Loans and Allowance for Credit Losses - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($) loan	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($) loan	Dec. 31, 2022 USD ($) loan
Receivables [Abstract]
Unearned income	$ 7.1		$ 7.1		$ 7.5
Purchase accounting fair value adjustments	$ 3.6		$ 3.6		$ 4.7
Number of contracts, modified, subsequent default | loan	0	7	0	23
Financing receivable, modified, commitment to lend	$ 0.2		$ 0.2
Threshold period of satisfactory performance for troubled debt restructuring to be restored to accruing status			6 months
Number of troubled debt restructuring loans returned to accruing status | loan					1
Reclassified to accruing status					$ 0.2
Number of commitments to lend additional funds on TDRs | loan		16		16
Commitments to lend additional funds on TDRs		$ 0.4		$ 0.4
Number of contracts, troubled debt restructuring, subsequent default | loan		1		2
Financing receivable, modified, subsequent default		$ 0.1		$ 0.2