Income Taxes - Schedule of Significant Components of Net Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Deferred Tax Assets
Allowance for credit losses, net of recapture	$ 75,316	$ 28,843
Benefit plan accruals	11,781	18,348
Net operating loss carryforwards	46,649	14,823
Deferred gain on securities	991	1,215
Acquired loans	41,387	8,039
Operating lease liabilities	64,227	22,961
Unrealized losses on available-for-sale investment securities	99,240	3,003
Unrealized losses on held-to-maturity investment securities	5,126	0
Deferred Tax Assets Unrealized Losses Hedges	2,323	0
Tax credit investments and other partnerships	441	301
Purchase accounting	11,414	0
Other, net	3,424	1,914
Total deferred tax assets	362,319	99,447
Deferred Tax Liabilities
Purchase accounting	0	(18,524)
Loan servicing rights	(9,799)	(7,379)
Premises and equipment	(14,254)	(16,972)
Prepaid expenses	(835)	(796)
Operating lease right-of-use assets	(55,749)	(21,129)
Deferred loan origination fees	(5,423)	0
Unrealized gains on hedges	0	(177)
Other, net	(2,480)	(1,564)
Total deferred tax liabilities	(88,540)	(66,541)
Net deferred tax assets	$ 273,779	$ 32,906