Loss and Loss Adjustment Expense Reserves - Incurred and paid claims development, net of reinsurance (Details) $ in Thousands	Dec. 31, 2021 USD ($) claim	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	$ 213,487
IBNR Reserves
Cumulative Number of Reported Claims | claim
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 140,083
All outstanding liabilities before 2017, net of reinsurance	34
Liabilities for loss and LAE, net of reinsurance	73,438
2017
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	38,619	$ 37,529	$ 36,326	$ 36,244	$ 34,309
IBNR Reserves	$ 1,090
Cumulative Number of Reported Claims | claim	29,064,000
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 36,898	36,121	33,987	29,988	$ 21,246
2018
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	38,585	38,657	36,501	37,879
IBNR Reserves	$ 2,529
Cumulative Number of Reported Claims | claim	44,097,000
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 34,142	34,465	30,154	$ 20,771
2019
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	31,097	32,954	31,705
IBNR Reserves	$ 3,804
Cumulative Number of Reported Claims | claim	51,101,000
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 21,630	25,235	$ 17,032
2020
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	16,546	16,140
IBNR Reserves	$ 6,585
Cumulative Number of Reported Claims | claim	37,239,000
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 1,773	$ 6,426
2021
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Incurred loss and loss adjustment expenses, net of reinsurance	88,640
IBNR Reserves	$ 23,136
Cumulative Number of Reported Claims | claim	41,483,000
Cumulative paid loss and loss adjustment expenses, net of reinsurance	$ 45,640