Endurance Specialty (ENH) 10-Q 7 Nov 13 2013 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013
Document and Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Entity Registrant Name	'Endurance Specialty Holdings Ltd.	'
Entity Central Index Key	'0001179755	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	44,335,250

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS	'	'
Fixed maturity investments, available for sale at fair value (amortized cost: $4,759,092 and $4,728,596 at September 30, 2013 and December 31, 2012, respectively)	$4,800,838	$4,868,150
Short-term investments, available for sale at fair value (amortized cost: $11,600 and $42,224 at September 30, 2013 and December 31, 2012, respectively)	11,599	42,230
Equity securities, available for sale at fair value (cost: $246,288 and $76,997 at September 30, 2013 and December 31, 2012, respectively)	262,866	86,997
Other investments	594,156	517,546
Total investments	5,669,459	5,514,923
Cash and cash equivalents	789,999	1,124,019
Premiums receivable, net	1,006,227	601,952
Insurance and reinsurance balances receivable	123,777	105,663
Deferred acquisition costs	197,048	168,252
Prepaid reinsurance premiums	263,499	166,702
Reinsurance recoverables on unpaid losses	513,080	691,783
Reinsurance recoverable on paid losses	428,300	83,159
Accrued investment income	21,783	27,166
Goodwill and intangible assets	167,000	172,000
Deferred tax asset	50,148	43,501
Net receivable on sales of investments	124,236	9,144
Other assets	192,104	86,708
Total assets	9,546,660	8,794,972
LIABILITIES	'	'
Reserve for losses and loss expenses	4,052,102	4,240,876
Reserve for unearned premiums	1,314,687	965,244
Deposit liabilities	17,577	22,220
Reinsurance balances payable	347,048	110,843
Debt	527,506	527,339
Net payable on purchases of investments	224,473	81,469
Other liabilities	224,257	136,384
Total liabilities	6,707,650	6,084,375
Commitments and contingent liabilities	'	'
SHAREHOLDERS' EQUITY	'	'
Preferred shares Series A and B, total liquidation preference $430,000 (2012 - $430,000)	17,200	17,200
Common shares Ordinary - 44,249,622 issued and outstanding (2012 - 43,116,394)	44,250	43,116
Additional paid-in capital	560,204	527,915
Accumulated other comprehensive income	69,457	152,463
Retained earnings	2,147,899	1,969,903
Total shareholders' equity	2,839,010	2,710,597
Total liabilities and shareholders' equity	$9,546,660	$8,794,972

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Available for Sale Securities	'	'
Available for sale securities, fixed maturity investments, amortized cost	$4,759,092	$4,728,596
Available for sale, short-term investments, amortized cost	11,600	42,224
Available for sale, equity Securities, cost	246,288	76,997
Shareholders' Equity	'	'
Preferred stock, aggregate liquidation preference	$430,000	$430,000
Common stock, shares issued	44,249,622	43,116,394
Common stock, shares outstanding	44,249,622	43,116,394

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Income And Comprehensive (Loss) Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Gross premiums written	$544,363	$621,255	$2,294,435	$2,286,980
Ceded premiums written	-149,030	-107,175	-525,566	-445,431
Net premiums written	395,333	514,080	1,768,869	1,841,549
Change in unearned premiums	158,212	37,792	-251,872	-358,702
Net premiums earned	553,545	551,872	1,516,997	1,482,847
Net investment income	38,097	45,882	119,870	134,723
Net realized and unrealized investment (losses) gains	-6,640	10,097	9,967	30,258
Total other-than-temporary impairment losses	-190	-126	-1,575	-274
Portion of loss recognized in other comprehensive income (loss)	0	-5	0	-483
Net impairment losses recognized in earnings	-190	-131	-1,575	-757
Other underwriting (loss) income	-943	-1,347	694	-1,663
Total revenues	583,869	606,373	1,645,953	1,645,408
Expenses	'	'	'	'
Net losses and loss expenses	339,036	407,523	917,064	1,016,187
Acquisition expenses	78,775	88,782	222,279	229,399
General and administrative expenses	67,470	52,715	215,307	181,365
Amortization of intangibles	1,652	2,434	5,378	7,988
Net foreign exchange losses (gains)	2,201	3,774	8,496	-14,699
Interest expense	9,048	9,041	27,138	27,132
Total expenses	498,182	564,269	1,395,662	1,447,372
Income before income taxes	85,687	42,104	250,291	198,036
Income tax expense	-2,271	-1,986	-5,557	-2,893
Net income	83,416	40,118	244,734	195,143
Preferred dividends	-8,188	-8,188	-24,564	-24,564
Net income available to common and participating common shareholders	75,228	31,930	220,170	170,579
Comprehensive income	'	'	'	'
Net income	83,416	40,118	244,734	195,143
Other comprehensive income (loss)	'	'	'	'
Net unrealized holding gains (losses) on investments arising during the period (net of other-than-temporary impairment losses recognized in other comprehensive income (loss), reclassification adjustment and applicable deferred income taxes of $8,582 and ($1,576) for the nine months ended September 30, 2013 and 2012, respectively)	29,079	38,290	-82,016	60,706
Foreign currency translation adjustments	8,918	4,675	-1,057	2,075
Reclassification adjustment for net losses on derivative designated as cash flow hedge included in net income	22	22	67	66
Other comprehensive income (loss)	38,019	42,987	-83,006	62,847
Comprehensive income	$121,435	$83,105	$161,728	$257,990
Per share data	'	'	'	'
Basic earnings per common share	$1.70	$0.74	$5.04	$3.94
Diluted earnings per common share	$1.70	$0.74	$5.04	$3.94
Dividend per common share	$0.32	$0.31	$0.96	$0.93

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements Of Income And Comprehensive Income (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Condensed Consolidated Statements Of Income And Comprehensive Income	'	'
Other comprehensive income (loss), net unrealized holding gains (losses) on investments arising during the period, tax	$8,582	($1,576)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements Of Changes In Shareholders' Equity (USD $)	Total	Preferred Shares [Member]	Common Shares [Member]	Additional Paid-In Capital [Member]	Cumulative Foreign Currency Translation Adjustments [Member]	Unrealized Holding Gains On Investments, Net Of Deferred Taxes [Member]	Accumulated Derivative Loss On Cash Flow Hedging Instruments [Member]	Total Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
In Thousands
Balance, beginning of period at Dec. 31, 2011	'	$17,200	$43,087	$526,910	$9,609	$122,815	($2,032)	'	$1,893,576
Net income	195,143	'	'	'	'	'	'	'	195,143
Issuance of common shares net of forfeitures	'	'	207	1,182	'	'	'	'	'
Repurchase of common shares and share equivalents	'	'	0	0	'	'	'	'	'
Settlement of equity awards	-3,234	'	'	-3,234	'	'	'	'	'
Stock-based compensation expense	'	'	'	8,426	'	'	'	'	'
Foreign currency translation adjustments	2,075	'	'	'	2,075	'	'	'	'
Net unrealized holding (losses) gains arising during the period, net of other-than-temporary impairment losses and reclassification adjustment	60,706	'	'	'	'	60,706	'	'	'
Net change from current period hedging transactions, net of reclassification adjustment	'	'	'	'	'	'	66	'	'
Dividends on preferred shares	-24,564	'	'	'	'	'	'	'	-24,564
Dividends on common shares	'	'	'	'	'	'	'	'	-40,298
Balance, end of period at Sep. 30, 2012	2,810,874	17,200	43,294	533,284	11,684	183,521	-1,966	193,239	2,023,857
Balance, beginning of period at Dec. 31, 2012	2,710,597	17,200	43,116	527,915	12,676	141,731	-1,944	'	1,969,903
Net income	244,734	'	'	'	'	'	'	'	244,734
Issuance of common shares net of forfeitures	'	'	1,452	29,961	'	'	'	'	'
Repurchase of common shares and share equivalents	'	'	-318	-14,266	'	'	'	'	'
Settlement of equity awards	-2,975	'	'	-2,975	'	'	'	'	'
Stock-based compensation expense	'	'	'	19,569	'	'	'	'	'
Foreign currency translation adjustments	-1,057	'	'	'	-1,057	'	'	'	'
Net unrealized holding (losses) gains arising during the period, net of other-than-temporary impairment losses and reclassification adjustment	-82,016	'	'	'	'	-82,016	'	'	'
Net change from current period hedging transactions, net of reclassification adjustment	'	'	'	'	'	'	67	'	'
Dividends on preferred shares	-24,564	'	'	'	'	'	'	'	-24,564
Dividends on common shares	'	'	'	'	'	'	'	'	-42,174
Balance, end of period at Sep. 30, 2013	$2,839,010	$17,200	$44,250	$560,204	$11,619	$59,715	($1,877)	$69,457	$2,147,899

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements Of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows (used in) provided by operating activities	'	'
Net income	$244,734	$195,143
Adjustments to reconcile net income to net cash (used in) provided by operating activities:	'	'
Amortization of net premium on investments	39,933	16,512
Amortization of other intangibles and depreciation	15,131	17,609
Net realized and unrealized investment gains	-9,967	-30,258
Net impairment losses recognized in earnings	1,575	757
Deferred taxes	1,935	-6,151
Stock-based compensation expense	19,569	8,426
Equity in earnings of other investments	-43,083	-38,101
Premiums receivable, net	-404,275	-592,113
Insurance and reinsurance balances receivable	-18,114	-20,216
Deferred acquisition costs	-28,796	-49,762
Prepaid reinsurance premiums	-96,797	-79,184
Reinsurance recoverable on unpaid losses	178,703	-403,954
Reinsurance recoverable on paid losses	-345,141	-5,765
Accrued investment income	5,383	5,771
Other assets	-6,875	-2,668
Reserve for losses and loss expenses	-188,774	685,218
Reserve for unearned premiums	349,443	438,383
Deposit liabilities	-4,643	-3,330
Reinsurance balances payable	236,205	67,186
Other liabilities	37,280	7,946
Net cash (used in) provided by operating activities	-16,574	211,449
Cash flows used in investing activities:	'	'
Proceeds from sales of available for sale investments	2,382,068	2,460,861
Proceeds from maturities and calls on available for sale investments	542,059	654,976
Proceeds from the redemption of other investments	28,485	78,043
Purchases of available for sale investments	-3,094,718	-3,224,163
Purchases of other investments	-62,012	-86,195
Net settlements of other assets	-38,223	-18,208
Purchases of fixed assets	-10,768	-10,446
Net cash paid for subsidiary acquisition	-378	-1,468
Net cash flows used in investing activities	-253,487	-146,600
Cash flows used in financing activities	'	'
Issuance of common shares net of forfeitures	31,289	1,262
Repurchase of common shares	-14,584	0
Settlement of equity awards	-2,975	-3,234
Proceeds from issuance of debt	640	812
Repayments and repurchases of debt	-624	-1,806
Dividends on preferred shares	-24,564	-24,564
Dividends on common shares	-42,174	-40,298
Net cash flows used in financing activities	-52,992	-67,828
Effect of exchange rate changes on cash and cash equivalents	-10,967	7,841
Net (decrease) increase in cash and cash equivalents	-334,020	4,862
Cash and cash equivalents, beginning of period	1,124,019	890,914
Cash and cash equivalents, end of period	$789,999	$895,776

General

General	9 Months Ended
	Sep. 30, 2013
General	'
General	'
	1.       General
	Endurance Specialty Holdings Ltd. (“Endurance Holdings” or the “Company”) was organized as a Bermuda holding company on June 27, 2002. Endurance Holdings writes specialty lines of insurance and reinsurance on a global basis through its wholly-owned operating subsidiaries:
		Operating Subsidiaries	Domicile
		Endurance Specialty Insurance Ltd.	Bermuda
		Endurance Worldwide Insurance Limited	England
		Endurance Reinsurance Corporation of America	Delaware
		Endurance American Insurance Company	Delaware
		Endurance American Specialty Insurance Company	Delaware
		Endurance Risk Solutions Assurance Co.	Delaware
		American Agri-Business Insurance Company	Texas

