Income Taxes - Schedule of Significant Components of Net Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets
Unrealized losses on available-for-sale investment securities	$ 217,018	$ 202,101
Allowance for credit losses on loans, net of recapture	86,224	85,619
Operating lease liabilities	57,996	58,288
Unrealized losses on held-to-maturity investment securities	32,150	36,197
Acquired loans	32,011	40,723
Benefit plan accruals	31,679	38,038
Purchase accounting	22,473	20,063
Net operating loss carryforwards	21,004	25,135
FDIC deductible premiums	4,891	0
Unrealized losses on hedges	0	10,277
Other, net	4,860	4,962
Total deferred tax assets	510,306	521,403
Deferred Tax Liabilities
Operating lease right-of-use assets	(52,710)	(51,845)
Premises and equipment	(12,141)	(14,844)
Loan servicing rights	(9,188)	(9,636)
Prepaid expenses	(3,856)	(2,774)
Unrealized gains on hedges	(3,202)	0
Deferred loan origination fees	(2,361)	(3,566)
Other, net	(3,588)	(2,983)
Total deferred tax liabilities	(87,046)	(85,648)
Net deferred tax assets	$ 423,260	$ 435,755