Investments (Details Textual) (USD $)	6 Months Ended
Jun. 30, 2013 Security	Jun. 30, 2012
Investments (Textual) [Abstract]
Available for sale securities	$ 778,900,000	$ 18,400,000
Net realized gains	42,700,000	50,000
Net unrealized holding losses	0	10,000
Available for sale and trading equity securities Sales Proceeds	11,300,000	0
Number of securities available for sale	203
Number of available for sale securities in unrealized loss position for period of less than twelve	67
Number of available for sale securities in unrealized loss position for period of twelve months or greater	2
Available for sale and trading equity securities Realized Gross Gain	1,100,000	0
Fixed Maturities [Member]
Investments (Textual) [Abstract]
Available-for-sale and trading equity securities Gross realized losses	4,900,000	10,000
Equity Securities [Member]
Investments (Textual) [Abstract]
Available-for-sale and trading equity securities Gross realized losses	$ 0	$ 0

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Number of available for sale securities in unrealized loss position for period of twelve months or greater.

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The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

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