Summary_Of_Significant_Account

Summary Of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Summary Of Significant Accounting Policies	'
Summary Of Significant Accounting Policies	'
	The accompanying unaudited condensed consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for the year ending December 31, 2013. The unaudited condensed consolidated financial statements include the accounts of Endurance Holdings and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Management is required to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying disclosures. Actual results could differ from those estimates. Among other matters, significant estimates and assumptions are used to record premiums written and ceded, to record the fair value of investments and to record reserves for losses and loss expenses and contingencies. Estimates and assumptions are periodically reviewed and the effects of revisions are recorded in the consolidated financial statements in the period that they are determined to be necessary.
	The balance sheet at December 31, 2012 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. These unaudited condensed consolidated financial statements and notes thereto should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2012 contained in Endurance Holdings' Annual Report on Form 10-K for the fiscal year ended December 31, 2012 (the “2012 Form 10-K”).
	Certain comparative information has been reclassified to conform to current year presentation.
	There were no material changes in the Company's significant accounting and reporting policies subsequent to the 2012 Form 10-K.
	In December 2011, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2011-11 “Disclosures About Offsetting Assets and Liabilities” (“ASU 2011-11”). ASU 2011-11 requires additional disclosures about financial instruments and derivative instruments relating to netting arrangements.
	ASU 2011-11 was effective for interim and annual periods beginning on or after January 1, 2013, with retrospective presentation required. The Company adopted this standard effective January 1, 2013. This standard did not have a material impact on the Company's consolidated financial statements.
	In February 2013, the FASB issued ASU 2013-02 “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-02”). ASU 2013-02 requires entities to report, in one location, information about reclassifications out of accumulated other comprehensive income (“AOCI”). ASU 2013-02 also requires companies to report changes in AOCI balances. For significant items reclassified out of AOCI into net income in their entirety in the same reporting period, reporting (either on the face of the statement where net income is presented or in the notes to the financial statements) is required about the effect of the reclassifications on the respective line items in the statement where net income is presented. For items that are not reclassified into net income in their entirety in the same reporting period, a cross reference to other disclosures currently required under US GAAP is required in the notes. The above information must be presented in one place (parenthetically on the face of the financial statements by income statement line item or in a note to the financial statements).
	ASU 2013-02 was effective for fiscal years and interim periods beginning after December 15, 2012. The Company adopted this standard prospectively on January 1, 2013. This standard resulted in an additional note to the consolidated financial statements (see Note 6).
	In July 2013, the FASB issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” (“ASU 2013-11”). ASU 2013-11 provides guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist.
	ASU 2013-11 will be effective for annual and interim reporting periods beginning after December 15, 2013, with both early adoption and retrospective application permitted. The Company does not expect this standard to have a material impact on the Company's consolidated financial statements.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments	'
Investments	'
	3.       Investments
	Composition of Net Investment Income and of Invested Assets
	The components of net investment income for the three and nine months ended September 30, 2013 and 2012 are as follows:
				Three Months Ended September 30,						Nine Months Ended September 30,
					2013			2012			2013			2012
			Available for sale investments	$	27,889		$	33,946		$	86,036		$	105,606
			Other investments		13,244			15,050			43,083			38,101
			Cash and cash equivalents		752			289			2,043			978
				$	41,885		$	49,285		$	131,162		$	144,685
			Investment expenses		-3,788			-3,403			-11,292			-9,962
			Net investment income	$	38,097		$	45,882		$	119,870		$	134,723
	The following table summarizes the composition of the investment portfolio by investment type at September 30, 2013 and December 31, 2012:
					30-Sep-13						31-Dec-12
			Type of Investment		Fair Value		Percentage				Fair Value		Percentage
			Fixed maturity investments	$	4,800,838		75.6	%		$	4,868,150		74.2	%
			Cash and cash equivalents(1)		689,762		10.8	%			1,051,694		16	%
			Other investments(2)		594,156		9.3	%			517,546		7.9	%
			Short-term investments		11,599		0.2	%			42,230		0.6	%
			Equity securities		262,866		4.1	%			86,997		1.3	%
			Total	$	6,359,221		100	%		$	6,566,617		100	%
			(1) Includes net receivable on sales of investments and net payable on purchases of investments.
			(2) Consists of investments in alternative funds and specialty funds.
	The following table summarizes the composition by investment rating of the fixed maturity and short-term investments at September 30, 2013 and December 31, 2012. In some cases, where bonds are unrated, the rating of the issuer has been applied.
					30-Sep-13						31-Dec-12
			Ratings(1)		Fair Value		Percentage				Fair Value		Percentage
			U.S. government and agencies securities	$	823,761		17.1	%		$	737,535		15	%
			AAA / Aaa		1,031,149		21.4	%			993,277		20.2	%
			AA / Aa		1,781,679		37	%			1,821,250		37.1	%
			A / A		807,509		16.8	%			993,307		20.2	%
			BBB		296,489		6.2	%			219,017		4.5	%
			Below BBB		67,269		1.4	%			143,198		2.9	%
			Not rated		4,581		0.1	%			2,796		0.1	%
			Total	$	4,812,437		100	%		$	4,910,380		100	%
			(1) The credit rating for each security reflected above was determined based on the rating assigned to the individual security by Standard & Poor's Financial Services LLC ("Standard & Poor's"). If a rating is not supplied by Standard & Poor's, the equivalent rating supplied by either Moody's Investors Service, Inc. ("Moody's") or Fitch Ratings is used.
	3.        Investments, cont'd.
	Contractual maturities of the Company's fixed maturity and short-term investments are shown below as of September 30, 2013 and December 31, 2012. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
				30-Sep-13						31-Dec-12
					Amortized						Amortized
					Cost			Fair Value			Cost			Fair Value
		Due within one year		$	128,110		$	129,417		$	136,283		$	137,567
		Due after one year through five years			1,775,192			1,787,984			1,725,927			1,765,662
		Due after five years through ten years			265,740			266,962			410,755			429,099
		Due after ten years			27,207			27,847			29,654			33,803
		Residential mortgage-backed securities			1,235,668			1,240,222			1,252,468			1,280,579
		Commercial mortgage-backed securities			872,259			889,460			741,178			781,379
		Asset-backed securities			466,516			470,545			474,555			482,291
		Total		$	4,770,692		$	4,812,437		$	4,770,820		$	4,910,380
	In addition to the Company's fixed maturity, short-term and equity investments, the Company invests in (i) hedge funds and private investment funds that generally invest in senior secured bank debt, high yield credit, distressed debt, distressed real estate, derivatives, equity long/short strategies, currencies and commodities (“alternative funds”) and (ii) high yield loan and convertible debt funds (“specialty funds”). The Company's alternative funds and specialty funds are recorded on the Company's balance sheet as “other investments.” At September 30, 2013 and December 31, 2012, the Company had invested, net of capital returned, a total of $438.9 million and $394.5 million, respectively, in other investments. At September 30, 2013 and December 31, 2012, the carrying value of other investments was $594.2 million and $517.5 million, respectively. The following table summarizes the composition and redemption restrictions of other investments as of September 30, 2013 and December 31, 2012:
		30-Sep-13			Market Value			Unfunded Commitments			Ineligible for Redemption over next 12 months
		Alternative funds
			Hedge funds	$	385,913		$	-		$	44,791
			Private investment funds		55,531			60,790			55,531
		Total alternative funds			441,444			60,790			100,322
		Specialty funds
			High yield loan funds		109,171			-			-
			Convertible debt funds		43,541			-			-
		Total specialty funds			152,712			-			-
		Total other investments		$	594,156		$	60,790		$	100,322
		31-Dec-12			Market Value			Unfunded Commitments			Ineligible for Redemption in 2013
		Alternative funds
			Hedge funds	$	337,200		$	-		$	61,161
			Private investment funds		35,219			29,483			35,219
		Total alternative funds			372,419			29,483			96,380
	Specialty funds
		High yield loan funds		105,886			-			-
		Convertible debt funds		39,241			-			-
	Total specialty funds			145,127			-			-
	Total other investments		$	517,546		$	29,483		$	96,380
Hedge funds – The redemption frequency of the hedge funds range from monthly to biennially with notice periods from 30 to 90 days. Over one year, it is estimated that the Company can liquidate approximately 88.2% of the hedge fund portfolio, with the remainder over the following two years.
Private investment funds – The Company generally has no right to redeem its interest in any private investment funds in advance of dissolution of the applicable partnership. Instead, the nature of these investments is that distributions are received by the Company in connection with the liquidation of the underlying assets of the applicable limited partnership. It is estimated that the majority of the underlying assets of the limited partnerships would liquidate over 5 to 10 years from inception of the limited partnership. A secondary market, with unpredictable liquidity, exists for limited partner interests in private equity funds.
High yield loan funds – There are generally no restrictions on the Company's right to redeem its interest in high yield loan funds with the exception of certain redemption frequency and notice requirements. The redemption frequency of these funds ranges from monthly to quarterly with notice periods from 30 to 90 days.
Convertible debt funds – There are generally no restrictions on the Company's right to redeem its interest in convertible debt funds with the exception of certain redemption frequency and notice requirements. The redemption frequency of these funds is monthly with a required notice period of 5 days.
Net Realized and Unrealized Investment (Losses) Gains
Realized and unrealized investment gains and losses are recognized in earnings using the first in, first out method. The analysis of net realized and unrealized investment (losses) gains for the three and nine months ended September 30, 2013 and 2012 is as follows:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
	Gross realized gains on investment sales	$	6,180		$	11,976		$	30,191		$	34,837
	Gross realized losses on investment sales		-13,178			-2,222			-19,924			-5,391
	Change in fair value of derivative financial instruments(1)		358			343			-300			812
	Net realized and unrealized investment (losses) gains	$	-6,640		$	10,097		$	9,967		$	30,258
	(1) For additional information on the Company's derivative financial instruments, see Note 7.
3.       Investments, cont'd.
Unrealized Gains and Losses and Other-than-temporary Impairments
The Company classifies its investments in fixed maturity investments, short-term investments and equities as available for sale. The amortized cost, fair value and related gross unrealized gains and losses and non-credit other-than-temporary impairment (“OTTI”) losses on the Company's securities classified as available for sale at September 30, 2013 and December 31, 2012 are as follows:
						Gross			Gross
			Amortized			Unrealized			Unrealized						Non-Credit
	30-Sep-13		Cost			Gains			Losses			Fair Value			OTTI (2)
	Fixed maturity investments
		U.S. government and agencies securities	$	819,585		$	9,332		$	-5,156		$	823,761		$	-
		U.S. state and municipal securities		27,731			129			-490			27,370			-
		Foreign government securities		175,280			1,725			-1,496			175,509			-
		Government guaranteed corporate securities		34,244			328			-52			34,520			-
		Corporate securities		1,127,809			18,130			-6,488			1,139,451			-
		Residential mortgage-backed securities		1,235,668			20,278			-15,724			1,240,222			-4,785
		Commercial mortgage-backed securities(1)		872,259			26,341			-9,140			889,460			-47
		Asset-backed securities		466,516			5,067			-1,038			470,545			-
	Total fixed maturity investments		$	4,759,092		$	81,330		$	-39,584		$	4,800,838		$	-4,832
	Short-term investments			11,600			-			-1			11,599			-
	Total fixed income investments		$	4,770,692		$	81,330		$	-39,585		$	4,812,437		$	-4,832
	Equity securities
		Equity investments	$	152,328		$	17,197		$	-2,697		$	166,828		$	-
		Emerging market debt funds		60,250			255			-			60,505			-
		Preferred equity investments		10,184			1,883			-64			12,003			-
		Short-term fixed income fund		23,526			4			-			23,530			-
	Total equity securities		$	246,288		$	19,339		$	-2,761		$	262,866		$	-
-1	Balances include amounts related to collateralized debt obligations held with total fair values of $14.1 million.
-2	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At September 30, 2013, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.1 million.
							Gross			Gross
				Amortized			Unrealized			Unrealized						Non-Credit
		31-Dec-12		Cost			Gains			Losses			Fair Value			OTTI (2)
		Fixed maturity investments
			U.S. government and agencies securities	$	718,992		$	18,596		$	-53		$	737,535		$	-
			U.S. state and municipal securities		37,952			1,119			-177			38,894			-
			Foreign government securities		106,218			3,264			-145			109,337			-
			Government guaranteed corporate
			securities		62,782			1,682			-			64,464			-
			Corporate securities		1,334,451			40,555			-1,335			1,373,671			-
			Residential mortgage-backed securities		1,252,468			30,426			-2,315			1,280,579			-5,884
			Commercial mortgage-backed securities(1)		741,178			41,737			-1,536			781,379			-53
			Asset-backed securities		474,555			8,435			-699			482,291			-
		Total fixed maturity investments		$	4,728,596		$	145,814		$	-6,260		$	4,868,150		$	-5,937
		Short-term investments			42,224			6			-			42,230			-
		Total fixed income investments		$	4,770,820		$	145,820		$	-6,260		$	4,910,380		$	-5,937
		Equity securities
			Equity investments	$	59,736		$	7,194		$	-620		$	66,310		$	-
			Emerging market debt funds		10,000			576			-			10,576			-
			Preferred equity investments		7,261			2,851			-1			10,111			-
		Total equity securities		$	76,997		$	10,621		$	-621		$	86,997		$	-
-1	Balances include amounts related to collateralized debt obligations held with total fair values of $8.5 million.
-2	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At December 31, 2012, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.4 million.
The following tables summarize, for all available for sale securities in an unrealized loss position at September 30, 2013 and December 31, 2012, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position.
						Less than 12 months						12 months or greater						Total
						Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
	30-Sep-13					Losses(1)			Value			Losses(1)			Value			Losses(1)		Value
	Fixed maturity investments
		U.S. government and agencies
			securities		$	-5,156		$	265,417		$	-		$	-		$	-5,156	$	265,417
		U.S. state and municipal
			securities			-490			19,711			-			-			-490		19,711
		Foreign government securities				-1,495			109,722			-1			4,858			-1,496		114,580
		Government guaranteed
			corporate securities			-52			11,301			-			-			-52		11,301
		Corporate securities				-6,488			422,818			-			-			-6,488		422,818
		Residential mortgage-backed
			securities			-15,641			510,138			-83			1,619			-15,724		511,757
		Commercial mortgage-backed
			securities			-8,822			351,269			-318			4,936			-9,140		356,205
		Asset-backed securities				-853			184,964			-185			4,193			-1,038		189,157
	Total fixed maturity investments				$	-38,997		$	1,875,340		$	-587		$	15,606		$	-39,584	$	1,890,946
	Short-term investments					-1			1,246			-			-			-1		1,246
	Total fixed income investments				$	-38,998		$	1,876,586		$	-587		$	15,606		$	-39,585	$	1,892,192
	Equity securities
		Equity investments			$	-2,697		$	43,925		$	-		$	-		$	-2,697	$	43,925
		Preferred equity investments				-64			5,924			-			-			-64		5,924
	Total equity securities				$	-2,761		$	49,849		$	-		$	-		$	-2,761	$	49,849
-1	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at September 30, 2013.
As of September 30, 2013, 743 available for sale securities were in an unrealized loss position aggregating $42.3 million. Of those, 31 securities with aggregated unrealized losses of $0.6 million at September 30, 2013 had been in a continuous unrealized loss position for twelve months or greater.
3	Investments, cont’d.
						Less than 12 months						12 months or greater						Total
						Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
	31-Dec-12					Losses(1)			Value			Losses(1)			Value			Losses(1)		Value
	Fixed maturity investments
		U.S. government and agencies
			securities		$	-53		$	48,570		$	-		$	-		$	-53	$	48,570
		U.S. state and municipal
			securities			-177			6,905			-			-			-177		6,905
		Foreign government securities				-139			23,157			-6			4,870			-145		28,027
		Corporate securities				-1,305			245,232			-30			1,849			-1,335		247,081
		Residential mortgage-backed
			securities			-1,920			327,473			-395			7,511			-2,315		334,984
		Commercial mortgage-backed
			securities			-474			79,125			-1,062			11,625			-1,536		90,750
		Asset-backed securities				-94			53,471			-605			8,123			-699		61,594
	Total fixed maturity investments				$	-4,162		$	783,933		$	-2,098		$	33,978		$	-6,260	$	817,911
	Equity securities
		Equity investments			$	-580		$	9,183		$	-40		$	387		$	-620	$	9,570
		Preferred equity investments				-1			201			-			-			-1		201
	Total equity securities				$	-581		$	9,384		$	-40		$	387		$	-621	$	9,771
-1	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at December 31, 2012.
As of December 31, 2012, 403 available for sale securities were in an unrealized loss position aggregating $6.9 million. Of those, 55 securities with aggregated unrealized losses of $2.1 million had been in a continuous unrealized loss position for twelve months or greater.
The analysis of OTTI for the three and nine months ended September 30, 2013 and 2012 is as follows:
			Three months ended September 30,						Nine months ended September 30,
			2013			2012			2013			2012
	Total other-than-temporary impairment losses	$	-190		$	-126		$	-1,575		$	-274
	Portion of loss recognized in other
	comprehensive income (loss)		-			-5			-			-483
	Net impairment losses recognized in earnings	$	-190		$	-131		$	-1,575		$	-757
Of the $0.2 million (2012: $0.1 million) of OTTI losses recognized by the Company in the third quarter of 2013, the majority was related to expected losses following the Company's decision to sell a corporate security. At September 30, 2013, the Company did not have the intent to sell any of the remaining fixed maturity investments in an unrealized loss position and determined that it was unlikely that the Company would be required to sell securities in an unrealized loss position.
3.       Investments, cont'd.
The unrealized losses on the Company's available for sale securities at September 30, 2013 were primarily due to an increase in interest rates and widening of credit spreads, rather than any actual credit losses on these securities. Because the Company has the ability and intent to hold its equity securities until recovery, the Company currently believes it is probable that it will collect all amounts due according to their respective contractual terms. Therefore, the Company does not consider these securities to be other-than-temporarily impaired at September 30, 2013.
The following table provides a roll-forward of the amount related to credit losses for the Company's available for sale investments recognized in earnings for which a portion of an OTTI loss was recognized in accumulated other comprehensive income for the three and nine months ended September 30, 2013:
			Three months ended September 30,						Nine months ended September 30,
			2013			2012			2013			2012
	Beginning balance		$	-1,769		$	-2,268		$	-2,000		$	-2,225
	Addition for the amount related to the credit loss for
		which an other-than-temporary impairment was
		not previously recognized		-			-			-			-3
	Addition for the amount related to the credit loss for
		which an other-than-temporary impairment was
		previously recognized		-			-5			-			-503
	Reductions for increases in cash flows expected to be
		collected that are recognized over the remaining life
		of the security		-			-			-			-
	Reductions for securities sold during the period			113			216			344			674
	Ending balance		$	-1,656		$	-2,057		$	-1,656		$	-2,057
Variable Interest Entities
Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristics of a controlling financial interest are referred to as variable interest entities (“VIE”). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis.
The Company is involved in the normal course of business with VIEs primarily as a passive investor in residential and commercial mortgage-backed securities and through its interests in other investments in alternative and specialty funds that are structured as limited partnerships considered to be third party VIEs. The Company determined that it was not the primary beneficiary for any of these investments as of September 30, 2013. The Company believes its exposure to loss with respect to these investments is generally limited to the investment carrying amounts reported in the Company's Condensed Consolidated Balance Sheets and any unfunded investment commitments.

Fair_Value_Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2013
Fair Value Measurement	'
Fair Value Measurement	'
	4.       Fair value measurement
	The Company determines the fair value of the fixed maturity investments, short-term investments, equity securities, other investments, debt, and other assets and liabilities in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. Valuation inputs by security type may include the following:
	Government and agencies fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical models which may incorporate option adjusted spreads, daily interest rate data and market/sector news. The Company generally classifies the fair values of government and agencies securities in Level 2. Current issue U.S. government securities are generally valued based on Level 1 inputs, which use the market approach valuation technique.
	Government guaranteed corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing service or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical spread models which may incorporate inputs from the U.S treasury curve or LIBOR. The Company generally classifies the fair values of its government guaranteed corporate securities in Level 2.
	Corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers typically use discounted cash flow models that incorporate benchmark curves for treasury, swap and high issuance credits. Credit spreads are developed from current market observations for like or similar securities. The Company generally classifies the fair values of its corporate securities in Level 2.
	Equity securities – These securities are generally priced by pricing services or index providers. Depending on the type of underlying equity security or equity fund, the securities are priced by pricing services or index providers based on quoted market prices in active markets or through a discounted cash flow model that incorporates benchmark curves for treasury, swap and credits for like or similar securities. The Company generally classifies the fair values of its equity securities in Level 1 or 2.
	Other assets and liabilities – These balances include a variety of derivative instruments used to enhance the efficiency of the investment portfolio and economically hedge certain risks. These instruments are generally priced by pricing services, broker/dealers and/or recent trading activity. The market value approach valuation technique is used to estimate the fair value for these derivatives based on significant observable market inputs. Certain derivative instruments are priced by pricing services based on quoted market prices in active markets. These derivative instruments are generally classified in Level 1. Other derivative instruments are priced using industry valuation models and are considered Level 2, as the inputs to the valuation model are based on observable market inputs. Also included in this line item are proprietary, non-exchange traded derivative-based risk management products primarily used to address weather and energy risks. The trading market for these weather derivatives is generally linked to energy and agriculture commodities, weather and other natural phenomena. In instances where market prices are not available, the Company uses industry or internally developed valuation techniques such as spread option, Black Scholes, quanto and simulation modeling to determine fair value and classifies these in Level 3. These models may reference prices for similar instruments.
	Structured securities including agency and non-agency, residential and commercial, mortgage and asset-backed securities – These securities are generally priced by broker/dealers. Broker/dealers may use current market trades for securities with similar qualities. If no such trades are available, inputs such as bid and offer, prepayment speeds, the U.S. treasury curve, swap curve and cash settlement may be used in a discounted cash flow model to determine the fair value of a security. The Company generally classifies the fair values of its structured securities in Level 2.
	Other investments – Other investments, including alternative funds and specialty funds, are generally priced on net asset values (“NAV”) received from the fund managers or administrators. Due to the timing of the delivery of the final NAV by certain of the fund managers, valuations of certain alternative funds and specialty funds are estimated based on the most recently available information, including period end NAVs, period end estimates, or, in some cases, prior month or prior quarter NAVs. As this valuation technique incorporates both observable and significant unobservable inputs, the Company generally classifies the fair value of its other investments in Level 3.
	Debt – Outstanding debt consists of the Company's 6.15% Senior Notes due October 15, 2015 and the 7.0% Senior Notes due July 15, 2034 (the “Senior Notes”). The fair values of these securities were obtained from a third party pricing service and pricing was based on the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of the Senior Notes are classified in Level 2.
	The carrying values of cash and cash equivalents, accrued investment income, net receivable on sales of investments, net payable on purchases of investments and other financial instruments not described above approximated their fair values at September 30, 2013.
	Transfers between levels are assumed to occur at the end of each period.
	The following table sets forth the Company's available for sale investments, other investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at September 30, 2013:
					Fair Value Measurements at September 30, 2013
							Quoted
							Prices in
							Active
							Markets		Significant
							for		Other		Significant
					Total at		Identical		Observable		Unobservable
					September 30,		Assets		Inputs		Inputs
					2013		(Level 1)		(Level 2)		(Level 3)
		Assets
		Fixed maturity investments
			U.S. government and agencies securities	$	823,761	$	17,865	$	805,896	$	-
			U.S. state and municipal securities		27,370		-		27,370		-
			Foreign government securities		175,509		-		175,509		-
			Government guaranteed corporate securities		34,520		-		34,520		-
			Corporate securities		1,139,451		-		1,138,692		759
			Residential mortgage-backed securities		1,240,222		-		1,240,015		207
			Commercial mortgage-backed securities		889,460		-		880,878		8,582
			Asset-backed securities		470,545		-		467,635		2,910
		Total fixed maturity investments		$	4,800,838	$	17,865	$	4,770,515	$	12,458
		Equity securities
			Equity investments		166,828		80,596		86,232		-
			Emerging market debt funds		60,505		-		60,505		-
			Preferred equity investments		12,003		-		12,003		-
			Short-term fixed income fund		23,530		23,530		-		-
		Total equity securities		$	262,866	$	104,126	$	158,740	$	-
		Short-term investments			11,599		-		11,599		-
		Other investments			594,156		-		-		594,156
		Other assets (see Note 7)			122,853		-		120,526		2,327
		Total assets		$	5,792,312	$	121,991	$	5,061,380	$	608,941
		Liabilities
		Other liabilities (see Note 7)		$	74,237	$	-	$	69,405	$	4,832
		Debt			582,296		-		582,296		-
		Total liabilities		$	656,533	$	-	$	651,701	$	4,832
	During the nine months ended September 30, 2013, there were net transfers into Level 3 from Level 2 of $9.8 million, excluding other investments. Transfers into Level 3 consisted of corporate securities, mortgage-backed securities and asset-backed securities for which observable inputs were no longer available in the current period.
	4. Fair value measurement, cont'd.
	The following table sets forth the Company's available for sale investments, other investments, other assets and liabilities and debt categorized by the level within the hierarchy in which the fair value measurements fall at December 31, 2012:
					Fair Value Measurements at December 31, 2012
							Quoted
							Prices in
							Active		Significant
							Markets for		Other		Significant
					Total at		Identical		Observable		Unobservable
					December 31,		Assets		Inputs		Inputs
					2012		(Level 1)		(Level 2)		(Level 3)
		Assets
		Fixed maturity investments
			U.S. government and agencies securities	$	737,535	$	39,889	$	697,646	$	-
			U.S. state and municipal securities		38,894		-		38,894		-
			Foreign government securities		109,337		-		109,337		-
		Government guaranteed corporate securities		64,464		-		64,464		-
		Corporate securities		1,373,671		-		1,373,671		-
		Residential mortgage-backed securities		1,280,579		-		1,280,223		356
		Commercial mortgage-backed securities		781,379		-		777,049		4,330
		Asset-backed securities		482,291		-		478,480		3,811
	Total fixed maturity investments		$	4,868,150	$	39,889	$	4,819,764	$	8,497
	Equity securities
		Equity investments		66,310		66,310		-		-
		Emerging market debt funds		10,576		-		10,576		-
		Preferred equity investments		10,111		-		10,111		-
	Total equity securities		$	86,997	$	66,310	$	20,687	$	-
	Short-term investments			42,230		-		42,230		-
	Other investments			517,546		-		-		517,546
	Other assets (see Note 7)			23,649		-		20,688		2,961
	Total assets		$	5,538,572	$	106,199	$	4,903,369	$	529,004
	Liabilities
	Other liabilities (see Note 7)			10,660		-		7,699		2,961
	Debt			592,677		-		592,677		-
	Total liabilities		$	603,337	$	-	$	600,376	$	2,961
Level 3 assets represented 10.5% and 9.6% of the Company's total available for sale investments, other investments and derivative instruments at September 30, 2013 and December 31, 2012, respectively. There were no material changes in the Company's valuation techniques for the nine months ended September 30, 2013. No impairment losses on Level 3 securities were recognized in earnings for the three and nine months ended September 30, 2013 or 2012.
The following tables present a reconciliation of the beginning and ending balances for all assets and liabilities measured at fair value on a recurring basis using Level 3 inputs during the three and nine months ended September 30, 2013 and 2012, respectively:
			Three Months Ended September 30, 2013
			Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
	Level 3, beginning of period		$	7,546	$	569,393	$	-	$	576,939	$	-
	Total net realized gains included in earnings			56		19,108		-		19,164		-
	Total net realized and unrealized losses included in earnings			-15		-5,864		-		-5,879		-
	Change in unrealized gains included in other comprehensive income (loss)			111		-		-		111		-
	Change in unrealized losses included in other comprehensive income (loss)			-62		-		-		-62		-
	Purchases			-		16,597		-		16,597		-
	Sales			-1,879		-5,078		-		-6,957		-
	Transfers in to Level 3			7,903		-		-		7,903		-
	Transfers out of Level 3			-1,202		-		-		-1,202		-
	Level 3, end of period		$	12,458	$	594,156	$	-	$	606,614	$	-
			Nine Months Ended September 30, 2013
			Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
	Level 3, beginning of period		$	8,497	$	517,546	$	2,961	$	529,004	$	2,961
	Total net realized gains included in earnings			104		61,010		-		61,114		-
	Total net realized and unrealized losses included in earnings			-17		-17,927		-		-17,944		-
	Change in unrealized gains included in other comprehensive income (loss)			438		-		-		438		-
	Change in unrealized losses included in other comprehensive income (loss)			-270		-		-		-270		-
	Purchases			-		62,011		6		62,017		12
	Sales			-6,081		-28,484		-2,967		-37,532		-2,973
	Transfers in to Level 3			11,550		-		-		11,550		-
	Transfers out of Level 3			-1,763		-		-		-1,763		-
	Level 3, end of period		$	12,458	$	594,156	$	-	$	606,614	$	-
			Three Months Ended September 30, 2012
			Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
	Level 3, beginning of period		$	9,819	$	478,860	$	-	$	488,679	$	-
	Total net realized gains included in earnings			44		18,461		-		18,505		-
	Total net realized and unrealized losses included in earnings			-		-3,411		-		-3,411		-
	Change in unrealized gains included in other comprehensive income (loss)			570		-		-		570		-
	Change in unrealized losses included in other comprehensive income (loss)			-14		-		-		-14		-
	Purchases			2		37,319		-		37,321		-
	Sales			-1,536		-52,319		-		-53,855		-
	Transfers in to Level 3			5,695		-		-		5,695		-
	Transfers out of Level 3			-762		-		-		-762		-
	Level 3, end of period		$	13,818	$	478,910	$	-	$	492,728	$	-
			Nine Months Ended September 30, 2012
			Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
	Level 3, beginning of period		$	10,394	$	-	$	-	$	10,394	$	-
	Total net realized gains included in earnings			54		29,286		-		29,340		-
	Total net realized and unrealized losses included in earnings			-13		-14,310		-		-14,323		-
	Change in unrealized gains included in other comprehensive income (loss)			1,732		-		-		1,732		-
	Change in unrealized losses included in other comprehensive income (loss)			-243		-		-		-243		-
	Purchases			-38		84,519		-		84,481		-
	Sales			-2,568		-53,013		-		-55,581		-
	Transfers in to Level 3			7,771		432,428(1)		-		440,199		-
	Transfers out of Level 3			-3,271		-		-		-3,271		-
	Level 3, end of period		$	13,818	$	478,910	$	-	$	492,728	$	-
	-1	As required by ASU 2011-04, the fair value of the Company's other investments was transferred into Level 3 at March 31, 2012.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share	'
Earnings Per Share	'
	5.       Earnings per share
	The two-class method utilized by the Company is an earnings allocation formula that determines earnings per share for the holders of Endurance Holdings' ordinary shares (also referred to as “common shares”) and participating common shares, which includes unvested restricted shares that receive cash dividends, according to dividends declared and participation rights in undistributed earnings. Net income available to common and participating common shareholders is reduced by the amount of dividends declared in the current period and by the contractual amount of dividends that must be paid for the current period related to the Company's common and participating common shares. Any remaining undistributed earnings are allocated to the common and participating common shareholders to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. In periods of loss, no losses are allocated to participating common shareholders. Instead, all such losses are allocated solely to the common shareholders.
	Basic earnings per common share are calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. The weighted average number of common shares excludes any dilutive effect of outstanding options and convertible securities such as unvested restricted shares.
	Diluted earnings per common share are based on the weighted average number of common shares and assumes the exercise of all dilutive stock options and the vesting or conversion of all convertible securities such as unvested restricted shares using the two-class method described above.
	The following table sets forth the computation of basic and diluted earnings per share for the three and nine months ended September 30, 2013 and 2012:
						Three Months Ended						Nine Months Ended
						September 30,						September 30,
						2013			2012			2013			2012
		Numerator:
			Net income available to common and participating
				common shareholders	$	75,228		$	31,930		$	220,170		$	170,579
			Less amount allocated to participating
				common shareholders(1)		-1,997			-494			-4,742			-2,828
			Net income allocated to common shareholders		$	73,231		$	31,436		$	215,428		$	167,751
		Denominator:
			Weighted average shares – basic			43,099,841			42,628,248			42,719,837			42,555,617
			Share equivalents:
				Options		-			28,880			-			36,130
				Restricted share units		298			778			594			2,546
			Weighted average shares – diluted			43,100,139			42,657,906			42,720,431			42,594,293
		Basic earnings per common share			$	1.7		$	0.74		$	5.04		$	3.94
		Diluted earnings per common share			$	1.7		$	0.74		$	5.04		$	3.94
		(1) Represents earnings attributable to holders of unvested restricted shares issued by the Company. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares).
	5.       Earnings per share, cont'd.
	Endurance Holdings declared a dividend of $0.484375 per Series A preferred share and $0.46875 per Series B preferred share on August 8, 2013 (2012 - Series A: $0.484375, Series B: $0.46875). The Series A and Series B preferred share dividends were paid on September 16, 2013 to shareholders of record on August 30, 2013. Endurance Holdings also declared a dividend of $0.32 per common share on August 8, 2013 (2012 - $0.31). The dividend was paid on September 30, 2013 to shareholders of record on September 16, 2013.
				Three Months Ended						Nine Months Ended
				September 30,						September 30,
				2013			2012			2013			2012
		Dividends declared per Series A preferred share		$	0.484375		$	0.484375		$	1.453125		$	1.453125
		Dividends declared per Series B preferred share		$	0.46875		$	0.46875		$	1.40625		$	1.40625
		Dividends declared per common share		$	0.32		$	0.31		$	0.96		$	0.93

