W. R. Berkley (WRB) 10-Q 7 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 30, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'BERKLEY W R CORP	'
Entity Central Index Key	'0000011544	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	127,530,366

Consolidated_Balance_Sheet_Con

Consolidated Balance Sheet Consolidated Balance Sheet (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets [Abstract]	'	'
Fixed maturity securities	$12,088,055	$11,616,844
Equity securities	257,059	283,338
Arbitrage trading account	732,279	522,128
Investment funds	984,836	1,067,495
Loans receivable	655,691	343,583
Real estate	530,239	715,242
Total investments	15,248,159	14,548,630
Cash and cash equivalents	842,671	839,738
Premiums and fees receivable	1,748,916	1,557,480
Due from reinsurers	1,464,003	1,533,103
Accrued investment income	123,168	118,329
Prepaid reinsurance premiums	431,933	367,803
Deferred policy acquisition costs	483,714	452,101
Property, furniture and equipment	335,741	339,448
Federal and foreign income taxes	0	44,857
Goodwill	103,565	110,146
Trading account receivables from brokers and clearing organizations	57,454	304,936
Other assets	327,870	335,225
Total assets	21,167,194	20,551,796
Liabilities:	'	'
Reserves for losses and loss expenses	10,256,219	10,080,941
Unearned premiums	3,081,888	2,781,437
Due to reinsurers	272,455	276,755
Trading account securities sold but not yet purchased	111,991	162,278
Federal and foreign income taxes	24,779	0
Other liabilities	728,337	848,749
Junior subordinated debentures	339,930	339,800
Senior notes and other debt	1,697,037	1,692,442
Total liabilities	16,512,636	16,182,402
Equity:	'	'
Authorized 5,000,000 shares; issued and outstanding - none	0	0
Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 127,613,325 and 132,233,167 shares, respectively	47,024	47,024
Additional paid-in capital	974,794	967,440
Retained earnings	5,587,824	5,265,015
Accumulated other comprehensive income	333,899	189,391
Treasury stock, at cost, 107,504,593 and 102,884,751 shares, respectively	2,323,828	2,132,835
Total stockholders’ equity	4,619,713	4,336,035
Noncontrolling interests	34,845	33,359
Total equity	4,654,558	4,369,394
Total liabilities and equity	$21,167,194	$20,551,796

Consolidated_Balance_Sheet_Con1

Consolidated Balance Sheet Consolidated Balance Sheet (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value $.10 per share:	$0.10	$0.10
Preferred shares authorized	5,000,000	5,000,000
Preferred shares issued	0	0
Preferred shares outstanding	0	0
Common stock, par value $.20 per share:	$0.20	$0.20
Common shares authorized	500,000,000	500,000,000
Common shares issued	127,613,325	132,233,167
Common shares outstanding	127,613,325	132,233,167
Treasury stock issued at cost	107,504,593	102,884,751

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
REVENUES:	'	'	'	'
Net premiums written	$1,489,776	$1,341,898	$3,015,656	$2,718,864
Change in net unearned premiums	-72,131	-59,383	-234,399	-204,230
Net premiums earned	1,417,645	1,282,515	2,781,257	2,514,634
Net investment income	138,729	143,737	307,440	279,666
Insurance service fees	26,922	27,652	55,625	54,388
Net investment gains	109,168	33,058	161,922	53,027
Revenues from wholly-owned investees	104,285	83,775	197,125	175,510
Other income	240	225	526	506
Total revenues	1,796,989	1,570,962	3,503,895	3,077,731
OPERATING COSTS AND EXPENSES:	'	'	'	'
Losses and loss expenses	867,778	805,470	1,689,873	1,550,149
Other operating costs and expenses	534,150	494,286	1,049,316	975,890
Expenses from wholly-owned investees	101,296	81,293	193,026	170,445
Interest expense	30,311	31,207	60,641	62,318
Total operating costs and expenses	1,533,535	1,412,256	2,992,856	2,758,802
Income before income taxes	263,454	158,706	511,039	318,929
Income tax expense	-83,277	-43,579	-161,178	-87,204
Net income before noncontrolling interests	180,177	115,127	349,861	231,725
Noncontrolling interests	-216	830	-227	847
Net income to common stockholders	$179,961	$115,957	$349,634	$232,572
NET INCOME PER SHARE:	'	'	'	'
Basic	$1.41	$0.85	$2.72	$1.71
Diluted	$1.35	$0.82	$2.60	$1.65

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income Statement (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income before noncontrolling interests	$180,177	$115,127	$349,861	$231,725
Other comprehensive income (loss):	'	'	'	'
Change in unrealized currency translation adjustments	24,815	-23,156	20,790	-69,779
Change in unrealized investment gains, net of taxes	48,200	-197,060	121,144	-189,250
Change in net pension asset, net of taxes	2,020	1,814	2,611	3,628
Other comprehensive income (loss)	75,035	-218,402	144,545	-255,401
Comprehensive income (loss)	255,212	-103,275	494,406	-23,676
Comprehensive (income) loss to the noncontrolling interest	-235	865	-264	842
Comprehensive income (loss) to common stockholders	$254,977	($102,410)	$494,142	($22,834)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity Statement (USD $)	Total	Common stocks	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Accumulated Translation Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
In Thousands, unless otherwise specified
Beginning and end of period at Dec. 31, 2012	'	$47,024	$945,166	$4,817,807	$517,658	($36,676)	($15,351)	'	($1,969,411)	$29,249
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Options exercised and restricted stock units issued, net of tax	'	'	-311	'	'	'	'	'	'	'
Restricted stock units expensed	'	'	10,694	'	'	'	'	'	'	'
Stock issued to directors	'	'	535	'	'	'	'	'	597	'
Net income before noncontrolling interests	231,725	'	'	232,572	'	'	'	'	'	-847
Dividends	'	'	'	-25,814	'	'	'	'	'	'
Change in unrealized investment gains, net of taxes	-189,250	'	'	'	-189,594	'	'	'	'	'
Unrealized gains on other-than-temporarily impaired securities	'	'	'	'	339	'	'	'	'	'
Change in unrealized currency translation adjustments	-69,779	'	'	'	'	-69,779	'	'	'	'
Change in net pension asset, net of taxes	3,628	'	'	'	'	'	3,628	'	'	'
Stock exercised/vested	'	'	'	'	'	'	'	'	882	'
Stock repurchased	'	'	'	'	'	'	'	'	-31,362	'
Stock issued to directors	'	'	535	'	'	'	'	'	597	'
Contributions	'	'	'	'	'	'	'	'	'	-1,356
Other comprehensive income (loss)	-255,401	'	'	'	'	-69,779	3,628	-255,401	'	5
End of period at Jun. 30, 2013	'	'	956,084	5,024,565	328,403	-106,455	-11,723	210,225	-1,999,294	27,051
Beginning and end of period at Mar. 31, 2013	'	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Net income before noncontrolling interests	115,127	'	'	'	'	'	'	'	'	'
Change in unrealized investment gains, net of taxes	-197,060	'	'	'	'	'	'	'	'	'
Change in unrealized currency translation adjustments	-23,156	'	'	'	'	'	'	'	'	'
Change in net pension asset, net of taxes	1,814	'	'	'	'	'	'	'	'	'
Other comprehensive income (loss)	-218,402	'	'	'	'	-23,156	1,814	-218,402	'	'
End of period at Jun. 30, 2013	'	'	'	'	'	-106,455	-11,723	210,225	'	'
Beginning and end of period at Dec. 31, 2013	4,369,394	47,024	967,440	5,265,015	256,566	-60,524	-6,651	'	-2,132,835	33,359
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Options exercised and restricted stock units issued, net of tax	'	'	-5,692	'	'	'	'	'	'	'
Restricted stock units expensed	'	'	12,455	'	'	'	'	'	'	'
Stock issued to directors	'	'	591	'	'	'	'	'	594	'
Net income before noncontrolling interests	349,861	'	'	349,634	'	'	'	'	'	227
Dividends	'	'	'	-26,825	'	'	'	'	'	'
Change in unrealized investment gains, net of taxes	121,144	'	'	'	120,618	'	'	'	'	'
Unrealized gains on other-than-temporarily impaired securities	'	'	'	'	489	'	'	'	'	'
Change in unrealized currency translation adjustments	20,790	'	'	'	'	20,790	'	'	'	'
Change in net pension asset, net of taxes	2,611	'	'	'	'	'	2,611	'	'	'
Stock exercised/vested	'	'	'	'	'	'	'	'	5,667	'
Stock repurchased	'	'	'	'	'	'	'	'	-197,254	'
Stock issued to directors	'	'	591	'	'	'	'	'	594	'
Contributions	'	'	'	'	'	'	'	'	'	1,222
Other comprehensive income (loss)	144,545	'	'	'	'	20,790	2,611	144,545	'	37
End of period at Jun. 30, 2014	4,654,558	'	974,794	5,587,824	377,673	-39,734	-4,040	333,899	-2,323,828	34,845
Beginning and end of period at Mar. 31, 2014	'	'	'	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Net income before noncontrolling interests	180,177	'	'	'	'	'	'	'	'	'
Change in unrealized investment gains, net of taxes	48,200	'	'	'	'	'	'	'	'	'
Change in unrealized currency translation adjustments	24,815	'	'	'	'	'	'	'	'	'
Change in net pension asset, net of taxes	2,020	'	'	'	'	'	'	'	'	'
Other comprehensive income (loss)	75,035	'	'	'	'	24,815	2,020	75,035	'	'
End of period at Jun. 30, 2014	$4,654,558	'	'	'	'	($39,734)	($4,040)	$333,899	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
CASH FROM (USED IN) OPERATING ACTIVITIES:	'	'
Net income to common stockholders	$349,634	$232,572
Adjustments to reconcile net income to net cash from operating activities:	'	'
Net investment gains	-161,922	-53,027
Depreciation and amortization	50,832	50,617
Noncontrolling interests	227	-847
Investment funds	-84,385	-33,057
Stock incentive plans	13,615	12,395
Change in:	'	'
Arbitrage trading account	-12,956	1,590
Premiums and fees receivable	-197,004	-162,853
Reinsurance accounts	-57	-67,447
Deferred policy acquisition costs	-31,527	-34,039
Income taxes	7,742	-46,642
Reserves for losses and loss expenses	172,759	221,525
Unearned premiums	297,721	269,931
Other	-150,056	-76,786
Net cash from operating activities	254,623	313,932
CASH FROM (USED IN) INVESTING ACTIVITIES:	'	'
Proceeds from sale of fixed maturity securities	513,281	555,694
Proceeds from sale of equity securities	112,590	66,969
Distributions from (contributions to) investment funds	211,974	-60,000
Proceeds from maturities and prepayments of fixed maturity securities	1,214,221	1,561,236
Purchase of fixed maturity securities	-2,034,009	-2,214,201
Purchase of equity securities	-48,484	-111,540
Real estate sold (purchased)	-63,919	-13,390
SEC Schedule III, Real Estate, Cost of Real Estate Sold	343,723	0
Change in loans receivable	-312,071	-46,854
Net additions to property, furniture and equipment	-22,555	-43,446
Change in balances due to security brokers	28,313	-6,167
Net cash from businesses sold (purchased)	15,548	-59,964
Net cash from (used in) investing activities	-41,388	-371,663
CASH USED IN FINANCING ACTIVITIES:	'	'
Repayment of senior notes and other debt	0	-486,297
Proceeds from Issuance of Debt	4,988	371,923
Net proceeds from options exercised	53	51
Cash dividends to common stockholders	-26,825	-12,243
Purchase of common treasury shares	-197,254	-31,362
Other, net	1,365	7,273
Net cash used in financing activities	-217,673	-150,655
Net impact on cash due to change in foreign exchange rates	7,371	-38,445
Net change in cash and cash equivalents	2,933	-246,831
Cash and cash equivalents at beginning of year	839,738	905,670
Cash and cash equivalents at end of period	$842,671	$658,839

General_General

General General	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	General
	The accompanying unaudited consolidated financial statements of W. R. Berkley Corporation and its subsidiaries (the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information. Accordingly, they do not include all the information and notes required by GAAP for annual financial statements. The unaudited consolidated financial statements reflect all adjustments, consisting only of normal recurring items, which are necessary to present fairly the Company’s financial position and results of operations on a basis consistent with the prior audited consolidated financial statements. Operating results for interim periods are not necessarily indicative of the results that may be expected for the year. All significant intercompany accounts and transactions have been eliminated. The preparation of financial statements requires the use of management estimates. For further information related to a description of areas of judgment and estimates and other information necessary to understand the Company’s financial position and results of operations, refer to the audited consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. Reclassifications have been made in the 2013 financial statements as originally reported to conform to the presentation of the 2014 financial statements.
	The income tax provision has been computed based on the Company’s estimated annual effective tax rate. The effective tax rate for the quarter differs from the federal income tax rate of 35% principally because of tax-exempt investment income.

