Summary of Significant Accounting Policies - Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 46,062	$ 46,062
State insurance licenses	7,500	7,500
Definite-lived intangibles, net of accumulated amortization of $4,035 at 12/31/21 and $3,878 at 12/31/20		157
Total intangibles	7,500	7,657
Total goodwill and intangibles	53,562	53,719
Surety
Business Acquisition [Line Items]
Goodwill	40,816	40,816
Casualty
Business Acquisition [Line Items]
Goodwill	$ 5,246	$ 5,246