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income	'
Accumulated Other Comprehensive Income	'
	6.       Accumulated other comprehensive income
	The following table presents the changes in accumulated other comprehensive income balances by component for the three and nine months ended September 30, 2013:
				For the Three Months Ended September 30, 2013
				Gains and losses on cash flow hedges			Unrealized gains and losses on available-for-sale securities		Foreign currency items		Total
	Beginning balance			$	-1,899		$	30,636	$	2,701	$	31,438
		Other comprehensive income before reclassifications			-			22,358		8,918		31,276
		Amounts reclassified from accumulated other comprehensive income(1)			22			6,721		-		6,743
	Net current period other comprehensive income				22			29,079		8,918		38,019
	Ending balance			$	-1,877		$	59,715	$	11,619	$	69,457
	(1) All amounts are net of tax.
				Nine Months Ended September 30, 2013
				Gains and losses on cash flow hedges			Unrealized gains and losses on available-for-sale securities		Foreign currency items		Total
	Beginning balance			$	-1,944		$	141,731	$	12,676	$	152,463
		Other comprehensive loss before reclassifications			-			-74,001		-1,057		-75,058
		Amounts reclassified from accumulated other comprehensive income(1)			67			-8,015		-		-7,948
	Net current period other comprehensive income (loss)				67			-82,016		-1,057		-83,006
	Ending balance			$	-1,877		$	59,715	$	11,619	$	69,457
	(1) All amounts are net of tax.
	6.       Accumulated other comprehensive income, cont'd.
	The following table presents the significant items reclassified out of accumulated other comprehensive income during the three and nine months ended September 30, 2013:
		Three Months Ended September 30, 2013
		Details about accumulated other comprehensive income components				Amount reclassified from accumulated other comprehensive income		Affected line item in the Unaudited Condensed Consolidated Statements of Income and Comprehensive Income
		Gains and losses on cash flow hedges -
			Debt		$	22		Interest expense
						22		Total before income taxes
						-		Income tax expense
					$	22		Total net of income taxes
		Unrealized losses (gains) on available-for-sale securities			$	6,999		Net realized and unrealized investment losses
						190		Net impairment losses recognized in earnings
						7,189		Total before income taxes
						-468		Income tax benefit
					$	6,721		Total net of income taxes
		Nine Months Ended September 30, 2013
		Details about accumulated other comprehensive income components				Amount reclassified from accumulated other comprehensive income		Affected line item in the Unaudited Condensed Consolidated Statements of Income and Comprehensive Income
		Gains and losses on cash flow hedges -
			Debt		$	67		Interest expense
						67		Total before income taxes
						-		Income tax expense
					$	67		Total net of income taxes
		Unrealized (gains) losses on available-for-sale securities			$	-10,267		Net realized and unrealized investment gains
						1,575		Net impairment losses recognized in earnings
						-8,692		Total before income taxes
						677		Income tax expense
					$	-8,015		Total net of income taxes

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2013
Derivatives	'
Derivatives	'
	7.       Derivatives
	The Company's derivative instruments are recorded in the Condensed Consolidated Balance Sheets at fair value, with changes in fair value and gains and losses recognized in net realized and unrealized investment (losses) gains, net foreign exchange losses (gains) and other underwriting (loss) income in the Condensed Consolidated Statements of Income and Comprehensive Income.
	During 2012, the Company entered into the weather risk management business through its newly formed unit, Endurance Global Weather. Endurance Global Weather regularly transacts in certain derivative-based risk management products primarily to address weather and energy risks. The trading markets for these derivatives are generally linked to energy and agriculture commodities, weather and other natural phenomena. Generally, the Company's current portfolio of such derivative contracts is of short duration and such contracts are predominantly seasonal in nature.
	The Company's derivatives are not designated as hedges under current accounting guidance. The Company invests a portion of its fixed maturity assets with third party investment managers with investment guidelines that permit the use of derivative instruments. The Company may enter derivative transactions directly or as part of strategies employed by its external investment managers. The Company's objectives for holding these derivatives are as follows:
	Interest Rate Futures, Swaps, Swaptions and Options - to manage exposure to interest rate risk, which can include increasing or decreasing its exposure to this risk through modification of the portfolio composition and duration.
	Foreign Exchange Forwards, Futures and Options - as part of overall currency risk management and investment strategies.
	Credit Default Swaps - to manage market exposures. The Company may assume or economically hedge credit risk through credit default swaps to replicate or hedge investment positions. The original term of these credit default swaps is generally five years or less.
	Commodity Futures and Options - to economically hedge certain underwriting risks.
	To-Be-Announced Mortgage-backed Securities (“TBAs”) - to enhance investment performance and as part of overall investment strategy. TBAs represent commitments to purchase or sell a future issuance of agency mortgage-backed securities. For the period between purchase of a TBA and allocation of the underlying securities, the Company's position is accounted for as a derivative.
	Energy and Weather Contracts – to address weather and energy risks. The Company may purchase or sell contracts
	with financial settlements based on the performance of an index linked to a quantifiable weather element, such as
	temperature, precipitation, snowfall or wind speed, and structures with multiple risk triggers indexed to a quantifiable weather element and a weather sensitive commodity price, such as temperature and electrical power or natural gas.
	The fair values and the related notional values of derivatives at September 30, 2013 and December 31, 2012 are noted below.
				30-Sep-13				31-Dec-12
						Notional				Notional
				Fair		Principal		Fair		Principal
				Value		Amount		Value		Amount
		Derivatives recorded in other assets
			Foreign exchange forward contracts	$	74	$	9,539	$	23	$	1,652
			Credit default swaps		-		-		9		410
			Interest rate swaps		1		5,600		76		5,000
			Interest rate swaptions		37		23,900		57		2,200
			Interest rate futures		-		64,217		-		-
			TBAs		120,414		119,000		20,523		19,000
			Energy and weather contracts		2,327		35,627		2,961		15,573
			Total recorded in other assets	$	122,853			$	23,649
		Derivatives recorded in other liabilities
			Foreign exchange forward contracts	$	333	$	15,285	$	60	$	5,296
			Interest rate swaps		764		23,214		-		-
			Interest rate swaptions		134		74,200		133		14,500
			TBAs		68,174		67,000		7,506		7,000
			Energy and weather contracts		4,832		35,627		2,961		15,573
			Total recorded in other liabilities	$	74,237			$	10,660
			Net derivative asset	$	48,616			$	12,989
	On January 1, 2013, the Company adopted new guidance that requires disclosure of financial instruments subject to a master netting agreement. At September 30, 2013, derivative assets of $2.4 million and liabilities of $6.1 million were traded under International Swaps and Derivatives Association Master Agreements (“ISDAs”) which provide for the ability to settle the derivative asset and liability with each counterparty on a net basis. TBAs and interest rate futures are not subject to ISDAs. At September 30, 2013 and December 31, 2012, none of the Company's derivative instruments were netted. See Note 10 for information on collateral pledged.
	7.       Derivatives, cont'd.
	The gains and losses on the Condensed Consolidated Statements of Income and Comprehensive Income for derivatives for the three and nine months ended September 30, 2013 and 2012 were as follows:
				Three Months Ended				Nine Months Ended
				September 30,				September 30,
				2013		2012		2013		2012
		Total (losses) gains included in net foreign exchange losses
			(gains) from foreign exchange forward contracts	$	-123	$	-10	$	207	$	141
			Futures contracts	$	112	$	-	$	64	$	87
			Credit default swaps		-68		3		49		46
			Interest rate swaps		-67		29		-228		-14
			Interest rate swaptions		392		-16		291		31
			TBAs		-11		327		-476		662
		Total gains (losses) included in net realized and unrealized
			investment (losses) gains	$	358	$	343	$	-300	$	812
			Commodity put options	$	-	$	-1,384	$	-	$	-2,684
			Energy and weather contracts		-		-		1,172		-
		Total (losses) gains included in other underwriting (loss) income		$	-	$	-1,384	$	1,172	$	-2,684
		Total gains (losses) from derivatives		$	235	$	-1,051	$	1,079	$	-1,731

StockBased_Employee_Compensati

Stock-Based Employee Compensation And Other Stock Plans	9 Months Ended
	Sep. 30, 2013
Stock-Based Employee Compensation And Other Stock Plans	'
Stock-Based Employee Compensation And Other Stock Plans	'
	8.       Stock-based employee compensation and other stock plans
	The Company has a stock-based employee compensation plan, that provides the Company with the ability to grant to employees and non-employee directors restricted shares, restricted share units, stock appreciation rights, share bonuses, options to purchase the Company's ordinary shares and other forms of equity incentive awards, as determined by the Compensation Committee of the Company's Board of Directors.
	On May 28, 2013, the Board of Directors elected John R. Charman as the Company's Chairman and Chief Executive Officer. Mr. Charman received a stock option to purchase 800,000 ordinary shares at an exercise price of $48.20 per share, and a grant of 708,890 restricted shares, as an employment inducement pursuant to Rule 303A.08 of the New York Stock Exchange Corporate Governance Standards.
	Stock Options
	The 800,000 options awarded to Mr. Charman will vest annually, in five equal tranches commencing on May 28, 2013, subject to Mr. Charman's continued employment, or in the event of certain terminations of employment and other events. Mr. Charman's option awards have a 10-year contractual life.
	8.       Stock-based employee compensation and other stock plans, cont'd.
	A summary of option activity, including options held by employees and non-employee directors, during the nine months ended September 30, 2013 is presented below:
			Nine Months Ended September 30, 2013
						Weighted Average
				Weighted		Remaining
			Number of	Average		Contractual Life		Aggregate
		Options Outstanding	Options	Exercise Price		(years)		Intrinsic Value
		Beginning, December 31, 2012	39,501	$	27.78
		Granted	800,000		48.2
		Exercised	24,501		23.88
		Forfeited	-		-
		Outstanding, September 30, 2013	815,000	$	47.94		9.5	$	4,711
		Exercisable and vested options, September 30, 2013	175,000	$	46.98		8.89	$	1,180
	No options were granted during the three months ended September 30, 2013 (2012 - Nil). During the nine months ended September 30, 2013, 800,000 options were granted (2012 – Nil) with a weighted average grant date fair value of $10.2 million (2012 – Nil). The Company uses the Black-Scholes-Merton formula to estimate the value of stock options granted. No options expired during the three and nine months ended September 30, 2013 and 2012. During the three and nine months ended September 30, 2013, Nil (2012 - 3,500) and 24,501 (2012 - 30,300) options were exercised, respectively. No options vested during the three months ended September 30, 2013 (2012 - Nil). During the nine months ended September 30, 2013, 160,000 options vested (2012 – Nil). The total intrinsic value of options exercised during the three and nine months ended September 30, 2013 was Nil (2012 - $64,000) and $0.5 million (2012 - $0.7 million), respectively. The Company received proceeds of Nil (2012 - $63,000) and $0.6 million (2012 - $0.5 million) from the exercise of options during the three and nine months ended September 30, 2013, respectively. The Company issued new ordinary shares in connection with the exercise of the above options.
	For the three and nine months ended September 30, 2013, compensation costs recognized in earnings for all options totaled $1.0 million (2012 – Nil) and $3.5 million (2012 - Nil), respectively.
	There was unrecognized stock-based compensation expenses of $6.7 million related to unvested stock options at September 30, 2013. This expense is expected to be recognized between 2013 and 2017, with approximately 15.8% expected to be recognized during the remainder of 2013.
	Restricted Shares and Restricted Share Units
	The 708,890 restricted shares awarded to Mr. Charman, as discussed above, will vest annually, in five equal tranches commencing on May 28, 2013, subject to Mr. Charman's continued employment, or in the event of certain terminations of employment and other events.
	8.       Stock-based employee compensation and other stock plans, cont'd.
	A summary of the restricted share and restricted share unit activity during the nine months ended September 30, 2013 is presented below:
			Nine Months Ended September 30, 2013
			Number of	Aggregate
			Shares/Units	Intrinsic Value
		Unvested, December 31, 2012	686,633
		Granted	1,079,108
		Settled	-406,495
		Forfeited	-211,227
		Unvested, September 30, 2013	1,148,019
		Outstanding, September 30, 2013	1,148,019	$	61,672
	During the three and nine months ended September 30, 2013, the Company granted an aggregate of 8,453 (2012 - 6,790) and 1,079,108 (2012 - 407,358) restricted shares and restricted share units with weighted average grant date fair values of $0.4 million (2012 - $0.2 million) and $50.7 million (2012 - $15.6 million), respectively. During the three and nine months ended September 30, 2013, the aggregate fair value of restricted shares and restricted share units that vested was $0.1 million (2012 - $0.2 million) and $17.0 million (2012 - $11.7 million), respectively.
	For the three and nine months ended September 30, 2013, compensation costs recognized in earnings for all restricted shares and restricted share units were $2.6 million (2012 - $1.9 million) and $16.1 million (2012 - $8.4 million), respectively. At September 30, 2013, compensation costs not yet recognized related to non-vested awards was $31.6 million. This expense is expected to be recognized between 2013 and 2017, with approximately 18.2% expected to be recognized during the remainder of 2013.
	Employee Share Purchase Plan
	The Company also has an Employee Share Purchase Plan under which employees of Endurance Holdings and certain of its subsidiaries may purchase Endurance Holdings' ordinary shares. Total expenses related to this plan for the three and nine months ended September 30, 2013 were approximately $42,000 (2012 - $39,000) and $124,000 (2012 - $127,000), respectively.

