Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	$ 111,738,870	$ 109,194,192
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	51,047	29,572
Reinsurance recoverables	3,023,119	4,897,545
Receivables from parent and affiliates	173,703	177,672
Subtotal excluding separate account assets	9,896,037	11,567,629
Separate account assets	111,738,870	109,194,192
Total assets	121,634,907	120,761,821
Future policy benefits	3,117,171	4,993,611
Total liabilities	3,117,171	4,993,611
Level 3 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	19,222	6,290
Other long-term investments	2,327	2,115
Reinsurance recoverables	3,023,119	4,897,545
Receivables from parent and affiliates	2,550	19,203
Subtotal excluding separate account assets	3,299,900	5,110,171
Separate account assets	337,406	302,924
Total assets	3,637,306	5,413,095
Future policy benefits	3,117,171	4,993,611
Total liabilities	3,117,171	4,993,611
Level 3 | Fair Value, Measurements, Recurring | Separate account assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	337,406	302,924
Level 3 | Fair Value, Measurements, Recurring | Corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	80,482	84,801
Level 3 | Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	172,200	100,217
Level 3 | Fair Value, Measurements, Recurring | Internal
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	853	750
Other long-term investments	796	565
Reinsurance recoverables	3,023,119	4,897,545
Receivables from parent and affiliates	0	0
Subtotal excluding separate account assets	3,049,786	4,922,836
Total assets	3,134,677	5,006,947
Future policy benefits	3,117,171	4,993,611
Total liabilities	3,117,171	4,993,611
Level 3 | Fair Value, Measurements, Recurring | Internal | Separate account assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	84,891	84,111
Level 3 | Fair Value, Measurements, Recurring | Internal | Corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	24,797	23,712
Level 3 | Fair Value, Measurements, Recurring | Internal | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	221	264
Level 3 | Fair Value, Measurements, Recurring | External
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	18,369	5,540
Other long-term investments	1,531	1,550
Reinsurance recoverables	0	0
Receivables from parent and affiliates	2,550	19,203
Subtotal excluding separate account assets	250,114	187,335
Total assets	502,629	406,148
Future policy benefits	0	0
Total liabilities	0	0
Level 3 | Fair Value, Measurements, Recurring | External | Separate account assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	252,515	218,813
Level 3 | Fair Value, Measurements, Recurring | External | Corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	55,685	61,089
Level 3 | Fair Value, Measurements, Recurring | External | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	$ 171,979	$ 99,953