Per_Share_Data_Per_Share_Data

Per Share Data Per Share Data	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Per Share Data
	The Company presents both basic and diluted net income per share (“EPS”) amounts. Basic EPS is calculated by dividing net income by the weighted average number of common shares outstanding during the period. Diluted EPS is based upon the weighted average number of common and common equivalent shares outstanding during the period and is calculated using the treasury stock method for stock incentive plans. Common equivalent shares are excluded from the computation in periods in which they have an anti-dilutive effect.
	The weighted average number of common shares used in the computation of basic and diluted earnings per share was as follows:
		For the Three Months		For the Six Months
		Ended June 30,		Ended June 30,
	(In thousands)	2014	2013	2014	2013
	Basic	127,668	135,894	128,765	135,959
	Diluted	133,304	141,274	134,323	141,257

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements Recent Accounting Pronouncements	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In January 2014, the Financial Accounting Standards Board issued guidance relating to Accounting for Investments in Qualified Affordable Housing Projects. This guidance modified the amortization method on these investments and the statement of operations classification as pre-adoption amounts were presented in both pre-tax income and income tax expense while post adoption all impacts are recorded in income tax expense. The Company adopted this guidance effective January 1, 2014, and the impact of applying this guidance was immaterial.
	All recently issued but not yet effective accounting and reporting standards are either not applicable to the Company or are not expected to have a material impact on the Company.

Acquistions_Acquisitions

Acquistions Acquisitions	6 Months Ended
	Jun. 30, 2014
Business Combinations [Abstract]	'
Business Combination Disclosure	'
	Acquisitions/Dispositions
	In June 2014, the Company sold an aviation-related business for $16 million. The business had a net carrying value of $15 million, including $7 million of goodwill.
	In 2012, the Company acquired a 49% interest in a worldwide supplier of after-market original equipment manufacturer (OEM) parts, systems and custom logistic support services for military aircraft operations for $43 million. In January 2013, the Company acquired the remaining 51% of this business for $43 million. The estimated useful lives of the intangible assets acquired range from 2 years to 15 years, with approximately $3 million having an indefinite life.
	The following table summarizes the estimated fair value of net assets acquired and liabilities assumed at the date of acquisition:
	(In thousands)
	Cash and cash equivalents	$	3,911
	Real estate, furniture and equipment	898
	Goodwill	19,664
	Intangible assets	44,800
	Other assets	60,661
	Total assets acquired	129,934
	Debt	(27,612		)
	Other liabilities assumed	(17,076		)
	Net assets acquired	$	85,246

Statements_of_Comprehensive_In

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Notes)	6 Months Ended
	Jun. 30, 2014
Equity [Abstract]	'
Comprehensive Income (Loss)	'
	Statement of Comprehensive Income (Loss)
	The following table presents the components of the changes in accumulated other comprehensive income (loss) ("AOCI"):
	(In thousands)	Unrealized Investment Gains (Losses)				Currency Translation Adjustments			Net Pension Asset				Accumulated Other Comprehensive Income (Loss)
	As of and for the six months ended June 30, 2014:
	Changes in AOCI
	Beginning of period	$	256,566			$	(60,524	)	$	(6,651	)		$	189,391
	Other comprehensive income (loss) before reclassifications	140,289				20,790			—				161,079
	Amounts reclassified from AOCI	(19,145		)		—			2,611				(16,534		)
	Other comprehensive income (loss)	121,144				20,790			2,611				144,545
	Unrealized investment gain (loss) related to non-controlling interest	(37		)		—			—				(37		)
	End of period	$	377,673			$	(39,734	)	$	(4,040	)		$	333,899
	Amounts reclassified from AOCI
	Pre-tax	$	(29,454	)	-1	$	—		$	4,017		-2	$	(25,437	)
	Tax effect (3)	10,309				—			(1,406		)		8,903
	After-tax amounts reclassified	$	(19,145	)		$	—		$	2,611			$	(16,534	)
	Other comprehensive income (loss)
	Pre-tax	$	188,680			$	20,790		$	4,017			$	213,487
	Tax effect	(67,536		)		—			(1,406		)		(68,942		)
	Other comprehensive income (loss)	$	121,144			$	20,790		$	2,611			$	144,545
	As of and for the three months ended June 30, 2014:
	Changes in AOCI
	Beginning of period	$	329,492			$	(64,549	)	$	(6,060	)		$	258,883
	Other comprehensive income (loss) before reclassifications	62,846				24,815			—				87,661
	Amounts reclassified from AOCI	(14,646		)		—			2,020				(12,626		)
	Other comprehensive income (loss)	48,200				24,815			2,020				75,035
	Unrealized investment gain (loss) related to non-controlling interest	(19		)		—			—				(19		)
	End of period	$	377,673			$	(39,734	)	$	(4,040	)		$	333,899
	Amounts reclassified from AOCI
	Pre-tax	$	(22,532	)	-1	$	—		$	3,108		-2	$	(19,424	)
	Tax effect (3)	7,886				—			(1,088		)		6,798
	After-tax amounts reclassified	$	(14,646	)		$	—		$	2,020			$	(12,626	)
	Other comprehensive income (loss)
	Pre-tax	$	76,390			$	24,815		$	3,108			$	104,313
	Tax effect	(28,190		)		—			(1,088		)		(29,278		)
	Other comprehensive income (loss)	$	48,200			$	24,815		$	2,020			$	75,035
		Unrealized Investment Gains				Currency Translation Adjustments			Net Pension Asset				Accumulated Other Comprehensive Income (Loss)
	(In thousands)
	As of and for the six months ended June 30, 2013:
	Changes in AOCI
	Beginning of period	$	517,658			$	(36,676	)	$	(15,351	)		$	465,631
	Other comprehensive income (loss) before reclassifications	(161,945		)		(69,779		)	—				(231,724		)
	Amounts reclassified from AOCI	(27,305		)		—			3,628				(23,677		)
	Other comprehensive income (loss)	(189,250		)		(69,779		)	3,628				(255,401		)
	Unrealized investment gain related to non-controlling interest	(5		)		—			—				(5		)
	End of period	$	328,403			$	(106,455	)	$	(11,723	)		$	210,225
	Amounts reclassified from AOCI
	Pre-tax	$	(42,008	)	-1	$	—		$	5,582		-2	$	(36,426	)
	Tax effect (3)	14,703				—			(1,954		)		12,749
	After-tax amounts reclassified	$	(27,305	)		$	—		$	3,628			$	(23,677	)
	Other comprehensive income (loss)
	Pre-tax	$	(291,154	)		$	(69,779	)	$	5,582			$	(355,351	)
	Tax effect	101,904				—			(1,954		)		99,950
	Other comprehensive income (loss)	$	(189,250	)		$	(69,779	)	$	3,628			$	(255,401	)
	As of and for the three months ended June 30, 2013:
	Changes in AOCI
	Beginning of period	$	525,428			$	(83,299	)	$	(13,537	)		$	428,592
	Other comprehensive income (loss) before reclassifications	(182,934		)		(23,156		)	—				(206,090		)
	Amounts reclassified from AOCI	(14,126		)		—			1,814				(12,312		)
	Other comprehensive income (loss)	(197,060		)		(23,156		)	1,814				(218,402		)
	Unrealized investment gain related to non-controlling interest	35							—				35
	End of period	$	328,403			$	(106,455	)	$	(11,723	)		$	210,225
	Amounts reclassified from AOCI
	Pre-tax	$	(21,933	)	-1	$	—		$	2,790		-2	$	(19,143	)
Tax effect (3)	7,807				—			(976		)		6,831
After-tax amounts reclassified	$	(14,126	)		$	—		$	1,814			$	(12,312	)
Other comprehensive income (loss)
Pre-tax	$	(303,169	)		$	(23,156	)	$	2,790			$	(323,535	)
Tax effect	106,109				—			(976		)		105,133
Other comprehensive income (loss)	$	(197,060	)		$	(23,156	)	$	1,814			$	(218,402	)
(1) Net investment gains in the consolidated statements of operations.
(2) Other operating costs and expenses in the consolidated statements of operations.
(3) Income tax expense in the consolidated statements of operations.

Statements_of_Cash_Flow_Statem

Statements of Cash Flow Statements of Cash Flow	6 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Cash Flow, Supplemental Disclosures	'
	Statements of Cash Flow
	Interest payments were $59,811,000 and $65,365,000 and income taxes paid were $152,439,000 and $137,618,000 in the six months ended June 30, 2014 and 2013, respectively.

Investments_In_Fixed_Maturity_

Investments In Fixed Maturity Securities (Debt Securities [Member])	6 Months Ended
	Jun. 30, 2014
Debt Securities [Member]	'
Schedule of Marketable Securities [Line Items]	'
Investments In Fixed Maturity Securities	'
	Investments in Fixed Maturity Securities
	At June 30, 2014 and December 31, 2013, investments in fixed maturity securities were as follows:
	(In thousands)	Amortized		Gross Unrealized					Fair		Carrying
		Cost		Gains		Losses			Value		Value
	June 30, 2014
	Held to maturity:
	State and municipal	$	70,956	$	16,135	$	—		$	87,091	$	70,956
	Residential mortgage-backed	25,398		3,182		—			28,580		25,398
	Corporate	4,998		314		—			5,312		4,998
	Total held to maturity	101,352		19,631		—			120,983		101,352
	Available for sale:
	U.S. government and government agency	839,914		34,766		(7,553		)	867,127		867,127
	State and municipal	4,004,308		221,995		(5,563		)	4,220,740		4,220,740
	Mortgage-backed securities:
	Residential (1)	1,209,584		29,930		(13,765		)	1,225,749		1,225,749
	Commercial	74,378		6,056		(47		)	80,387		80,387
	Corporate	4,436,526		206,290		(18,492		)	4,624,324		4,624,324
	Foreign	917,558		68,553		(17,735		)	968,376		968,376
	Total available for sale	11,482,268		567,590		(63,155		)	11,986,703		11,986,703
	Total investments in fixed maturity securities	$	11,583,620	$	587,221	$	(63,155	)	$	12,107,686	$	12,088,055
	December 31, 2013
	Held to maturity:
	State and municipal	$	68,929	$	11,172	$	—		$	80,101	$	68,929
	Residential mortgage-backed	27,393		3,311		—			30,704		27,393
	Corporate	4,998		417		—			5,415		4,998
	Total held to maturity	101,320		14,900		—			116,220		101,320
	Available for sale:
	U.S. government and government agency	858,319		34,522		(7,982		)	884,859		884,859
	State and municipal	4,085,791		162,330		(29,837		)	4,218,284		4,218,284
	Mortgage-backed securities:
	Residential (1)	1,248,693		25,895		(25,941		)	1,248,647		1,248,647
	Commercial	76,454		5,670		(988		)	81,136		81,136
	Corporate	4,076,585		156,256		(30,100		)	4,202,741		4,202,741
	Foreign	844,469		51,674		(16,286		)	879,857		879,857
	Total available for sale	11,190,311		436,347		(111,134		)	11,515,524		11,515,524
	Total investments in fixed maturity securities	$	11,291,631	$	451,247	$	(111,134	)	$	11,631,744	$	11,616,844
	___________
	-1	Gross unrealized losses for residential mortgage-backed securities include $1,208,000 and $1,961,000 as of June 30, 2014 and December 31, 2013, respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.
	The amortized cost and fair value of fixed maturity securities at June 30, 2014, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations.
	(In thousands)	Amortized		Fair Value
		Cost
	Due in one year or less	$	886,256	$	896,523
	Due after one year through five years	3,860,527		4,039,960
	Due after five years through ten years	3,035,251		3,229,746
	Due after ten years	2,492,226		2,606,741
	Mortgage-backed securities	1,309,360		1,334,716
	Total	$	11,583,620	$	12,107,686
	At June 30, 2014, there were no investments, other than investments in United States government and government agency securities, which exceeded 10% of common stockholders’ equity.

Investments_in_Equity_Securiti

Investments in Equity Securities (Equity securities available for sale)	6 Months Ended
	Jun. 30, 2014
Equity securities available for sale	'
Schedule of Available-for-sale Securities [Line Items]	'
Investments in Equity Securities	'
	Investments in Equity Securities
	At June 30, 2014 and December 31, 2013, investments in equity securities were as follows:
	(In thousands)	Cost		Gross Unrealized					Fair		Carrying
				Gains		Losses			Value		Value
	June 30, 2014
	Common stocks	$	75,167	$	28,360	$	—		$	103,527	$	103,527
	Preferred stocks	92,797		63,740		(3,005		)	153,532		153,532
	Total	$	167,964	$	92,100	$	(3,005	)	$	257,059	$	257,059
	December 31, 2013
	Common stocks	$	118,536	$	42,239	$	—		$	160,775	$	160,775
	Preferred stocks	85,091		43,791		(6,319		)	122,563		122,563
	Total	$	203,627	$	86,030	$	(6,319	)	$	283,338	$	283,338

Arbitrage_Trading_Account_Arbi

Arbitrage Trading Account Arbitrage Trading Account	6 Months Ended
	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Arbitrage Trading Account	'
	Arbitrage Trading Account
	At June 30, 2014 and December 31, 2013, the carrying value of the arbitrage trading account was $732 million and $522 million, respectively. The primary focus of the trading account is merger arbitrage. Merger arbitrage is the business of investing in the securities of publicly held companies which are the targets in announced tender offers and mergers. Arbitrage investing differs from other types of investing in its focus on transactions and events believed likely to bring about a change in value over a relatively short time period (usually four months or less). The Company believes that this makes merger arbitrage investments less vulnerable to changes in general financial market conditions.

