Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 1,469,226	$ 1,736,387	$ 1,051,071
Allowance on acquired PCD loans	99,000
Provision for credit losses	517,000	(75,000)	800,000
Net charge-offs
Charge-offs	(302,957)	(338,154)	(333,507)
Recoveries	143,062	145,993	86,366
Net charge-offs	(159,895)	(192,161)	(247,141)
Ending balance	1,925,331	1,469,226	1,736,387
Adoption of new accounting standard			132,457
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	283,899	405,846	366,094
Allowance on acquired PCD loans	41,003
Provision for credit losses	235,702	(40,378)	220,544
Net charge-offs
Charge-offs	(117,223)	(122,651)	(135,083)
Recoveries	58,772	41,082	15,765
Net charge-offs	58,451	81,569	119,318
Ending balance	502,153	283,899	405,846
Adoption of new accounting standard			(61,474)
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	557,239	670,719	322,201
Allowance on acquired PCD loans	55,812
Provision for credit losses	100,445	(42,825)	356,203
Net charge-offs
Charge-offs	(61,641)	(101,306)	(35,891)
Recoveries	24,829	30,651	4,550
Net charge-offs	36,812	70,655	31,341
Ending balance	676,684	557,239	670,719
Adoption of new accounting standard			23,656
One-to-Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	71,726	103,590	56,033
Allowance on acquired PCD loans	1,833
Provision for credit losses	43,574	(29,817)	(3,172)
Net charge-offs
Charge-offs	(11,783)	(10,904)	(10,283)
Recoveries	9,742	8,857	7,116
Net charge-offs	2,041	2,047	3,167
Ending balance	115,092	71,726	103,590
Adoption of new accounting standard			53,896
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	556,362	556,232	229,118
Allowance on acquired PCD loans	352
Provision for credit losses	137,279	38,020	226,425
Net charge-offs
Charge-offs	(112,310)	(103,293)	(152,250)
Recoveries	49,719	65,403	58,935
Net charge-offs	62,591	37,890	93,315
Ending balance	$ 631,402	$ 556,362	556,232
Adoption of new accounting standard			194,004
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance			77,625
Net charge-offs
Adoption of new accounting standard			$ (77,625)