Investment Securities - Allowance for Credit Losses HTM (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	$ 1,132	$ 307	$ 2,915	$ 0
Provision for credit loss expense	0	66	(1,183)	4
Securities charged-off			(600)
Recoveries	147		147
Ending balance	1,279	373	1,279	373
State and political subdivisions
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	871	95	2,307	0
Provision for credit loss expense	325	(22)	(1,111)	15
Securities charged-off			0
Recoveries	0		0
Ending balance	1,196	73	1,196	73
Other securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	261	212	608	0
Provision for credit loss expense	(325)	88	(72)	(11)
Securities charged-off			(600)
Recoveries	147		147
Ending balance	$ 83	$ 300	$ 83	300
Cumulative Effect, Period of Adoption, Adjustment
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance				369
Cumulative Effect, Period of Adoption, Adjustment | State and political subdivisions
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance				58
Cumulative Effect, Period of Adoption, Adjustment | Other securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance				$ 311