CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011		Dec. 31, 2010
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Change in net unrealized gains (losses) on investments, income tax	$ 392,372	$ 400,626	[1]	$ 328,597	[1]
Reclassification adjustment for investment amounts included in net income, income tax	(3,317)	(14,646)	[1]	(5,951)	[1]
Change in net unrealized gains (losses) relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax	16,227	(13,195)	[1]	11,515	[1]
Change in accumulated gain - derivatives, income tax	2,609	2,382	[1]	4,441	[1]
Reclassification adjustment for derivative amounts included in net income, income tax	$ (381)	$ (138)	[1]	$ (614)	[1]

[1] Recast from previously reported information