Investment Securities - Allowance for Credit Losses AFS (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Available-for-sale
Beginning balance	$ 2,396	$ 0
Provision for credit loss expense	0	12,800
Reduction due to sales		(2,078)
Net decrease in allowance on previously impaired securities	(1,200)	(2,526)
Securities charged-off		(7,000)
Ending balance	1,196	1,196
State and political subdivisions
Available-for-sale
Beginning balance	0	0
Provision for credit loss expense	0	0
Reduction due to sales		0
Net decrease in allowance on previously impaired securities	0	0
Securities charged-off		0
Ending balance	0	0
Other securities
Available-for-sale
Beginning balance	2,396	0
Provision for credit loss expense	0	12,800
Reduction due to sales		(2,078)
Net decrease in allowance on previously impaired securities	(1,200)	(2,526)
Securities charged-off		(7,000)
Ending balance	$ 1,196	$ 1,196