Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	$ 2,533,299	$ 2,800,593
Trading account assets:	5,943	6,131
Equity securities, available-for-sale	17	17
Receivables from parent and affiliates	61,108	60,490
Separate account assets	42,651,548	44,101,699
Payables to parent and affiliates	56,135	71,675
Margin Deposit Assets	1,400	3,000
Embedded Derivative Fair Value of Embedded Derivative	2,300,000	3,112,000
Embedded Derivative Gross Asset	62,000	55,000
Embedded Derivative Gross Liability	2,362,000	3,167,000
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	225	225
Other long-term investments	638	633
Reinsurance recoverables	2,213,966	2,996,154
Receivables from parent and affiliates	4,777	22,320
Total assets	2,380,830	3,175,926
Future policy benefits	2,300,419	3,112,411
Total liabilities	2,300,419	3,112,411
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	2,533,299	2,800,593
Trading account assets:	5,943	6,131
Equity securities, available-for-sale	17	17
Short-term investments	66,454	57,185
Cash equivalents	225	225
Other long-term investments	82,479	95,191
Reinsurance recoverables	2,213,966	2,996,154
Receivables from parent and affiliates	40,590	41,068
Sub total excluding separate account assets	4,942,973	5,996,564
Separate account assets	42,651,548	44,101,699
Total assets	47,594,521	50,098,263
Future policy benefits	2,300,419	3,112,411
Payables to parent and affiliates	0	0
Total liabilities	2,300,419	3,112,411
Netting	(31,083)	(24,288)
Netting	(29,671)	(21,249)
Fair Value, Measurements, Recurring | Other long-term investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Netting	(31,083)	(24,288)
Fair Value, Measurements, Recurring | Payables to parent and affiliates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Netting	(29,671)	(21,249)
Fair Value, Measurements, Recurring | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	6,371	6,336
Fair Value, Measurements, Recurring | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	20,447	70,789
Fair Value, Measurements, Recurring | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	43,451	37,355
Fair Value, Measurements, Recurring | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	1,934,964	2,101,684
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	151,031	149,011
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	259,898	302,185
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	117,137	133,233
Fair Value, Measurements, Recurring | Equity securities, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets:	5,943	6,131
Fair Value, Measurements, Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Trading account assets:	5,943	6,131
Equity securities, available-for-sale	0	0
Short-term investments	65,947	57,185
Cash equivalents	0	0
Other long-term investments	0	0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	0	0
Sub total excluding separate account assets	71,890	63,316
Separate account assets	0	0
Total assets	71,890	63,316
Future policy benefits	0	0
Payables to parent and affiliates	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 1 | Equity securities, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets:	5,943	6,131
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	2,372,375	2,643,999
Trading account assets:	0	0
Equity securities, available-for-sale	17	17
Short-term investments	207	0
Cash equivalents	0	0
Other long-term investments	112,924	118,846
Reinsurance recoverables	0	0
Receivables from parent and affiliates	35,813	18,748
Sub total excluding separate account assets	2,521,336	2,781,610
Separate account assets	42,651,548	44,101,699
Total assets	45,172,884	46,883,309
Future policy benefits	0	0
Payables to parent and affiliates	29,671	21,249
Total liabilities	29,671	21,249
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	6,371	6,336
Fair Value, Measurements, Recurring | Level 2 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	20,447	70,789
Fair Value, Measurements, Recurring | Level 2 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	43,451	37,355
Fair Value, Measurements, Recurring | Level 2 | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	1,817,481	1,985,614
Fair Value, Measurements, Recurring | Level 2 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	107,590	108,487
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	259,898	302,185
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	117,137	133,233
Fair Value, Measurements, Recurring | Level 2 | Equity securities, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets:	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	160,924	156,594
Trading account assets:	0	0
Equity securities, available-for-sale	0	0
Short-term investments	300	0
Cash equivalents	225	225
Other long-term investments	638	633
Reinsurance recoverables	2,213,966	2,996,154
Receivables from parent and affiliates	4,777	22,320
Sub total excluding separate account assets	2,380,830	3,175,926
Separate account assets	0	0
Total assets	2,380,830	3,175,926
Future policy benefits	2,300,419	3,112,411
Payables to parent and affiliates	0	0
Total liabilities	2,300,419	3,112,411
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury securities and obligations of U.S. government authorities and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 3 | Obligations of U.S. states and their political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 3 | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	117,483	116,070
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	43,441	40,524
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available-for-sale:	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets:	$ 0	$ 0