397
Business Banking [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		203,630		344,976
Net Income (Loss)		70,536		111,647
Business Banking [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		203,630		344,976
Net Income (Loss)		67,583		107,115
Business Banking [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)		(2,953)		(4,532)
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	165,562	161,810	385,541	290,270
Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	460,625	448,439	967,645	727,374
Commercial Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	9,292	940	19,518	1,803
Commercial Banking [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		343,353		632,725
Net Income (Loss)		130,431		275,039
Commercial Banking [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		448,439		727,374
Net Income (Loss)		161,810		290,270
Commercial Banking [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		105,086		94,649
Net Income (Loss)		31,379		15,231
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	39,288	117,945	120,097	229,191
Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	217,254	246,245	442,973	458,769
Commercial Real Estate [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	268	259	557	438
Commercial Real Estate [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		239,610		441,697
Net Income (Loss)		121,737		219,347
Commercial Real Estate [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		246,245		458,769
Net Income (Loss)		117,945		229,191
Commercial Real Estate [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		6,635		17,072
Net Income (Loss)		(3,792)		9,844
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	(31,695)	44,411	(72,092)	79,096
Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	(23,937)	(74,527)	(57,333)	139,254
Discretionary Portfolio [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	(14,809)	(24,103)	(30,014)	(51,908)
Discretionary Portfolio [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		89,412		154,139
Net Income (Loss)		56,085		91,470
Discretionary Portfolio [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		74,527		139,254
Net Income (Loss)		44,411		79,096
Discretionary Portfolio [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		(14,885)		(14,885)
Net Income (Loss)		(11,674)		(12,374)
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	(14,900)	7,929	(27,254)	35,043
Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	102,556	113,874	180,210	251,318
Residential Mortgage Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	20,754	37,875	41,226	75,339
Residential Mortgage Banking [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		113,874		251,318
Net Income (Loss)		9,347		38,311
Residential Mortgage Banking [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		113,874		251,318
Net Income (Loss)		7,929		35,043
Residential Mortgage Banking [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)		(1,418)		(3,268)
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	336,633	104,569	653,227	183,651
Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	864,566	518,617	1,696,408	873,765
Retail Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	(39)	(4)	(78)	(7)
Retail Banking [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		593,228		948,376
Net Income (Loss)		139,431		223,595
Retail Banking [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		518,617		873,765
Net Income (Loss)		104,569		183,651
Retail Banking [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		(74,611)		(74,611)
Net Income (Loss)		(34,862)		(39,944)
All Other [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	255,983	(286,725)	279,725	(344,670)
All Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	704,055	377,485	1,227,062	632,422
All Other [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	$ (16,513)	(15,693)	$ (33,133)	(27,062)
All Other [Member] | Previously Reported [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		399,710		654,647
Net Income (Loss)		(310,045)		(379,713)
All Other [Member] | Revision of Prior Period, Reclassification, Adjustment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		377,485		632,422
Net Income (Loss)		(286,725)		(344,670)
All Other [Member] | Impact Of Changes [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues		(22,225)		(22,225)
Net Income (Loss)		$ 23,320		$ 35,043