Borrowings - Narrative (Details) - Subordinated notes, 5.75% - USD ($) $ in Millions	Aug. 05, 2014	Sep. 30, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Face amount	$ 70.0
Interest rate (as a percent)	5.75%	5.75%	5.75%
Net proceeds from issuance of subordinated long-term debt	$ 68.8
Payments of debt issuance costs	$ 1.2