Securities Securities - Allowance for Credit Losses on Held to Maturity Securities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Securities, held-to-maturity, allowance for credit loss	$ 158		$ 158			$ 160
Impact of adopting ASC 326	0	$ 0	0	$ 39,377
Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities, held-to-maturity, allowance for credit loss	158	160	158	160	$ 158	$ 160	$ 172	$ 0
Impact of adopting ASC 326	0	0	0	215
Credit loss expense (benefit)	$ 0	$ (12)	$ (2)	$ (55)