Accumulated Other Comprehensive Income - Changes in AOCI, net of tax (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period		$ 1,484,458	$ 736,657	$ 1,520,020
OCI before reclassifications		(514,094)	916,952	(795,980)
Amounts reclassified from AOCI		(326,979)	(128,094)	(85,692)
Tax benefit (expense)		43,231	(41,057)	98,309
Net current period OCI - net of tax		(797,842)	747,801	(783,363)
Balance, net of tax, end of period		686,616	1,484,458	736,657
Cumulative adjustments recorded to value of future policy benefit reserves, amount		(170,688)	400,456	44,660
Unrealized Gains (Losses) on Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period	[1]	1,590,114	822,432	1,591,210
OCI before reclassifications	[1]	(474,304)	954,326	(742,768)
Amounts reclassified from AOCI	[1]	(346,911)	(143,330)	(119,970)
Tax benefit (expense)	[1]	34,195	(43,314)	93,960
Net current period OCI - net of tax	[1]	(787,020)	767,682	(768,778)
Balance, net of tax, end of period	[1]	803,094	1,590,114	822,432
Cumulative adjustments recorded to value of future policy benefit reserves, amount		(170,700)
Cumulative impact of net unrealized gains (losses) on future policy benefit reserve		274,400	445,100
OTTI Losses Recognized in AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period		(76,047)	(89,190)	(121,371)
OCI before reclassifications		0	0	0
Amounts reclassified from AOCI		18,987	14,082	32,193
Tax benefit (expense)		(442)	(939)	(12)
Net current period OCI - net of tax		18,545	13,143	32,181
Balance, net of tax, end of period		(57,502)	(76,047)	(89,190)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period		(11,188)	14,541	69,399
OCI before reclassifications		(33,690)	(26,497)	(62,934)
Amounts reclassified from AOCI		0	87	206
Tax benefit (expense)		8,375	681	7,870
Net current period OCI - net of tax		(25,315)	(25,729)	(54,858)
Balance, net of tax, end of period		(36,503)	(11,188)	14,541
Underfunded Pension Liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period		(20,789)	(13,239)	(20,892)
OCI before reclassifications		(6,100)	(10,877)	9,722
Amounts reclassified from AOCI		1,145	812	1,440
Tax benefit (expense)		1,103	2,515	(3,509)
Net current period OCI - net of tax		(3,852)	(7,550)	7,653
Balance, net of tax, end of period		(24,641)	(20,789)	(13,239)
Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, net of tax, beginning of period		2,368	2,113	1,674
OCI before reclassifications		0	0	0
Amounts reclassified from AOCI		(200)	255	439
Tax benefit (expense)		0	0	0
Net current period OCI - net of tax		(200)	255	439
Balance, net of tax, end of period		$ 2,168	$ 2,368	$ 2,113

[1] Included in these amounts is the impact of Shadow Adjustments. As of December 31, 2014, $445.1 million was recorded. During the year ended December 31, 2015, additional net impacts of $(170.7) million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $274.4 million at December 31, 2015.