Net_Investment_Income_Net_Inve

Net Investment Income Net Investment Income	6 Months Ended
	Jun. 30, 2014
Income Statement [Abstract]	'
Net Investment Income	'
	Net Investment Income
	Net investment income consists of the following:
		For the Three Months						For the Six Months
		Ended June 30,						Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Investment income earned on:
	Fixed maturity securities, including cash and cash equivalents and loans receivable	$	107,760		$	111,203		$	214,658		$	229,039
	Investment funds	22,356			22,576			76,155			33,510
	Arbitrage trading account	6,942			4,990			12,461			8,773
	Equity securities available for sale	2,103			3,634			4,049			5,881
	Real estate	3,063			3,116			6,165			6,257
	Gross investment income	142,224			145,519			313,488			283,460
	Investment expense	(3,495		)	(1,782		)	(6,048		)	(3,794		)
	Net investment income	$	138,729		$	143,737		$	307,440		$	279,666

Investment_Funds_Investment_Fu

Investment Funds Investment Funds	6 Months Ended
	Jun. 30, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Net Investment Income	'
	Investment Funds
	Investment funds consist of the following:
		Carrying Value as of				Income (Loss) from Investment Funds
		June 30,		December 31,		For the Six Months Ended June 30,
	(In thousands)	2014		2013		2014		2013
	Real estate	$	280,255	$	378,435	$	16,482	$	1,260
	Energy	159,645		155,026		12,596		25,199
	Arbitrage	279,806		271,575		8,231		1,731
	Other	265,130		262,459		38,846		5,320
	Total	$	984,836	$	1,067,495	$	76,155	$	33,510
	The Company's share of the earnings or losses of investment funds is generally reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.

Real_Estate_Real_Estate

Real Estate Real Estate	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Real Estate	'
	Real Estate
	Investment in real estate represents directly owned property held for investment, as follows:
		Carrying Value
		June 30,		December 31,
	(In thousands)	2014		2013
	Properties in operation	$	47,617	$	283,393
	Properties under development	482,622		431,849
	Total	$	530,239	$	715,242
	The primary property in operation is a long-term ground lease in Washington, D.C. Properties in operation are net of accumulated depreciation and amortization of $78,000 and $17,827,000 as of June 30, 2014 and December 31, 2013, respectively. Related depreciation expense was $3,219,000 and $3,420,000 for the six months ended June 30, 2014 and 2013, respectively. Future minimum rental income expected on operating leases relating to properties in operation is $760,000 in 2014, $1,549,000 in 2015, $1,596,000 in 2016, $1,644,000 in 2017, $1,693,000 in 2018 and $327,320,000 thereafter.
	The properties under development are an office building in London, a mixed-use project in Washington, D.C. and an office complex in New York City.
	In June 2014, the Company sold an office building in London for $67 million in cash and a $270 million, 2% bridge loan, which was repaid in July 2014. The carrying value of the building at the time of sale was $251 million.

Loans_Receivable_Loans_Receiva

Loans Receivable Loans Receivable	6 Months Ended
	Jun. 30, 2014
Receivables [Abstract]	'
Loans Receivable	'
	Loans Receivable
	Loans receivable are as follows:
	(In thousands)	June 30, 2014		31-Dec-13
	Amortized cost:
	Real estate loans	$	569,530	$	282,357
	Commercial loans	86,161		61,226
	Total	$	655,691	$	343,583
	Fair value:
	Real estate loans	$	571,520	$	284,017
	Commercial loans	87,663		62,729
	Total	$	659,183	$	346,746
	Valuation allowance:
	Specific	$	—	$	—
	General	2,566		2,087
	Total	$	2,566	$	2,087
		For the Three Months
		Ended June 30,
		2014		2013
	Increase (decrease) in valuation allowance	$	16	$	(30	)
	Loans receivable charged off	—		—
		For the Six Months
		Ended June 30,
		2014		2013
	Increase in valuation allowance	$	479	$	65
	Loans receivable charged off	—		—
	There were no loans receivable in non-accrual status as of June 30, 2014 and December 31, 2013.
	The Company monitors the performance of its loans receivable and assesses the ability of the borrower to pay principal and interest based upon loan structure, underlying property values, cash flow and related financial and operating performance of the property and market conditions. Loans receivable with a potential for default are further assessed using discounted cash flow analysis and comparable cost and sales methodologies, if appropriate.
	The real estate loans are secured by commercial real estate primarily located in Arizona, California, Hawaii, Illinois, New York, North Carolina and Texas. These loans generally earn interest at floating LIBOR-based interest rates and have maturities (inclusive of extension options) through August 2025. The commercial loans are with small business owners who have secured the related financing with the assets of the business. These loans generally earn interest on a fixed basis and have varying maturities not exceeding 10 years.
	The Company utilizes an internal risk rating system to assign a risk to each of its real estate loans. The loan rating system takes into consideration credit quality indicators including loan to value ratios, which compare the outstanding loan amount to the estimated value of the property, the borrower’s financial condition and performance with respect to loan terms, the Company’s position in the capital structure, and the overall leverage in the capital structure. Based on this rating system, none of the real estate loans were considered to be impaired at June 30, 2014, and accordingly, the Company determined that a specific valuation allowance was not required.

Realized_And_Unrealized_Invest

Realized And Unrealized Investment Gains (Losses)	6 Months Ended
	Jun. 30, 2014
Realized and Unrealized Investment Gains (Losses) [Abstract]	'
Realized and Unrealized Investment Gains (Losses)	'
	Realized and Unrealized Investment Gains (Losses)
	Realized and unrealized investment gains (losses) are as follows:
		For the Three Months Ended June 30,						For the Six Months Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Realized investment gains (losses):
	Fixed maturity securities:
	Gains	$	1,941		$	9,147		$	4,003		$	20,143
	Losses	(464		)	(5,500		)	(2,062		)	(11,466		)
	Equity securities available for sale	23,124			18,086			29,581			33,331
	Investment funds	(1,076		)	10,843			44,757			11,037
	Real estate	85,643			—			85,643			—
	Other	—			482			—			(18		)
	Total	109,168			33,058			161,922			53,027
	Change in valuation allowance, net of other-than-temporary impairments:
	Decrease in valuation allowance	—			—			—			—
	Other-than-temporary impairments	—			—			—			—
	Total	—			—			—			—
	Net investment gains	109,168			33,058			161,922			53,027
	Income tax expense	(38,208		)	(11,570		)	(56,673		)	(18,559		)
	Total after-tax realized investment gains	$	70,960		$	21,488		$	105,249		$	34,468
	Change in unrealized investment gains (losses):
	Fixed maturity securities	$	87,882		$	(277,791	)	$	179,520		$	(293,380	)
	Previously impaired fixed maturity securities	194			(590		)	753			522
	Equity securities available for sale	(17,870		)	(16,191		)	8,333			8,370
	Investment funds	6,184			(5,906		)	74			(9,174		)
	Total change in unrealized investment gains (losses)	76,390			(300,478		)	188,680			(293,662		)
	Income tax benefit (expense)	(28,190		)	103,418			(67,536		)	104,412
	Noncontrolling interests	(19		)	35			(37		)	(5		)
	Total after-tax unrealized gains (losses)	$	48,181		$	(197,025	)	$	121,107		$	(189,255	)

Securities_In_An_Unrealized_Lo

Securities In An Unrealized Loss Position	6 Months Ended
	Jun. 30, 2014
Investments [Abstract]	'
Securities in Unrealized Loss Position	'
	Securities in an Unrealized Loss Position
	The following tables summarize all securities in an unrealized loss position at June 30, 2014 and December 31, 2013 by the length of time those securities have been continuously in an unrealized loss position:
		Less Than 12 Months						12 Months or Greater				Total
	(In thousands)	Fair Value			Gross			Fair Value		Gross		Fair Value		Gross
					Unrealized					Unrealized				Unrealized
					Losses					Losses				Losses
	June 30, 2014
	U.S. government and government agency	$	191,360		$	4,176		$	74,427	$	3,377	$	265,787	$	7,553
	State and municipal	136,081			1,796			185,605		3,767		321,686		5,563
	Mortgage-backed securities	129,004			725			341,219		13,087		470,223		13,812
	Corporate	549,991			7,099			285,261		11,393		835,252		18,492
	Foreign	183,837			7,461			101,882		10,274		285,719		17,735
	Fixed maturity securities	1,190,273			21,257			988,394		41,898		2,178,667		63,155
	Common stocks	—			—			—		—		—		—
	Preferred stocks	—			—			25,714		3,005		25,714		3,005
	Equity securities	—			—			25,714		3,005		25,714		3,005
	Total	$	1,190,273		$	21,257		$	1,014,108	$	44,903	$	2,204,381	$	66,160
	December 31, 2013
	U.S. government and government agency	$	260,882		$	7,927		$	2,163	$	55	$	263,045	$	7,982
	State and municipal	899,613			24,503			87,345		5,334		986,958		29,837
	Mortgage-backed securities	578,603			17,964			140,648		8,965		719,251		26,929
	Corporate	1,013,373			17,066			105,074		13,034		1,118,447		30,100
	Foreign	320,215			16,286			—		—		320,215		16,286
	Fixed maturity securities	3,072,686			83,746			335,230		27,388		3,407,916		111,134
	Common stocks	—			—			—		—		—		—
	Preferred stocks	13,291			513			19,868		5,806		33,159		6,319
	Equity securities	13,291			513			19,868		5,806		33,159		6,319
	Total	$	3,085,977		$	84,259		$	355,098	$	33,194	$	3,441,075	$	117,453
	Fixed Maturity Securities – A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at June 30, 2014 is presented in the table below.
	($ in thousands)	Number of		Aggregate			Gross
		Securities		Fair Value			Unrealized
							Loss
	Mortgage-backed securities	11		$	44,646		$	1,772
	Corporate	8		18,070			633
	Foreign	3		21,374			1,463
	Total	22		$	84,090		$	3,868
	For OTTI of fixed maturity securities that management does not intend to sell or, more likely than not, would not be required to sell, the portion of the decline in value considered to be due to credit factors is recognized in earnings and the portion of the decline in value considered to be due to non-credit factors is recognized in other comprehensive income. For the six months ended June 30, 2014 and 2013, there were no changes in the portion of impairments recognized in earnings for those securities that have been impaired due to both credit factors and non-credit factors.
	The Company has evaluated its fixed maturity securities in an unrealized loss position and believes the unrealized losses are due primarily to temporary market and sector-related factors rather than to issuer-specific factors. None of these securities are delinquent or in default under financial covenants. Based on its assessment of these issuers, the Company expects them to continue to meet their contractual payment obligations as they become due and does not consider any of these securities to be OTTI.
	Preferred Stocks – At June 30, 2014, there were two preferred stocks in an unrealized loss position, with an aggregate fair value of $26 million and a gross unrealized loss of $3 million. Based upon management’s view of the underlying value of these securities, the Company does not consider these preferred stocks to be OTTI.
	Common Stocks – At June 30, 2014, the Company did not own any common stocks in an unrealized loss position.