Segment_Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2013
Segment Reporting	'
Segment Reporting	'
	9.        Segment reporting
	The determination of the Company's business segments is based on how the Company monitors the performance of its underwriting operations. The Company has two reportable business segments, Insurance and Reinsurance, which are comprised of the following lines of business:
	Insurance segment lines of business
	•       Agriculture
	•       Casualty and other specialty
	•       Professional lines
	•       Property
	9.        Segment reporting, cont'd.
	Reinsurance segment lines of business
	•       Catastrophe
	•       Property
	•       Casualty
	•       Other specialty
	Management measures segment results on the basis of the combined ratio, which is obtained by dividing the sum of the net losses and loss expenses, acquisition expenses and general and administrative expenses by net premiums earned. When purchased within a single line of business, ceded reinsurance and recoveries are accounted for within that line of business. When purchased across multiple lines of business, ceded reinsurance and recoveries are allocated to the lines of business in proportion to the related risks assumed. The Company does not manage its assets by segment; accordingly, investment income and total assets are not allocated to the individual business segments. General and administrative expenses incurred by the segments are allocated directly. Remaining general and administrative expenses not directly incurred by the segments are allocated primarily based on estimated consumption, headcount and other variables deemed relevant to the allocation of such expenses. Ceded reinsurance and recoveries are recorded within the business segment to which they apply.
	The following table provides a summary of segment revenues, results and reserves for losses and loss expenses for the three months ended September 30, 2013:
					Three Months Ended September 30, 2013
						Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	344,819		$	199,544			$	544,363
				Ceded premiums written			-120,481			-28,549				-149,030
				Net premiums written			224,338			170,995				395,333
				Net premiums earned			291,477			262,068				553,545
				Other underwriting loss			-			-943				-943
							291,477			261,125				552,602
			Expenses
				Net losses and loss expenses			228,409			110,627				339,036
				Acquisition expenses			18,440			60,335				78,775
				General and administrative expenses			35,641			31,829				67,470
							282,490			202,791				485,281
			Underwriting income			$	8,987		$	58,334			$	67,321
			Net loss ratio				78.4	%		42.3	%			61.3	%
			Acquisition expense ratio				6.3	%		23	%			14.2	%
			General and administrative expense ratio				12.2	%		12.1	%			12.2	%
			Combined ratio				96.9	%		77.4	%			87.7	%
			Reserve for losses and loss expenses			$	2,146,136		$	1,905,966			$	4,052,102
	9.       Segment reporting, cont'd.
	The following table provides a summary of segment revenues, results and reserves for losses and loss expenses for the three months ended September 30, 2012:
					Three Months Ended September 30, 2012
							Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	324,808		$	296,447			$	621,255
				Ceded premiums written			-103,543			-3,632				-107,175
				Net premiums written			221,265			292,815				514,080
				Net premiums earned			283,273			268,599				551,872
				Other underwriting (loss) income			-1,384			37				-1,347
							281,889			268,636				550,525
			Expenses
				Net losses and loss expenses			288,750			118,773				407,523
				Acquisition expenses			24,506			64,276				88,782
				General and administrative expenses			29,409			23,306				52,715
							342,665			206,355				549,020
			Underwriting (loss) income			$	-60,776		$	62,281			$	1,505
			Net loss ratio				101.9	%		44.2	%			73.8	%
			Acquisition expense ratio				8.7	%		23.9	%			16.1	%
			General and administrative expense ratio				10.4	%		8.7	%			9.6	%
			Combined ratio				121	%		76.8	%			99.5	%
			Reserve for losses and loss expenses			$	2,635,086		$	1,874,356			$	4,509,442
	The following table reconciles total segment results to income before income taxes for the three months ended September 30, 2013 and 2012:
				Three Months Ended
				September 30,
					2013			2012
			Total underwriting income	$	67,321		$	1,505
			Net investment income		38,097			45,882
		Net foreign exchange losses		-2,201			-3,774
		Net realized and unrealized investment (losses) gains		-6,640			10,097
		Net impairment losses recognized in earnings		-190			-131
		Amortization of intangibles		-1,652			-2,434
		Interest expense		-9,048			-9,041
		Income before income taxes	$	85,687		$	42,104
The following table provides gross and net premiums written by line of business for the three months ended September 30, 2013 and 2012:
				Gross			Net		Gross			Net
				premiums			premiums		premiums			premiums
				written			written		written			written
	Business Segment			2013			2013		2012			2012
	Insurance
		Agriculture	$	200,062		$	120,617	$	171,826		$	106,180
		Casualty and other specialty		95,862			72,431		90,873			66,686
		Professional lines		34,221			20,972		43,209			34,804
		Property		14,674			10,318		18,900			13,595
	Total Insurance			344,819			224,338		324,808			221,265
	Reinsurance
		Catastrophe		38,676			12,551		38,871			36,484
		Casualty		53,691			53,690		77,781			77,781
		Property		91,653			90,528		157,742			157,742
		Other specialty		15,524			14,226		22,053			20,808
	Total Reinsurance			199,544			170,995		296,447			292,815
	Total		$	544,363		$	395,333	$	621,255		$	514,080
The following table provides a summary of the segment revenues and results for the nine months ended September 30, 2013:
				Nine Months Ended September 30, 2013
						Insurance			Reinsurance				Total
		Revenues
			Gross premiums written		$	1,274,703		$	1,019,732			$	2,294,435
			Ceded premiums written			-454,169			-71,397				-525,566
			Net premiums written			820,534			948,335				1,768,869
			Net premiums earned			710,507			806,490				1,516,997
			Other underwriting income			-			694				694
						710,507			807,184				1,517,691
		Expenses
			Net losses and loss expenses			543,717			373,347				917,064
			Acquisition expenses			48,024			174,255				222,279
			General and administrative expenses			114,792			100,515				215,307
						706,533			648,117				1,354,650
		Underwriting income			$	3,974		$	159,067			$	163,041
		Net loss ratio				76.4	%		46.3	%			60.4	%
		Acquisition expense ratio				6.8	%		21.6	%			14.7	%
		General and administrative expense ratio				16.2	%		12.5	%			14.2	%
		Combined ratio				99.4	%		80.4	%			89.3	%
The following table provides a summary of the segment revenues and results for the nine months ended September 30, 2012:
				Nine Months Ended September 30, 2012
						Insurance			Reinsurance				Total
		Revenues
			Gross premiums written		$	1,252,814		$	1,034,166			$	2,286,980
			Ceded premiums written			-417,109			-28,322				-445,431
			Net premiums written			835,705			1,005,844				1,841,549
			Net premiums earned			710,988			771,859				1,482,847
			Other underwriting (loss) income			-2,684			1,021				-1,663
						708,304			772,880				1,481,184
		Expenses
			Net losses and loss expenses			610,956			405,231				1,016,187
			Acquisition expenses			58,265			171,134				229,399
			General and administrative expenses			96,663			84,702				181,365
						765,884			661,067				1,426,951
		Underwriting (loss) income			$	-57,580		$	111,813			$	54,233
		Net loss ratio				85.9	%		52.4	%			68.5	%
		Acquisition expense ratio				8.2	%		22.2	%			15.5	%
		General and administrative expense ratio				13.6	%		11	%			12.2	%
		Combined ratio				107.7	%		85.6	%			96.2	%
The following table reconciles total segment results to income before income taxes for the nine months ended September 30, 2013 and 2012, respectively:
		Nine Months Ended
		September 30,
			2013			2012
	Total underwriting income	$	163,041		$	54,233
	Net investment income		119,870			134,723
	Net foreign exchange (losses) gains		-8,496			14,699
	Net realized and unrealized investment gains		9,967			30,258
	Net impairment losses recognized in earnings		-1,575			-757
	Amortization of intangibles		-5,378			-7,988
	Interest expense		-27,138			-27,132
	Income before income taxes	$	250,291		$	198,036
The following table provides gross and net premiums written by line of business for the nine months ended September 30, 2013 and 2012:
				Gross			Net		Gross			Net
				premiums			premiums		premiums			premiums
				written			written		written			written
	Business Segment			2013			2013		2012			2012
	Insurance
		Agriculture	$	896,169		$	546,284	$	838,932		$	528,349
		Casualty and other specialty		239,943			179,065		236,383			173,097
		Professional lines		93,481			62,963		130,573			107,841
		Property		45,110			32,222		46,926			26,418
	Total Insurance			1,274,703			820,534		1,252,814			835,705
	Reinsurance
		Catastrophe		341,973			281,990		354,275			329,067
		Casualty		272,602			271,174		258,352			257,113
		Property		288,448			283,455		318,514			318,521
		Other specialty		116,709			111,716		103,025			101,143
	Total Reinsurance			1,019,732			948,335		1,034,166			1,005,844
	Total		$	2,294,435		$	1,768,869	$	2,286,980		$	1,841,549

Commitments_And_Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies	'
Commitments And Contingencies	'
	10. Commitments and contingencies
	Concentrations of credit risk. The Company's reinsurance recoverables on paid and unpaid losses at September 30, 2013 and December 31, 2012 amounted to $941.4 million and $774.9 million, respectively. At September 30, 2013, substantially all reinsurance recoverables on paid and unpaid losses were due from the U.S. government or from reinsurers rated A- or better by A.M. Best Company Inc. or Standard & Poor's Corporation.
	Major production sources. The following table shows the percentage of net premiums written generated through the Company's largest brokers for the nine months ended September 30, 2013 and 2012, respectively:
		Broker	2013		2012
		Aon Benfield	18.5	%	17.3	%
		Marsh & McLennan Companies, Inc.	15	%	16.6	%
		Willis Companies	12.4	%	15.8	%
		Total of largest brokers	45.9	%	49.7	%
	Letters of credit. As of September 30, 2013, the Company had issued letters of credit of $259.5 million (December 31, 2012 – $320.4 million) under its credit facility in favor of certain ceding companies to collateralize obligations.
	10. Commitments and contingencies, cont'd.
	Investment commitments. As of September 30, 2013 and December 31, 2012, the Company had pledged cash and cash equivalents and fixed maturity investments of $215.8 million and $224.4 million, respectively, in favor of certain ceding companies to collateralize obligations. As of September 30, 2013 and December 31, 2012, the Company had also pledged $303.3 million and $380.0 million of its cash and fixed maturity investments as required to meet collateral obligations for $259.5 million and $320.4 million in letters of credit outstanding under its credit facility, respectively. In addition, as of September 30, 2013 and December 31, 2012, cash and fixed maturity investments with fair values of $274.6 million and $280.0 million were on deposit with U.S. state regulators, respectively.
	The Company is subject to certain commitments with respect to other investments at September 30, 2013 and December 31, 2012. See Note 3.
	Reinsurance commitments. In the ordinary course of business, the Company periodically enters into reinsurance agreements that include terms which could require the Company to collateralize certain of its obligations.
	Employment agreements. The Company has entered into employment agreements with certain officers that provide for equity incentive awards, executive benefits and severance payments under certain circumstances.
	Operating leases. The Company leases office space and office equipment under operating leases. Future minimum lease commitments at September 30, 2013 are as follows:
		Twelve months ended September 30,	Amount
		2014	$	14,586
		2015		13,822
		2016		11,298
		2017		9,791
		2018		9,575
		2019 and thereafter		41,135
			$	100,207
	Total net lease expense under operating leases for the nine months ended September 30, 2013 was $11.2 million (2012 – $11.3 million).
	Legal proceedings. The Company is party to various legal proceedings generally arising in the normal course of its business. While any proceeding contains an element of uncertainty, the Company does not believe that the eventual outcome of any litigation or arbitration proceeding to which it is presently a party could have a material adverse effect on its financial condition or business. Pursuant to the Company's insurance and reinsurance agreements, disputes are generally required to be settled by arbitration.

Summary_Of_Significant_Account1

Summary Of Significant Accounting Policies (Policy)	9 Months Ended
	Sep. 30, 2013
Summary Of Significant Accounting Policies	'
New Accounting Pronouncements Adopted	'
	In December 2011, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2011-11 “Disclosures About Offsetting Assets and Liabilities” (“ASU 2011-11”). ASU 2011-11 requires additional disclosures about financial instruments and derivative instruments relating to netting arrangements.
	ASU 2011-11 was effective for interim and annual periods beginning on or after January 1, 2013, with retrospective presentation required. The Company adopted this standard effective January 1, 2013. This standard did not have a material impact on the Company's consolidated financial statements.
	In February 2013, the FASB issued ASU 2013-02 “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-02”). ASU 2013-02 requires entities to report, in one location, information about reclassifications out of accumulated other comprehensive income (“AOCI”). ASU 2013-02 also requires companies to report changes in AOCI balances. For significant items reclassified out of AOCI into net income in their entirety in the same reporting period, reporting (either on the face of the statement where net income is presented or in the notes to the financial statements) is required about the effect of the reclassifications on the respective line items in the statement where net income is presented. For items that are not reclassified into net income in their entirety in the same reporting period, a cross reference to other disclosures currently required under US GAAP is required in the notes. The above information must be presented in one place (parenthetically on the face of the financial statements by income statement line item or in a note to the financial statements).
	ASU 2013-02 was effective for fiscal years and interim periods beginning after December 15, 2012. The Company adopted this standard prospectively on January 1, 2013. This standard resulted in an additional note to the consolidated financial statements (see Note 6).
New Accounting Pronouncements Not Yet Adopted	'
	In July 2013, the FASB issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” (“ASU 2013-11”). ASU 2013-11 provides guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist.
	ASU 2013-11 will be effective for annual and interim reporting periods beginning after December 15, 2013, with both early adoption and retrospective application permitted. The Company does not expect this standard to have a material impact on the Company's consolidated financial statements.

Investments_Policy

Investments (Policy)	9 Months Ended
	Sep. 30, 2013
Investments	'
Other Investments	'
	In addition to the Company's fixed maturity, short-term and equity investments, the Company invests in (i) hedge funds and private investment funds that generally invest in senior secured bank debt, high yield credit, distressed debt, distressed real estate, derivatives, equity long/short strategies, currencies and commodities (“alternative funds”) and (ii) high yield loan and convertible debt funds (“specialty funds”). The Company's alternative funds and specialty funds are recorded on the Company's balance sheet as “other investments.”
Variable Interest Entities	'
	Variable Interest Entities
	Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristics of a controlling financial interest are referred to as variable interest entities (“VIE”). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis.
	The Company is involved in the normal course of business with VIEs primarily as a passive investor in residential and commercial mortgage-backed securities and through its interests in other investments in alternative and specialty funds that are structured as limited partnerships considered to be third party VIEs. The Company determined that it was not the primary beneficiary for any of these investments as of September 30, 2013. The Company believes its exposure to loss with respect to these investments is generally limited to the investment carrying amounts reported in the Company's Condensed Consolidated Balance Sheets and any unfunded investment commitments.
Gain Loss On Investments	'
	Realized and unrealized investment gains and losses are recognized in earnings using the first in, first out method.

Fair_Value_Measurement_Policy

Fair Value Measurement (Policy)	9 Months Ended
	Sep. 30, 2013
Fair Value Measurement	'
Fair Value Of Financial Instruments	'
	The Company determines the fair value of the fixed maturity investments, short-term investments, equity securities, other investments, debt, and other assets and liabilities in accordance with current accounting guidance, which defines fair value and establishes a fair value hierarchy based on inputs to the various valuation techniques used for each fair value measurement. The Company determines the estimated fair value of each individual security utilizing the highest level inputs available. Valuation inputs by security type may include the following:
	Government and agencies fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical models which may incorporate option adjusted spreads, daily interest rate data and market/sector news. The Company generally classifies the fair values of government and agencies securities in Level 2. Current issue U.S. government securities are generally valued based on Level 1 inputs, which use the market approach valuation technique.
	Government guaranteed corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing service or index providers may use current market trades for securities with similar quality, maturity and coupon. If no such trades are available, the pricing service typically uses analytical spread models which may incorporate inputs from the U.S treasury curve or LIBOR. The Company generally classifies the fair values of its government guaranteed corporate securities in Level 2.
	Corporate fixed maturity securities – These securities are generally priced by pricing services or index providers. The pricing services or index providers typically use discounted cash flow models that incorporate benchmark curves for treasury, swap and high issuance credits. Credit spreads are developed from current market observations for like or similar securities. The Company generally classifies the fair values of its corporate securities in Level 2.
	Equity securities – These securities are generally priced by pricing services or index providers. Depending on the type of underlying equity security or equity fund, the securities are priced by pricing services or index providers based on quoted market prices in active markets or through a discounted cash flow model that incorporates benchmark curves for treasury, swap and credits for like or similar securities. The Company generally classifies the fair values of its equity securities in Level 1 or 2.
	Other assets and liabilities – These balances include a variety of derivative instruments used to enhance the efficiency of the investment portfolio and economically hedge certain risks. These instruments are generally priced by pricing services, broker/dealers and/or recent trading activity. The market value approach valuation technique is used to estimate the fair value for these derivatives based on significant observable market inputs. Certain derivative instruments are priced by pricing services based on quoted market prices in active markets. These derivative instruments are generally classified in Level 1. Other derivative instruments are priced using industry valuation models and are considered Level 2, as the inputs to the valuation model are based on observable market inputs. Also included in this line item are proprietary, non-exchange traded derivative-based risk management products primarily used to address weather and energy risks. The trading market for these weather derivatives is generally linked to energy and agriculture commodities, weather and other natural phenomena. In instances where market prices are not available, the Company uses industry or internally developed valuation techniques such as spread option, Black Scholes, quanto and simulation modeling to determine fair value and classifies these in Level 3. These models may reference prices for similar instruments.
	Structured securities including agency and non-agency, residential and commercial, mortgage and asset-backed securities – These securities are generally priced by broker/dealers. Broker/dealers may use current market trades for securities with similar qualities. If no such trades are available, inputs such as bid and offer, prepayment speeds, the U.S. treasury curve, swap curve and cash settlement may be used in a discounted cash flow model to determine the fair value of a security. The Company generally classifies the fair values of its structured securities in Level 2.
	Other investments – Other investments, including alternative funds and specialty funds, are generally priced on net asset values (“NAV”) received from the fund managers or administrators. Due to the timing of the delivery of the final NAV by certain of the fund managers, valuations of certain alternative funds and specialty funds are estimated based on the most recently available information, including period end NAVs, period end estimates, or, in some cases, prior month or prior quarter NAVs. As this valuation technique incorporates both observable and significant unobservable inputs, the Company generally classifies the fair value of its other investments in Level 3.
	Debt – Outstanding debt consists of the Company's 6.15% Senior Notes due October 15, 2015 and the 7.0% Senior Notes due July 15, 2034 (the “Senior Notes”). The fair values of these securities were obtained from a third party pricing service and pricing was based on the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of the Senior Notes are classified in Level 2.
	The carrying values of cash and cash equivalents, accrued investment income, net receivable on sales of investments, net payable on purchases of investments and other financial instruments not described above approximated their fair values at September 30, 2013.
Fair Value Transfer Between Levels	'
	Transfers between levels are assumed to occur at the end of each period.

Earnings_Per_Share_Policy

Earnings Per Share (Policy)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share	'
Earnings Per Share	'
	The two-class method utilized by the Company is an earnings allocation formula that determines earnings per share for the holders of Endurance Holdings' ordinary shares (also referred to as “common shares”) and participating common shares, which includes unvested restricted shares that receive cash dividends, according to dividends declared and participation rights in undistributed earnings. Net income available to common and participating common shareholders is reduced by the amount of dividends declared in the current period and by the contractual amount of dividends that must be paid for the current period related to the Company's common and participating common shares. Any remaining undistributed earnings are allocated to the common and participating common shareholders to the extent that each security may share in earnings as if all of the earnings for the period had been distributed. In periods of loss, no losses are allocated to participating common shareholders. Instead, all such losses are allocated solely to the common shareholders.
	Basic earnings per common share are calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. The weighted average number of common shares excludes any dilutive effect of outstanding options and convertible securities such as unvested restricted shares.
	Diluted earnings per common share are based on the weighted average number of common shares and assumes the exercise of all dilutive stock options and the vesting or conversion of all convertible securities such as unvested restricted shares using the two-class method described above.

Derivatives_Policy

Derivatives (Policy)	9 Months Ended
	Sep. 30, 2013
Derivatives	'
Accounting policy for derivativess	'
	The Company's derivative instruments are recorded in the Condensed Consolidated Balance Sheets at fair value, with changes in fair value and gains and losses recognized in net realized and unrealized investment (losses) gains, net foreign exchange losses (gains) and other underwriting (loss) income in the Condensed Consolidated Statements of Income and Comprehensive Income.
	During 2012, the Company entered into the weather risk management business through its newly formed unit, Endurance Global Weather. Endurance Global Weather regularly transacts in certain derivative-based risk management products primarily to address weather and energy risks. The trading markets for these derivatives are generally linked to energy and agriculture commodities, weather and other natural phenomena. Generally, the Company's current portfolio of such derivative contracts is of short duration and such contracts are predominantly seasonal in nature.
	The Company's derivatives are not designated as hedges under current accounting guidance. The Company invests a portion of its fixed maturity assets with third party investment managers with investment guidelines that permit the use of derivative instruments. The Company may enter derivative transactions directly or as part of strategies employed by its external investment managers. The Company's objectives for holding these derivatives are as follows:
	Interest Rate Futures, Swaps, Swaptions and Options - to manage exposure to interest rate risk, which can include increasing or decreasing its exposure to this risk through modification of the portfolio composition and duration.
	Foreign Exchange Forwards, Futures and Options - as part of overall currency risk management and investment strategies.
	Credit Default Swaps - to manage market exposures. The Company may assume or economically hedge credit risk through credit default swaps to replicate or hedge investment positions. The original term of these credit default swaps is generally five years or less.
	Commodity Futures and Options - to economically hedge certain underwriting risks.
	To-Be-Announced Mortgage-backed Securities (“TBAs”) - to enhance investment performance and as part of overall investment strategy. TBAs represent commitments to purchase or sell a future issuance of agency mortgage-backed securities. For the period between purchase of a TBA and allocation of the underlying securities, the Company's position is accounted for as a derivative.
	Energy and Weather Contracts – to address weather and energy risks. The Company may purchase or sell contracts
	with financial settlements based on the performance of an index linked to a quantifiable weather element, such as
	temperature, precipitation, snowfall or wind speed, and structures with multiple risk triggers indexed to a quantifiable weather element and a weather sensitive commodity price, such as temperature and electrical power or natural gas.

Segment_Reporting_Policy

Segment Reporting (Policy)	9 Months Ended
	Sep. 30, 2013
Segment Reporting	'
Segment Reporting	'
	The determination of the Company's business segments is based on how the Company monitors the performance of its underwriting operations. The Company has two reportable business segments, Insurance and Reinsurance, which are comprised of the following lines of business:
	Insurance segment lines of business
	•       Agriculture
	•       Casualty and other specialty
	•       Professional lines
	•       Property
	9.        Segment reporting, cont'd.
	Reinsurance segment lines of business
	•       Catastrophe
	•       Property
	•       Casualty
	•       Other specialty
	Management measures segment results on the basis of the combined ratio, which is obtained by dividing the sum of the net losses and loss expenses, acquisition expenses and general and administrative expenses by net premiums earned. When purchased within a single line of business, ceded reinsurance and recoveries are accounted for within that line of business. When purchased across multiple lines of business, ceded reinsurance and recoveries are allocated to the lines of business in proportion to the related risks assumed. The Company does not manage its assets by segment; accordingly, investment income and total assets are not allocated to the individual business segments. General and administrative expenses incurred by the segments are allocated directly. Remaining general and administrative expenses not directly incurred by the segments are allocated primarily based on estimated consumption, headcount and other variables deemed relevant to the allocation of such expenses. Ceded reinsurance and recoveries are recorded within the business segment to which they apply.

