Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Unrealized losses resulting in deferred tax asset		$ (247,400,000)	$ (9,300,000)
Deferred tax assets from unrealized losses on certain investments in debt securities		59,392,000	2,287,000
Net deferred tax assets		94,457,000	27,321,000
Deferred tax assets		94,457,000	27,321,000
Accrual for income tax interest or penalties		0
Income tax benefit related to share-based compensation		1,100,000	900,000	$ 100,000
Amortization reflected as income expense related to affordable housing project investments		2,500,000	1,600,000	900,000
Affordable housing project tax credits		2,000,000	1,200,000	800,000
Affordable housing project tax benefits		1,000,000	700,000	200,000
Carrying value of affordable housing tax credits		27,300,000	30,100,000
Affordable housing tax credits, unfunded amounts		17,600,000	23,200,000
Unrecognized income tax benefits		0
Tax expense (benefit) from change in enacted tax rate		29,009,000	33,335,000	21,122,000
Income tax benefit from CARES act		0	0	$ 375,000
U.S. Federal
Operating Loss Carryforwards [Line Items]
Net deferred tax assets		76,800,000
Deferred tax assets		3,100,000	20,800,000
State
Operating Loss Carryforwards [Line Items]
Net deferred tax assets		17,700,000
Deferred tax assets		$ 1,100,000	6,500,000
Tax expense (benefit) from change in enacted tax rate	$ 1,100,000		$ (800,000)