Provision for Unpaid Losses and Loss Adjustment Expenses - Incurred and Paid Losses (Details) $ in Thousands	Dec. 31, 2022 USD ($) claim	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Auto
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 515,878
Cumulative paid losses and loss adjustment expenses from the table below	(405,131)
Reserves for losses and loss adjustment expenses before 2017, net of reinsurance	0
Effect of foreign currency rate changes	(15)
Reserves for losses and loss adjustment expenses, undiscounted and net of reinsurance	110,732
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	44,782
Effect of foreign currency rate changes	(15)
Reserves for losses and loss adjustment expenses, undiscounted and net of reinsurance	$ 44,767
Cumulative Number of Reported Claims | claim	154,264
Auto | 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 18,284	$ 18,409	$ 18,594	$ 18,594	$ 18,594	$ 18,594
Cumulative paid losses and loss adjustment expenses from the table below	(18,122)	(17,897)	(17,530)	(17,442)	(16,655)	(11,410)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 44
Cumulative Number of Reported Claims | claim	11,031
Auto | 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 37,491	37,516	40,287	40,287	40,422
Cumulative paid losses and loss adjustment expenses from the table below	(36,807)	(36,414)	(35,899)	(34,992)	(23,915)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 3
Cumulative Number of Reported Claims | claim	20,641
Auto | 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 59,660	59,660	63,642	63,642
Cumulative paid losses and loss adjustment expenses from the table below	(57,393)	(55,617)	(51,491)	(37,910)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 631
Cumulative Number of Reported Claims | claim	23,780
Auto | 2020
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 85,111	86,608	90,110
Cumulative paid losses and loss adjustment expenses from the table below	(78,079)	(73,402)	(53,167)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 2,833
Cumulative Number of Reported Claims | claim	27,092
Auto | 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 129,259	131,643
Cumulative paid losses and loss adjustment expenses from the table below	(105,475)	(75,933)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 9,215
Cumulative Number of Reported Claims | claim	35,116
Auto | 2022
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 186,073
Cumulative paid losses and loss adjustment expenses from the table below	(109,255)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 32,056
Cumulative Number of Reported Claims | claim	36,604
Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 3,696
Cumulative paid losses and loss adjustment expenses from the table below	(3,530)
Reserves for losses and loss adjustment expenses before 2017, net of reinsurance	0
Reserves for losses and loss adjustment expenses, undiscounted and net of reinsurance	166
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 150
Cumulative Number of Reported Claims | claim	1,034
Marine | 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 183	183	198	198	198	198
Cumulative paid losses and loss adjustment expenses from the table below	(183)	(182)	(182)	(183)	(183)	$ (138)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 0
Cumulative Number of Reported Claims | claim	124
Marine | 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 514	489	437	437	437
Cumulative paid losses and loss adjustment expenses from the table below	(514)	(431)	(425)	(426)	$ (332)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 0
Cumulative Number of Reported Claims | claim	189
Marine | 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 835	835	893	893
Cumulative paid losses and loss adjustment expenses from the table below	(835)	(835)	(828)	$ (514)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 0
Cumulative Number of Reported Claims | claim	192
Marine | 2020
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 1,002	975	915
Cumulative paid losses and loss adjustment expenses from the table below	(985)	(967)	$ (568)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 16
Cumulative Number of Reported Claims | claim	205
Marine | 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 757	854
Cumulative paid losses and loss adjustment expenses from the table below	(713)	$ (625)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 44
Cumulative Number of Reported Claims | claim	210
Marine | 2022
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and loss adjustment expense	$ 405
Cumulative paid losses and loss adjustment expenses from the table below	(300)
Reserves for Losses and Loss Adjustment Expenses Incurred But Not Reported	$ 90
Cumulative Number of Reported Claims | claim	114