Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 420,302	$ 435,969
Liability Derivatives, Fair Value	1,489,795	1,355,326
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	18,469	4,239
Liability Derivatives, Fair Value	900	9,103
Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	339,417	379,868
Liability Derivatives, Fair Value	1,435,029	1,300,184
Fair Value Hedges [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	62,416	51,862
Liability Derivatives, Fair Value	53,866	46,039
Interest Rate Swap Agreements [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	12,471	1,202
Liability Derivatives, Fair Value	286	9,094
Commitments to Sell Real Estate Loans [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	5,998	3,037
Liability Derivatives, Fair Value	614	9
Commitments to Sell Real Estate Loans [Member] | Fair Value Hedges [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	60,036	51,410
Liability Derivatives, Fair Value	83	14
Mortgage-Related Commitments to Originate Real Estate Loans for Sale [Member] | Fair Value Hedges [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	2,380	452
Liability Derivatives, Fair Value	53,783	46,025
Interest Rate Contracts [Member] | Fair Value Hedges [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	323,865	355,806
Liability Derivatives, Fair Value	1,420,668	1,278,180
Foreign Exchange and Other Option and Futures Contracts [Member] | Fair Value Hedges [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	15,552	24,062
Liability Derivatives, Fair Value	$ 14,361	$ 22,004