Investments (Tables)

9 Months Ended

Sep. 30, 2011

Investments [Abstract]

Schedule Of Available For Sale Securities

			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses			Fair Value
September 30, 2011
U.S. Government and Government agencies	$	32,971	$	2,327	$	—		$	35,298
States, municipalities and political subdivisions		29,099		4,008		—			33,107
Corporate debt:
Financial institutions		38,368		1,501		(302	)		39,567
Industrials		87,661		6,250		—			93,911
Utilities		75,951		7,132		—			83,083
Total fixed maturity investments, available for sale	$	264,050	$	21,218	$	(302	)	$	284,966
December 31, 2010
U.S. Government and Government agencies	$	85,030	$	6,923	$	—		$	91,953
Non-U.S. Government and Government agencies		138,386		9,539		(2,541	)		145,384
States, municipalities and political subdivisions		107,289		10,901		(13	)		118,177
Corporate debt:
Financial institutions		66,660		6,776		(38	)		73,398
Industrials		310,664		20,548		(2	)		331,210
Utilities		120,515		11,212		—			131,727
Total fixed maturity investments, available for sale	$	828,544	$	65,899	$	(2,594	)	$	891,849

Schedule Of Trading Securities

	September 30, 2011		December 31, 2010
U.S. Government and Government agencies	$	1,067,673	$	1,229,720
Non-U.S. Government and Government agencies		225,782		120,793
States, municipalities and political subdivisions		103,180		127,436
Corporate debt:
Financial institutions		1,292,078		1,261,219
Industrials		827,425		627,524
Utilities		115,214		101,472
Residential mortgage-backed:
Non-agency residential		328,395		371,935
Agency residential		1,374,564		1,195,905
Commercial mortgage-backed:		350,704		184,043
Asset-backed		594,600		549,050
Total fixed maturity investments, trading		6,279,615		5,769,097
Equity securities		424,104		174,976
Other invested assets (1)		552,074		347,632
Total	$	7,255,793	$	6,291,705

(1) Within the Company's financial statements and footnotes "other invested assets" include the Company's investments in both hedge funds and private equity funds.

Schedule Of Contractual Maturity Dates Of Available For Sale Fixed Maturity Investments

	September 30, 2011
	Amortized Cost		Fair Value
Due within one year	$	26,354	$	26,819
Due after one year through five years		198,860		213,579
Due after five years through ten years		35,815		40,787
Due after ten years		3,021		3,781
	$	264,050	$	284,966

Schedule Of Investments And Cash And Cash Equivalents

					Long			Short
	Fair Value as of		Unfunded		Exposure(1)			Exposure(2)			Gross			Net
Fund Type	September 30, 2011		Commitments		(% of funded)			(% of funded)			Exposure(3)			Exposure(4)
Private equity (primary and secondary)	$	78,078	$	162,162		100	%		0	%		100	%		100	%
Mezzanine debt		3,308		111,621		100	%		0	%		100	%		100	%
Distressed		8,744		36,392		100	%		0	%		100	%		100	%
Total private equity		90,130		310,175
Distressed hedge funds		46,767		—		64	%		42	%		106	%		22	%
Equity long/short		175,170		—		78	%		58	%		136	%		20	%
Multi-strategy		157,479		—		88	%		66	%		154	%		22	%
Event driven		82,528		—		93	%		69	%		162	%		24	%
Total	$	552,074	$	310,175

(1)	Long exposure represents the ratio of the fund's long investments in securities to the fund's equity capital (over 100% may denote explicit borrowing). Two of the Company's hedge funds, one event driven fund and one multi-strategy fund had long exposure greater than 100% of the funds' net asset value (indicating explicit leverage) of 140% and 110%, respectively, as of September 30, 2011.
(2)	Short exposure represents the ratio of the securities sold short to the fund's equity capital.
(3)	Gross exposure is the addition of the long and short exposures (over 100% may denote explicit borrowing).
(4)	Net exposure is the subtraction of the short exposure from the long exposure.

