Property and Casualty Insurance Activity - Cumulative Paid Loss and Allocated Loss Adjustment Expenses, Net of Reinsurance (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Effects of Reinsurance [Line Items]
Total	$ 496,516
Net liability for unpaid loss and allocated loss adjustment expenses for the accident years presented	81,985
All outstanding liabilities before 2015, net of reinsurance	976
Liabilities for loss and allocated loss adjustment expenses, net of reinsurance	82,960
2015
Effects of Reinsurance [Line Items]
2015	12,295
2016
Effects of Reinsurance [Line Items]
2015	16,181
2016	15,364
2017
Effects of Reinsurance [Line Items]
2015	18,266
2016	19,001
2017	16,704
2018
Effects of Reinsurance [Line Items]
2015	19,984
2016	21,106
2017	24,820
2018	32,383
2019
Effects of Reinsurance [Line Items]
2015	21,067
2016	23,974
2017	28,693
2018	44,516
2019	40,933
2020
Effects of Reinsurance [Line Items]
2015	22,104
2016	25,234
2017	31,393
2018	50,553
2019	54,897
2020	39,045
2021
Effects of Reinsurance [Line Items]
2015	22,318
2016	25,750
2017	32,529
2018	52,025
2019	58,055
2020	50,719
2021	56,282
2022
Effects of Reinsurance [Line Items]
2015	22,473
2016	26,382
2017	33,522
2018	54,424
2019	60,374
2020	53,432
2021	77,756
2022	45,856
2023
Effects of Reinsurance [Line Items]
2015	22,519
2016	26,854
2017	34,683
2018	56,199
2019	63,932
2020	56,523
2021	82,317
2022	65,732
2023	46,280
2024
Effects of Reinsurance [Line Items]
2015	22,539
2016	26,806
2017	34,990
2018	56,867
2019	65,602
2020	59,081
2021	84,987
2022	67,834
2023	56,139
2024	$ 21,671