Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 19, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Noninterest expense		$ 418,602	$ 388,649	$ 360,955
Net reduction of the lease ROU assets		(2,400)	14,400
Impairment charge		400	600
Discontinued Operations, Held-for-Sale | Insurance Agency Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross cash consideration					$ 515,000
Net cash consideration	$ 498,100
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	408,600
Noninterest expense	$ 22,300
Total compensation		1,000
ROU lease asset			8,700
Lease liability			9,200
Net reduction of the lease ROU assets		6,400
Impairment charge		2,000
Disposal Group, Not Discontinued Operations, Transferrable Upon Sale to Entity | Insurance Agency Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
ROU lease asset		500	1,900
Lease liability		$ 300	$ 2,200