Investments (Balance of and Changes in AOCI Components) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	$ 178,691
Income tax benefit (expense)	8,005	$ (140,373)	$ (566,420)
Accumulated other comprehensive income (loss), ending balance	64,805	178,691
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	(67)	403	257
Change in other comprehensive income before reclassifications	(507)	(470)	146
Amounts reclassified from AOCI	0
Income tax benefit (expense)	177
Accumulated other comprehensive income (loss), ending balance	(397)	(67)	403
Total net unrealized investment gains (losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	178,758	56,243	267,204
Change in other comprehensive income before reclassifications	(164,799)	122,515	(210,961)
Amounts reclassified from AOCI	(9,902)	(18,649)	(33,920)
Income tax benefit (expense)	61,145
Accumulated other comprehensive income (loss), ending balance	65,202	178,758	56,243
Cash Flow Hedge Gain Loss To AOCI	48,000	12,000	(5,000)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	178,691	56,646	267,461
Change in other comprehensive income before reclassifications	(165,306)	122,045	(210,815)
Amounts reclassified from AOCI	(9,902)	(18,649)	(33,920)
Income tax benefit (expense)	61,322
Accumulated other comprehensive income (loss), ending balance	$ 64,805	$ 178,691	$ 56,646