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments	'
Composition Of Net Investment Income	'
				Three Months Ended September 30,						Nine Months Ended September 30,
					2013			2012			2013			2012
			Available for sale investments	$	27,889		$	33,946		$	86,036		$	105,606
			Other investments		13,244			15,050			43,083			38,101
			Cash and cash equivalents		752			289			2,043			978
				$	41,885		$	49,285		$	131,162		$	144,685
			Investment expenses		-3,788			-3,403			-11,292			-9,962
			Net investment income	$	38,097		$	45,882		$	119,870		$	134,723
Composition of the Investment Portfolio by Investment Type	'
					30-Sep-13						31-Dec-12
			Type of Investment		Fair Value		Percentage				Fair Value		Percentage
			Fixed maturity investments	$	4,800,838		75.6	%		$	4,868,150		74.2	%
			Cash and cash equivalents(1)		689,762		10.8	%			1,051,694		16	%
			Other investments(2)		594,156		9.3	%			517,546		7.9	%
			Short-term investments		11,599		0.2	%			42,230		0.6	%
			Equity securities		262,866		4.1	%			86,997		1.3	%
			Total	$	6,359,221		100	%		$	6,566,617		100	%
			(1) Includes net receivable on sales of investments and net payable on purchases of investments.
			(2) Consists of investments in alternative funds and specialty funds.
Composition Of Fixed Income Portfolio, Including Fixed Maturity Investments And Short Term Investments, By Investment Ratings	'
					30-Sep-13						31-Dec-12
			Ratings(1)		Fair Value		Percentage				Fair Value		Percentage
			U.S. government and agencies securities	$	823,761		17.1	%		$	737,535		15	%
			AAA / Aaa		1,031,149		21.4	%			993,277		20.2	%
			AA / Aa		1,781,679		37	%			1,821,250		37.1	%
			A / A		807,509		16.8	%			993,307		20.2	%
			BBB		296,489		6.2	%			219,017		4.5	%
			Below BBB		67,269		1.4	%			143,198		2.9	%
			Not rated		4,581		0.1	%			2,796		0.1	%
			Total	$	4,812,437		100	%		$	4,910,380		100	%
			(1) The credit rating for each security reflected above was determined based on the rating assigned to the individual security by Standard & Poor's Financial Services LLC ("Standard & Poor's"). If a rating is not supplied by Standard & Poor's, the equivalent rating supplied by either Moody's Investors Service, Inc. ("Moody's") or Fitch Ratings is used.
Contractual Maturities Of Fixed Maturity And Short Term Investments	'
				30-Sep-13						31-Dec-12
					Amortized						Amortized
					Cost			Fair Value			Cost			Fair Value
		Due within one year		$	128,110		$	129,417		$	136,283		$	137,567
		Due after one year through five years			1,775,192			1,787,984			1,725,927			1,765,662
		Due after five years through ten years			265,740			266,962			410,755			429,099
		Due after ten years			27,207			27,847			29,654			33,803
		Residential mortgage-backed securities			1,235,668			1,240,222			1,252,468			1,280,579
		Commercial mortgage-backed securities			872,259			889,460			741,178			781,379
		Asset-backed securities			466,516			470,545			474,555			482,291
		Total		$	4,770,692		$	4,812,437		$	4,770,820		$	4,910,380
Other Investments	'
		30-Sep-13			Market Value			Unfunded Commitments			Ineligible for Redemption over next 12 months
		Alternative funds
			Hedge funds	$	385,913		$	-		$	44,791
			Private investment funds		55,531			60,790			55,531
		Total alternative funds			441,444			60,790			100,322
		Specialty funds
			High yield loan funds		109,171			-			-
			Convertible debt funds		43,541			-			-
		Total specialty funds			152,712			-			-
		Total other investments		$	594,156		$	60,790		$	100,322
		31-Dec-12			Market Value			Unfunded Commitments			Ineligible for Redemption in 2013
		Alternative funds
			Hedge funds	$	337,200		$	-		$	61,161
			Private investment funds		35,219			29,483			35,219
		Total alternative funds			372,419			29,483			96,380
		Specialty funds
			High yield loan funds		105,886			-			-
			Convertible debt funds		39,241			-			-
		Total specialty funds			145,127			-			-
		Total other investments		$	517,546		$	29,483		$	96,380
Net Realized And Unrealized Investment (Losses) Gains	'
				Three Months Ended						Nine Months Ended
				September 30,						September 30,
				2013			2012			2013			2012
		Gross realized gains on investment sales	$	6,180		$	11,976		$	30,191		$	34,837
		Gross realized losses on investment sales		-13,178			-2,222			-19,924			-5,391
		Change in fair value of derivative financial instruments(1)		358			343			-300			812
		Net realized and unrealized investment (losses) gains	$	-6,640		$	10,097		$	9,967		$	30,258
		(1) For additional information on the Company's derivative financial instruments, see Note 7.
Unrealized Gains and Losses And Other-Then-Temporary Impairments	'
							Gross			Gross
				Amortized			Unrealized			Unrealized						Non-Credit
		30-Sep-13		Cost			Gains			Losses			Fair Value			OTTI (2)
		Fixed maturity investments
			U.S. government and agencies securities	$	819,585		$	9,332		$	-5,156		$	823,761		$	-
			U.S. state and municipal securities		27,731			129			-490			27,370			-
			Foreign government securities		175,280			1,725			-1,496			175,509			-
			Government guaranteed corporate securities		34,244			328			-52			34,520			-
			Corporate securities		1,127,809			18,130			-6,488			1,139,451			-
			Residential mortgage-backed securities		1,235,668			20,278			-15,724			1,240,222			-4,785
			Commercial mortgage-backed securities(1)		872,259			26,341			-9,140			889,460			-47
			Asset-backed securities		466,516			5,067			-1,038			470,545			-
		Total fixed maturity investments		$	4,759,092		$	81,330		$	-39,584		$	4,800,838		$	-4,832
		Short-term investments			11,600			-			-1			11,599			-
		Total fixed income investments		$	4,770,692		$	81,330		$	-39,585		$	4,812,437		$	-4,832
		Equity securities
			Equity investments	$	152,328		$	17,197		$	-2,697		$	166,828		$	-
			Emerging market debt funds		60,250			255			-			60,505			-
			Preferred equity investments		10,184			1,883			-64			12,003			-
			Short-term fixed income fund		23,526			4			-			23,530			-
		Total equity securities		$	246,288		$	19,339		$	-2,761		$	262,866		$	-
	-1	Balances include amounts related to collateralized debt obligations held with total fair values of $14.1 million.
	-2	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At September 30, 2013, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.1 million.
								Gross			Gross
					Amortized			Unrealized			Unrealized						Non-Credit
			31-Dec-12		Cost			Gains			Losses			Fair Value			OTTI (2)
			Fixed maturity investments
				U.S. government and agencies securities	$	718,992		$	18,596		$	-53		$	737,535		$	-
				U.S. state and municipal securities		37,952			1,119			-177			38,894			-
				Foreign government securities		106,218			3,264			-145			109,337			-
				Government guaranteed corporate
				securities		62,782			1,682			-			64,464			-
				Corporate securities		1,334,451			40,555			-1,335			1,373,671			-
				Residential mortgage-backed securities		1,252,468			30,426			-2,315			1,280,579			-5,884
				Commercial mortgage-backed securities(1)		741,178			41,737			-1,536			781,379			-53
				Asset-backed securities		474,555			8,435			-699			482,291			-
			Total fixed maturity investments		$	4,728,596		$	145,814		$	-6,260		$	4,868,150		$	-5,937
			Short-term investments			42,224			6			-			42,230			-
			Total fixed income investments		$	4,770,820		$	145,820		$	-6,260		$	4,910,380		$	-5,937
			Equity securities
				Equity investments	$	59,736		$	7,194		$	-620		$	66,310		$	-
				Emerging market debt funds		10,000			576			-			10,576			-
				Preferred equity investments		7,261			2,851			-1			10,111			-
			Total equity securities		$	76,997		$	10,621		$	-621		$	86,997		$	-
	-1	Balances include amounts related to collateralized debt obligations held with total fair values of $8.5 million.
	-2	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At December 31, 2012, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.4 million.
Available For Sale Securities In An Unrealized Loss Position	'
							Less than 12 months						12 months or greater						Total
							Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
		30-Sep-13					Losses(1)			Value			Losses(1)			Value			Losses(1)		Value
		Fixed maturity investments
			U.S. government and agencies
				securities		$	-5,156		$	265,417		$	-		$	-		$	-5,156	$	265,417
			U.S. state and municipal
				securities			-490			19,711			-			-			-490		19,711
			Foreign government securities				-1,495			109,722			-1			4,858			-1,496		114,580
			Government guaranteed
				corporate securities			-52			11,301			-			-			-52		11,301
			Corporate securities				-6,488			422,818			-			-			-6,488		422,818
			Residential mortgage-backed
				securities			-15,641			510,138			-83			1,619			-15,724		511,757
			Commercial mortgage-backed
				securities			-8,822			351,269			-318			4,936			-9,140		356,205
			Asset-backed securities				-853			184,964			-185			4,193			-1,038		189,157
		Total fixed maturity investments				$	-38,997		$	1,875,340		$	-587		$	15,606		$	-39,584	$	1,890,946
		Short-term investments					-1			1,246			-			-			-1		1,246
		Total fixed income investments				$	-38,998		$	1,876,586		$	-587		$	15,606		$	-39,585	$	1,892,192
		Equity securities
			Equity investments			$	-2,697		$	43,925		$	-		$	-		$	-2,697	$	43,925
			Preferred equity investments				-64			5,924			-			-			-64		5,924
		Total equity securities				$	-2,761		$	49,849		$	-		$	-		$	-2,761	$	49,849
	-1	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at September 30, 2013.
	3	Investments, cont’d.
							Less than 12 months						12 months or greater						Total
							Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
		31-Dec-12					Losses(1)			Value			Losses(1)			Value			Losses(1)		Value
		Fixed maturity investments
			U.S. government and agencies
				securities		$	-53		$	48,570		$	-		$	-		$	-53	$	48,570
			U.S. state and municipal
				securities			-177			6,905			-			-			-177		6,905
			Foreign government securities				-139			23,157			-6			4,870			-145		28,027
			Corporate securities				-1,305			245,232			-30			1,849			-1,335		247,081
			Residential mortgage-backed
				securities			-1,920			327,473			-395			7,511			-2,315		334,984
			Commercial mortgage-backed
				securities			-474			79,125			-1,062			11,625			-1,536		90,750
			Asset-backed securities				-94			53,471			-605			8,123			-699		61,594
		Total fixed maturity investments				$	-4,162		$	783,933		$	-2,098		$	33,978		$	-6,260	$	817,911
		Equity securities
			Equity investments			$	-580		$	9,183		$	-40		$	387		$	-620	$	9,570
			Preferred equity investments				-1			201			-			-			-1		201
		Total equity securities				$	-581		$	9,384		$	-40		$	387		$	-621	$	9,771
	-1	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at December 31, 2012.
Analysis Of OTTI	'
				Three months ended September 30,						Nine months ended September 30,
				2013			2012			2013			2012
		Total other-than-temporary impairment losses	$	-190		$	-126		$	-1,575		$	-274
		Portion of loss recognized in other
		comprehensive income (loss)		-			-5			-			-483
		Net impairment losses recognized in earnings	$	-190		$	-131		$	-1,575		$	-757
Credit Losses Recognized For Available For Sale Investments In Earnings, OTTI Loss Was Recognized In Accumulated Other Comprehensive Income	'
				Three months ended September 30,						Nine months ended September 30,
				2013			2012			2013			2012
		Beginning balance		$	-1,769		$	-2,268		$	-2,000		$	-2,225
		Addition for the amount related to the credit loss for
			which an other-than-temporary impairment was
			not previously recognized		-			-			-			-3
		Addition for the amount related to the credit loss for
			which an other-than-temporary impairment was
			previously recognized		-			-5			-			-503
		Reductions for increases in cash flows expected to be
			collected that are recognized over the remaining life
			of the security		-			-			-			-
		Reductions for securities sold during the period			113			216			344			674
		Ending balance		$	-1,656		$	-2,057		$	-1,656		$	-2,057

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Measurement	'
Schedule Of Available For Sale Investments, Other Investments, Other Assets And Liabilities And Debt	'
					Fair Value Measurements at September 30, 2013
							Quoted
							Prices in
							Active
							Markets		Significant
							for		Other		Significant
					Total at		Identical		Observable		Unobservable
					September 30,		Assets		Inputs		Inputs
					2013		(Level 1)		(Level 2)		(Level 3)
		Assets
		Fixed maturity investments
			U.S. government and agencies securities	$	823,761	$	17,865	$	805,896	$	-
			U.S. state and municipal securities		27,370		-		27,370		-
			Foreign government securities		175,509		-		175,509		-
			Government guaranteed corporate securities		34,520		-		34,520		-
			Corporate securities		1,139,451		-		1,138,692		759
			Residential mortgage-backed securities		1,240,222		-		1,240,015		207
			Commercial mortgage-backed securities		889,460		-		880,878		8,582
			Asset-backed securities		470,545		-		467,635		2,910
		Total fixed maturity investments		$	4,800,838	$	17,865	$	4,770,515	$	12,458
		Equity securities
			Equity investments		166,828		80,596		86,232		-
			Emerging market debt funds		60,505		-		60,505		-
			Preferred equity investments		12,003		-		12,003		-
			Short-term fixed income fund		23,530		23,530		-		-
		Total equity securities		$	262,866	$	104,126	$	158,740	$	-
		Short-term investments			11,599		-		11,599		-
		Other investments			594,156		-		-		594,156
		Other assets (see Note 7)			122,853		-		120,526		2,327
		Total assets		$	5,792,312	$	121,991	$	5,061,380	$	608,941
		Liabilities
		Other liabilities (see Note 7)		$	74,237	$	-	$	69,405	$	4,832
		Debt			582,296		-		582,296		-
		Total liabilities		$	656,533	$	-	$	651,701	$	4,832
					Fair Value Measurements at December 31, 2012
							Quoted
							Prices in
							Active		Significant
							Markets for		Other		Significant
					Total at		Identical		Observable		Unobservable
					December 31,		Assets		Inputs		Inputs
					2012		(Level 1)		(Level 2)		(Level 3)
		Assets
		Fixed maturity investments
			U.S. government and agencies securities	$	737,535	$	39,889	$	697,646	$	-
			U.S. state and municipal securities		38,894		-		38,894		-
			Foreign government securities		109,337		-		109,337		-
			Government guaranteed corporate securities		64,464		-		64,464		-
			Corporate securities		1,373,671		-		1,373,671		-
			Residential mortgage-backed securities		1,280,579		-		1,280,223		356
			Commercial mortgage-backed securities		781,379		-		777,049		4,330
			Asset-backed securities		482,291		-		478,480		3,811
		Total fixed maturity investments		$	4,868,150	$	39,889	$	4,819,764	$	8,497
		Equity securities
			Equity investments		66,310		66,310		-		-
			Emerging market debt funds		10,576		-		10,576		-
			Preferred equity investments		10,111		-		10,111		-
		Total equity securities		$	86,997	$	66,310	$	20,687	$	-
		Short-term investments			42,230		-		42,230		-
		Other investments			517,546		-		-		517,546
		Other assets (see Note 7)			23,649		-		20,688		2,961
		Total assets		$	5,538,572	$	106,199	$	4,903,369	$	529,004
		Liabilities
	Other liabilities (see Note 7)			10,660		-		7,699		2,961
	Debt			592,677		-		592,677		-
	Total liabilities		$	603,337	$	-	$	600,376	$	2,961
Reconciliation Of The Beginning And Ending Balances For All Available For Sale Investments, Other Investments And Derivative Instruments Measured At Fair Value On A Recurring Basis Using Level 3 Inputs	'
				Three Months Ended September 30, 2013
				Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
		Level 3, beginning of period		$	7,546	$	569,393	$	-	$	576,939	$	-
		Total net realized gains included in earnings			56		19,108		-		19,164		-
		Total net realized and unrealized losses included in earnings			-15		-5,864		-		-5,879		-
		Change in unrealized gains included in other comprehensive income (loss)			111		-		-		111		-
		Change in unrealized losses included in other comprehensive income (loss)			-62		-		-		-62		-
		Purchases			-		16,597		-		16,597		-
		Sales			-1,879		-5,078		-		-6,957		-
		Transfers in to Level 3			7,903		-		-		7,903		-
		Transfers out of Level 3			-1,202		-		-		-1,202		-
		Level 3, end of period		$	12,458	$	594,156	$	-	$	606,614	$	-
				Nine Months Ended September 30, 2013
				Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
		Level 3, beginning of period		$	8,497	$	517,546	$	2,961	$	529,004	$	2,961
		Total net realized gains included in earnings			104		61,010		-		61,114		-
		Total net realized and unrealized losses included in earnings			-17		-17,927		-		-17,944		-
		Change in unrealized gains included in other comprehensive income (loss)			438		-		-		438		-
		Change in unrealized losses included in other comprehensive income (loss)			-270		-		-		-270		-
		Purchases			-		62,011		6		62,017		12
		Sales			-6,081		-28,484		-2,967		-37,532		-2,973
		Transfers in to Level 3			11,550		-		-		11,550		-
		Transfers out of Level 3			-1,763		-		-		-1,763		-
		Level 3, end of period		$	12,458	$	594,156	$	-	$	606,614	$	-
				Three Months Ended September 30, 2012
				Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
		Level 3, beginning of period		$	9,819	$	478,860	$	-	$	488,679	$	-
		Total net realized gains included in earnings			44		18,461		-		18,505		-
		Total net realized and unrealized losses included in earnings			-		-3,411		-		-3,411		-
		Change in unrealized gains included in other comprehensive income (loss)			570		-		-		570		-
		Change in unrealized losses included in other comprehensive income (loss)			-14		-		-		-14		-
		Purchases			2		37,319		-		37,321		-
		Sales			-1,536		-52,319		-		-53,855		-
		Transfers in to Level 3			5,695		-		-		5,695		-
		Transfers out of Level 3			-762		-		-		-762		-
		Level 3, end of period		$	13,818	$	478,910	$	-	$	492,728	$	-
				Nine Months Ended September 30, 2012
				Fixed maturity investments		Other investments		Other assets		Total assets		Other liabilities
		Level 3, beginning of period		$	10,394	$	-	$	-	$	10,394	$	-
		Total net realized gains included in earnings			54		29,286		-		29,340		-
		Total net realized and unrealized losses included in earnings			-13		-14,310		-		-14,323		-
		Change in unrealized gains included in other comprehensive income (loss)			1,732		-		-		1,732		-
		Change in unrealized losses included in other comprehensive income (loss)			-243		-		-		-243		-
		Purchases			-38		84,519		-		84,481		-
		Sales			-2,568		-53,013		-		-55,581		-
		Transfers in to Level 3			7,771		432,428(1)		-		440,199		-
		Transfers out of Level 3			-3,271		-		-		-3,271		-
		Level 3, end of period		$	13,818	$	478,910	$	-	$	492,728	$	-
		-1	As required by ASU 2011-04, the fair value of the Company's other investments was transferred into Level 3 at March 31, 2012.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share	'
Schedule Of Computation Of Basic And Diluted Earnings Per Share	'
						Three Months Ended						Nine Months Ended
						September 30,						September 30,
						2013			2012			2013			2012
		Numerator:
			Net income available to common and participating
				common shareholders	$	75,228		$	31,930		$	220,170		$	170,579
			Less amount allocated to participating
				common shareholders(1)		-1,997			-494			-4,742			-2,828
			Net income allocated to common shareholders		$	73,231		$	31,436		$	215,428		$	167,751
		Denominator:
			Weighted average shares – basic			43,099,841			42,628,248			42,719,837			42,555,617
			Share equivalents:
				Options		-			28,880			-			36,130
				Restricted share units		298			778			594			2,546
			Weighted average shares – diluted			43,100,139			42,657,906			42,720,431			42,594,293
		Basic earnings per common share			$	1.7		$	0.74		$	5.04		$	3.94
		Diluted earnings per common share			$	1.7		$	0.74		$	5.04		$	3.94
		(1) Represents earnings attributable to holders of unvested restricted shares issued by the Company. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares).
Schedule Of Dividends Declared	'
				Three Months Ended						Nine Months Ended
				September 30,						September 30,
				2013			2012			2013			2012
		Dividends declared per Series A preferred share		$	0.484375		$	0.484375		$	1.453125		$	1.453125
		Dividends declared per Series B preferred share		$	0.46875		$	0.46875		$	1.40625		$	1.40625
		Dividends declared per common share		$	0.32		$	0.31		$	0.96		$	0.93