Schedule Of Net Investment Income

	For the Three Months Ended						For the Nine Months Ended
	September 30,						September 30,
	2011			2010			2011			2010
Fixed maturity investments	$	47,877		$	55,165		$	149,471		$	193,815
Equity securities and other invested assets		3,397			6,438			10,608			7,684
Cash and cash equivalents		166			183			611			346
Expenses		(3,557	)		(2,307	)		(10,231	)		(7,870	)
Net investment income	$	47,883		$	59,479		$	150,459		$	193,975

Schedule Of Realized Gains And Losses

	For the Three Months Ended						For the Nine Months Ended
	September 30,						September 30,
	2011			2010			2011			2010
Gross realized gains on sale of securities	$	44,674		$	33,222		$	122,842		$	163,461
Gross realized losses on sale of securities		(10,634	)		(2,533	)		(35,896	)		(15,663	)
Treasury yield hedge		—			—			—			(3,958	)
Futures not designated as hedges		(27,060	)		—			(47,470	)		—
Foreign exchange forwards not designated as hedges		1,442			—			882			—
Mark-to-market changes: debt securities trading		(46,078	)		73,563			(742	)		134,040
Mark-to-market changes: foreign exchange forwards and futures not designated as hedges		(17,667	)		—			(12,233	)		—
Mark-to-market changes: hedge funds and equity securities		(75,486	)		10,818			(48,938	)	$	9,610
Gain on sale of Program Administrator		—			1,860			—			1,860
Net realized investment (losses) gains	$	(130,809	)	$	116,930		$	(21,555	)	$	289,350
Proceeds from sale of available for sale securities	$	60,043		$	208,473		$	606,234		$	2,054,547
Proceeds from sale of trading securities	$	1,321,722		$	2,517,784		$	4,740,270		$	7,815,137

Schedule Of Company's Trust Accounts On Deposit, Outstanding And Remaining Letter Of Credit Facilities, Collateral Committed To Support The Letter Of Credit Facilities

	As of		As of
	September 30,		December 31,
	2011		2010
Total trust accounts on deposit	$	1,641,805	$	1,657,441
Total letter of credit facilities:
Citibank Europe plc		900,000		900,000
Credit Facility		800,000		800,000
Total letter of credit facilities		1,700,000		1,700,000
Total letter of credit facilities outstanding:
Citibank Europe plc		752,412		689,851
Credit Facility		161,677		158,983
Total letter of credit facilities outstanding		914,089		848,834
Total letter of credit facilities remaining:
Citibank Europe plc		147,588		210,149
Credit Facility (1)		638,323		641,017
Total letter of credit facilities remaining		785,911		851,166
Collateral committed to support the letter of credit facilities	$	1,062,380	$	1,121,345

(1) Net of any borrowing or repayments under the Unsecured Facility (as defined in Note 8). See Note 8 for further details on the Unsecured Facility.

Summarizes The Market Value Of Those Investments In An Unrealized Loss Position For Periods Less Than And Greater Than 12 Months

	September 30, 2011					December 31, 2010
	Gross Fair		Unrealized			Gross Fair		Unrealized
	Value		Loss			Value		Loss
Less than 12 months
Non-U.S. Government and Government agencies	$	—	$	—		$	34,204	$	(1,116	)
States, municipalities and political subdivisions		—		—			472		(13	)
Corporate debt:		—		—
Financial institutions		9,477		(302	)		2,796		(38	)
Industrials		—		—			2,150		(2	)
	$	9,477	$	(302	)	$	39,622	$	(1,169	)
More than 12 months
Non-U.S. Government and Government agencies	$	—	$	—		$	10,998	$	(1,425	)
	$	—	$	—		$	10,998	$	(1,425	)
	$	9,477	$	(302	)	$	50,620	$	(2,594	)

Schedule Of Amounts Related To Credit Losses On Debt Securities For Which A Portion Of The OTTI Was Recognized In Other Comprehensive Income

	For the Three Months			For the Nine Months
	Ended September 30,			Ended September 30,
	2010			2010
Beginning balance of credit losses	$	1,264		$	1,096
Additions for credit loss for which OTTI was not previously recognized		—			168
Reductions for securities sold during the period (realized)		—			—
Reductions for OTTI previously recognized due to intent to sell		—			—
Additions resulting from the increase in credit losses		—			—
Reductions resulting from the improvement in expected cash flows		—			—
Adoption of ASU 2010-11		(1,264	)		(1,264	)
Ending balance of credit losses	$	—		$	—