Policyholders' Liabilities - Policyholders' Account Balance Reconciliation to Policyholders' Account Balances' Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Policyholder Account Balance [Line Items]
Annuities	$ 136,965	$ 133,216	$ 124,528
Premiums paid in advance	32,391	$ 32,446	36,697
Supplemental Contracts Without Life Contingencies
Policyholder Account Balance [Line Items]
Annuities	48,670		35,835
Fixed Annuity
Policyholder Account Balance [Line Items]
Annuities	86,804		87,161
Unearned Revenue Reserve
Policyholder Account Balance [Line Items]
Annuities	1,491		1,531
Other
Policyholder Account Balance [Line Items]
Annuities	0		1
Premiums paid in advance	1,910		2,575
Premiums Paid In Advance
Policyholder Account Balance [Line Items]
Premiums paid in advance	$ 30,481		$ 34,122