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income	'
Schedule Of Accumulated Other Comprehensive Income	'
				For the Three Months Ended September 30, 2013
				Gains and losses on cash flow hedges			Unrealized gains and losses on available-for-sale securities		Foreign currency items		Total
	Beginning balance			$	-1,899		$	30,636	$	2,701	$	31,438
		Other comprehensive income before reclassifications			-			22,358		8,918		31,276
		Amounts reclassified from accumulated other comprehensive income(1)			22			6,721		-		6,743
	Net current period other comprehensive income				22			29,079		8,918		38,019
	Ending balance			$	-1,877		$	59,715	$	11,619	$	69,457
	(1) All amounts are net of tax.
				Nine Months Ended September 30, 2013
				Gains and losses on cash flow hedges			Unrealized gains and losses on available-for-sale securities		Foreign currency items		Total
	Beginning balance			$	-1,944		$	141,731	$	12,676	$	152,463
		Other comprehensive loss before reclassifications			-			-74,001		-1,057		-75,058
		Amounts reclassified from accumulated other comprehensive income(1)			67			-8,015		-		-7,948
	Net current period other comprehensive income (loss)				67			-82,016		-1,057		-83,006
	Ending balance			$	-1,877		$	59,715	$	11,619	$	69,457
	(1) All amounts are net of tax.
Reclassification Out Of Accumulated Other Comprehensive Income	'
		Three Months Ended September 30, 2013
		Details about accumulated other comprehensive income components				Amount reclassified from accumulated other comprehensive income		Affected line item in the Unaudited Condensed Consolidated Statements of Income and Comprehensive Income
		Gains and losses on cash flow hedges -
			Debt		$	22		Interest expense
						22		Total before income taxes
						-		Income tax expense
					$	22		Total net of income taxes
		Unrealized losses (gains) on available-for-sale securities			$	6,999		Net realized and unrealized investment losses
						190		Net impairment losses recognized in earnings
						7,189		Total before income taxes
						-468		Income tax benefit
					$	6,721		Total net of income taxes
		Nine Months Ended September 30, 2013
		Details about accumulated other comprehensive income components				Amount reclassified from accumulated other comprehensive income		Affected line item in the Unaudited Condensed Consolidated Statements of Income and Comprehensive Income
		Gains and losses on cash flow hedges -
			Debt		$	67		Interest expense
						67		Total before income taxes
						-		Income tax expense
					$	67		Total net of income taxes
		Unrealized (gains) losses on available-for-sale securities			$	-10,267		Net realized and unrealized investment gains
						1,575		Net impairment losses recognized in earnings
						-8,692		Total before income taxes
						677		Income tax expense
					$	-8,015		Total net of income taxes

Derivatives_Tables

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2013
Derivatives	'
Schedule Of The Fair Value And Related Notional Amounts Of Derivatives Included In The Company's Consolidated Balance Sheet	'
				30-Sep-13				31-Dec-12
						Notional				Notional
				Fair		Principal		Fair		Principal
				Value		Amount		Value		Amount
		Derivatives recorded in other assets
			Foreign exchange forward contracts	$	74	$	9,539	$	23	$	1,652
			Credit default swaps		-		-		9		410
			Interest rate swaps		1		5,600		76		5,000
			Interest rate swaptions		37		23,900		57		2,200
			Interest rate futures		-		64,217		-		-
			TBAs		120,414		119,000		20,523		19,000
			Energy and weather contracts		2,327		35,627		2,961		15,573
			Total recorded in other assets	$	122,853			$	23,649
		Derivatives recorded in other liabilities
			Foreign exchange forward contracts	$	333	$	15,285	$	60	$	5,296
			Interest rate swaps		764		23,214		-		-
			Interest rate swaptions		134		74,200		133		14,500
			TBAs		68,174		67,000		7,506		7,000
			Energy and weather contracts		4,832		35,627		2,961		15,573
			Total recorded in other liabilities	$	74,237			$	10,660
			Net derivative asset	$	48,616			$	12,989
Schedule Of The Gains And Losses On The Consolidated Statements Of Income And Comprehensive Income From Derivatives	'
				Three Months Ended				Nine Months Ended
				September 30,				September 30,
				2013		2012		2013		2012
		Total (losses) gains included in net foreign exchange losses
			(gains) from foreign exchange forward contracts	$	-123	$	-10	$	207	$	141
			Futures contracts	$	112	$	-	$	64	$	87
			Credit default swaps		-68		3		49		46
			Interest rate swaps		-67		29		-228		-14
			Interest rate swaptions		392		-16		291		31
			TBAs		-11		327		-476		662
		Total gains (losses) included in net realized and unrealized
			investment (losses) gains	$	358	$	343	$	-300	$	812
			Commodity put options	$	-	$	-1,384	$	-	$	-2,684
			Energy and weather contracts		-		-		1,172		-
		Total (losses) gains included in other underwriting (loss) income		$	-	$	-1,384	$	1,172	$	-2,684
		Total gains (losses) from derivatives		$	235	$	-1,051	$	1,079	$	-1,731

StockBased_Employee_Compensati1

Stock-Based Employee Compensation And Other Stock Plans (Tables)	9 Months Ended
	Sep. 30, 2013
Stock-Based Employee Compensation And Other Stock Plans	'
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	'
			Nine Months Ended September 30, 2013
						Weighted Average
				Weighted		Remaining
			Number of	Average		Contractual Life		Aggregate
		Options Outstanding	Options	Exercise Price		(years)		Intrinsic Value
		Beginning, December 31, 2012	39,501	$	27.78
		Granted	800,000		48.2
		Exercised	24,501		23.88
		Forfeited	-		-
		Outstanding, September 30, 2013	815,000	$	47.94		9.5	$	4,711
		Exercisable and vested options, September 30, 2013	175,000	$	46.98		8.89	$	1,180
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	'
			Nine Months Ended September 30, 2013
			Number of	Aggregate
			Shares/Units	Intrinsic Value
		Unvested, December 31, 2012	686,633
		Granted	1,079,108
		Settled	-406,495
		Forfeited	-211,227
		Unvested, September 30, 2013	1,148,019
		Outstanding, September 30, 2013	1,148,019	$	61,672

Segment_Reporting_Tables

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting	'
Summary Of The Segment Revenues, Results And Reserve For Losses And Loss Expenses	'
					Three Months Ended September 30, 2013
						Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	344,819		$	199,544			$	544,363
				Ceded premiums written			-120,481			-28,549				-149,030
				Net premiums written			224,338			170,995				395,333
				Net premiums earned			291,477			262,068				553,545
				Other underwriting loss			-			-943				-943
							291,477			261,125				552,602
			Expenses
				Net losses and loss expenses			228,409			110,627				339,036
				Acquisition expenses			18,440			60,335				78,775
				General and administrative expenses			35,641			31,829				67,470
							282,490			202,791				485,281
			Underwriting income			$	8,987		$	58,334			$	67,321
			Net loss ratio				78.4	%		42.3	%			61.3	%
			Acquisition expense ratio				6.3	%		23	%			14.2	%
			General and administrative expense ratio				12.2	%		12.1	%			12.2	%
			Combined ratio				96.9	%		77.4	%			87.7	%
			Reserve for losses and loss expenses			$	2,146,136		$	1,905,966			$	4,052,102
					Three Months Ended September 30, 2012
							Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	324,808		$	296,447			$	621,255
				Ceded premiums written			-103,543			-3,632				-107,175
				Net premiums written			221,265			292,815				514,080
				Net premiums earned			283,273			268,599				551,872
				Other underwriting (loss) income			-1,384			37				-1,347
							281,889			268,636				550,525
			Expenses
				Net losses and loss expenses			288,750			118,773				407,523
				Acquisition expenses			24,506			64,276				88,782
				General and administrative expenses			29,409			23,306				52,715
							342,665			206,355				549,020
			Underwriting (loss) income			$	-60,776		$	62,281			$	1,505
			Net loss ratio				101.9	%		44.2	%			73.8	%
			Acquisition expense ratio				8.7	%		23.9	%			16.1	%
			General and administrative expense ratio				10.4	%		8.7	%			9.6	%
			Combined ratio				121	%		76.8	%			99.5	%
			Reserve for losses and loss expenses			$	2,635,086		$	1,874,356			$	4,509,442
					Nine Months Ended September 30, 2013
							Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	1,274,703		$	1,019,732			$	2,294,435
				Ceded premiums written			-454,169			-71,397				-525,566
				Net premiums written			820,534			948,335				1,768,869
				Net premiums earned			710,507			806,490				1,516,997
				Other underwriting income			-			694				694
							710,507			807,184				1,517,691
			Expenses
				Net losses and loss expenses			543,717			373,347				917,064
				Acquisition expenses			48,024			174,255				222,279
				General and administrative expenses			114,792			100,515				215,307
							706,533			648,117				1,354,650
			Underwriting income			$	3,974		$	159,067			$	163,041
			Net loss ratio				76.4	%		46.3	%			60.4	%
			Acquisition expense ratio				6.8	%		21.6	%			14.7	%
			General and administrative expense ratio				16.2	%		12.5	%			14.2	%
			Combined ratio				99.4	%		80.4	%			89.3	%
					Nine Months Ended September 30, 2012
							Insurance			Reinsurance				Total
			Revenues
				Gross premiums written		$	1,252,814		$	1,034,166			$	2,286,980
			Ceded premiums written			-417,109			-28,322				-445,431
			Net premiums written			835,705			1,005,844				1,841,549
			Net premiums earned			710,988			771,859				1,482,847
			Other underwriting (loss) income			-2,684			1,021				-1,663
						708,304			772,880				1,481,184
		Expenses
			Net losses and loss expenses			610,956			405,231				1,016,187
			Acquisition expenses			58,265			171,134				229,399
			General and administrative expenses			96,663			84,702				181,365
						765,884			661,067				1,426,951
		Underwriting (loss) income			$	-57,580		$	111,813			$	54,233
		Net loss ratio				85.9	%		52.4	%			68.5	%
		Acquisition expense ratio				8.2	%		22.2	%			15.5	%
		General and administrative expense ratio				13.6	%		11	%			12.2	%
		Combined ratio				107.7	%		85.6	%			96.2	%
Schedule Of Segment Results To Income Before Income Taxes	'
				Three Months Ended
				September 30,
					2013			2012
			Total underwriting income	$	67,321		$	1,505
			Net investment income		38,097			45,882
			Net foreign exchange losses		-2,201			-3,774
			Net realized and unrealized investment (losses) gains		-6,640			10,097
			Net impairment losses recognized in earnings		-190			-131
			Amortization of intangibles		-1,652			-2,434
			Interest expense		-9,048			-9,041
			Income before income taxes	$	85,687		$	42,104
			Nine Months Ended
			September 30,
				2013			2012
		Total underwriting income	$	163,041		$	54,233
		Net investment income		119,870			134,723
		Net foreign exchange (losses) gains		-8,496			14,699
		Net realized and unrealized investment gains		9,967			30,258
		Net impairment losses recognized in earnings		-1,575			-757
		Amortization of intangibles		-5,378			-7,988
		Interest expense		-27,138			-27,132
		Income before income taxes	$	250,291		$	198,036
Schedule Of Gross And Net Premiums By Line Of Business	'
					Gross			Net		Gross			Net
					premiums			premiums		premiums			premiums
					written			written		written			written
		Business Segment			2013			2013		2012			2012
		Insurance
			Agriculture	$	200,062		$	120,617	$	171,826		$	106,180
			Casualty and other specialty		95,862			72,431		90,873			66,686
			Professional lines		34,221			20,972		43,209			34,804
			Property		14,674			10,318		18,900			13,595
		Total Insurance			344,819			224,338		324,808			221,265
		Reinsurance
			Catastrophe		38,676			12,551		38,871			36,484
			Casualty		53,691			53,690		77,781			77,781
			Property		91,653			90,528		157,742			157,742
			Other specialty		15,524			14,226		22,053			20,808
		Total Reinsurance			199,544			170,995		296,447			292,815
		Total		$	544,363		$	395,333	$	621,255		$	514,080
					Gross			Net		Gross			Net
					premiums			premiums		premiums			premiums
					written			written		written			written
		Business Segment			2013			2013		2012			2012
		Insurance
			Agriculture	$	896,169		$	546,284	$	838,932		$	528,349
			Casualty and other specialty		239,943			179,065		236,383			173,097
			Professional lines		93,481			62,963		130,573			107,841
			Property		45,110			32,222		46,926			26,418
		Total Insurance			1,274,703			820,534		1,252,814			835,705
		Reinsurance
			Catastrophe		341,973			281,990		354,275			329,067
			Casualty		272,602			271,174		258,352			257,113
			Property		288,448			283,455		318,514			318,521
			Other specialty		116,709			111,716		103,025			101,143
		Total Reinsurance			1,019,732			948,335		1,034,166			1,005,844
		Total		$	2,294,435		$	1,768,869	$	2,286,980		$	1,841,549

Commitments_And_Contingencies_

Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies	'
Schedule Of Percentage Of Net Premiums	'
		Broker	2013		2012
		Aon Benfield	18.5	%	17.3	%
		Marsh & McLennan Companies, Inc.	15	%	16.6	%
		Willis Companies	12.4	%	15.8	%
		Total of largest brokers	45.9	%	49.7	%
Schedule Of Future Minimum Lease Commitments	'
		Twelve months ended September 30,	Amount
		2014	$	14,586
		2015		13,822
		2016		11,298
		2017		9,791
		2018		9,575
		2019 and thereafter		41,135
			$	100,207

Investments_Narrative_Details

Investments (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Investments	'	'	'	'	'
Other investments amount invested, net of capital returned	$438,900,000	'	$438,900,000	'	$394,500,000
Market value of other investments	594,156,000	'	594,156,000	'	517,546,000
Number of available for sale securities in an unrealized loss position	743	'	743	'	403
Number of securities in a continuous unrealized loss position for twelve months or greater	31	'	31	'	55
OTTI losses recognized	190,000	131,000	1,575,000	757,000	'
Unrealized Losses	-42,346,000	'	-42,346,000	'	-6,881,000	[1]
Unrealized Losses, 12 months or greater	($587,000)	'	($587,000)	'	($2,138,000)
[1]	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at December 31, 2012.

Investments_Composition_Of_Net

Investments (Composition Of Net Investment Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments	'	'	'	'
Available for sale investments	$27,889	$33,946	$86,036	$105,606
Other investments	13,244	15,050	43,083	38,101
Cash and cash equivalents	752	289	2,043	978
Gross investment income	41,885	49,285	131,162	144,685
Investment expenses	-3,788	-3,403	-11,292	-9,962
Net investment income	$38,097	$45,882	$119,870	$134,723

Investments_Summary_Of_Investm

Investments (Summary Of Investment Portfolio By Type) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Summary of Investment Holdings [Line Items]	'		'
Fair Value	$6,359,221		$6,566,617
Percentage of Investment	100.00%		100.00%
Fixed Maturity Securities [Member]	'		'
Summary of Investment Holdings [Line Items]	'		'
Fair Value	4,800,838		4,868,150
Percentage of Investment	75.60%		74.20%
Cash and Cash Equivalents [Member]	'		'
Summary of Investment Holdings [Line Items]	'		'
Fair Value	689,762	[1]	1,051,694	[1]
Percentage of Investment	10.80%	[1]	16.00%	[1]
Other Investments [Member]	'		'
Summary of Investment Holdings [Line Items]	'		'
Fair Value	594,156	[2]	517,546	[2]
Percentage of Investment	9.30%	[2]	7.90%	[2]
Short Term Investments [Member]	'		'
Summary of Investment Holdings [Line Items]	'		'
Fair Value	11,599		42,230
Percentage of Investment	0.20%		0.60%
Equity Securities [Member]	'		'
Summary of Investment Holdings [Line Items]	'		'
Fair Value	$262,866		$86,997
Percentage of Investment	4.10%		1.30%
[1]	Includes net receivable on sales of investments and net payable on purchases of investments.
[2]	Consists of investments in alternative funds and specialty funds.

Investments_Composition_Of_The

Investments (Composition Of The Fixed Income Portfolio By Investment Ratings Assigned By Rating Agencies) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
AAA/Aaa [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	$1,031,149	[1]	$993,277	[1]
Percentage of fixed income portfolio by investment ratings	21.40%	[1]	20.20%	[1]
AA/Aa [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	1,781,679	[1]	1,821,250	[1]
Percentage of fixed income portfolio by investment ratings	37.00%	[1]	37.10%	[1]
A/A [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	807,509	[1]	993,307	[1]
Percentage of fixed income portfolio by investment ratings	16.80%	[1]	20.20%	[1]
BBB [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	296,489	[1]	219,017	[1]
Percentage of fixed income portfolio by investment ratings	6.20%	[1]	4.50%	[1]
Below BBB [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	67,269	[1]	143,198	[1]
Percentage of fixed income portfolio by investment ratings	1.40%	[1]	2.90%	[1]
Not Rated [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	4,581	[1]	2,796	[1]
Percentage of fixed income portfolio by investment ratings	0.10%	[1]	0.10%	[1]
U.S. Government And Agencies Securities [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	823,761	[1]	737,535	[1]
Percentage of fixed income portfolio by investment ratings	17.10%	[1]	15.00%	[1]
Fixed Income Investments [Member]	'		'
Investments By Rating [Line Items]	'		'
Fair Value of fixed income portfolio by investment ratings	$4,812,437	[1]	$4,910,380	[1]
Percentage of fixed income portfolio by investment ratings	100.00%	[1]	100.00%	[1]
[1]	The credit rating for each security reflected above was determined based on the rating assigned to the individual security by Standard & Poor's Financial Services LLC ("Standard & Poor's"). If a rating is not supplied by Standard & Poor's, the equivalent rating supplied by either Moody's Investors Service, Inc. ("Moody's") or Fitch Ratings is used.

Investments_Contractual_Maturi

Investments (Contractual Maturities Of Fixed Income Securities) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'		'
Due within one year, Amortized Cost	$128,110		$136,283
Due within one year, Fair Value	129,417		137,567
Due after one year through five years, Amortized Cost	1,775,192		1,725,927
Due after one year through five years, Fair Value	1,787,984		1,765,662
Due after five years through ten years, Amortized Cost	265,740		410,755
Due after five years through ten years, Fair Value	266,962		429,099
Due after ten years, Amortized Cost	27,207		29,654
Due after ten years, Fair Value	27,847		33,803
Amortized Cost	4,759,092		4,728,596
Debt Securities, Fair Value	4,800,838		4,868,150
Residential Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
No single maturity date, amortized cost	1,235,668		1,252,468
No single maturity date, fair value	1,240,222		1,280,579
Amortized Cost	1,235,668		1,252,468
Debt Securities, Fair Value	1,240,222		1,280,579
Commercial Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
No single maturity date, amortized cost	872,259		741,178
No single maturity date, fair value	889,460		781,379
Amortized Cost	872,259	[1]	741,178	[2]
Debt Securities, Fair Value	889,460	[1]	781,379	[2]
Asset-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
No single maturity date, amortized cost	466,516		474,555
No single maturity date, fair value	470,545		482,291
Amortized Cost	466,516		474,555
Debt Securities, Fair Value	470,545		482,291
Fixed Income Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost	4,770,692		4,770,820
Debt Securities, Fair Value	$4,812,437		$4,910,380
[1]	Balances include amounts related to collateralized debt obligations held with total fair values of $14.1 million.
[2]	Balances include amounts related to collateralized debt obligations held with total fair values of $8.5 million.

