Fair Value of Financial Instruments - Level 3 Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement Of Income, Extensible List, Not Disclosed Flag	Realized gains (loss) (1)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Change in net unrealized appreciation on investments
Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 1,670	$ 1,771
Realized gains (loss)	(595)
Unrealized gains (losses)	(124)	(1)
Purchases	0
Disposals	(150)
Amortization	0
Transfers in	5,675
Transfers out	0	(100)
Ending Balance	6,476	1,670
Recurring | Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	150	250
Realized gains (loss)	0
Unrealized gains (losses)	0	0
Purchases	0
Disposals	(150)
Amortization	0
Transfers in	5,675
Transfers out	0	(100)
Ending Balance	5,675	150
Recurring | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	925	926
Realized gains (loss)	0
Unrealized gains (losses)	(124)	(1)
Purchases	0
Disposals	0
Amortization	0
Transfers in	0
Transfers out	0	0
Ending Balance	801	925
Recurring | Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	595	595
Realized gains (loss)	(595)
Unrealized gains (losses)	0	0
Purchases	0
Disposals	0
Amortization	0
Transfers in	0
Transfers out	0	0
Ending Balance	$ 0	$ 595