Investments - Schedule of Changes in Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	$ 705,193	$ 798,973	$ 759,409
Included in realized gains/losses	0	(3,594)	1,579
Included in other comprehensive income	(105,156)	(8,308)	14,386
Acquisitions	0	25,000	67,820
Sales	0	(26,064)	0
Amortization	4,526	4,514	4,563
Other	(76,116)	(85,328)	(48,784)
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Ending Balance	528,447	$ 705,193	$ 798,973
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Realized gains (losses)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]		Attributable to Parent Company	Attributable to Parent Company
Asset- backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	0	$ 12,870	$ 13,177
Included in realized gains/losses	0	(82)	0
Included in other comprehensive income	0	63	(173)
Acquisitions	0	0	0
Sales	0	(12,851)	0
Amortization	0	0	0
Other	0	0	(134)
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Ending Balance	0	0	12,870
Collateralized debt obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	63,505	71,598	74,104
Included in realized gains/losses	0	(6,787)	0
Included in other comprehensive income	(13,771)	12,447	(2,523)
Acquisitions	0	0	0
Sales	0	(13,213)	0
Amortization	4,519	4,505	4,551
Other	(3,889)	(5,045)	(4,534)
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Ending Balance	50,364	63,505	71,598
Corporates
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning Balance	641,688	714,505	672,128
Included in realized gains/losses	0	3,275	1,579
Included in other comprehensive income	(91,385)	(20,818)	17,082
Acquisitions	0	25,000	67,820
Sales	0	0	0
Amortization	7	9	12
Other	(72,227)	(80,283)	(44,116)
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Ending Balance	$ 478,083	$ 641,688	$ 714,505