v3.25.2
Fair Value Measurements - Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value $ 16,612,686 $ 15,043,625
Trading account securities 45,290 33,910
Derivative assets 97,265 101,329
Derivative liabilities 45,918 26,019
Interest rate swaps, caps and floors [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 65,682 79,122
Derivative liabilities 65,682 79,122
Commodity swaps and options [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 77,844 48,503
Derivative liabilities 75,824 47,304
Foreign Exchange Forward [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 459  
Derivative liabilities 459  
U.S. Treasury [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 2,840,939 3,442,320
Trading account securities 35,515 33,910
Residential Mortgage Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 8,850,263 6,997,902
States and political subdivisions [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 4,878,124 4,560,224
Trading account securities 9,775 0
Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 43,360 43,179
Level 1 [Member] | U.S. Treasury [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 2,840,939 3,442,320
Trading account securities 35,515 33,910
Level 2 [Member] | Interest rate swaps, caps and floors [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 65,682 79,122
Derivative liabilities 65,682 79,122
Level 2 [Member] | Commodity swaps and options [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 77,844 48,503
Derivative liabilities 75,824 47,304
Level 2 [Member] | Foreign Exchange Forward [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets 459  
Derivative liabilities 459  
Level 2 [Member] | Residential Mortgage Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 8,850,263 6,997,902
Level 2 [Member] | States and political subdivisions [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value 4,878,124 4,560,224
Trading account securities 9,775 0
Level 2 [Member] | Other [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale, at estimated fair value $ 43,360 $ 43,179