Investments (Details - Net Realized and Unrealized Investment Gains) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Net realized and unrealized investment gains (losses)	$ 74,600,000	$ 26,100,000	$ 78,200,000	$ (112,200,000)	$ (83,200,000)	$ 293,200,000	$ 46,000,000	$ 145,500,000	$ 66,692,000	$ 401,482,000	$ 591,707,000
[EquitySecuritiesMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Gain related to Company's equity investment in Paris Re prior to the Acquisition Date											18,300,000
[TradingSecuritiesMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Net realized and unrealized investment gains (losses)									66,692,000	401,482,000	591,707,000
[TradingSecuritiesMember] | [FixedMaturitiesAndShortTermInvestmentsMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Change in net unrealized investment gains (losses)									128,224,000	142,634,000	322,944,000
Net realized gains (losses) on trading securities									157,207,000	173,426,000	105,249,000
[TradingSecuritiesMember] | [OtherInvestedAssetsMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Change in net unrealized investment gains (losses)									(46,278,000)	3,742,000	58,196,000
Net realized gains (losses) on trading securities									(176,295,000)	(68,568,000)	(35,426,000)
[TradingSecuritiesMember] | [EquitySecuritiesMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Change in net unrealized investment gains (losses)									(101,860,000)	64,825,000	185,925,000
Net realized gains (losses) on trading securities									90,866,000	44,736,000	(45,258,000)
[TradingSecuritiesMember] | [OtherInvestmentIncomeMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Other net realized gains									3,617,000	13,335,000	1,777,000
[TradingSecuritiesMember] | [FundsHeldDirectlyManagedInvestmentMember]
Schedule of Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Income Statement, Reported Amounts, Summary [Line Items]
Net realized and unrealized investment gains (losses)									$ 11,211,000	$ 27,352,000	$ (1,700,000)