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value Measurements	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Disclosures	'
	Fair Value Measurements
	The Company’s fixed maturity and equity securities available for sale and its arbitrage trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for similar assets in active markets. Level 3 inputs are unobservable inputs for the asset or liability. Unobservable inputs may only be used to measure fair value to the extent that observable inputs are not available.
	Because many fixed maturity securities do not trade on a daily basis, the Company utilizes pricing models and processes, which may include benchmark curves, benchmarking of like securities, sector groupings and matrix pricing. Market inputs used to evaluate securities include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data. Quoted prices are often unavailable for recently issued securities, securities that are infrequently traded or securities that are only traded in private transactions. For publicly traded securities for which quoted prices are unavailable, the Company determines fair value based on independent broker quotations and other observable market data. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information.
	The following tables present the assets and liabilities measured at fair value, on a recurring basis, as of June 30, 2014 and December 31, 2013 by level:
	(In thousands)	Total		Level 1			Level 2		Level 3
	June 30, 2014
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	867,127	$	—		$	867,127	$	—
	State and municipal	4,220,740		—			4,220,740		—
	Mortgage-backed securities	1,306,136		—			1,306,136		—
	Corporate	4,624,324		—			4,587,282		37,042
	Foreign government	968,376		—			968,376		—
	Total fixed maturity securities available for sale	11,986,703		—			11,949,661		37,042
	Equity securities available for sale:
	Common stocks	103,527		102,762			—		765
	Preferred stocks	153,532		—			149,763		3,769
	Total equity securities available for sale	257,059		102,762			149,763		4,534
	Arbitrage trading account	732,279		255,073			474,524		2,682
	Total	$	12,976,041	$	357,835		$	12,573,948	$	44,258
	Liabilities:
	Securities sold but not yet purchased	$	111,991	$	111,986		$	5	$	—
	December 31, 2013
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	884,859	$	—		$	884,859	$	—
	State and municipal	4,218,284		—			4,218,284		—
	Mortgage-backed securities	1,329,783		—			1,329,783		—
	Corporate	4,202,741		—			4,159,877		42,864
	Foreign government	879,857		—			879,857		—
	Total fixed maturity securities available for sale	11,515,524		—			11,472,660		42,864
	Equity securities available for sale:
	Common stocks	160,775		159,537			—		1,238
	Preferred stocks	122,563		—			118,811		3,752
	Total equity securities available for sale	283,338		159,537			118,811		4,990
	Arbitrage trading account	522,128		192,281			328,067		1,780
	Total	$	12,320,990	$	351,818		$	11,919,538	$	49,634
	Liabilities:
	Securities sold but not yet purchased	$	162,278	$	162,126		$	152	$	—
	There were no significant transfers between Levels 1 and 2 during the six months ended June 30, 2014 or during the year ended December 31, 2013.
	The following tables summarize changes in Level 3 assets and liabilities for the six months ended June 30, 2014 and for the year ended December 31, 2013:
				Gains (Losses) Included in
	(In thousands)	Beginning		Earnings			Other		Purchases		(Sales)			Maturities			Transfer in (out)			Ending
		Balance					Comprehensive													Balance
							Income
	Six months ended June 30, 2014:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	42,864	$	43		$	144	$	84	$	(5,247	)	$	(846	)	$	—		$	37,042
	Total	42,864		43			144		84		(5,247		)	(846		)	—			37,042
	Equity securities available for sale:
	Common stocks	1,238		—			—		—		(473		)	—			—			765
	Preferred stocks	3,752		39			—		—		(22		)	—			—			3,769
	Total	4,990		39			—		—		(495		)	—			—			4,534
	Arbitrage trading account	1,780		(1,429		)	—		2,539		(9,230		)	—			9,022			2,682
	Total	$	49,634	$	(1,347	)	$	144	$	2,623	$	(14,972	)	$	(846	)	$	9,022		$	44,258
	Year ended December 31, 2013:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	59,065	$	677		$	309	$	170	$	(4,753	)	$	(12,604	)	$	—		$	42,864
	Total	59,065		677			309		170		(4,753		)	(12,604		)	—			42,864
	Equity securities available for sale:
	Common stocks	1,408		—			—		—		(170		)	—			—			1,238
Preferred stocks	621		(299		)	—		3,430		—			—			—			3,752
Total	2,029		(299		)	—		3,430		(170		)	—			—			4,990
Arbitrage trading account	928		1,458			730		824		(853		)	—			(1,307		)	1,780
Total	$	62,022	$	1,836		$	1,039	$	4,424	$	(5,776	)	$	(12,604	)	$	(1,307	)	$	49,634
Liabilities:
Securities sold but not yet purchased	$	20	$	(4	)	$	—	$	4	$	(20	)	$	—		$	—		$	—
During the six months ended June 30, 2014, one security was transferred into Level 3 where the quoted price was no longer available. This security was subsequently sold during the second quarter of 2014. There were no significant transfers in or out of Level 3 during the year ended December 31, 2013.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments:
	June 30, 2014					December 31, 2013
(In thousands)	Carrying Value		Fair Value			Carrying Value		Fair Value
Assets:
Fixed maturity securities	$	12,088,055	$	12,107,686		$	11,616,844	$	11,631,744
Equity securities available for sale	257,059		257,059			283,338		283,338
Arbitrage trading account	732,279		732,279			522,128		522,128
Loans receivable	655,691		659,183			343,583		346,746
Cash and cash equivalents	842,671		842,671			839,738		839,738
Trading account receivables from brokers and clearing organizations	57,454		57,454			304,936		304,936
Due from broker	—		—			17,735		17,735
Liabilities:
Due to broker	18,850		18,850			8,273		8,273
Trading account securities sold but not yet purchased	111,991		111,991			162,278		162,278
Junior subordinated debentures	339,930		325,500			339,800		288,540
Senior notes and other debt	1,697,037		1,939,000			1,692,442		1,861,898
The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 16 above. The fair value of loans receivable are estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the junior subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.

Reinsurance_Reinsurance

Reinsurance Reinsurance	6 Months Ended
	Jun. 30, 2014
Insurance [Abstract]	'
Reinsurance [Text Block]	'
	Reinsurance
	The following is a summary of reinsurance financial information:
		For the Three Months						For the Six Months
		Ended June 30,						Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Written premiums:
	Direct	$	1,580,639		$	1,405,183		$	3,145,827		$	2,805,595
	Assumed	191,762			212,753			431,841			443,962
	Ceded	(282,625		)	(276,038		)	(562,012		)	(530,693		)
	Total net premiums written	$	1,489,776		$	1,341,898		$	3,015,656		$	2,718,864
	Earned premiums:
	Direct	$	1,449,152		$	1,301,702		$	2,830,724		$	2,542,264
	Assumed	224,916			217,517			450,678			431,533
	Ceded	(256,423		)	(236,704		)	(500,145		)	(459,163		)
	Total net premiums earned	$	1,417,645		$	1,282,515		$	2,781,257		$	2,514,634
	Ceded losses incurred	$	89,569		$	142,360		$	190,253		$	252,911
	The Company reinsures a portion of its insurance exposures in order to reduce its net liability on individual risks and catastrophe losses. The Company also cedes premiums to state assigned risk plans and captive insurance companies. Estimated amounts due from reinsurers are reported net of reserves for uncollectible reinsurance of $2 million as of June 30, 2014 and $1 million as of December 31, 2013.

Fair_Value_Of_Financial_Instru

Fair Value Of Financial Instruments Fair Value of Financial Instruments (Notes)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Disclosures	'
	Fair Value Measurements
	The Company’s fixed maturity and equity securities available for sale and its arbitrage trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for similar assets in active markets. Level 3 inputs are unobservable inputs for the asset or liability. Unobservable inputs may only be used to measure fair value to the extent that observable inputs are not available.
	Because many fixed maturity securities do not trade on a daily basis, the Company utilizes pricing models and processes, which may include benchmark curves, benchmarking of like securities, sector groupings and matrix pricing. Market inputs used to evaluate securities include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data. Quoted prices are often unavailable for recently issued securities, securities that are infrequently traded or securities that are only traded in private transactions. For publicly traded securities for which quoted prices are unavailable, the Company determines fair value based on independent broker quotations and other observable market data. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information.
	The following tables present the assets and liabilities measured at fair value, on a recurring basis, as of June 30, 2014 and December 31, 2013 by level:
	(In thousands)	Total		Level 1			Level 2		Level 3
	June 30, 2014
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	867,127	$	—		$	867,127	$	—
	State and municipal	4,220,740		—			4,220,740		—
	Mortgage-backed securities	1,306,136		—			1,306,136		—
	Corporate	4,624,324		—			4,587,282		37,042
	Foreign government	968,376		—			968,376		—
	Total fixed maturity securities available for sale	11,986,703		—			11,949,661		37,042
	Equity securities available for sale:
	Common stocks	103,527		102,762			—		765
	Preferred stocks	153,532		—			149,763		3,769
	Total equity securities available for sale	257,059		102,762			149,763		4,534
	Arbitrage trading account	732,279		255,073			474,524		2,682
	Total	$	12,976,041	$	357,835		$	12,573,948	$	44,258
	Liabilities:
	Securities sold but not yet purchased	$	111,991	$	111,986		$	5	$	—
	December 31, 2013
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	884,859	$	—		$	884,859	$	—
	State and municipal	4,218,284		—			4,218,284		—
	Mortgage-backed securities	1,329,783		—			1,329,783		—
	Corporate	4,202,741		—			4,159,877		42,864
	Foreign government	879,857		—			879,857		—
	Total fixed maturity securities available for sale	11,515,524		—			11,472,660		42,864
	Equity securities available for sale:
	Common stocks	160,775		159,537			—		1,238
	Preferred stocks	122,563		—			118,811		3,752
	Total equity securities available for sale	283,338		159,537			118,811		4,990
	Arbitrage trading account	522,128		192,281			328,067		1,780
	Total	$	12,320,990	$	351,818		$	11,919,538	$	49,634
	Liabilities:
	Securities sold but not yet purchased	$	162,278	$	162,126		$	152	$	—
	There were no significant transfers between Levels 1 and 2 during the six months ended June 30, 2014 or during the year ended December 31, 2013.
	The following tables summarize changes in Level 3 assets and liabilities for the six months ended June 30, 2014 and for the year ended December 31, 2013:
				Gains (Losses) Included in
	(In thousands)	Beginning		Earnings			Other		Purchases		(Sales)			Maturities			Transfer in (out)			Ending
		Balance					Comprehensive													Balance
							Income
	Six months ended June 30, 2014:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	42,864	$	43		$	144	$	84	$	(5,247	)	$	(846	)	$	—		$	37,042
	Total	42,864		43			144		84		(5,247		)	(846		)	—			37,042
	Equity securities available for sale:
	Common stocks	1,238		—			—		—		(473		)	—			—			765
	Preferred stocks	3,752		39			—		—		(22		)	—			—			3,769
	Total	4,990		39			—		—		(495		)	—			—			4,534
	Arbitrage trading account	1,780		(1,429		)	—		2,539		(9,230		)	—			9,022			2,682
	Total	$	49,634	$	(1,347	)	$	144	$	2,623	$	(14,972	)	$	(846	)	$	9,022		$	44,258
	Year ended December 31, 2013:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	59,065	$	677		$	309	$	170	$	(4,753	)	$	(12,604	)	$	—		$	42,864
	Total	59,065		677			309		170		(4,753		)	(12,604		)	—			42,864
	Equity securities available for sale:
	Common stocks	1,408		—			—		—		(170		)	—			—			1,238
Preferred stocks	621		(299		)	—		3,430		—			—			—			3,752
Total	2,029		(299		)	—		3,430		(170		)	—			—			4,990
Arbitrage trading account	928		1,458			730		824		(853		)	—			(1,307		)	1,780
Total	$	62,022	$	1,836		$	1,039	$	4,424	$	(5,776	)	$	(12,604	)	$	(1,307	)	$	49,634
Liabilities:
Securities sold but not yet purchased	$	20	$	(4	)	$	—	$	4	$	(20	)	$	—		$	—		$	—
During the six months ended June 30, 2014, one security was transferred into Level 3 where the quoted price was no longer available. This security was subsequently sold during the second quarter of 2014. There were no significant transfers in or out of Level 3 during the year ended December 31, 2013.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments:
	June 30, 2014					December 31, 2013
(In thousands)	Carrying Value		Fair Value			Carrying Value		Fair Value
Assets:
Fixed maturity securities	$	12,088,055	$	12,107,686		$	11,616,844	$	11,631,744
Equity securities available for sale	257,059		257,059			283,338		283,338
Arbitrage trading account	732,279		732,279			522,128		522,128
Loans receivable	655,691		659,183			343,583		346,746
Cash and cash equivalents	842,671		842,671			839,738		839,738
Trading account receivables from brokers and clearing organizations	57,454		57,454			304,936		304,936
Due from broker	—		—			17,735		17,735
Liabilities:
Due to broker	18,850		18,850			8,273		8,273
Trading account securities sold but not yet purchased	111,991		111,991			162,278		162,278
Junior subordinated debentures	339,930		325,500			339,800		288,540
Senior notes and other debt	1,697,037		1,939,000			1,692,442		1,861,898
The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 16 above. The fair value of loans receivable are estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the junior subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.

Restricted_Stock_Units_Restric

Restricted Stock Units Restricted Stock Units (Notes)	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Restricted Stock Units	'
	Restricted Stock Units
	Pursuant to its stock incentive plan, the Company may issue restricted stock units (RSUs) to employees of the Company and its subsidiaries. The RSUs generally vest five years from the award date and are subject to other vesting and forfeiture provisions contained in the award agreement. RSUs are expensed pro-ratably over the vesting period. RSU expenses were $12 million and $11 million for the six months ended June 30, 2014 and 2013, respectively. A summary of RSUs issued in the six months ended June 30, 2014 and 2013 follows:
	($ in thousands)	Units	Fair Value
	Six months ended June 30,
	2014	25,950	$	1,079
	2013	55,150	$	2,312

Litigation_and_Contingent_Liab

Litigation and Contingent Liabilities Litigation and Contingent Liabilities	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies Disclosure [Text Block]	'
	Litigation and Contingent Liabilities
	In the ordinary course of business, the Company is subject to disputes, litigation and arbitration arising from its insurance and reinsurance businesses. These matters are generally related to insurance and reinsurance claims and are considered in the establishment of loss and loss expense reserves. In addition, the Company may also become involved in legal actions which seek extra-contractual damages, punitive damages or penalties, including claims alleging bad faith in handling of insurance claims. The Company expects its ultimate liability with respect to such matters will not be material to its financial condition. However, adverse outcomes on such matters are possible, from time to time, and could be material to the Company’s results of operations in any particular financial reporting period.

