Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Receivables from parent and affiliates	$ 64,722	$ 60,490
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	450
Cash equivalents	225	225
Other long-term investments	599	633
Reinsurance recoverables	3,271,227	2,996,154
Receivables from parent and affiliates	5,755	22,320
Total assets	3,447,232	3,175,926
Future policy benefits	3,400,599	3,112,411
Total liabilities	3,400,599	3,112,411
Level 3 | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	117,521	116,070
Level 3 | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	49,890	40,524
Level 3 | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	1,565
Level 3 | Internal
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	450
Cash equivalents	225	225
Other long-term investments	0	0
Reinsurance recoverables	3,271,227	2,996,154
Receivables from parent and affiliates	0	0
Total assets	3,374,423	3,095,588
Future policy benefits	3,400,599	3,112,411
Total liabilities	3,400,599	3,112,411
Level 3 | Internal | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	102,521	99,209
Level 3 | Internal | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	0	0
Level 3 | Internal | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	0
Level 3 | External
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0
Cash equivalents	0	0
Other long-term investments	599	633
Reinsurance recoverables	0	0
Receivables from parent and affiliates	5,755	22,320
Total assets	72,809	80,338
Future policy benefits	0	0
Total liabilities	0	0
Level 3 | External | All other corporate securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	15,000	16,861
Level 3 | External | Asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	49,890	$ 40,524
Level 3 | External | Commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, fixed maturities	$ 1,565