Basis of Presentation and Summary of Significant Accounting Policies - Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Business Acquisition
Goodwill	$ 46,062	$ 46,062
Indefinite-lived intangibles	7,500	7,500
Total goodwill and intangibles	53,562	53,562
Surety
Business Acquisition
Goodwill	40,816	40,816
Casualty
Business Acquisition
Goodwill	$ 5,246	$ 5,246