Fair Value Of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Of Financial Instruments [Abstract]

Fair value hierarchy and related disclosures

							Fair value measurement using:
							Quoted prices in				Significant
							active markets for		Significant other		unobservable
			Carrying				identical assets		observable inputs		inputs
December 31, 2012			amount		Total fair value		(Level 1)		(Level 2)		(Level 3)
Trading securities:
	U.S. Government and Government
		agencies	$	1,865,913	$	1,865,913	$	1,529,158	$	336,755	$	0
	Non-U.S. Government and Government
		agencies		261,627		261,627		0		261,627		0
	States, municipalities and political
		subdivisions		40,444		40,444		0		40,444		0
	Corporate debt			2,089,202		2,089,202		0		2,089,202		0
	Mortgage-backed			1,958,373		1,958,373		0		1,790,548		167,825
	Asset-backed			410,895		410,895		0		348,649		62,246
Total trading fixed maturity investments				6,626,454		6,626,454
Total fixed maturity investments				6,626,454		6,626,454
Equity securities				523,949		523,949		469,269		0		54,680
Other invested assets (1)				655,888		655,888		0		0		655,888
Total investments			$	7,806,291	$	7,806,291	$	1,998,427	$	4,867,225	$	940,639
Derivative assets: (2)
	Foreign exchange contracts		$	1,713	$	1,713	$	0	$	1,713	$	0
	Interest rate futures			0		0		0		0		0
Derivative liabilities: (2)
	Foreign exchange contracts		$	2,656	$	2,656	$	0	$	2,656	$	0
	Interest rate futures			0		0		0		0		0
Senior notes			$	798,215	$	918,627	$	0	$	918,627	$	0

_________

(1)       Excludes assets that the Company did not measure at fair value related to the Company's investments that are accounted for using the equity method of accounting.

(2)       Asset and liability derivatives relating to foreign exchange contracts and interest rate futures are classified within “other assets” or “accounts payable and accrued liabilities” on the consolidated balance sheets.

								Fair value measurement using:
								Quoted prices in				Significant
								active markets for		Significant other		unobservable
				Carrying				identical assets		observable inputs		inputs
December 31, 2011				amount		Total fair value		(Level 1)		(Level 2)		(Level 3)
Available for sale securities:
		U.S. Government and Government
			agencies	$	33,630	$	33,630	$	33,630	$	0	$	0
		States, municipalities and political
			subdivisions		33,479		33,479		0		33,479		0
		Corporate debt			176,907		176,907		0		176,907		0
Total available for sale fixed maturity
	investments				244,016		244,016
Trading securities:
		U.S. Government and Government
			agencies	$	1,278,265	$	1,278,265	$	1,054,003	$	224,262	$	0
		Non-U.S. Government and Government
			agencies		256,756		256,756		0		256,756		0
		States, municipalities and political
			subdivisions		133,902		133,902		0		133,902		0
		Corporate debt			2,254,474		2,254,474		0		2,254,474		0
		Mortgage-backed			1,818,091		1,818,091		0		1,568,887		249,204
		Asset-backed			513,198		513,198		0		418,453		94,745
Total trading fixed maturity investments					6,254,686		6,254,686
Total fixed maturity investments					6,498,702		6,498,702
Equity securities					367,483		367,483		367,483		0		0
Other invested assets					540,409		540,409		0		0		540,409
Total investments				$	7,406,594	$	7,406,594	$	1,455,116	$	5,067,120	$	884,358
Derivative assets: (1)
		Foreign exchange contracts		$	2,030	$	2,030	$	0	$	2,030	$	0
		Interest rate futures			977		977		0		977		0
Derivative liabilities: (1)
		Foreign exchange contracts		$	8,934	$	8,934	$	0	$	8,934	$	0
		Interest rate futures			3,467		3,467		0		3,467		0
Senior notes				$	797,949	$	872,731	$	0	$	872,731	$	0

(1)       Asset and liability derivatives relating to foreign exchange contracts and interest rate futures are classified within “other assets” or “accounts payable and accrued liabilities” on the consolidated balance sheets.

Fair value measurements using significant unobservable inputs (Level 3)

	Fair value measurement using significant
	unobservable inputs (Level 3):
	Other invested assets		Mortgage-backed		Asset-backed		Equities
Year Ended December 31, 2012
Opening balance	$	540,409	$	249,204	$	94,745	$	0
Realized and unrealized gains included in net income		37,109		11,027		1,897		4,680
Purchases		207,509		106,322		26,885		50,000
Sales		(129,139)		(174,664)		(75,774)		0
Transfers into Level 3 from Level 2		0		11,716		22,950		0
Transfers out of Level 3 into Level 2 (1)		0		(35,780)		(8,457)		0
Ending balance	$	655,888	$	167,825	$	62,246	$	54,680
Year Ended December 31, 2011
Opening balance	$	347,632	$	172,559	$	48,707	$	0
Realized and unrealized losses included in net income		(3,620)		(2,131)		(362)		0
Purchases		311,185		101,302		24,056		0
Sales		(114,788)		(44,549)		(3,204)		0
Transfers into Level 3 from Level 2		0		63,717		30,536		0
Transfers out of Level 3 into Level 2 (1)		0		(41,694)		(4,988)		0
Ending balance	$	540,409	$	249,204	$	94,745	$	0

(1) Transfers out of Level 3 are primarily attributable to the availability of market observable information.