Industry_Segments

Industry Segments	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Industry Segments	'
	Business Segments
	The Company’s financial results are presented for the following reportable business segments, plus a corporate segment:
	•	Insurance-Domestic - commercial insurance business, including excess and surplus lines and admitted lines, primarily throughout the United States;
	•	Insurance-International - insurance business primarily in the United Kingdom, Continental Europe, South America, Canada, Scandinavia, and Australia; and
	•	Reinsurance-Global - reinsurance business on a facultative and treaty basis, primarily in the United States, United Kingdom, Continental Europe, Australia, and the Asia-Pacific Region.
	The accounting policies of the segments are the same as those described in the summary of significant accounting policies. Income tax expense and benefits are calculated based upon the Company’s overall effective tax rate.
	Summary financial information about the Company's business segments is presented in the following tables.
		Revenues
	(In thousands)	Earned		Investment				Other			Total		Pre-Tax			Net
		Premiums		Income									Income			Income
													(Loss)			(Loss) to Common Stockholders
	Three months ended June 30, 2014:
	Insurance-Domestic	$	1,041,745	$	103,073			$	26,985		$	1,171,803	$	176,855		$	121,834
	Insurance-International	201,868		11,276				—			213,144		11,510			8,253
	Reinsurance-Global	174,032		17,608				—			191,640		25,866			18,025
	Corporate and eliminations (1)	—		6,772				104,462			111,234		(59,945		)	(39,110		)
	Net investment gains	—		—				109,168			109,168		109,168			70,959
	Total	$	1,417,645	$	138,729			$	240,615		$	1,796,989	$	263,454		$	179,961
	Three months ended June 30, 2013:
	Insurance-Domestic	$	925,997	$	107,562			$	27,652		$	1,061,211	$	152,334		$	106,478
	Insurance-International	180,192		13,171				—			193,363		12,583			9,092
	Reinsurance-Global	176,326		23,036				—			199,362		24,752			17,681
	Corporate and eliminations (1)	—		(32		)		84,000			83,968		(64,021		)	(38,782		)
	Net investment gains	—		—				33,058			33,058		33,058			21,488
	Total	$	1,282,515	$	143,737			$	144,710		$	1,570,962	$	158,706		$	115,957
	Six months ended June 30, 2014:
	Insurance-Domestic	$	2,045,252	$	221,210			$	55,751		$	2,322,213	$	379,040		$	259,870
	Insurance-International	387,192		27,928				—			415,120		29,257			20,721
	Reinsurance-Global	348,813		45,186				—			393,999		57,940			40,417
	Corporate and eliminations (1)	—		13,116				197,525			210,641		(117,120		)	(76,623		)
	Net investment gains	—		—				161,922			161,922		161,922			105,249
	Total	$	2,781,257	$	307,440			$	415,198		$	3,503,895	$	511,039		$	349,634
	Six months ended June 30, 2013:
	Insurance-Domestic	$	1,810,375	$	205,359			$	54,388		$	2,070,122	$	293,684		$	205,886
	Insurance-International	351,311		25,232				—			376,543		34,965			24,569
	Reinsurance-Global	352,948		45,535				—			398,483		62,693			44,075
	Corporate and eliminations (1)	—		3,540				176,016			179,556		(125,440		)	(76,426		)
	Net investment gains	—		—				53,027			53,027		53,027			34,468
	Total	$	2,514,634	$	279,666			$	283,431		$	3,077,731	$	318,929		$	232,572
	___________
	(1) Corporate and eliminations represent corporate revenues and expenses that are not allocated to business segments.
	Identifiable assets by segment are as follows:
	(In thousands)	June 30, 2014		31-Dec-13
	Insurance-Domestic	$	15,565,600	$	15,247,807
	Insurance-International	1,963,689		1,516,310
	Reinsurance-Global	2,767,108		3,103,193
	Corporate and eliminations	870,797		684,486
	Total	$	21,167,194	$	20,551,796
	Net premiums earned by major line of business are as follows:
		For the Three Months					For the Six Months
		Ended June 30,					Ended June 30,
	(In thousands)	2014		2013			2014			2013
	Insurance-Domestic:
	Other liability	$	362,074	$	307,444		$	701,707		$	603,032
	Workers’ compensation	270,212		241,191			533,244			470,202
	Short-tail lines	215,506		192,938			420,272			371,687
	Commercial automobile	127,102		119,900			251,470			236,022
	Professional liability	66,851		64,524			138,559			129,432
	Total	1,041,745		925,997			2,045,252			1,810,375
	Insurance-International:
	Other liability	22,956		15,070			42,331			30,288
	Workers’ compensation	17,241		21,746			34,566			44,635
	Short-tail lines	106,428		84,301			202,702			156,424
Commercial automobile	29,649		32,392			57,242			67,031
Professional liability	25,594		26,683			50,351			52,933
Total	201,868		180,192			387,192			351,311
Reinsurance-Global:
Casualty	124,550		122,117			250,153			243,444
Property	49,482		54,209			98,660			109,504
Total	174,032		176,326			348,813			352,948
Total	$	1,417,645	$	1,282,515		$	2,781,257		$	2,514,634

Subsequent_Event_Subsequent_Ev

Subsequent Event Subsequent Event	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	(22) Subsequent Event
	On August 6, 2014, the Company issued $350 million of 4.75% senior notes due 2044.

Per_Share_Data_Tables

Per Share Data (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Weighted Average Number of Shares [Table Text Block]	'
	The weighted average number of common shares used in the computation of basic and diluted earnings per share was as follows:
		For the Three Months		For the Six Months
		Ended June 30,		Ended June 30,
	(In thousands)	2014	2013	2014	2013
	Basic	127,668	135,894	128,765	135,959
	Diluted	133,304	141,274	134,323	141,257

Acquistions_Acquisitions_Table

Acquistions Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2014
Business Combinations [Abstract]	'
Summary of fair value of net assets acquired and liabilities assumed	'
	The following table summarizes the estimated fair value of net assets acquired and liabilities assumed at the date of acquisition:
	(In thousands)
	Cash and cash equivalents	$	3,911
	Real estate, furniture and equipment	898
	Goodwill	19,664
	Intangible assets	44,800
	Other assets	60,661
	Total assets acquired	129,934
	Debt	(27,612		)
	Other liabilities assumed	(17,076		)
	Net assets acquired	$	85,246

Statements_of_Comprehensive_In1

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2014
Equity [Abstract]	'
Components of changes in accumulated other comprehensive income (loss)	'
	The following table presents the components of the changes in accumulated other comprehensive income (loss) ("AOCI"):
	(In thousands)	Unrealized Investment Gains (Losses)				Currency Translation Adjustments			Net Pension Asset				Accumulated Other Comprehensive Income (Loss)
	As of and for the six months ended June 30, 2014:
	Changes in AOCI
	Beginning of period	$	256,566			$	(60,524	)	$	(6,651	)		$	189,391
	Other comprehensive income (loss) before reclassifications	140,289				20,790			—				161,079
	Amounts reclassified from AOCI	(19,145		)		—			2,611				(16,534		)
	Other comprehensive income (loss)	121,144				20,790			2,611				144,545
	Unrealized investment gain (loss) related to non-controlling interest	(37		)		—			—				(37		)
	End of period	$	377,673			$	(39,734	)	$	(4,040	)		$	333,899
	Amounts reclassified from AOCI
	Pre-tax	$	(29,454	)	-1	$	—		$	4,017		-2	$	(25,437	)
	Tax effect (3)	10,309				—			(1,406		)		8,903
	After-tax amounts reclassified	$	(19,145	)		$	—		$	2,611			$	(16,534	)
	Other comprehensive income (loss)
	Pre-tax	$	188,680			$	20,790		$	4,017			$	213,487
	Tax effect	(67,536		)		—			(1,406		)		(68,942		)
	Other comprehensive income (loss)	$	121,144			$	20,790		$	2,611			$	144,545
	As of and for the three months ended June 30, 2014:
	Changes in AOCI
	Beginning of period	$	329,492			$	(64,549	)	$	(6,060	)		$	258,883
	Other comprehensive income (loss) before reclassifications	62,846				24,815			—				87,661
	Amounts reclassified from AOCI	(14,646		)		—			2,020				(12,626		)
	Other comprehensive income (loss)	48,200				24,815			2,020				75,035
	Unrealized investment gain (loss) related to non-controlling interest	(19		)		—			—				(19		)
	End of period	$	377,673			$	(39,734	)	$	(4,040	)		$	333,899
	Amounts reclassified from AOCI
	Pre-tax	$	(22,532	)	-1	$	—		$	3,108		-2	$	(19,424	)
	Tax effect (3)	7,886				—			(1,088		)		6,798
	After-tax amounts reclassified	$	(14,646	)		$	—		$	2,020			$	(12,626	)
	Other comprehensive income (loss)
	Pre-tax	$	76,390			$	24,815		$	3,108			$	104,313
	Tax effect	(28,190		)		—			(1,088		)		(29,278		)
	Other comprehensive income (loss)	$	48,200			$	24,815		$	2,020			$	75,035
		Unrealized Investment Gains				Currency Translation Adjustments			Net Pension Asset				Accumulated Other Comprehensive Income (Loss)
	(In thousands)
	As of and for the six months ended June 30, 2013:
	Changes in AOCI
	Beginning of period	$	517,658			$	(36,676	)	$	(15,351	)		$	465,631
	Other comprehensive income (loss) before reclassifications	(161,945		)		(69,779		)	—				(231,724		)
	Amounts reclassified from AOCI	(27,305		)		—			3,628				(23,677		)
	Other comprehensive income (loss)	(189,250		)		(69,779		)	3,628				(255,401		)
	Unrealized investment gain related to non-controlling interest	(5		)		—			—				(5		)
	End of period	$	328,403			$	(106,455	)	$	(11,723	)		$	210,225
	Amounts reclassified from AOCI
	Pre-tax	$	(42,008	)	-1	$	—		$	5,582		-2	$	(36,426	)
	Tax effect (3)	14,703				—			(1,954		)		12,749
	After-tax amounts reclassified	$	(27,305	)		$	—		$	3,628			$	(23,677	)
	Other comprehensive income (loss)
	Pre-tax	$	(291,154	)		$	(69,779	)	$	5,582			$	(355,351	)
	Tax effect	101,904				—			(1,954		)		99,950
	Other comprehensive income (loss)	$	(189,250	)		$	(69,779	)	$	3,628			$	(255,401	)
	As of and for the three months ended June 30, 2013:
	Changes in AOCI
	Beginning of period	$	525,428			$	(83,299	)	$	(13,537	)		$	428,592
	Other comprehensive income (loss) before reclassifications	(182,934		)		(23,156		)	—				(206,090		)
	Amounts reclassified from AOCI	(14,126		)		—			1,814				(12,312		)
	Other comprehensive income (loss)	(197,060		)		(23,156		)	1,814				(218,402		)
	Unrealized investment gain related to non-controlling interest	35							—				35
	End of period	$	328,403			$	(106,455	)	$	(11,723	)		$	210,225
	Amounts reclassified from AOCI
	Pre-tax	$	(21,933	)	-1	$	—		$	2,790		-2	$	(19,143	)
	Tax effect (3)	7,807				—			(976		)		6,831
After-tax amounts reclassified	$	(14,126	)		$	—		$	1,814			$	(12,312	)
Other comprehensive income (loss)
Pre-tax	$	(303,169	)		$	(23,156	)	$	2,790			$	(323,535	)
Tax effect	106,109				—			(976		)		105,133
Other comprehensive income (loss)	$	(197,060	)		$	(23,156	)	$	1,814			$	(218,402	)
(1) Net investment gains in the consolidated statements of operations.
(2) Other operating costs and expenses in the consolidated statements of operations.
(3) Income tax expense in the consolidated statements of operations.

