Subsequent Events (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Oct. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Nov. 03, 2023	Sep. 19, 2023
Subsequent Event [Line Items]
Noninterest expense		$ 101,748	$ 95,765	$ 297,573	$ 276,066
Discontinued Operations, Held-for-Sale | Insurance Agency Business
Subsequent Event [Line Items]
Gross cash consideration							$ 515,000
Discontinued Operations, Held-for-Sale | Insurance Agency Business | Subsequent Event
Subsequent Event [Line Items]
Net cash consideration	$ 498,100
Gross cash consideration	515,000
Working capital adjustment	4,200
Transaction expenses	17,000
Post-retirement liabilities	4,100
Fiduciary cash transferred	7,400
Gain (loss) on disposition of assets	389,300
Noninterest expense	$ 24,200
Discontinued Operations, Held-for-Sale | Insurance Agency Business | Subsequent Event | Minimum
Subsequent Event [Line Items]
Estimated curtailment gain at the time of the amendments to the Plans						$ 13,000
Discontinued Operations, Held-for-Sale | Insurance Agency Business | Subsequent Event | Maximum
Subsequent Event [Line Items]
Estimated curtailment gain at the time of the amendments to the Plans						$ 18,000