Borrowings - Amounts and Interest Rates of Short-term Borrowings (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	4.24%	0.01%	0.01%
Daily-average amount outstanding	$ 935,980,000	$ 68,073,000	$ 61,551,000
Weighted-average interest rate	2.08%	0.01%	0.05%
Federal funds purchased and short term borrowings	$ 3,554,951,000	$ 47,046,000	$ 59,482,000
Federal Funds Purchased and Repurchase Agreements [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	1.01%	0.01%	0.01%
Highest amount at a month-end	$ 633,684,000	$ 103,548,000	$ 82,893,000
Daily-average amount outstanding	$ 368,326,000	$ 68,073,000	$ 61,551,000
Weighted-average interest rate	0.20%	0.01%	0.05%
Federal Funds Purchased and Repurchase Agreements	$ 354,670,000	$ 47,046,000	$ 59,482,000
Other Short-term Borrowings [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	4.59%
Highest amount at a month-end	$ 3,200,283,000
Daily-average amount outstanding	$ 567,654,000
Weighted-average interest rate	3.29%
Other Short-Term Borrowings	$ 3,200,281,000