Investments_In_Fixed_Maturity_1

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Tables)	6 Months Ended
	Jun. 30, 2014
Schedule of Marketable Securities [Line Items]	'
Amortized cost and fair value of fixed maturity securities by contractual maturity	'
	The amortized cost and fair value of fixed maturity securities at June 30, 2014, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations.
	(In thousands)	Amortized		Fair Value
		Cost
	Due in one year or less	$	886,256	$	896,523
	Due after one year through five years	3,860,527		4,039,960
	Due after five years through ten years	3,035,251		3,229,746
	Due after ten years	2,492,226		2,606,741
	Mortgage-backed securities	1,309,360		1,334,716
	Total	$	11,583,620	$	12,107,686
Debt Securities [Member]	'
Schedule of Marketable Securities [Line Items]	'
Schedule of investments in fixed maturity securities	'
	At June 30, 2014 and December 31, 2013, investments in fixed maturity securities were as follows:
	(In thousands)	Amortized		Gross Unrealized					Fair		Carrying
		Cost		Gains		Losses			Value		Value
	June 30, 2014
	Held to maturity:
	State and municipal	$	70,956	$	16,135	$	—		$	87,091	$	70,956
	Residential mortgage-backed	25,398		3,182		—			28,580		25,398
	Corporate	4,998		314		—			5,312		4,998
	Total held to maturity	101,352		19,631		—			120,983		101,352
	Available for sale:
	U.S. government and government agency	839,914		34,766		(7,553		)	867,127		867,127
	State and municipal	4,004,308		221,995		(5,563		)	4,220,740		4,220,740
	Mortgage-backed securities:
	Residential (1)	1,209,584		29,930		(13,765		)	1,225,749		1,225,749
	Commercial	74,378		6,056		(47		)	80,387		80,387
	Corporate	4,436,526		206,290		(18,492		)	4,624,324		4,624,324
	Foreign	917,558		68,553		(17,735		)	968,376		968,376
	Total available for sale	11,482,268		567,590		(63,155		)	11,986,703		11,986,703
	Total investments in fixed maturity securities	$	11,583,620	$	587,221	$	(63,155	)	$	12,107,686	$	12,088,055
	December 31, 2013
	Held to maturity:
	State and municipal	$	68,929	$	11,172	$	—		$	80,101	$	68,929
	Residential mortgage-backed	27,393		3,311		—			30,704		27,393
	Corporate	4,998		417		—			5,415		4,998
	Total held to maturity	101,320		14,900		—			116,220		101,320
	Available for sale:
	U.S. government and government agency	858,319		34,522		(7,982		)	884,859		884,859
	State and municipal	4,085,791		162,330		(29,837		)	4,218,284		4,218,284
	Mortgage-backed securities:
	Residential (1)	1,248,693		25,895		(25,941		)	1,248,647		1,248,647
	Commercial	76,454		5,670		(988		)	81,136		81,136
	Corporate	4,076,585		156,256		(30,100		)	4,202,741		4,202,741
	Foreign	844,469		51,674		(16,286		)	879,857		879,857
	Total available for sale	11,190,311		436,347		(111,134		)	11,515,524		11,515,524
	Total investments in fixed maturity securities	$	11,291,631	$	451,247	$	(111,134	)	$	11,631,744	$	11,616,844
	___________
	-1	Gross unrealized losses for residential mortgage-backed securities include $1,208,000 and $1,961,000 as of June 30, 2014 and December 31, 2013, respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.

Investments_in_Equity_Securiti1

Investments in Equity Securities Investments in Equity Securities (Tables) (Equity securities available for sale)	6 Months Ended
	Jun. 30, 2014
Equity securities available for sale	'
Schedule of Available-for-sale Securities [Line Items]	'
Schedule of Investments in Equity Securities	'
	At June 30, 2014 and December 31, 2013, investments in equity securities were as follows:
	(In thousands)	Cost		Gross Unrealized					Fair		Carrying
				Gains		Losses			Value		Value
	June 30, 2014
	Common stocks	$	75,167	$	28,360	$	—		$	103,527	$	103,527
	Preferred stocks	92,797		63,740		(3,005		)	153,532		153,532
	Total	$	167,964	$	92,100	$	(3,005	)	$	257,059	$	257,059
	December 31, 2013
	Common stocks	$	118,536	$	42,239	$	—		$	160,775	$	160,775
	Preferred stocks	85,091		43,791		(6,319		)	122,563		122,563
	Total	$	203,627	$	86,030	$	(6,319	)	$	283,338	$	283,338

Net_Investment_Income_Tables

Net Investment Income (Tables)	6 Months Ended
	Jun. 30, 2014
Net Investment Income [Abstract]	'
Schedule of Net Investment Income	'
	Net investment income consists of the following:
		For the Three Months						For the Six Months
		Ended June 30,						Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Investment income earned on:
	Fixed maturity securities, including cash and cash equivalents and loans receivable	$	107,760		$	111,203		$	214,658		$	229,039
	Investment funds	22,356			22,576			76,155			33,510
	Arbitrage trading account	6,942			4,990			12,461			8,773
	Equity securities available for sale	2,103			3,634			4,049			5,881
	Real estate	3,063			3,116			6,165			6,257
	Gross investment income	142,224			145,519			313,488			283,460
	Investment expense	(3,495		)	(1,782		)	(6,048		)	(3,794		)
	Net investment income	$	138,729		$	143,737		$	307,440		$	279,666

Investment_Funds_Investment_Fu1

Investment Funds Investment Funds (Tables)	6 Months Ended
	Jun. 30, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Schedule of Net Investment Funds	'
	Investment funds consist of the following:
		Carrying Value as of				Income (Loss) from Investment Funds
		June 30,		December 31,		For the Six Months Ended June 30,
	(In thousands)	2014		2013		2014		2013
	Real estate	$	280,255	$	378,435	$	16,482	$	1,260
	Energy	159,645		155,026		12,596		25,199
	Arbitrage	279,806		271,575		8,231		1,731
	Other	265,130		262,459		38,846		5,320
	Total	$	984,836	$	1,067,495	$	76,155	$	33,510

Real_Estate_Real_Estate_Tables

Real Estate Real Estate (Tables)	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Schedule of Real Estate Investments	'
	Investment in real estate represents directly owned property held for investment, as follows:
		Carrying Value
		June 30,		December 31,
	(In thousands)	2014		2013
	Properties in operation	$	47,617	$	283,393
	Properties under development	482,622		431,849
	Total	$	530,239	$	715,242

Loans_Receivable_Loans_Receiva1

Loans Receivable Loans Receivable (Tables)	6 Months Ended
	Jun. 30, 2014
Receivables [Abstract]	'
Schedule of Loans Receivable	'
	Loans receivable are as follows:
	(In thousands)	June 30, 2014		31-Dec-13
	Amortized cost:
	Real estate loans	$	569,530	$	282,357
	Commercial loans	86,161		61,226
	Total	$	655,691	$	343,583
	Fair value:
	Real estate loans	$	571,520	$	284,017
	Commercial loans	87,663		62,729
	Total	$	659,183	$	346,746
	Valuation allowance:
	Specific	$	—	$	—
	General	2,566		2,087
	Total	$	2,566	$	2,087
		For the Three Months
		Ended June 30,
		2014		2013
	Increase (decrease) in valuation allowance	$	16	$	(30	)
	Loans receivable charged off	—		—
		For the Six Months
		Ended June 30,
		2014		2013
	Increase in valuation allowance	$	479	$	65
	Loans receivable charged off	—		—

Realized_And_Unrealized_Invest1

Realized And Unrealized Investment Gains (Losses) (Tables)	6 Months Ended
	Jun. 30, 2014
Realized and Unrealized Investment Gains (Losses) [Abstract]	'
Realized and Unrealized Investment Gains (Losses)	'
	Realized and unrealized investment gains (losses) are as follows:
		For the Three Months Ended June 30,						For the Six Months Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Realized investment gains (losses):
	Fixed maturity securities:
	Gains	$	1,941		$	9,147		$	4,003		$	20,143
	Losses	(464		)	(5,500		)	(2,062		)	(11,466		)
	Equity securities available for sale	23,124			18,086			29,581			33,331
	Investment funds	(1,076		)	10,843			44,757			11,037
	Real estate	85,643			—			85,643			—
	Other	—			482			—			(18		)
	Total	109,168			33,058			161,922			53,027
	Change in valuation allowance, net of other-than-temporary impairments:
	Decrease in valuation allowance	—			—			—			—
	Other-than-temporary impairments	—			—			—			—
	Total	—			—			—			—
	Net investment gains	109,168			33,058			161,922			53,027
	Income tax expense	(38,208		)	(11,570		)	(56,673		)	(18,559		)
	Total after-tax realized investment gains	$	70,960		$	21,488		$	105,249		$	34,468
Unrealized Gain (Loss) on Investments	'
	Change in unrealized investment gains (losses):
	Fixed maturity securities	$	87,882		$	(277,791	)	$	179,520		$	(293,380	)
	Previously impaired fixed maturity securities	194			(590		)	753			522
	Equity securities available for sale	(17,870		)	(16,191		)	8,333			8,370
	Investment funds	6,184			(5,906		)	74			(9,174		)
	Total change in unrealized investment gains (losses)	76,390			(300,478		)	188,680			(293,662		)
	Income tax benefit (expense)	(28,190		)	103,418			(67,536		)	104,412
	Noncontrolling interests	(19		)	35			(37		)	(5		)
	Total after-tax unrealized gains (losses)	$	48,181		$	(197,025	)	$	121,107		$	(189,255	)

Securities_In_An_Unrealized_Lo1

Securities In An Unrealized Loss Position Securities In An Unrealized Loss Position (Tables)	6 Months Ended
	Jun. 30, 2014
Statement of Financial Position [Abstract]	'
Securities in an unrealized loss position	'
	The following tables summarize all securities in an unrealized loss position at June 30, 2014 and December 31, 2013 by the length of time those securities have been continuously in an unrealized loss position:
		Less Than 12 Months						12 Months or Greater				Total
	(In thousands)	Fair Value			Gross			Fair Value		Gross		Fair Value		Gross
					Unrealized					Unrealized				Unrealized
					Losses					Losses				Losses
	June 30, 2014
	U.S. government and government agency	$	191,360		$	4,176		$	74,427	$	3,377	$	265,787	$	7,553
	State and municipal	136,081			1,796			185,605		3,767		321,686		5,563
	Mortgage-backed securities	129,004			725			341,219		13,087		470,223		13,812
	Corporate	549,991			7,099			285,261		11,393		835,252		18,492
	Foreign	183,837			7,461			101,882		10,274		285,719		17,735
	Fixed maturity securities	1,190,273			21,257			988,394		41,898		2,178,667		63,155
	Common stocks	—			—			—		—		—		—
	Preferred stocks	—			—			25,714		3,005		25,714		3,005
	Equity securities	—			—			25,714		3,005		25,714		3,005
	Total	$	1,190,273		$	21,257		$	1,014,108	$	44,903	$	2,204,381	$	66,160
	December 31, 2013
	U.S. government and government agency	$	260,882		$	7,927		$	2,163	$	55	$	263,045	$	7,982
	State and municipal	899,613			24,503			87,345		5,334		986,958		29,837
	Mortgage-backed securities	578,603			17,964			140,648		8,965		719,251		26,929
	Corporate	1,013,373			17,066			105,074		13,034		1,118,447		30,100
	Foreign	320,215			16,286			—		—		320,215		16,286
	Fixed maturity securities	3,072,686			83,746			335,230		27,388		3,407,916		111,134
	Common stocks	—			—			—		—		—		—
	Preferred stocks	13,291			513			19,868		5,806		33,159		6,319
	Equity securities	13,291			513			19,868		5,806		33,159		6,319
	Total	$	3,085,977		$	84,259		$	355,098	$	33,194	$	3,441,075	$	117,453
Non-Investment Grade Fixed Maturity Securities	'
	Fixed Maturity Securities – A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at June 30, 2014 is presented in the table below.
	($ in thousands)	Number of		Aggregate			Gross
		Securities		Fair Value			Unrealized
							Loss
	Mortgage-backed securities	11		$	44,646		$	1,772
	Corporate	8		18,070			633
	Foreign	3		21,374			1,463
	Total	22		$	84,090		$	3,868

