Accumulated Other Comprehensive Income (Loss) - Details About AOCI Components (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		$ (51,147)	$ (114,842)
Provision (benefit) for income tax		(13,092)	(22,295)
Unrealized gains (losses) on investments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	[1]	(52,554)	(117,114)
OTTI losses recognized in AOCI
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		1,455	2,311
Cash flow hedge
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(48)	(39)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(51,147)	(114,842)
Provision (benefit) for income tax		(487)	1,533
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(51,634)	(113,309)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized gains (losses) on investments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold		(47,020)	(116,988)
OTTI on investments transferred to (from) OCI		6,874	21,928
Reclassification adjustment for investments transferred to equity method		0	0
Total before tax		(52,554)	(117,114)
Provision (benefit) for income tax		(474)	1,577
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(53,028)	(115,537)
Reclassification out of Accumulated Other Comprehensive Income [Member] | OTTI losses recognized in AOCI
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold		1,455	2,313
OTTI on investments transferred to (from) OCI		0	(2)
Total before tax		1,455	2,311
Provision (benefit) for income tax		(13)	(44)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		1,442	2,267
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash flow hedge
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(48)	(39)
Provision (benefit) for income tax		0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(48)	(39)
Life Funds Withheld Assets
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses) on investments sold		34,474	34,416
OTTI on investments transferred to (from) OCI		0	(2,346)
Change in adjustments related to future policy benefit reserves, net of tax		(12,408)	(22,053)
Life Funds Withheld Assets | Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized gains (losses) on investments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Change in adjustments related to future policy benefit reserves, net of tax		$ (12,408)	$ (22,054)

[1] For certain annuity contracts that are subject to the GreyCastle Life Retro Arrangements, policy benefit reserves were historically increased for the impact of changes in unrealized gains on investments supporting such contracts as if the gains had been realized, with a corresponding entry to other comprehensive income ("Shadow Adjustments"). Upon completion of the GreyCastle Life Retro Arrangements, no further Shadow Adjustments were recorded. At December 31, 2016, the cumulative impact of the Shadow Adjustments was $212.1 million. During the three months ended March 31, 2017, net movements of $(5.1) million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $207.0 million at March 31, 2017.