Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Liabilities
Separate account liabilities	$ 4,876,874	$ 4,758,449
Estimated Fair Value
Assets
Mortgage loans	407,235	404,079
Premiums, reinsurance and other receivables	28,264	32,367
Liabilities
Policyholder account balances	1,263,486	1,283,338
Estimated Fair Value | Level 1
Assets
Mortgage loans	0	0
Premiums, reinsurance and other receivables	0	0
Liabilities
Policyholder account balances	0	0
Estimated Fair Value | Level 2
Assets
Mortgage loans	0	0
Premiums, reinsurance and other receivables	223	2,095
Liabilities
Policyholder account balances	0	0
Estimated Fair Value | Level 3
Assets
Mortgage loans	407,235	404,079
Premiums, reinsurance and other receivables	28,041	30,272
Liabilities
Policyholder account balances	1,263,486	1,283,338
Carrying Value
Assets
Mortgage loans	407,390	406,085
Premiums, reinsurance and other receivables	27,425	30,122
Liabilities
Policyholder account balances	$ 1,195,566	$ 1,214,186