Investments_Other_Investments_

Investments (Other Investments) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	$594,156	$517,546
Commitments under investment fund classified within other investments	60,790	29,483
Prohibited amount under redemption requests over the next 12 months	100,322	96,380
Alternative Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	441,444	372,419
Commitments under investment fund classified within other investments	60,790	29,483
Prohibited amount under redemption requests over the next 12 months	100,322	96,380
Hedge Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	385,913	337,200
Commitments under investment fund classified within other investments	0	0
Prohibited amount under redemption requests over the next 12 months	44,791	61,161
Private Equity Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	55,531	35,219
Commitments under investment fund classified within other investments	60,790	29,483
Prohibited amount under redemption requests over the next 12 months	55,531	35,219
Specialty Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	152,712	145,127
Commitments under investment fund classified within other investments	0	0
Prohibited amount under redemption requests over the next 12 months	0	0
High Yield Loan Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	109,171	105,886
Commitments under investment fund classified within other investments	0	0
Prohibited amount under redemption requests over the next 12 months	0	0
Convertible Debt Funds [Member]	'	'
Schedule Of Equity Method Investments [Line Items]	'	'
Market value of other investments	43,541	39,241
Commitments under investment fund classified within other investments	0	0
Prohibited amount under redemption requests over the next 12 months	$0	$0

Investments_Other_Investments_1

Investments (Other Investments) (Details 2)	9 Months Ended
	Sep. 30, 2013
Hedge Funds [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated remaining liquidation period in years	'2 years 0 months 0 days
Estimated liquidation, percentage in next 12 months	88.20%
Hedge Funds [Member] | Maximum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated notice period, in days	'90
Hedge Funds [Member] | Minimum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated notice period, in days	'30
Private Equity Funds [Member] | Maximum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated remaining liquidation period in years	'10 years 0 months 0 days
Private Equity Funds [Member] | Minimum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated remaining liquidation period in years	'5 years 0 months 0 days
High Yield Loan Funds [Member] | Maximum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated notice period, in days	'90
High Yield Loan Funds [Member] | Minimum [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated notice period, in days	'30
Convertible Debt Funds [Member]	'
Schedule Of Equity Method Investments [Line Items]	'
Estimated notice period, in days	'5

Investments_Net_Realized_and_U

Investments (Net Realized and Unrealized Investment (Losses) Gains) (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Investments	'		'		'		'
Gross realized gains on investment sales	$6,180		$11,976		$30,191		$34,837
Gross realized losses on investment sales	-13,178		-2,222		-19,924		-5,391
Change in fair value of derivatives financial instruments	358	[1]	343	[1]	-300	[1]	812	[1]
Net realized and unrealized investment (losses) gains	($6,640)		$10,097		$9,967		$30,258
[1]	For additional information on the Company's derivative financial instruments, see Note 7

Investments_Unrealized_Gains_A

Investments (Unrealized Gains And Losses And Other-Than-Temporary Impairments) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	$4,759,092,000		$4,728,596,000
Debt Securities, Fair Value	4,800,838,000		4,868,150,000
Available for sale, equity Securities, cost	246,288,000		76,997,000
Equity Securities, Fair Value	262,866,000		86,997,000
Gross unrealized loss related to securities, non-credit OTTI	100,000		400,000
U.S. Government And Agencies Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	819,585,000		718,992,000
Debt Securities, Gross Unrealized Gains	9,332,000		18,596,000
Debt Securities, Gross Unrealized Losses	-5,156,000		-53,000
Debt Securities, Fair Value	823,761,000		737,535,000
Non-Credit OTTI	0	[1]	0	[2]
U.S. State And Municipal Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	27,731,000		37,952,000
Debt Securities, Gross Unrealized Gains	129,000		1,119,000
Debt Securities, Gross Unrealized Losses	-490,000		-177,000
Debt Securities, Fair Value	27,370,000		38,894,000
Non-Credit OTTI	0	[1]	0	[2]
Foreign Government Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	175,280,000		106,218,000
Debt Securities, Gross Unrealized Gains	1,725,000		3,264,000
Debt Securities, Gross Unrealized Losses	-1,496,000		-145,000
Debt Securities, Fair Value	175,509,000		109,337,000
Non-Credit OTTI	0	[1]	0	[2]
Government Guaranteed Corporate Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	34,244,000		62,782,000
Debt Securities, Gross Unrealized Gains	328,000		1,682,000
Debt Securities, Gross Unrealized Losses	-52,000		0
Debt Securities, Fair Value	34,520,000		64,464,000
Non-Credit OTTI	0	[1]	0	[2]
Corporate Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	1,127,809,000		1,334,451,000
Debt Securities, Gross Unrealized Gains	18,130,000		40,555,000
Debt Securities, Gross Unrealized Losses	-6,488,000		-1,335,000
Debt Securities, Fair Value	1,139,451,000		1,373,671,000
Non-Credit OTTI	0	[1]	0	[2]
Residential Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	1,235,668,000		1,252,468,000
Debt Securities, Gross Unrealized Gains	20,278,000		30,426,000
Debt Securities, Gross Unrealized Losses	-15,724,000		-2,315,000
Debt Securities, Fair Value	1,240,222,000		1,280,579,000
Non-Credit OTTI	-4,785,000	[1]	-5,884,000	[2]
Commercial Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	872,259,000	[3]	741,178,000	[4]
Debt Securities, Gross Unrealized Gains	26,341,000	[3]	41,737,000	[4]
Debt Securities, Gross Unrealized Losses	-9,140,000	[3]	-1,536,000	[4]
Debt Securities, Fair Value	889,460,000	[3]	781,379,000	[4]
Non-Credit OTTI	-47,000	[1],[3]	-53,000	[2],[4]
Asset-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	466,516,000		474,555,000
Debt Securities, Gross Unrealized Gains	5,067,000		8,435,000
Debt Securities, Gross Unrealized Losses	-1,038,000		-699,000
Debt Securities, Fair Value	470,545,000		482,291,000
Non-Credit OTTI	0	[1]	0	[2]
Fixed Maturity Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	4,759,092,000		4,728,596,000
Debt Securities, Gross Unrealized Gains	81,330,000		145,814,000
Debt Securities, Gross Unrealized Losses	-39,584,000		-6,260,000
Debt Securities, Fair Value	4,800,838,000		4,868,150,000
Non-Credit OTTI	-4,832,000	[1]	-5,937,000	[2]
Short Term Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	11,600,000		42,224,000
Debt Securities, Gross Unrealized Gains	0		6,000
Debt Securities, Gross Unrealized Losses	-1,000		0
Debt Securities, Fair Value	11,599,000		42,230,000
Non-Credit OTTI	0	[1]	0	[2]
Fixed Income Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Amortized Cost	4,770,692,000		4,770,820,000
Debt Securities, Gross Unrealized Gains	81,330,000		145,820,000
Debt Securities, Gross Unrealized Losses	-39,585,000		-6,260,000
Debt Securities, Fair Value	4,812,437,000		4,910,380,000
Non-Credit OTTI	-4,832,000	[1]	-5,937,000	[2]
Equity Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Available for sale, equity Securities, cost	152,328,000		59,736,000
Equity Securities, Gross Unrealized Gains	17,197,000		7,194,000
Equity Securities, Gross Unrealized Losses	-2,697,000		-620,000
Equity Securities, Fair Value	166,828,000		66,310,000
Non-Credit OTTI	0	[1]	0	[2]
Emerging Market Debt Funds [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Available for sale, equity Securities, cost	60,250,000		10,000,000
Equity Securities, Gross Unrealized Gains	255,000		576,000
Equity Securities, Gross Unrealized Losses	0		0
Equity Securities, Fair Value	60,505,000		10,576,000
Non-Credit OTTI	0	[1]	0	[2]
Preferred Equity Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Available for sale, equity Securities, cost	10,184,000		7,261,000
Equity Securities, Gross Unrealized Gains	1,883,000		2,851,000
Equity Securities, Gross Unrealized Losses	-64,000		-1,000
Equity Securities, Fair Value	12,003,000		10,111,000
Non-Credit OTTI	0	[1]	0	[2]
Short-term Fixed Income Fund [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Available for sale, equity Securities, cost	23,526,000		'
Equity Securities, Gross Unrealized Gains	4,000		'
Equity Securities, Gross Unrealized Losses	0		'
Equity Securities, Fair Value	23,530,000		'
Non-Credit OTTI	0	[1]	'
Total Equity Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Available for sale, equity Securities, cost	246,288,000		76,997,000
Equity Securities, Gross Unrealized Gains	19,339,000		10,621,000
Equity Securities, Gross Unrealized Losses	-2,761,000		-621,000
Equity Securities, Fair Value	262,866,000		86,997,000
Non-Credit OTTI	0	[1]	0	[2]
Collateralized Debt Obligations [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Debt Securities, Fair Value	$14,100,000		$8,500,000
[1]	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At September 30, 2013, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.1 million.
[2]	Represents total OTTI recognized in accumulated other comprehensive income. It does not include the change in fair value subsequent to the impairment measurement date. At December 31, 2012, the gross unrealized loss related to fixed income investments for which a non-credit OTTI was recognized in accumulated other comprehensive income was $0.4 million.
[3]	Balances include amounts related to collateralized debt obligations held with total fair values of $14.1 million.
[4]	Balances include amounts related to collateralized debt obligations held with total fair values of $8.5 million.

Investments_Available_For_Sale

Investments (Available For Sale Securities In An Unrealized Loss Position) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, 12 months or greater	($587)		($2,138)
Unrealized Losses	-42,346		-6,881	[1]
U.S. Government And Agencies Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-5,156	[2]	-53	[1]
Fair Value, Less than 12 months	265,417		48,570
Unrealized Losses, 12 months or greater	0	[2]	0	[1]
Fair Value, 12 months or greater	0		0
Unrealized Losses	-5,156	[2]	-53	[1]
Fair Value	265,417		48,570
U.S. State And Municipal Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-490	[2]	-177	[1]
Fair Value, Less than 12 months	19,711		6,905
Unrealized Losses, 12 months or greater	0	[2]	0	[1]
Fair Value, 12 months or greater	0		0
Unrealized Losses	-490	[2]	-177	[1]
Fair Value	19,711		6,905
Foreign Government Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-1,495	[2]	-139	[1]
Fair Value, Less than 12 months	109,722		23,157
Unrealized Losses, 12 months or greater	-1	[2]	-6	[1]
Fair Value, 12 months or greater	4,858		4,870
Unrealized Losses	-1,496	[2]	-145	[1]
Fair Value	114,580		28,027
Government Guaranteed Corporate Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-52	[2]	0	[1]
Fair Value, Less than 12 months	11,301		'
Unrealized Losses, 12 months or greater	0	[2]	0	[1]
Fair Value, 12 months or greater	0		'
Unrealized Losses	-52	[2]	0	[1]
Fair Value	11,301		'
Corporate Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-6,488	[2]	-1,305	[1]
Fair Value, Less than 12 months	422,818		245,232
Unrealized Losses, 12 months or greater	0	[2]	-30	[1]
Fair Value, 12 months or greater	0		1,849
Unrealized Losses	-6,488	[2]	-1,335	[1]
Fair Value	422,818		247,081
Residential Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-15,641	[2]	-1,920	[1]
Fair Value, Less than 12 months	510,138		327,473
Unrealized Losses, 12 months or greater	-83	[2]	-395	[1]
Fair Value, 12 months or greater	1,619		7,511
Unrealized Losses	-15,724	[2]	-2,315	[1]
Fair Value	511,757		334,984
Commercial Mortgage-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-8,822	[2]	-474	[1]
Fair Value, Less than 12 months	351,269		79,125
Unrealized Losses, 12 months or greater	-318	[2]	-1,062	[1]
Fair Value, 12 months or greater	4,936		11,625
Unrealized Losses	-9,140	[2]	-1,536	[1]
Fair Value	356,205		90,750
Asset-Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-853	[2]	-94	[1]
Fair Value, Less than 12 months	184,964		53,471
Unrealized Losses, 12 months or greater	-185	[2]	-605	[1]
Fair Value, 12 months or greater	4,193		8,123
Unrealized Losses	-1,038	[2]	-699	[1]
Fair Value	189,157		61,594
Fixed Maturity Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-38,997	[2]	-4,162	[1]
Fair Value, Less than 12 months	1,875,340		783,933
Unrealized Losses, 12 months or greater	-587	[2]	-2,098	[1]
Fair Value, 12 months or greater	15,606		33,978
Unrealized Losses	-39,584	[2]	-6,260	[1]
Fair Value	1,890,946		817,911
Short Term Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-1	[2]	'
Fair Value, Less than 12 months	1,246		'
Unrealized Losses, 12 months or greater	0	[2]	'
Fair Value, 12 months or greater	0		'
Unrealized Losses	-1	[2]	'
Fair Value	1,246		'
Fixed Income Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-38,998	[2]	'
Unrealized Losses, 12 months or greater	-587	[2]	'
Unrealized Losses	-39,585	[2]	'
Equity Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-2,697	[2]	-580	[1]
Fair Value, Less than 12 months	43,925		9,183
Unrealized Losses, 12 months or greater	0	[2]	-40	[1]
Fair Value, 12 months or greater	0		387
Unrealized Losses	-2,697	[2]	-620	[1]
Fair Value	43,925		9,570
Preferred Equity Investments [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-64	[2]	-1	[1]
Fair Value, Less than 12 months	5,924		201
Unrealized Losses, 12 months or greater	0	[2]	0	[1]
Fair Value, 12 months or greater	0		0
Unrealized Losses	-64	[2]	-1	[1]
Fair Value	5,924		201
Total Equity Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Unrealized Losses, Less than 12 months	-2,761	[2]	-581	[1]
Fair Value, Less than 12 months	49,849		9,384
Unrealized Losses, 12 months or greater	0	[2]	-40	[1]
Fair Value, 12 months or greater	0		387
Unrealized Losses	-2,761	[2]	-621	[1]
Fair Value	$49,849		$9,771
[1]	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at December 31, 2012.
[2]	Gross unrealized losses include unrealized losses on non-OTTI and non-credit OTTI securities recognized in accumulated other comprehensive income at September 30, 2013.

Investments_Analysis_Of_OTTI_D

Investments (Analysis Of OTTI) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments	'	'	'	'
Total other-than-temporary impairment losses	($190)	($126)	($1,575)	($274)
Portion of loss recognized in other comprehensive income (loss)	0	-5	0	-483
Net impairment losses recognized in earnings	($190)	($131)	($1,575)	($757)

Investments_Credit_Losses_Roll

Investments (Credit Losses Rollforward) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments	'	'	'	'
Beginning balance	($1,769)	($2,268)	($2,000)	($2,225)
Addition for the amount related to the credit loss for which an other-than-temporary impairment was not previously recognized	0	0	0	-3
Addition for the amount related to the credit loss for which an other-than-temporary impairment was previously recognized	0	-5	0	-503
Reductions for increases in cash flows expected to be collected that are recognized over the remaining life of the security	0	0	0	0
Reductions for securities sold during the period	113	216	344	674
Ending balance	($1,656)	($2,057)	($1,656)	($2,057)

Fair_Value_Measurement_Narrati

Fair Value Measurement (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
					Significant Unobservable Inputs (Level 3) [Member]	Significant Unobservable Inputs (Level 3) [Member]	Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities [Line Items]	'	'	'	'	'	'	'
Percentage of level 3 assets	'	'	'	'	10.50%	'	9.60%
Net transfers into Level 3 from Level 2	'	'	'	'	$9,800	'	'
Net impairment losses recognized in earnings	$190	$131	$1,575	$757	$0	$0	'

Fair_Value_Measurement_Schedul

Fair Value Measurement (Schedule Of Available For Sale Investments, Other Investments, Derivative Instruments And Debt) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	$4,800,838		$4,868,150
Short term investments	11,599		42,230
Equity securities	262,866		86,997
Other investments	594,156		517,546
Other assets (see Note 7)	122,853		23,649
Total assets	5,792,312		5,538,572
Other liabilities (see Note 7)	74,237		10,660
Debt	582,296		592,677
Total liabilities	656,533		603,337
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	17,865		39,889
Short term investments	0		0
Other investments	0		0
Other assets (see Note 7)	0		0
Total assets	121,991		106,199
Other liabilities (see Note 7)	0		0
Debt	0		0
Total liabilities	0		0
Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	4,770,515		4,819,764
Short term investments	11,599		42,230
Other investments	0		0
Other assets (see Note 7)	120,526		20,688
Total assets	5,061,380		4,903,369
Other liabilities (see Note 7)	69,405		7,699
Debt	582,296		592,677
Total liabilities	651,701		600,376
Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	12,458		8,497
Short term investments	0		0
Other investments	594,156		517,546
Other assets (see Note 7)	2,327		2,961
Total assets	608,941		529,004
Other liabilities (see Note 7)	4,832		2,961
Debt	0		0
Total liabilities	4,832		2,961
U.S. Government And Agencies Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	823,761		737,535
U.S. Government And Agencies Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	17,865		39,889
U.S. Government And Agencies Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	805,896		697,646
U.S. Government And Agencies Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
U.S. State And Municipal Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	27,370		38,894
U.S. State And Municipal Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
U.S. State And Municipal Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	27,370		38,894
U.S. State And Municipal Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Foreign Government Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	175,509		109,337
Foreign Government Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Foreign Government Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	175,509		109,337
Foreign Government Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Government Guaranteed Corporate Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	34,520		64,464
Government Guaranteed Corporate Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Government Guaranteed Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	34,520		64,464
Government Guaranteed Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Corporate Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	1,139,451		1,373,671
Corporate Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	1,138,692		1,373,671
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	759		0
Residential Mortgage-Backed Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	1,240,222		1,280,579
Residential Mortgage-Backed Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Residential Mortgage-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	1,240,015		1,280,223
Residential Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	207		356
Commercial Mortgage-Backed Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	889,460	[1]	781,379	[2]
Commercial Mortgage-Backed Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Commercial Mortgage-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	880,878		777,049
Commercial Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	8,582		4,330
Asset-Backed Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	470,545		482,291
Asset-Backed Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	0		0
Asset-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	467,635		478,480
Asset-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	2,910		3,811
Fixed Maturity Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Total fixed maturity investments	4,800,838		4,868,150
Equity Investments [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	166,828		66,310
Equity Investments [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	80,596		66,310
Equity Investments [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	86,232		0
Equity Investments [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		0
Emerging Market Debt Funds [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	60,505		10,576
Emerging Market Debt Funds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		0
Emerging Market Debt Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	60,505		10,576
Emerging Market Debt Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		0
Preferred Equity Investments [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	12,003		10,111
Preferred Equity Investments [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		0
Preferred Equity Investments [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	12,003		10,111
Preferred Equity Investments [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		0
Short-term Fixed Income Fund [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	23,530		'
Short-term Fixed Income Fund [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	23,530		'
Short-term Fixed Income Fund [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		'
Short-term Fixed Income Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	0		'
Total Equity Securities [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	262,866		86,997
Total Equity Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	104,126		66,310
Total Equity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	158,740		20,687
Total Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]	'		'
Fair Value, Assets and Liabilities [Line Items]	'		'
Equity securities	$0		$0
[1]	Balances include amounts related to collateralized debt obligations held with total fair values of $14.1 million.
[2]	Balances include amounts related to collateralized debt obligations held with total fair values of $8.5 million.

Fair_Value_Measurement_Reconci

Fair Value Measurement (Reconciliation Of The Beginning And Ending Balances For All Available For Sale Investments Measured At Fair Value On A Recurring Basis Using Level 3 Inputs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Level 3, beginning of period	$576,939	$488,679	$529,004	$10,394
Total net realized gains included in earnings	19,164	18,505	61,114	29,340
Total net realized and unrealized losses included in earnings	-5,879	-3,411	-17,944	-14,323
Change in unrealized gains included in other comprehensive income (loss)	111	570	438	1,732
Change in unrealized losses included in other comprehensive income (loss)	-62	-14	-270	-243
Purchases	16,597	37,321	62,017	84,481
Sales	-6,957	-53,855	-37,532	-55,581
Transfers in to Level 3	7,903	5,695	11,550	440,199
Transfers out of Level 3	-1,202	-762	-1,763	-3,271
Level 3, end of period	606,614	492,728	606,614	492,728
Fixed Maturity Investments [Member]	'	'	'	'
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Level 3, beginning of period	7,546	9,819	8,497	10,394
Total net realized gains included in earnings	56	44	104	54
Total net realized and unrealized losses included in earnings	-15	0	-17	-13
Change in unrealized gains included in other comprehensive income (loss)	111	570	438	1,732
Change in unrealized losses included in other comprehensive income (loss)	-62	-14	-270	-243
Purchases	0	2	0	-38
Sales	-1,879	-1,536	-6,081	-2,568
Transfers in to Level 3	7,903	5,695	11,550	7,771
Transfers out of Level 3	-1,202	-762	-1,763	-3,271
Level 3, end of period	12,458	13,818	12,458	13,818
Other Investments [Member]	'	'	'	'
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Level 3, beginning of period	569,393	478,860	517,546	0
Total net realized gains included in earnings	19,108	18,461	61,010	29,286
Total net realized and unrealized losses included in earnings	-5,864	-3,411	-17,927	-14,310
Change in unrealized gains included in other comprehensive income (loss)	0	0	0	0
Change in unrealized losses included in other comprehensive income (loss)	0	0	0	0
Purchases	16,597	37,319	62,011	84,519
Sales	-5,078	-52,319	-28,484	-53,013
Transfers in to Level 3	0	0	0	432,428	[1]
Transfers out of Level 3	0	0	0	0
Level 3, end of period	594,156	478,910	594,156	478,910
Other Assets [Member]	'	'	'	'
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Level 3, beginning of period	0	0	2,961	0
Total net realized gains included in earnings	0	0	0	0
Total net realized and unrealized losses included in earnings	0	0	0	0
Change in unrealized gains included in other comprehensive income (loss)	0	0	0	0
Change in unrealized losses included in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	6	0
Sales	0	0	-2,967	0
Transfers in to Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Level 3, end of period	0	0	0	0
Other Liabilities [Member]	'	'	'	'
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]	'	'	'	'
Level 3, beginning of period	0	0	2,961	0
Total net realized gains included in earnings	0	0	0	0
Total net realized and unrealized losses included in earnings	0	0	0	0
Change in unrealized gains included in other comprehensive income (loss)	0	0	0	0
Change in unrealized losses included in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	12	0
Sales	0	0	-2,973	0
Transfers in to Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Level 3, end of period	$0	$0	$0	$0
[1]	As required by ASU 2011-04, the fair value of the Company's other investments was transferred into Level 3 at March 31, 2012.