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Assets And Liabilities Measured At Fair value, On A Recurring Basis	'
	The following tables present the assets and liabilities measured at fair value, on a recurring basis, as of June 30, 2014 and December 31, 2013 by level:
	(In thousands)	Total		Level 1			Level 2		Level 3
	June 30, 2014
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	867,127	$	—		$	867,127	$	—
	State and municipal	4,220,740		—			4,220,740		—
	Mortgage-backed securities	1,306,136		—			1,306,136		—
	Corporate	4,624,324		—			4,587,282		37,042
	Foreign government	968,376		—			968,376		—
	Total fixed maturity securities available for sale	11,986,703		—			11,949,661		37,042
	Equity securities available for sale:
	Common stocks	103,527		102,762			—		765
	Preferred stocks	153,532		—			149,763		3,769
	Total equity securities available for sale	257,059		102,762			149,763		4,534
	Arbitrage trading account	732,279		255,073			474,524		2,682
	Total	$	12,976,041	$	357,835		$	12,573,948	$	44,258
	Liabilities:
	Securities sold but not yet purchased	$	111,991	$	111,986		$	5	$	—
	December 31, 2013
	Assets:
	Fixed maturity securities available for sale:
	U.S. government and government agency	$	884,859	$	—		$	884,859	$	—
	State and municipal	4,218,284		—			4,218,284		—
	Mortgage-backed securities	1,329,783		—			1,329,783		—
	Corporate	4,202,741		—			4,159,877		42,864
	Foreign government	879,857		—			879,857		—
	Total fixed maturity securities available for sale	11,515,524		—			11,472,660		42,864
	Equity securities available for sale:
	Common stocks	160,775		159,537			—		1,238
	Preferred stocks	122,563		—			118,811		3,752
	Total equity securities available for sale	283,338		159,537			118,811		4,990
	Arbitrage trading account	522,128		192,281			328,067		1,780
	Total	$	12,320,990	$	351,818		$	11,919,538	$	49,634
	Liabilities:
	Securities sold but not yet purchased	$	162,278	$	162,126		$	152	$	—
Summarize Changes In Level 3 Assets	'
	The following tables summarize changes in Level 3 assets and liabilities for the six months ended June 30, 2014 and for the year ended December 31, 2013:
				Gains (Losses) Included in
	(In thousands)	Beginning		Earnings			Other		Purchases		(Sales)			Maturities			Transfer in (out)			Ending
		Balance					Comprehensive													Balance
							Income
	Six months ended June 30, 2014:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	42,864	$	43		$	144	$	84	$	(5,247	)	$	(846	)	$	—		$	37,042
	Total	42,864		43			144		84		(5,247		)	(846		)	—			37,042
	Equity securities available for sale:
	Common stocks	1,238		—			—		—		(473		)	—			—			765
	Preferred stocks	3,752		39			—		—		(22		)	—			—			3,769
	Total	4,990		39			—		—		(495		)	—			—			4,534
	Arbitrage trading account	1,780		(1,429		)	—		2,539		(9,230		)	—			9,022			2,682
	Total	$	49,634	$	(1,347	)	$	144	$	2,623	$	(14,972	)	$	(846	)	$	9,022		$	44,258
	Year ended December 31, 2013:
	Assets:
	Fixed maturities available for sale:
	Corporate	$	59,065	$	677		$	309	$	170	$	(4,753	)	$	(12,604	)	$	—		$	42,864
	Total	59,065		677			309		170		(4,753		)	(12,604		)	—			42,864
	Equity securities available for sale:
	Common stocks	1,408		—			—		—		(170		)	—			—			1,238
	Preferred stocks	621		(299		)	—		3,430		—			—			—			3,752
	Total	2,029		(299		)	—		3,430		(170		)	—			—			4,990
	Arbitrage trading account	928		1,458			730		824		(853		)	—			(1,307		)	1,780
	Total	$	62,022	$	1,836		$	1,039	$	4,424	$	(5,776	)	$	(12,604	)	$	(1,307	)	$	49,634
	Liabilities:
	Securities sold but not yet purchased	$	20	$	(4	)	$	—	$	4	$	(20	)	$	—		$	—		$	—

Reinsurance_Tables

Reinsurance (Tables)	6 Months Ended
	Jun. 30, 2014
Reinsurance Disclosures [Abstract]	'
Reinsurance Financial Information	'
	The following is a summary of reinsurance financial information:
		For the Three Months						For the Six Months
		Ended June 30,						Ended June 30,
	(In thousands)	2014			2013			2014			2013
	Written premiums:
	Direct	$	1,580,639		$	1,405,183		$	3,145,827		$	2,805,595
	Assumed	191,762			212,753			431,841			443,962
	Ceded	(282,625		)	(276,038		)	(562,012		)	(530,693		)
	Total net premiums written	$	1,489,776		$	1,341,898		$	3,015,656		$	2,718,864
	Earned premiums:
	Direct	$	1,449,152		$	1,301,702		$	2,830,724		$	2,542,264
	Assumed	224,916			217,517			450,678			431,533
	Ceded	(256,423		)	(236,704		)	(500,145		)	(459,163		)
	Total net premiums earned	$	1,417,645		$	1,282,515		$	2,781,257		$	2,514,634
	Ceded losses incurred	$	89,569		$	142,360		$	190,253		$	252,911

Recovered_Sheet1

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Carrying Amounts And Estimated Fair Values Of Financial Instruments	'
	The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments:
		June 30, 2014				December 31, 2013
	(In thousands)	Carrying Value		Fair Value		Carrying Value		Fair Value
	Assets:
	Fixed maturity securities	$	12,088,055	$	12,107,686	$	11,616,844	$	11,631,744
	Equity securities available for sale	257,059		257,059		283,338		283,338
	Arbitrage trading account	732,279		732,279		522,128		522,128
	Loans receivable	655,691		659,183		343,583		346,746
	Cash and cash equivalents	842,671		842,671		839,738		839,738
	Trading account receivables from brokers and clearing organizations	57,454		57,454		304,936		304,936
	Due from broker	—		—		17,735		17,735
	Liabilities:
	Due to broker	18,850		18,850		8,273		8,273
	Trading account securities sold but not yet purchased	111,991		111,991		162,278		162,278
	Junior subordinated debentures	339,930		325,500		339,800		288,540
	Senior notes and other debt	1,697,037		1,939,000		1,692,442		1,861,898

Restricted_Stock_Units_Tables

Restricted Stock Units (Tables)	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary Of Restricted Stock Units Issued	'
	A summary of RSUs issued in the six months ended June 30, 2014 and 2013 follows:
	($ in thousands)	Units	Fair Value
	Six months ended June 30,
	2014	25,950	$	1,079
	2013	55,150	$	2,312

Industry_Segments_Tables

Industry Segments (Tables)	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Financial Information Of Company Operating Segments	'
		Revenues
	(In thousands)	Earned		Investment				Other			Total		Pre-Tax			Net
		Premiums		Income									Income			Income
													(Loss)			(Loss) to Common Stockholders
	Three months ended June 30, 2014:
	Insurance-Domestic	$	1,041,745	$	103,073			$	26,985		$	1,171,803	$	176,855		$	121,834
	Insurance-International	201,868		11,276				—			213,144		11,510			8,253
	Reinsurance-Global	174,032		17,608				—			191,640		25,866			18,025
	Corporate and eliminations (1)	—		6,772				104,462			111,234		(59,945		)	(39,110		)
	Net investment gains	—		—				109,168			109,168		109,168			70,959
	Total	$	1,417,645	$	138,729			$	240,615		$	1,796,989	$	263,454		$	179,961
	Three months ended June 30, 2013:
	Insurance-Domestic	$	925,997	$	107,562			$	27,652		$	1,061,211	$	152,334		$	106,478
	Insurance-International	180,192		13,171				—			193,363		12,583			9,092
	Reinsurance-Global	176,326		23,036				—			199,362		24,752			17,681
	Corporate and eliminations (1)	—		(32		)		84,000			83,968		(64,021		)	(38,782		)
	Net investment gains	—		—				33,058			33,058		33,058			21,488
	Total	$	1,282,515	$	143,737			$	144,710		$	1,570,962	$	158,706		$	115,957
	Six months ended June 30, 2014:
	Insurance-Domestic	$	2,045,252	$	221,210			$	55,751		$	2,322,213	$	379,040		$	259,870
	Insurance-International	387,192		27,928				—			415,120		29,257			20,721
	Reinsurance-Global	348,813		45,186				—			393,999		57,940			40,417
	Corporate and eliminations (1)	—		13,116				197,525			210,641		(117,120		)	(76,623		)
	Net investment gains	—		—				161,922			161,922		161,922			105,249
	Total	$	2,781,257	$	307,440			$	415,198		$	3,503,895	$	511,039		$	349,634
	Six months ended June 30, 2013:
	Insurance-Domestic	$	1,810,375	$	205,359			$	54,388		$	2,070,122	$	293,684		$	205,886
	Insurance-International	351,311		25,232				—			376,543		34,965			24,569
	Reinsurance-Global	352,948		45,535				—			398,483		62,693			44,075
	Corporate and eliminations (1)	—		3,540				176,016			179,556		(125,440		)	(76,426		)
	Net investment gains	—		—				53,027			53,027		53,027			34,468
	Total	$	2,514,634	$	279,666			$	283,431		$	3,077,731	$	318,929		$	232,572
	___________
	(1) Corporate and eliminations represent corporate revenues and expenses that are not allocated to business segments.
Identifiable Assets By Segment	'
	Identifiable assets by segment are as follows:
	(In thousands)	June 30, 2014		31-Dec-13
	Insurance-Domestic	$	15,565,600	$	15,247,807
	Insurance-International	1,963,689		1,516,310
	Reinsurance-Global	2,767,108		3,103,193
	Corporate and eliminations	870,797		684,486
	Total	$	21,167,194	$	20,551,796
Net Premiums Earned By Major Line Of Business	'
	Net premiums earned by major line of business are as follows:
		For the Three Months					For the Six Months
		Ended June 30,					Ended June 30,
	(In thousands)	2014		2013			2014			2013
	Insurance-Domestic:
	Other liability	$	362,074	$	307,444		$	701,707		$	603,032
	Workers’ compensation	270,212		241,191			533,244			470,202
	Short-tail lines	215,506		192,938			420,272			371,687
	Commercial automobile	127,102		119,900			251,470			236,022
	Professional liability	66,851		64,524			138,559			129,432
	Total	1,041,745		925,997			2,045,252			1,810,375
	Insurance-International:
	Other liability	22,956		15,070			42,331			30,288
	Workers’ compensation	17,241		21,746			34,566			44,635
	Short-tail lines	106,428		84,301			202,702			156,424
	Commercial automobile	29,649		32,392			57,242			67,031
	Professional liability	25,594		26,683			50,351			52,933
	Total	201,868		180,192			387,192			351,311
	Reinsurance-Global:
	Casualty	124,550		122,117			250,153			243,444
	Property	49,482		54,209			98,660			109,504
	Total	174,032		176,326			348,813			352,948
	Total	$	1,417,645	$	1,282,515		$	2,781,257		$	2,514,634

General_General_Details

General General (Details)	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Federal Income Tax Rate	35.00%

Per_Share_Data_Weighted_Averag

Per Share Data (Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share) (Details)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Basic (shares)	127,668	135,894	128,765	135,959
Diluted (shares)	133,304	141,274	134,323	141,257

Acquistions_Acquisitions_Detai

Acquistions Acquisitions (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Business Acquisition [Line Items]	'	'
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds	$16,000,000	'
Assets of Disposal Group, Including Discontinued Operation	15,000,000	'
Goodwill	103,565,000	110,146,000
After Market Original Equipment Manufacturer	'	'
Business Acquisition [Line Items]	'	'
Cash and cash equivalents	'	3,911,000
Real estate, furniture and equipment	'	898,000
Goodwill	'	19,664,000
Intangible assets	'	44,800,000
Other assets	'	60,661,000
Total assets acquired	'	129,934,000
Debt	'	-27,612,000
Other liabilities assumed	'	-17,076,000
Net assets acquired	'	85,246,000
Aviation Related Business [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill	$7,000,000	'

Acquistions_Intangibles_Detail

Acquistions Intangibles (Details) (After Market Original Equipment Manufacturer, USD $)	1 Months Ended	6 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2013	Jun. 30, 2014	Dec. 31, 2012
Business Acquisition [Line Items]	'	'	'
Percentage acquired	51.00%	'	49.00%
Purchase amount	$43	'	$43
Acquired Indefinite-lived Intangible Assets	'	$3	'
Minimum	'	'	'
Business Acquisition [Line Items]	'	'	'
Amortization of Acquired Intangible Assets	'	'2 years	'
Maximum	'	'	'
Business Acquisition [Line Items]	'	'	'
Amortization of Acquired Intangible Assets	'	'15 years	'

