Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities [Abstract]
Net (loss) income	$ (451,468)	$ 302,150	$ (1,805,867)
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Net (gains) losses on investments and other financial instruments, change in fair value of derivatives and net impairment losses recognized in earnings	41,409	(1,022,699)	630,539
Net payments related to derivative contracts and VIE debt	(8,213)	(119,888)	(291,936)
Equity in net income of affiliates	13	(65)	(14,668)
Distributions from affiliates	92	0	29,498
Gain on sale of affiliate	(7,708)	0	(34,815)
Net cash (paid) received for commutations, terminations and recaptures	(240,110)	(92,599)	85,657
Impact of Commutation for Reconciling Net Income (Loss) to Net Cash Used in Operating Activities	36,500	0	0
Deferred income tax provision	6,000	6,758	381,408
Depreciation, Amortization and Accretion, Net	72,389	63,120	39,789
Change in:
Unearned premiums	82,910	(46,665)	(136,291)
Deferred policy acquisition costs	25,504	8,420	11,949
Reinsurance recoverables	66,385	86,047	58,266
Reserve for losses and LAE	(161,114)	(194,486)	252,908
Reserve for premium deficiency	41	(7,092)	(14,621)
Other Assets	7,706	65,388	(34,405)
Accounts payable and accrued expenses	19,164	53,836	(20,014)
Net cash (used in) provided by operating activities	(510,500)	(897,775)	(862,603)
Cash flows from investing activities:
Proceeds from sales of fixed-maturity investments available for sale	79,534	136,217	1,218,460
Proceeds from sales of equity securities available for sale	31,235	52,014	15,033
Proceeds from sales of trading securities (See Note 2)	6,004,371	6,028,267	4,735,215
Proceeds from redemptions of fixed-maturity investments available for sale	5,909	32,214	50,846
Proceeds from redemptions of fixed-maturity investments held to maturity	2,076	8,775	9,035
Purchases of trading securities	(5,895,099)	(5,456,565)	(6,126,303)
Sales and redemptions of short-term investments, net	484,347	276,082	(86,071)
Purchases of other invested assets, net	(65,090)	(1,373)	(33,501)
Proceeds from the sale of investment in affiliate	14,700	0	172,017
Purchases of property and equipment, net	(910)	(2,976)	(2,516)
Net cash provided by (used in) investing activities	661,073	1,072,655	(47,785)
Cash flows from financing activities:
Dividends paid	(1,335)	(1,330)	(1,202)
Issuance of long-term debt	0	0	391,310
Redemption of long-term debt	(153,261)	(160,000)	(29,348)
Issuance of common stock	0	0	525,887
Excess tax benefits from stock based awards	0	4	0
Net cash (used in) provided by financing activities	(154,596)	(161,326)	886,647
Effect of exchange rate changes on cash	(11)	1,701	2,501
Increase (decrease) in cash	(4,034)	15,255	(21,240)
Cash, beginning of period	35,589	20,334	41,574
Cash, end of period	31,555	35,589	20,334
Supplemental disclosures of cash flow information:
Income taxes paid (received)	2,079	1,573	(386)
Interest paid	$ 38,378	$ 48,643	$ 40,786