Significant Accounting Policies (Annuity Deposits (Net of Coinsurance), By Product Type) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) NMOs	Dec. 31, 2022 USD ($) NMOs	Dec. 31, 2021 USD ($) NMOs
Product Information [Line Items]
Fixed index annuities	$ 5,041,981	$ 2,202,688	$ 3,026,211
Annual reset fixed rate annuities	4,898	5,535	6,000
Multi-year fixed rate annuities	176,415	139,092	2,452,994
Single premium immediate annuities (SPIA)	1,224	18,935	59,816
Annuity deposits, net of coinsurance	$ 5,224,518	$ 2,366,250	$ 5,545,021
Customer Concentration Risk | Annuity Deposits Benchmark
Product Information [Line Items]
National marketing organizations, number of organizations accounting for more than 10% of annuity deposits collected | NMOs	4	4	2
Customer Concentration Risk | Annuity Deposits Benchmark | National Marketing Organization, Greater than 10%, NMO 1
Product Information [Line Items]
National marketing organizations, percent of annuity deposits collected individually	16.00%	22.00%	14.00%
Customer Concentration Risk | Annuity Deposits Benchmark | National Marketing Organization, Greater than 10%, NMO 2
Product Information [Line Items]
National marketing organizations, percent of annuity deposits collected individually	13.00%	16.00%	11.00%
Customer Concentration Risk | Annuity Deposits Benchmark | National Marketing Organization, Greater than 10%, NMO 3
Product Information [Line Items]
National marketing organizations, percent of annuity deposits collected individually	12.00%	10.00%
Customer Concentration Risk | Annuity Deposits Benchmark | National Marketing Organization, Greater than 10%, NMO 4
Product Information [Line Items]
National marketing organizations, percent of annuity deposits collected individually	11.00%	10.00%