Accumulated Other Comprehensive Income (Loss) - Changes in AOCI, net of tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016		Mar. 31, 2015	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	$ 686,616		$ 1,484,458
OCI before Reclassifications	558,557		287,646
Amounts reclassified from AOCI	(114,842)		(64,750)
Tax benefit (expense)	(35,774)		(2,184)
Comprehensive income (loss)	407,941		220,712
Ending balance, net of tax	1,094,557		1,705,170
Change in adjustments related to future policy benefit reserves, net of tax	(17,035)		(60,356)
Unrealized gains (losses) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	803,094	[1]	1,590,114
OCI before Reclassifications	575,022	[1]	254,267
Amounts reclassified from AOCI	(117,114)	[1]	(74,781)
Tax benefit (expense)	(34,707)	[1]	(5,805)
Comprehensive income (loss)	423,201	[1]	173,681
Ending balance, net of tax	1,226,295	[1]	1,763,795
Cumulative impact of net unrealized gains losses on future policy benefit reserve	257,400			$ 274,400
Change in adjustments related to future policy benefit reserves, net of tax	(17,000)
OTTI losses recognized in AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(57,502)		(76,047)
OCI before Reclassifications	0		0
Amounts reclassified from AOCI	2,311		9,936
Tax benefit (expense)	(44)		(78)
Comprehensive income (loss)	2,267		9,858
Ending balance, net of tax	(55,235)		(66,189)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(36,503)		(11,188)
OCI before Reclassifications	(15,416)		32,404
Amounts reclassified from AOCI	0		0
Tax benefit (expense)	(1,023)		3,699
Comprehensive income (loss)	(16,439)		36,103
Ending balance, net of tax	(52,942)		24,915
Underfunded pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(24,641)		(20,789)
OCI before Reclassifications	(1,049)		975
Amounts reclassified from AOCI	0		0
Tax benefit (expense)	0		0
Comprehensive income (loss)	(1,049)		975
Ending balance, net of tax	(25,690)		(19,814)
Cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	2,168		2,368
OCI before Reclassifications	0		0
Amounts reclassified from AOCI	(39)		95
Tax benefit (expense)	0		0
Comprehensive income (loss)	(39)		95
Ending balance, net of tax	$ 2,129		$ 2,463

[1] . As of December 31, 2015, the cumulative impact of the Shadow Adjustments was $274.4 million. During the three months ended March 31, 2016, net movements of $(17.0) million were recorded, resulting in a total cumulative net impact of Shadow Adjustments on future policy benefit reserves of $257.4 million as of March 31, 2016.