Loans and Leases and the Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 1,975,110	$ 1,472,359	$ 1,925,331	$ 1,469,226
Allowance on acquired PCD loans		99,000		99,000
Provision for credit losses	150,000	302,000	270,000	312,000
Net charge-offs
Charge-offs	(162,224)	(75,614)	(257,163)	(126,652)
Recoveries	35,480	26,045	60,198	70,216
Net (charge-offs) recoveries	(126,744)	(49,569)	(196,965)	(56,436)
Ending balance	1,998,366	1,823,790	1,998,366	1,823,790
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	504,779	307,055	502,153	283,899
Allowance on acquired PCD loans		41,003		41,003
Provision for credit losses	11,977	95,917	24,164	124,642
Net charge-offs
Charge-offs	(21,258)	(37,925)	(40,260)	(57,159)
Recoveries	16,431	8,423	25,872	22,088
Net (charge-offs) recoveries	(4,827)	(29,502)	(14,388)	(35,071)
Ending balance	511,929	414,473	511,929	414,473
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	743,621	539,444	676,684	557,239
Allowance on acquired PCD loans		55,812		55,812
Provision for credit losses	121,092	120,277	217,084	89,339
Net charge-offs
Charge-offs	(101,589)	(8,796)	(131,974)	(10,596)
Recoveries	2,552	1,656	3,882	16,599
Net (charge-offs) recoveries	(99,037)	(7,140)	(128,092)	6,003
Ending balance	765,676	708,393	765,676	708,393
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	113,192	72,581	115,092	71,726
Allowance on acquired PCD loans		1,833		1,833
Provision for credit losses	3,957	50,168	2,435	51,888
Net charge-offs
Charge-offs	(1,072)	(2,863)	(2,773)	(6,835)
Recoveries	2,315	2,607	3,638	5,714
Net (charge-offs) recoveries	1,243	(256)	865	(1,121)
Ending balance	118,392	124,326	118,392	124,326
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	613,518	553,279	631,402	556,362
Allowance on acquired PCD loans		352		352
Provision for credit losses	12,974	35,638	26,317	46,131
Net charge-offs
Charge-offs	(38,305)	(26,030)	(82,156)	(52,062)
Recoveries	14,182	13,359	26,806	25,815
Net (charge-offs) recoveries	(24,123)	(12,671)	(55,350)	(26,247)
Ending balance	$ 602,369	$ 576,598	$ 602,369	$ 576,598