Policyholders' Liabilities - Policyholders' Account Balance Reconciliation to Policyholders' Account Balances' Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Policyholder Account Balance [Line Items]
Annuities	$ 129,909	$ 121,422	$ 118,452
Premiums paid in advance	35,453	$ 36,384	38,437
Supplemental Contracts Without Life Contingencies
Policyholder Account Balance [Line Items]
Annuities	41,804		30,699
Fixed Annuity
Policyholder Account Balance [Line Items]
Annuities	86,581		86,133
Unearned Revenue Reserve
Policyholder Account Balance [Line Items]
Annuities	1,524		1,619
Other
Policyholder Account Balance [Line Items]
Annuities	0		1
Premiums paid in advance	2,141		2,461
Premiums Paid In Advance
Policyholder Account Balance [Line Items]
Premiums paid in advance	$ 33,312		$ 35,976