Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		$ 192		$ 192
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		0
Included in other comprehensive income (loss)		0		0
Net investment income		0		0
Purchases		0		0
Sales		(192)		(192)
Issuances		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		0		0
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		0
Fixed Maturities Available-For-Sale | Corporate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 118,322	99,255	$ 116,070	96,796
Included in earnings:
Realized investment gains (losses), net	0	0	62	0
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	(344)	236	(563)	483
Net investment income	1,309	1,249	2,586	2,473
Purchases	15,337	1,751	32,607	3,240
Sales	(15,217)	0	(30,429)	0
Issuances	0	0	0	0
Settlements	(197)	(483)	(1,123)	(984)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(1,727)	0	(1,727)	0
Fair Value, end of period	117,483	102,008	117,483	102,008
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	0	0	0	0
Fixed Maturities Available-For-Sale | Asset- Backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	48,838	102,725	40,524	63,789
Included in earnings:
Realized investment gains (losses), net	(1)	0	(1)	0
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	130	122	211	300
Net investment income	(1)	38	11	82
Purchases	7,871	0	7,871	14,933
Sales	(7,884)	0	(7,884)	0
Issuances	0	0	0	0
Settlements	(559)	(25,458)	(1,138)	(29,340)
Transfers into Level 3	985	489	10,768	28,152
Transfers out of Level 3	(5,938)	(3,615)	(6,921)	(3,615)
Fair Value, end of period	43,441	74,301	43,441	74,301
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	0	0	0	0
Fixed Maturities Available-For-Sale | Commercial Mortgage- Backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		45,365		0
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		0
Included in other comprehensive income (loss)		0		(83)
Net investment income		0		0
Purchases		0		45,448
Sales		0		0
Issuances		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		(45,365)		(45,365)
Fair Value, end of period		0		0
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		0
Trading Account Assets | Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period		328		313
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		15
Included in other comprehensive income (loss)		0		0
Net investment income		0		0
Purchases		0		0
Sales		0		0
Issuances		0		0
Settlements		(328)		(328)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, end of period		0		0
Included in earnings:
Realized investment gains (losses), net		0		0
Asset management fees and other income		0		15
Short-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0		0
Included in earnings:
Realized investment gains (losses), net	0		0
Asset management fees and other income	0		0
Included in other comprehensive income (loss)	0		0
Net investment income	0		0
Purchases	300		300
Sales	0		0
Issuances	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Fair Value, end of period	300		300
Included in earnings:
Realized investment gains (losses), net	0		0
Asset management fees and other income	0		0
Cash Equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	225	400	225	0
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	0	0	0	0
Net investment income	0	0	0	0
Purchases	0	0	0	400
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	225	400	225	400
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	0	0	0	0
Other Long- term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	635	520	633	486
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	3	7	5	(2)
Included in other comprehensive income (loss)	0	0	0	0
Net investment income	0	0	7	0
Purchases	0	14	0	57
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	(5)	(7)	(5)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	638	536	638	536
Included in earnings:
Realized investment gains (losses), net	0	0	0	0
Asset management fees and other income	3	0	5	0
Reinsurance Recoverables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	3,300,612	1,344,587	2,996,154	748,005
Included in earnings:
Realized investment gains (losses), net	(1,144,189)	191,020	(897,375)	728,874
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	0	0	0	0
Net investment income	0	0	0	0
Purchases	57,543	58,704	115,187	117,432
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	2,213,966	1,594,311	2,213,966	1,594,311
Included in earnings:
Realized investment gains (losses), net	(846,449)	204,298	(846,449)	749,020
Asset management fees and other income	0	0	0	0
Receivables from parent and affiliates
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	24,015	8,344	22,320	6,347
Included in earnings:
Realized investment gains (losses), net	(1)	0	0	1
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	104	68	(188)	79
Net investment income	0	0	0	0
Purchases	0	19,350	0	19,350
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	1,986	1,985
Transfers out of Level 3	(19,341)	0	(19,341)	0
Fair Value, end of period	4,777	27,762	4,777	27,762
Included in earnings:
Realized investment gains (losses), net	(269,305)	0	0	0
Asset management fees and other income	0	0	0	0
Future Policy Benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(3,430,249)	(1,402,029)	(3,112,411)	(778,226)
Included in earnings:
Realized investment gains (losses), net	1,190,254	(199,363)	932,939	(761,582)
Asset management fees and other income	0	0	0	0
Included in other comprehensive income (loss)	0	0	0	0
Net investment income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	(60,424)	(61,565)	(120,947)	(123,149)
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(2,300,419)	(1,662,957)	(2,300,419)	(1,662,957)
Included in earnings:
Realized investment gains (losses), net	1,160,988	(213,148)	880,403	(782,440)
Asset management fees and other income	$ 0	$ 0	$ 0	$ 0