Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) swap	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) swap	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)
Derivative [Line Items]
Notional amount	$ 21,088,124		$ 21,088,124		$ 19,865,937
Loans	49,272,823		49,272,823		48,799,711
Consumer loans
Derivative [Line Items]
Loans	4,036,197		4,036,197		3,590,837
Consumer loans | Automobile
Derivative [Line Items]
Loans	2,191,976		2,191,976		1,901,065
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	20,307,802		20,307,802		19,085,615
Interest rate swaps
Derivative [Line Items]
Accumulated net after-tax gains related to effective cash flow hedges	584		584		1,200
Amounts reclassified to income statement	805		805
Interest rate swaps | Fair value hedge interest rate swaps | Noninterest Income
Derivative [Line Items]
Fee income related to derivative interest rate swaps executed with commercial loan customers	7,000	$ 5,700	21,000	$ 17,000
Interest rate swaps | Derivatives designated as hedging instruments
Derivative [Line Items]
Derivative, notional amount, terminated		500,000		500,000
Notional amount	780,322		780,322		780,322
Interest rate swaps | Derivatives designated as hedging instruments | Fair value hedge interest rate swaps
Derivative [Line Items]
Notional amount	$ 780,322		$ 780,322		780,322
Interest rate swaps | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Number of instruments held | swap	64		64
Notional amount	$ 17,239,036		$ 17,239,036		16,209,499
Interest rate swaps | Derivatives not designated as hedging instruments: | Fair value hedge interest rate swaps
Derivative [Line Items]
Number of instruments held | swap	2		2
Notional amount	$ 10,400		$ 10,400
Interest rate swaps | Derivatives not designated as hedging instruments: | Risk Participation Agreement
Derivative [Line Items]
Notional amount	954,300		954,300
Credit default swap | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	759,221		759,221		$ 1,142,026	$ 1,500,000
Derivative, cost of hedge	$ 1,800	$ 3,200	$ 5,600	$ 4,700