Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from parent and affiliates	$ 49,087	$ 212,696
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	86,875	225
Other long-term investments	153,328	115,266
Reinsurance recoverables	3,693,262	3,012,653
Receivables from parent and affiliates	35,369	37,340
Total assets	45,023,572	45,103,812
Future policy benefits	3,842,607	3,134,077
Total liabilities	3,842,607	3,134,077
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,036
Short-term investments	450	450
Cash equivalents	375	225
Other long-term investments	0	1,565
Reinsurance recoverables	3,693,262	3,012,653
Receivables from parent and affiliates	2,847	7,664
Total assets	3,902,522	3,196,358
Future policy benefits	3,842,607	3,134,077
Total liabilities	3,842,607	3,134,077
Fair Value, Measurements, Recurring | Level 3 | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	140,833	127,308
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	62,719	46,493
Fair Value, Measurements, Recurring | Level 3 | Internal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,036
Short-term investments	450	450
Cash equivalents	375	225
Other long-term investments		1,565
Reinsurance recoverables	3,693,262	3,012,653
Receivables from parent and affiliates	0	0
Total assets	3,820,941	3,126,188
Future policy benefits	3,842,607	3,134,077
Total liabilities	3,842,607	3,134,077
Fair Value, Measurements, Recurring | Level 3 | Internal | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	124,818	111,295
Fair Value, Measurements, Recurring | Level 3 | Internal | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Fair Value, Measurements, Recurring | Level 3 | External
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0
Short-term investments	0	0
Cash equivalents	0	0
Other long-term investments		0
Reinsurance recoverables	0	0
Receivables from parent and affiliates	2,847	7,664
Total assets	81,581	70,170
Future policy benefits	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 3 | External | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	16,015	16,013
Fair Value, Measurements, Recurring | Level 3 | External | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	$ 62,719	$ 46,493