Accumulated Other Comprehensive Income (Loss) - Changes in AOCI, net of tax (Details) (USD $)	3 Months Ended					9 Months Ended
	Sep. 30, 2014		Jun. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	$ 1,207,035,000				$ 710,760,000	$ 736,657,000		$ 1,520,020,000
OCI before Reclassifications	37,383,000				127,958,000	656,423,000		(691,376,000)
Amounts reclassified from AOCI	(22,547,000)				2,068,000	(114,253,000)		(75,189,000)
Tax benefit (expense)	10,058,000				(78,470,000)	(46,898,000)		8,861,000
Net current period OCI - net of tax	24,894,000				51,556,000	495,272,000		(757,704,000)
Ending balance, net of tax	1,231,929,000				762,316,000	1,231,929,000		762,316,000
Unrealized gains (losses) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	1,301,178,000	[1]			789,451,000	822,432,000	[1]	1,591,210,000
OCI before Reclassifications	51,133,000	[1]			121,955,000	679,732,000	[1]	(667,099,000)
Amounts reclassified from AOCI	(28,795,000)	[1]			(5,516,000)	(125,770,000)	[1]	(102,618,000)
Tax benefit (expense)	7,906,000	[1]			(77,575,000)	(44,972,000)	[1]	6,822,000
Net current period OCI - net of tax	30,244,000	[1]			38,864,000	508,990,000	[1]	(762,895,000)
Ending balance, net of tax	1,331,422,000	[1]	1,301,178,000	[1]	828,315,000	1,331,422,000	[1]	828,315,000
AOCI Other Details [Abstract]
Change in adjustments related to future policy benefit reserves, net of tax	51,286,000		(440,500,000)		(37,503,000)	(423,179,000)		(70,305,000)
Cumulative impact on value of future policy benefit reserve, end of period	467,900,000					467,900,000			44,700,000
OTTI losses recognized in AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(84,258,000)				(101,751,000)	(89,190,000)		(121,371,000)
OCI before Reclassifications	0				0	0		0
Amounts reclassified from AOCI	6,078,000				7,474,000	11,127,000		27,099,000
Tax benefit (expense)	(115,000)				(5,000)	(232,000)		(10,000)
Net current period OCI - net of tax	5,963,000				7,469,000	10,895,000		27,089,000
Ending balance, net of tax	(78,295,000)				(94,282,000)	(78,295,000)		(94,282,000)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	1,060,000				41,763,000	14,541,000		69,399,000
OCI before Reclassifications	(14,168,000)				4,910,000	(23,688,000)		(25,665,000)
Amounts reclassified from AOCI	87,000				0	87,000		0
Tax benefit (expense)	2,267,000				(890,000)	(1,694,000)		2,049,000
Net current period OCI - net of tax	(11,814,000)				4,020,000	(25,295,000)		(23,616,000)
Ending balance, net of tax	(10,754,000)				45,783,000	(10,754,000)		45,783,000
Underfunded pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	(13,278,000)				(20,597,000)	(13,239,000)		(20,892,000)
OCI before Reclassifications	418,000				1,093,000	379,000		1,388,000
Amounts reclassified from AOCI	0				0	0		0
Tax benefit (expense)	0				0	0		0
Net current period OCI - net of tax	418,000				1,093,000	379,000		1,388,000
Ending balance, net of tax	(12,860,000)				(19,504,000)	(12,860,000)		(19,504,000)
Cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, net of tax	2,333,000				1,894,000	2,113,000		1,674,000
OCI before Reclassifications	0				0	0		0
Amounts reclassified from AOCI	83,000				110,000	303,000		330,000
Tax benefit (expense)	0				0	0		0
Net current period OCI - net of tax	83,000				110,000	303,000		330,000
Ending balance, net of tax	$ 2,416,000				$ 2,004,000	$ 2,416,000		$ 2,004,000

[1] Included in these amounts is the impact of Shadow Adjustments. During the year ended December 31, 2013, the initial impact of $44.7 million was recorded. During the nine months ended September 30, 2014, additional net impacts of $423.2 million were recorded, resulting in a total cumulative net impact of shadow adjustments on future policy benefit reserves of $467.9 million at September 30, 2014.