Investments - Schedule of Changes in Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Percent of total fixed maturities	100.00%		100.00%
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Realized gains (losses)	Realized gains (losses)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Significant Unobservable Inputs (Level 3)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	$ 496,879	$ 528,447
Included in realized gains / losses	0	0
Included in other comprehensive income	6,210	(24,392)
Acquisitions	22,676	0
Sales	0	0
Amortization	3,376	3,434
Other	(32,971)	(30,353)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	$ 496,170	$ 477,136
Percent of total fixed maturities	3.00%	3.00%	3.00%
Significant Unobservable Inputs (Level 3) | Asset- backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	$ 0	$ 0
Included in realized gains / losses	0	0
Included in other comprehensive income	0	0
Acquisitions	7,876	0
Sales	0	0
Amortization	0	0
Other	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	$ 7,876	$ 0
Percent of total fixed maturities	0.00%	0.00%
Significant Unobservable Inputs (Level 3) | Collateralized debt obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	$ 42,146	$ 50,364
Included in realized gains / losses	0	0
Included in other comprehensive income	762	(8,424)
Acquisitions	0	0
Sales	0	0
Amortization	3,414	3,429
Other	(3,839)	(3,684)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	$ 42,483	$ 41,685
Percent of total fixed maturities	0.00%	0.00%
Significant Unobservable Inputs (Level 3) | Corporates
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	$ 454,733	$ 478,083
Included in realized gains / losses	0	0
Included in other comprehensive income	5,448	(15,968)
Acquisitions	14,800	0
Sales	0	0
Amortization	(38)	5
Other	(29,132)	(26,669)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	$ 445,811	$ 435,451
Percent of total fixed maturities	3.00%	3.00%