Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Fixed maturity securities, available-for-sale, at fair value	$ 9,618,789	$ 9,638,404
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	193,956,481	182,235,798
Common stock, shares outstanding	193,956,481	182,235,798
Accumulated other comprehensive income, tax provision (in dollars)	$ 159,679	$ 135,344
Deferred equity compensation, shares	320,193	320,193