Reinsurance - Schedule of Net Reinsurance Balances Recoverable, After Consideration of Collateral, from Top Reinsurers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 806,787
Ceded Premiums Written	$ 323,950	$ 289,821	$ 244,344
Percent of Total Ceded Premium Written	100.00%
Reinsurance balances recoverable as a percentage of shareholder's equity, threshold for disclosure	2.00%
Reinsurer Concentration Risk | Reinsurance Recoverable
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	100.00%
Munich Re / HSB | AM Best Rating, A+, Superior | S&P Rating, AA-, Very Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 110,142
Ceded Premiums Written	$ 35,040
Percent of Total Ceded Premium Written	10.80%
Munich Re / HSB | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, AA-, Very Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	13.60%
Renaissance Re | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 82,929
Ceded Premiums Written	$ 22,865
Percent of Total Ceded Premium Written	7.10%
Renaissance Re | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	10.30%
Nationwide Mutual | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 45,492
Ceded Premiums Written	$ 21,493
Percent of Total Ceded Premium Written	6.60%
Nationwide Mutual | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	5.60%
Aspen UK Ltd. | AM Best Rating, A, Excellent | S&P Rating, A-, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 43,632
Ceded Premiums Written	$ 11,021
Percent of Total Ceded Premium Written	3.40%
Aspen UK Ltd. | Reinsurer Concentration Risk | AM Best Rating, A, Excellent | Reinsurance Recoverable | S&P Rating, A-, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	5.40%
Safety National | AM Best Rating, A++, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 42,218
Ceded Premiums Written	$ 14,971
Percent of Total Ceded Premium Written	4.60%
Safety National | Reinsurer Concentration Risk | AM Best Rating, A++, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	5.20%
Endurance Re | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 40,979
Ceded Premiums Written	$ 5,570
Percent of Total Ceded Premium Written	1.70%
Endurance Re | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	5.10%
Berkley Insurance Co. | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 36,105
Ceded Premiums Written	$ 8,931
Percent of Total Ceded Premium Written	2.80%
Berkley Insurance Co. | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	4.50%
Lloyds of London | AM Best Rating, A, Excellent | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 34,737
Ceded Premiums Written	$ 26,677
Percent of Total Ceded Premium Written	8.20%
Lloyds of London | Reinsurer Concentration Risk | AM Best Rating, A, Excellent | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	4.30%
Partner Re | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 34,322
Ceded Premiums Written	$ 15,363
Percent of Total Ceded Premium Written	4.70%
Partner Re | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	4.30%
Hannover Ruckversicherung | AM Best Rating, A+, Superior | S&P Rating, AA-, Very Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 33,507
Ceded Premiums Written	$ 16,746
Percent of Total Ceded Premium Written	5.20%
Hannover Ruckversicherung | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, AA-, Very Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	4.20%
Scor Re | AM Best Rating, A+, Superior | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 32,153
Ceded Premiums Written	$ 6,048
Percent of Total Ceded Premium Written	1.90%
Scor Re | Reinsurer Concentration Risk | AM Best Rating, A+, Superior | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	4.00%
Toa Re | AM Best Rating, A, Excellent | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 27,278
Ceded Premiums Written	$ 13,092
Percent of Total Ceded Premium Written	4.00%
Toa Re | Reinsurer Concentration Risk | AM Best Rating, A, Excellent | Reinsurance Recoverable | S&P Rating, A+, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	3.40%
Liberty Mutual | AM Best Rating, A, Excellent | S&P Rating, A, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 24,665
Ceded Premiums Written	$ 6,140
Percent of Total Ceded Premium Written	1.90%
Liberty Mutual | Reinsurer Concentration Risk | AM Best Rating, A, Excellent | Reinsurance Recoverable | S&P Rating, A, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	3.10%
Odyssey America Re | AM Best Rating, A, Excellent | S&P Rating, A, Strong
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 23,945
Ceded Premiums Written	$ 9,049
Percent of Total Ceded Premium Written	2.80%
Odyssey America Re | Reinsurer Concentration Risk | AM Best Rating, A, Excellent | Reinsurance Recoverable | S&P Rating, A, Strong
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	3.00%
All Other Reinsurers
Ceded Credit Risk [Line Items]
Net Reinsurer Exposure	$ 194,683
Ceded Premiums Written	$ 110,944
Percent of Total Ceded Premium Written	34.30%
All Other Reinsurers | Reinsurer Concentration Risk | Reinsurance Recoverable
Ceded Credit Risk [Line Items]
Percent of Total Net Reinsurer Exposure	24.00%