Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2023 USD ($) swap	Sep. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) swap	Sep. 30, 2023 USD ($) swap	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	$ 17,324,493			$ 17,324,493		$ 16,058,364
Interest rate swaps
Derivative [Line Items]
Number of instruments held | swap			6
Notional amount			$ 600,000
Income (loss) in other comprehensive income before tax			$ 3,600
Accumulated net after-tax gains related to effective cash flow hedges	2,300			2,300		2,200
Interest rate swaps | Interest income
Derivative [Line Items]
Amounts reclassified to income statement	1,200			1,200
Interest rate swaps | Interest expense
Derivative [Line Items]
Amounts reclassified to income statement	0			0
Interest rate swaps | Fair value hedge interest rate swaps | Interest expense
Derivative [Line Items]
Fee income related to derivative interest rate swaps executed with commercial loan customers	(52)	$ (989)		850	$ (383)
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	$ 5,700	$ 12,200		$ 29,700	$ 39,800
Interest rate swaps | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Number of instruments held | swap	37			37
Notional amount	$ 15,926,996			$ 15,926,996		$ 14,753,330
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	$ 497,900			$ 497,900