Fair Values of Financial Instruments (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) Basis_Points	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Basis_Points	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Level 1 to Level 2 transfers, amount	$ 0		$ 0		$ 0
Liabilities, Level 1 to Level 2 transfers, amount	0		0		0
Assets, Level 2 to Level 1 transfers, amount	0		0		0
Liabilities, Level 2 to Level 1 transfers, amount	0		0		$ 0
Assets, transfers into Level 3, amount	0	$ 0	0	$ 0
Liabilities, transfers into Level 3, amount	0	0	0	0
Assets, transfers out of Level 3, amount	0	0	0	0
Liabilities, transfers out of Level 3, amount	$ 0	$ 0	$ 0	$ 0
Maximum | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, sensitivity, discount rate adjustment (basis points) | Basis_Points	100		100
Fixed index annuities embedded derivative, adjustment due to change in discount rate			$ (868,600)
Deferred policy scquisition costs and deferred sales inducements, combined balance, adjustment due to change in discount rate			$ (360,200)
Minimum | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, sensitivity, discount rate adjustment (basis points) | Basis_Points	(100)		(100)
Fixed index annuities embedded derivative, adjustment due to change in discount rate			$ 967,600
Deferred policy scquisition costs and deferred sales inducements, combined balance, adjustment due to change in discount rate			$ 419,400