Accumulated Other Comprehensive Income (Loss) - Changes in AOCI, net of tax (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Jun. 30, 2013		Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	$ 710,760,000				$ 1,520,020,000
OCI before Reclassifications	127,068,000				(689,326,000)
Amounts reclassified from AOCI	2,068,000				(75,190,000)
Tax (benefit) expense	(77,580,000)				6,812,000
Net current period OCI - net of tax	51,556,000				(757,704,000)
Ending balance, net of tax	762,316,000				762,316,000
Unrealized gains (losses) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	796,073,000	[1]			1,597,832,000
OCI before Reclassifications	121,956,000	[2]			(667,097,000)	[3]
Amounts reclassified from AOCI	(5,516,000)				(102,619,000)
Tax (benefit) expense	(77,575,000)				6,822,000
Net current period OCI - net of tax	38,865,000				(762,894,000)
Ending balance, net of tax	834,938,000		796,073,000	[1]	834,938,000
AOCI Other Details [Abstract]
Cumulative adjustments recorded to the value of future policy benefit reserves	37,400,000		32,900,000		70,300,000
OTTI losses recognized in AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(101,751,000)				(121,371,000)
OCI before Reclassifications	0				0
Amounts reclassified from AOCI	7,474,000				27,099,000
Tax (benefit) expense	(5,000)				(10,000)
Net current period OCI - net of tax	7,469,000				27,089,000
Ending balance, net of tax	(94,282,000)				(94,282,000)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	41,755,000				69,391,000
OCI before Reclassifications	4,020,000				(23,616,000)
Amounts reclassified from AOCI	0				0
Tax (benefit) expense	0				0
Net current period OCI - net of tax	4,020,000				(23,616,000)
Ending balance, net of tax	45,775,000				45,775,000
Underfunded pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(27,211,000)				(27,506,000)
OCI before Reclassifications	1,092,000				1,387,000
Amounts reclassified from AOCI	0				0
Tax (benefit) expense	0				0
Net current period OCI - net of tax	1,092,000				1,387,000
Ending balance, net of tax	(26,119,000)				(26,119,000)
Cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	1,894,000				1,674,000
OCI before Reclassifications	0				0
Amounts reclassified from AOCI	110,000				330,000
Tax (benefit) expense	0				0
Net current period OCI - net of tax	110,000				330,000
Ending balance, net of tax	$ 2,004,000				$ 2,004,000

[1] Amounts include adjustments recorded to the value of future policy benefit reserves of $32.9 million. These amounts were recorded during the three months ended June 30, 2013.

[2] Amounts include adjustments recorded to the value of future policy benefit reserves of $37.4 million. These amounts were recorded during the three months ended September 30, 2013.

[3] Amounts include cumulative adjustments recorded to the value of future policy benefit reserves of $70.3 million. These amounts were recorded during the nine months ended September 30, 2013.