Earnings_Per_Share_Schedule_Of

Earnings Per Share (Schedule Of Computing Basic And Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Net income available to common and participating common shareholders	$75,228		$31,930		$220,170		$170,579
Less amount allocated to participating common shareholders	-1,997	[1]	-494	[1]	-4,742	[1]	-2,828	[1]
Net income allocated to common shareholders	$73,231		$31,436		$215,428		$167,751
Weighted average shares - basic	43,099,841		42,628,248		42,719,837		42,555,617
Weighted average shares - diluted	43,100,139		42,657,906		42,720,431		42,594,293
Basic earnings per common share	$1.70		$0.74		$5.04		$3.94
Diluted earnings per common share	$1.70		$0.74		$5.04		$3.94
Employee Stock Option [Member]	'		'		'		'
Share equivalents	0		28,880		0		36,130
Restricted Stock [Member]	'		'		'		'
Share equivalents	298		778		594		2,546
[1]	Represents earnings attributable to holders of unvested restricted shares issued by the Company. In periods of loss, no losses are allocated to participating common shareholders (unvested restricted shares).

Earnings_Per_Share_Schedule_Of1

Earnings Per Share (Schedule Of Dividends Declared) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Dividend Per Share Basic [Line Items]	'	'	'	'
Dividends declared per common share	$0.32	$0.31	$0.96	$0.93
Series A Preferred Stock [Member]	'	'	'	'
Dividend Per Share Basic [Line Items]	'	'	'	'
Dividends declared per preferred share	$0.48	$0.48	$1.45	$1.45
Series B Preferred Stock [Member]	'	'	'	'
Dividend Per Share Basic [Line Items]	'	'	'	'
Dividends declared per preferred share	$0.47	$0.47	$1.41	$1.41

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Schedule Of Changes In Accumulated Other Comprehensive Income By Component) (Details) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Accumulated Other Comprehensive Income [Line Items]	'		'	'		'
Accumulated Other Comprehensive Income, Beginning Balance	$31,438		'	$152,463		'
Other Comprehensive Income (Loss) Before Reclassifications	31,276		'	-75,058		'
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	6,743	[1]	'	-7,948	[1]	'
Other comprehensive income (loss)	38,019		42,987	-83,006		62,847
Accumulated Other Comprehensive Income, Ending Balance	69,457		'	69,457		'
Accumulated Derivative Loss On Cash Flow Hedging Instruments [Member]	'		'	'		'
Accumulated Other Comprehensive Income [Line Items]	'		'	'		'
Accumulated Other Comprehensive Income, Beginning Balance	-1,899		'	-1,944		'
Other Comprehensive Income (Loss) Before Reclassifications	0		'	0		'
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	22	[1]	'	67	[1]	'
Other comprehensive income (loss)	22		'	67		'
Accumulated Other Comprehensive Income, Ending Balance	-1,877		'	-1,877		'
Unrealized Holding Gains And Losses On AFS Investments, Net Of Deferred Taxes [Member]	'		'	'		'
Accumulated Other Comprehensive Income [Line Items]	'		'	'		'
Accumulated Other Comprehensive Income, Beginning Balance	30,636		'	141,731		'
Other Comprehensive Income (Loss) Before Reclassifications	22,358		'	-74,001		'
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	6,721	[1]	'	-8,015	[1]	'
Other comprehensive income (loss)	29,079		'	-82,016		'
Accumulated Other Comprehensive Income, Ending Balance	59,715		'	59,715		'
Cumulative Foreign Currency Translation Adjustments [Member]	'		'	'		'
Accumulated Other Comprehensive Income [Line Items]	'		'	'		'
Accumulated Other Comprehensive Income, Beginning Balance	2,701		'	12,676		'
Other Comprehensive Income (Loss) Before Reclassifications	8,918		'	-1,057		'
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax	0	[1]	'	0	[1]	'
Other comprehensive income (loss)	8,918		'	-1,057		'
Accumulated Other Comprehensive Income, Ending Balance	$11,619		'	$11,619		'
[1]	All amounts are net of tax.

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Schedule Of Reclassifications Out Of Accumulated Other Comprehensive Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Interest expense	($9,048)	($9,041)	($27,138)	($27,132)
Net realized and unrealized investment losses (gains)	-6,640	10,097	9,967	30,258
Net impairment losses recognized in earnings	-190	-131	-1,575	-757
Income before income taxes	85,687	42,104	250,291	198,036
Income tax expense	2,271	1,986	5,557	2,893
Net income	83,416	40,118	244,734	195,143
Accumulated Derivative Loss On Cash Flow Hedging Instruments [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Interest expense	22	'	67	'
Income before income taxes	22	'	67	'
Income tax expense	0	'	0	'
Net income	22	'	67	'
Unrealized Holding Gains And Losses On AFS Investments, Net Of Deferred Taxes [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Net realized and unrealized investment losses (gains)	6,999	'	-10,267	'
Net impairment losses recognized in earnings	190	'	1,575	'
Income before income taxes	7,189	'	-8,692	'
Income tax expense	468	'	-677	'
Net income	$6,721	'	($8,015)	'

Derivatives_Schedule_Of_Deriva

Derivatives (Schedule Of Derivative Fair Value And Notional Amount) (Details) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Foreign Exchange Forward Contracts [Member]

Foreign Exchange Forward Contracts [Member]

Credit Default Swaps [Member]

Credit Default Swaps [Member]

Credit Default Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Swaptions [Member]

Interest Rate Swaptions [Member]

TBA [Member]

TBA [Member]

Energy and weather contracts [Member]

Energy and weather contracts [Member]

Future [Member]

Future [Member]

Maximum [Member]

Derivatives, Fair Value [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative recorded in other liabilities, Fair Value

$74,237,000

$10,660,000

$333,000

$60,000

'

'

'

$764,000

$0

$134,000

$133,000

$68,174,000

$7,506,000

$4,832,000

$2,961,000

'

'

Derivatives recorded in other assets, Fair Value

122,853,000

23,649,000

74,000

23,000

0

9,000

'

1,000

76,000

37,000

57,000

120,414,000

20,523,000

2,327,000

2,961,000

0

0

Net derivative asset, Fair Value

48,616,000

12,989,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivatives recorded in other asset, Notional Principal Amount

'

'

9,539,000

1,652,000

0

410,000

'

5,600,000

5,000,000

23,900,000

2,200,000

119,000,000

19,000,000

35,627,000

15,573,000

64,217,000

0

Derivatives recorded in other liabilities, Notional Principal Amount

'

'

15,285,000

5,296,000

'

'

'

23,214,000

0

74,200,000

14,500,000

67,000,000

7,000,000

35,627,000

15,573,000

'

'

Original term of credit default swap, in years

'

'

'

'

'

'

'5 years 0 months 0 days

'

'

'

'

'

'

'

'

'

'

Derivative assets traded under ISDAs

2,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative liabilities traded under ISDAs

$6,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivatives_Schedule_Of_Deriva1

Derivatives (Schedule Of Derivative Gain (Loss)) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative [Line Items]	'	'	'	'
Derivatives included in net foreign exchange losses (gains) from foreign exchange forward contracts	($123)	($10)	$207	$141
Derivatives included in net realized and unrealized investment (losses) gains	358	343	-300	812
Derivatives included in other underwriting (loss) income	0	-1,384	1,172	-2,684
Total gains (losses) from derivatives	235	-1,051	1,079	-1,731
Future [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in net realized and unrealized investment (losses) gains	112	0	64	87
Credit Default Swaps [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in net realized and unrealized investment (losses) gains	-68	3	49	46
Interest Rate Swaps [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in net realized and unrealized investment (losses) gains	-67	29	-228	-14
Interest Rate Swaptions [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in net realized and unrealized investment (losses) gains	392	-16	291	31
TBA [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in net realized and unrealized investment (losses) gains	-11	327	-476	662
Energy and weather contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in other underwriting (loss) income	0	0	1,172	0
Commodity Put Option [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives included in other underwriting (loss) income	$0	($1,384)	$0	($2,684)

StockBased_Employee_Compensati2

Stock-Based Employee Compensation And Other Stock Plans (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
	28-May-13	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Contractual life of stock options	'10 years 0 months 0 days	'	'	'	'
Number of options granted	'	0	'	800,000	'
Number of options exercised	'	0	3,500	24,501	30,300
Number of options vested	'	0	'	160,000	'
Total intrinsic value of options exercised	'	$0	$64,000	$500,000	$700,000
Proceeds from stock options exercised	'	0	63,000	600,000	500,000
Expenses related to employee stock purchase plan	'	42,000	39,000	124,000	127,000
Number of restricted shares and RSUs granted	708,890	8,453	6,790	1,079,108	407,358
Restricted shares and RSUs weighted average grant date fair value	'	400,000	200,000	50,700,000	15,600,000
Options weighted average grant date fair value	'	0	'	10,200,000	'
Aggregate fair value of restricted shares and RSUs vested	'	100,000	200,000	17,000,000	11,700,000
Employee Stock Option [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Unrecognized stock-based compensation expenses related to unvested stock options	'	6,700,000	'	6,700,000	'
Compensation costs recognized	'	1,000,000	'	3,500,000	'
Percentage of compensation expense to be expensed in remainder of 2013	'	'	'	15.80%	'
Restricted Stock [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Compensation costs recognized	'	2,600,000	1,900,000	16,100,000	8,400,000
Compensation costs not yet recognized	'	$31,600,000	'	$31,600,000	'
Percentage of compensation expense to be expensed in remainder of 2013	'	'	'	18.20%	'

StockBased_Employee_Compensati3

Stock-Based Employee Compensation And Other Stock Plans (Summary of Stock Option Activity) (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	28-May-13	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation [Abstract]	'	'	'	'	'
Number of options, beginning of period	'	'	'	39,501	'
Number of options granted	800,000	'	'	800,000	'
Number of options exercised	'	0	3,500	24,501	30,300
Number of options forfeited	'	'	'	0	'
Number of options, end of period	'	815,000	'	815,000	'
Number of options, exercisable and vested options, end of period	'	175,000	'	175,000	'
Weighted average exercise price, beginning of period	'	'	'	$27.78	'
Weighted average exercise price, granted	$48.20	'	'	$48.20	'
Weighted average exercise price, exercised	'	'	'	$23.88	'
Weighted average exercise price, forfeited	'	'	'	$0	'
Weighted average exercise price, end of period	'	$47.94	'	$47.94	'
Weighted average exercise price, exercisable and vested options, end of period	'	$46.98	'	$46.98	'
Weighted average remaining contractual life (in years) outstanding, end of period	'	'	'	'9 years 6 months 0 days	'
Weighted average remaining contractual life (in years), exercisable and vested options, end of period	'	'	'	'8 years 10 months 25 days	'
Aggregate intrinsic value, outstanding, end of period	'	$4,711	'	$4,711	'
Aggregate intrinsic value, exercisable and vested options, end of period	'	$1,180	'	$1,180	'

StockBased_Employee_Compensati4

Stock-Based Employee Compensation And Other Stock Plans (Restricted Share And Restricted Share Unit Activity) (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	28-May-13	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested [Roll Forward]	'	'	'	'	'
Number of shares/units, unvested, beginning of period	'	'	'	686,633	'
Number of shares/units, granted	708,890	8,453	6,790	1,079,108	407,358
Number of shares/units, settled	'	'	'	-406,495	'
Number of shares/units, forfeited	'	'	'	-211,227	'
Number of shares/units, unvested, end of period	'	1,148,019	'	1,148,019	'
Number of shares/units, outstanding, end of period	'	1,148,019	'	1,148,019	'
Aggregate intrinsic value, outstanding, end of period	'	$61,672	'	$61,672	'

StockBased_Employee_Compensati5

Stock-Based Employee Compensation And Other Stock Plans (CEO) (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
	28-May-13	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'	'	'	'	'
Number of options granted	800,000	'	'	800,000	'
Exercise price of options	$48.20	'	'	$48.20	'
Number of restricted shares granted	708,890	8,453	6,790	1,079,108	407,358
Vesting period for employee awards	'4 years 0 months 0 days	'	'	'	'
Contractual life of stock options	'10 years 0 months 0 days	'	'	'	'

Segment_Reporting_Summary_Of_T

Segment Reporting (Summary Of The Segment Revenues, Results And Reserve For Losses And Loss Expenses) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross premiums written	$544,363	$621,255	$2,294,435	$2,286,980	'
Ceded premiums written	-149,030	-107,175	-525,566	-445,431	'
Net premiums written	395,333	514,080	1,768,869	1,841,549	'
Net premiums earned	553,545	551,872	1,516,997	1,482,847	'
Other underwriting (loss) income	-943	-1,347	694	-1,663	'
Total revenue	552,602	550,525	1,517,691	1,481,184	'
Net losses and loss expenses	339,036	407,523	917,064	1,016,187	'
Acquisition expenses	78,775	88,782	222,279	229,399	'
General and administrative expenses	67,470	52,715	215,307	181,365	'
Total expenses	485,281	549,020	1,354,650	1,426,951	'
Underwriting income (loss)	67,321	1,505	163,041	54,233	'
Net loss ratio	61.30%	73.80%	60.40%	68.50%	'
Acquisition expense ratio	14.20%	16.10%	14.70%	15.50%	'
General and administrative expense ratio	12.20%	9.60%	14.20%	12.20%	'
Combined ratio	87.70%	99.50%	89.30%	96.20%	'
Reserve for losses and loss expenses	4,052,102	4,509,442	4,052,102	4,509,442	4,240,876
Insurance [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross premiums written	344,819	324,808	1,274,703	1,252,814	'
Ceded premiums written	-120,481	-103,543	-454,169	-417,109	'
Net premiums written	224,338	221,265	820,534	835,705	'
Net premiums earned	291,477	283,273	710,507	710,988	'
Other underwriting (loss) income	0	-1,384	0	-2,684	'
Total revenue	291,477	281,889	710,507	708,304	'
Net losses and loss expenses	228,409	288,750	543,717	610,956	'
Acquisition expenses	18,440	24,506	48,024	58,265	'
General and administrative expenses	35,641	29,409	114,792	96,663	'
Total expenses	282,490	342,665	706,533	765,884	'
Underwriting income (loss)	8,987	-60,776	3,974	-57,580	'
Net loss ratio	78.40%	101.90%	76.40%	85.90%	'
Acquisition expense ratio	6.30%	8.70%	6.80%	8.20%	'
General and administrative expense ratio	12.20%	10.40%	16.20%	13.60%	'
Combined ratio	96.90%	121.00%	99.40%	107.70%	'
Reserve for losses and loss expenses	2,146,136	2,635,086	2,146,136	2,635,086	'
Reinsurance [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross premiums written	199,544	296,447	1,019,732	1,034,166	'
Ceded premiums written	-28,549	-3,632	-71,397	-28,322	'
Net premiums written	170,995	292,815	948,335	1,005,844	'
Net premiums earned	262,068	268,599	806,490	771,859	'
Other underwriting (loss) income	-943	37	694	1,021	'
Total revenue	261,125	268,636	807,184	772,880	'
Net losses and loss expenses	110,627	118,773	373,347	405,231	'
Acquisition expenses	60,335	64,276	174,255	171,134	'
General and administrative expenses	31,829	23,306	100,515	84,702	'
Total expenses	202,791	206,355	648,117	661,067	'
Underwriting income (loss)	58,334	62,281	159,067	111,813	'
Net loss ratio	42.30%	44.20%	46.30%	52.40%	'
Acquisition expense ratio	23.00%	23.90%	21.60%	22.20%	'
General and administrative expense ratio	12.10%	8.70%	12.50%	11.00%	'
Combined ratio	77.40%	76.80%	80.40%	85.60%	'
Reserve for losses and loss expenses	$1,905,966	$1,874,356	$1,905,966	$1,874,356	'

Segment_Reporting_Schedule_Of_

Segment Reporting (Schedule Of Segment Results To Income Before Income Taxes) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting	'	'	'	'
Total underwriting income	$67,321	$1,505	$163,041	$54,233
Net investment income	38,097	45,882	119,870	134,723
Net foreign exchange (losses) gains	-2,201	-3,774	-8,496	14,699
Net realized and unrealized investment (losses) gains	-6,640	10,097	9,967	30,258
Net impairment losses recognized in earnings	-190	-131	-1,575	-757
Amortization of intangibles	-1,652	-2,434	-5,378	-7,988
Interest expense	-9,048	-9,041	-27,138	-27,132
Income before income taxes	$85,687	$42,104	$250,291	$198,036

Segment_Reporting_Schedule_Of_1

Segment Reporting (Schedule Of Gross And Net Premiums By Line Of Business) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	$544,363	$621,255	$2,294,435	$2,286,980
Net premiums written	395,333	514,080	1,768,869	1,841,549
Insurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	344,819	324,808	1,274,703	1,252,814
Net premiums written	224,338	221,265	820,534	835,705
Agriculture Insurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	200,062	171,826	896,169	838,932
Net premiums written	120,617	106,180	546,284	528,349
Casualty And Other Specialty Insurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	95,862	90,873	239,943	236,383
Net premiums written	72,431	66,686	179,065	173,097
Professional Lines Insurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	34,221	43,209	93,481	130,573
Net premiums written	20,972	34,804	62,963	107,841
Property Insurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	14,674	18,900	45,110	46,926
Net premiums written	10,318	13,595	32,222	26,418
Reinsurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	199,544	296,447	1,019,732	1,034,166
Net premiums written	170,995	292,815	948,335	1,005,844
Catastrophe Reinsurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	38,676	38,871	341,973	354,275
Net premiums written	12,551	36,484	281,990	329,067
Casualty Reinsurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	53,691	77,781	272,602	258,352
Net premiums written	53,690	77,781	271,174	257,113
Property Reinsurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	91,653	157,742	288,448	318,514
Net premiums written	90,528	157,742	283,455	318,521
Other Specialty Reinsurance [Member]	'	'	'	'
Revenue from External Customer [Line Items]	'	'	'	'
Gross premiums written	15,524	22,053	116,709	103,025
Net premiums written	$14,226	$20,808	$111,716	$101,143

Commitments_And_Contingencies_1

Commitments And Contingencies (Narrative) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Commitments And Contingencies	'	'	'
Letters of credit outstanding, amount	$259.50	'	$320.40
Investments pledged under letters of credit facility	303.3	'	380
Securities pledged as collateral obligation	215.8	'	224.4
Total lease expenses under operating leases	11.2	11.3	'
Reinsurance recoverables	$941.40	'	$774.90

Commitments_And_Contingencies_2

Commitments And Contingencies (Deposits) (Details) (US, USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
US	'	'
Statutory Accounting Practices [Line Items]	'	'
Assets Held by Insurance Regulators	$274.60	$280

Commitments_And_Contingencies_3

Commitments And Contingencies (Schedule Of Future Minimum Lease Commitments) (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Commitments And Contingencies	'
2014	$14,586
2015	13,822
2016	11,298
2017	9,791
2018	9,575
2019 and thereafter	41,135
Total	$100,207

Commitments_And_Contingencies_4

Commitments And Contingencies (Schedule Of Percentage Of Net Premiums) (Details)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Revenue from External Customer [Line Items]	'	'
Percentage of net premium written	45.90%	49.70%
Aon Benfield [Member]	'	'
Revenue from External Customer [Line Items]	'	'
Percentage of net premium written	18.50%	17.30%
Marsh & Mclennan Companies, Inc. [Member]	'	'
Revenue from External Customer [Line Items]	'	'
Percentage of net premium written	15.00%	16.60%
Willis Companies [Member]	'	'
Revenue from External Customer [Line Items]	'	'
Percentage of net premium written	12.40%	15.80%