Statements_of_Comprehensive_In2

Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Beginning of Period	'		'		$189,391		'
Other comprehensive income (loss)	75,035		-218,402		144,545		-255,401
Accumulated Other Comprehensive Income (Loss), End of Period	333,899		'		333,899		'
Net investment gains	109,168		33,058		161,922		53,027
Income before income taxes	263,454		158,706		511,039		318,929
Income before taxes	534,150		494,286		1,049,316		975,890
Tax effect	-83,277		-43,579		-161,178		-87,204
After-tax amounts reclassified	180,177		115,127		349,861		231,725
Unrealized investment gains, pre-tax	76,390		-303,169		188,680		-291,154
Unrealized investment gains, tax effect	-28,190		106,109		-67,536		101,904
Unrealized investment gains, after-tax amounts	48,200		-197,060		121,144		-189,250
Currency translation adjustment, pre-tax	24,815		-23,156		20,790		-69,779
Currency translation adjustment, tax effect	0		0		0		0
Change in unrealized currency translation adjustments	24,815		-23,156		20,790		-69,779
Net pension asset, pre-tax	3,108		2,790		4,017		5,582
Net pension asset, tax effect	-1,088		-976		-1,406		-1,954
Net pension asset, after-tax amounts	2,020		1,814		2,611		3,628
Other comprehensive income (loss), pre-tax	104,313		-323,535		213,487		-355,351
Other comprehensive income (loss), tax effect	-29,278		105,133		-68,942		99,950
Accumulated Net Unrealized Investment Gain (Loss) [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Beginning of Period	329,492		525,428		256,566		517,658
Other comprehensive income (loss) before reclassifications	62,846		-182,934		140,289		-161,945
Amounts reclassified from AOCI	-14,646		-14,126		-19,145		-27,305
Other comprehensive income (loss)	48,200		-197,060		121,144		-189,250
Unrealized investment gain related to non-controlling interest	-19		35		-37		-5
Accumulated Other Comprehensive Income (Loss), End of Period	377,673		328,403		377,673		328,403
Currency Translation Adjustments [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Beginning of Period	-64,549		-83,299		-60,524		-36,676
Other comprehensive income (loss) before reclassifications	24,815		-23,156		20,790		-69,779
Amounts reclassified from AOCI	0		0		0		0
Other comprehensive income (loss)	24,815		-23,156		20,790		-69,779
Unrealized investment gain related to non-controlling interest	0		'		0		'
Accumulated Other Comprehensive Income (Loss), End of Period	-39,734		-106,455		-39,734		-106,455
Change in unrealized currency translation adjustments	'		'		20,790		-69,779
Net Pension Asset [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Beginning of Period	-6,060		-13,537		-6,651		-15,351
Other comprehensive income (loss) before reclassifications	0		0		0		0
Amounts reclassified from AOCI	2,020		1,814		2,611		3,628
Other comprehensive income (loss)	2,020		1,814		2,611		3,628
Unrealized investment gain related to non-controlling interest	0		'		0		'
Accumulated Other Comprehensive Income (Loss), End of Period	-4,040		-11,723		-4,040		-11,723
Accumulated Other Comprehensive Income (Loss) [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Beginning of Period	258,883		428,592		189,391		465,631
Other comprehensive income (loss) before reclassifications	87,661		-206,090		161,079		-231,724
Amounts reclassified from AOCI	-12,626		-12,312		-16,534		-23,677
Other comprehensive income (loss)	75,035		-218,402		144,545		-255,401
Unrealized investment gain related to non-controlling interest	-19		35		-37		-5
Accumulated Other Comprehensive Income (Loss), End of Period	333,899		210,225		333,899		210,225
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Net investment gains	-22,532	[1]	-21,933		-29,454	[1]	-42,008	[1]
Tax effect	7,886	[2]	7,807	[2]	10,309	[2]	14,703	[2]
After-tax amounts reclassified	-14,646		-14,126		-19,145		-27,305
Reclassification out of Accumulated Other Comprehensive Income [Member] | Currency Translation Adjustments [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Income before income taxes	0		0		0		0
Tax effect	0	[2]	0	[2]	0	[2]	0	[2]
After-tax amounts reclassified	0		0		0		0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension Asset [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Income before taxes	3,108	[3]	2,790		4,017	[3]	5,582	[3]
Tax effect	-1,088	[2]	-976	[2]	-1,406	[2]	-1,954	[2]
After-tax amounts reclassified	2,020		1,814		2,611		3,628
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Other Comprehensive Income (Loss) [Member]	'		'		'		'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]	'		'		'		'
Income before income taxes	-19,424		-19,143		-25,437		-36,426
Tax effect	6,798	[2]	6,831	[2]	8,903	[2]	12,749	[2]
After-tax amounts reclassified	($12,626)		($12,312)		($16,534)		($23,677)
[1]	Net investment gains in the consolidated statements of operations.
[2]	Income tax expense in the consolidated statements of operations.
[3]	Other operating costs and expenses in the consolidated statements of operations.

Statements_of_Cash_Flow_Detail

Statements of Cash Flow (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Supplemental Cash Flow Information [Abstract]	'	'
Interest payments	$59,811,000	$65,365,000
Income taxes paid	$152,439,000	$137,618,000

Investments_In_Fixed_Maturity_2

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Investments in fixed maturity securities) (Details) (USD $)	Jun. 30, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'		'
Total held to maturity, Amortized Cost	$101,352,000		$101,320,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain	19,631,000		14,900,000
Held to Maturity Securities Accumulated Unrecognized Holding Loss	0		0
Total held to maturity, Fair Value	120,983,000		116,220,000
Total held to maturity, Carrying Value	101,352,000		101,320,000
Total available for sale, Amortized Cost	11,482,268,000		11,190,311,000
Total available for sale, Gross Unrealized Gains	567,590,000		436,347,000
Total available for sale, Gross Unrealized Losses	-63,155,000		-111,134,000
Total available for sale, Fair Value	11,986,703,000		11,515,524,000
Total available for sale, Carrying Value	11,986,703,000		11,515,524,000
Total investments in fixed maturity securities, Amortized Value	11,583,620,000		11,291,631,000
Total investments in fixed maturity securities, Gross Unrealized Gains	587,221,000		451,247,000
Total investments in fixed maturity securities, Gross Unrealized Losses	-63,155,000		-111,134,000
Total investments in fixed maturity securities, Fair Value	12,107,686,000		11,631,744,000
Total investments in fixed maturity securities, Carrying Value	12,088,055,000		11,616,844,000
Minimum ownership of Common stockholders equity	10.00%		'
Foreign government	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	917,558,000		844,469,000
Total available for sale, Gross Unrealized Gains	68,553,000		51,674,000
Total available for sale, Gross Unrealized Losses	-17,735,000		-16,286,000
Total available for sale, Fair Value	968,376,000		879,857,000
Total available for sale, Carrying Value	968,376,000		879,857,000
Commercial Mortgage Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	74,378,000		76,454,000
Total available for sale, Gross Unrealized Gains	6,056,000		5,670,000
Total available for sale, Gross Unrealized Losses	-47,000		-988,000
Total available for sale, Fair Value	80,387,000		81,136,000
Total available for sale, Carrying Value	80,387,000		81,136,000
U.S. government and government agency	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	839,914,000		858,319,000
Total available for sale, Gross Unrealized Gains	34,766,000		34,522,000
Total available for sale, Gross Unrealized Losses	-7,553,000		-7,982,000
Total available for sale, Fair Value	867,127,000		884,859,000
Total available for sale, Carrying Value	867,127,000		884,859,000
Residential Mortgage Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	1,209,584,000	[1]	1,248,693,000	[1]
Total available for sale, Gross Unrealized Gains	29,930,000	[1]	25,895,000	[1]
Total available for sale, Gross Unrealized Losses	-13,765,000	[1]	-25,941,000	[1]
Total available for sale, Fair Value	1,225,749,000	[1]	1,248,647,000	[1]
Total available for sale, Carrying Value	1,225,749,000	[1]	1,248,647,000	[1]
Non-credit portion of other-than-temporary impairments (OTTI)	1,208,000		1,961,000
Corporate Debt Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	4,436,526,000		4,076,585,000
Total available for sale, Gross Unrealized Gains	206,290,000		156,256,000
Total available for sale, Gross Unrealized Losses	-18,492,000		-30,100,000
Total available for sale, Fair Value	4,624,324,000		4,202,741,000
Total available for sale, Carrying Value	4,624,324,000		4,202,741,000
State and municipal	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total available for sale, Amortized Cost	4,004,308,000		4,085,791,000
Total available for sale, Gross Unrealized Gains	221,995,000		162,330,000
Total available for sale, Gross Unrealized Losses	-5,563,000		-29,837,000
Total available for sale, Fair Value	4,220,740,000		4,218,284,000
Total available for sale, Carrying Value	4,220,740,000		4,218,284,000
State and municipal	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total held to maturity, Amortized Cost	70,956,000		68,929,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain	16,135,000		11,172,000
Held to Maturity Securities Accumulated Unrecognized Holding Loss	0		0
Total held to maturity, Fair Value	87,091,000		80,101,000
Total held to maturity, Carrying Value	70,956,000		68,929,000
Residential Mortgage Backed Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total held to maturity, Amortized Cost	25,398,000		27,393,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain	3,182,000		3,311,000
Held to Maturity Securities Accumulated Unrecognized Holding Loss	0		0
Total held to maturity, Fair Value	28,580,000		30,704,000
Total held to maturity, Carrying Value	25,398,000		27,393,000
Corporate Debt Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Total held to maturity, Amortized Cost	4,998,000		4,998,000
Held to Maturity Securities Accumulated Unrecognized Holding Gain	314,000		417,000
Held to Maturity Securities Accumulated Unrecognized Holding Loss	0		0
Total held to maturity, Fair Value	5,312,000		5,415,000
Total held to maturity, Carrying Value	$4,998,000		$4,998,000
[1]	Gross unrealized losses for residential mortgage-backed securities include $1,208,000 and $1,961,000 as of June 30, 2014 and December 31, 2013, respectively, related to the non-credit portion of other-than-temporary impairments (“OTTI”) recognized in accumulated other comprehensive income.

Investments_In_Fixed_Maturity_3

Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Amortized cost and fair value of fixed maturity securities) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Amortized Cost, Due in one year or less	$886,256	'
Amortized Cost, Due after one year through five years	3,860,527	'
Amortized Cost, Due after five years through ten years	3,035,251	'
Amortized Cost, Due after ten years	2,492,226	'
Amortized Cost, Mortgaged-backed securities	1,309,360	'
Total investments in fixed maturity securities, Amortized Value	11,583,620	11,291,631
Fair Value, Due in one year or less	896,523	'
Fair Value, Due after one year through five years	4,039,960	'
Fair Value, Due after five years through ten years	3,229,746	'
Fair Value, Due after ten years	2,606,741	'
Fair Value, Mortgage-backed securities	1,334,716	'
Total investments in fixed maturity securities, Fair Value	$12,107,686	$11,631,744

Investments_in_Equity_Securiti2

Investments in Equity Securities (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	$167,964	$203,627
Gross Unrealized, Gains	92,100	86,030
Gross Unrealized, Losses	-3,005	-6,319
Carrying and fair value of equity securities	257,059	283,338
Common stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	75,167	118,536
Gross Unrealized, Gains	28,360	42,239
Gross Unrealized, Losses	0	0
Carrying and fair value of equity securities	103,527	160,775
Preferred stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	92,797	85,091
Gross Unrealized, Gains	63,740	43,791
Gross Unrealized, Losses	-3,005	-6,319
Carrying and fair value of equity securities	$153,532	$122,563

Arbitrage_Trading_Account_Deta

Arbitrage Trading Account (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Trading Securities [Abstract]	'	'
Arbitrage trading account	$732,279	$522,128

Net_Investment_Income_Net_Inve1

Net Investment Income Net Investment Income (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net Investment Income [Line Items]	'	'	'	'
Investment income	$142,224	$145,519	$313,488	$283,460
Investment expense	-3,495	-1,782	-6,048	-3,794
Net investment income	138,729	143,737	307,440	279,666
Fixed maturity securities, including cash and cash equivalents and loans receivable	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Investment income	107,760	111,203	214,658	229,039
Investment funds	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Investment income	22,356	22,576	76,155	33,510
Arbitrage trading account	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Investment income	6,942	4,990	12,461	8,773
Equity securities available for sale	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Investment income	2,103	3,634	4,049	5,881
Real estate	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Investment income	$3,063	$3,116	$6,165	$6,257

Investment_Funds_Investment_Fu2

Investment Funds Investment Funds (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	$984,836	'	$1,067,495
Income (Loss) from Investment Funds	76,155	33,510	'
Real estate	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	280,255	'	378,435
Income (Loss) from Investment Funds	16,482	1,260	'
Energy	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	159,645	'	155,026
Income (Loss) from Investment Funds	12,596	25,199	'
Arbitrage	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	279,806	'	271,575
Income (Loss) from Investment Funds	8,231	1,731	'
Other	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	265,130	'	262,459
Income (Loss) from Investment Funds	$38,846	$5,320	'

Real_Estate_Real_Estate_Detail

Real Estate Real Estate (Details) (USD $)	1 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Real Estate [Abstract]	'	'
Proceeds from Sale of Real Estate	$67,000,000	'
Loans Receivable, Gross, Commercial, Real Estate	270,000,000	'
Properties in operation	47,617,000	283,393,000
Properties under development	482,622,000	431,849,000
Total	530,239,000	715,242,000
Real Estate Investment Property, Accumulated Depreciation	78,000	17,827,000
Other Real Estate, Non Covered	$251,000,000	'

Real_Estate_Real_Estate_Detail1

Real Estate Real Estate (Details 1) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Real Estate [Abstract]	'	'	'
Accumulated depreciation and amortization on properties	$78	'	$17,827
Real estate depreciation expense	3,219	3,420	'
Lease future minimum payments 2014	760	'	'
Lease future minimum payments 2015	1,549	'	'
Lease future minimum payments 2016	1,596	'	'
Lease future minimum payments 2016	1,644	'	'
Lease future minimum payments 2014	1,693	'	'
Lease future minimum payments after 2017	$327,320	'	'

Loans_Receivable_Details

Loans Receivable (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases Receivable, Gross	$655,691	'	$655,691	'	$343,583
Loans receivable	659,183	'	659,183	'	346,746
Valuation allowance, specific	0	'	0	'	0
Valuation allowance, general	2,566	'	2,566	'	2,087
Valuation allowance of loans receivable	2,566	'	2,566	'	2,087
Decrease in valuation allowance	16	-30	479	65	'
Loans receivable charged off	0	0	0	0	'
Real Estate	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases Receivable, Gross	569,530	'	569,530	'	282,357
Loans receivable	571,520	'	571,520	'	284,017
Commercial	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases Receivable, Gross	86,161	'	86,161	'	61,226
Loans receivable	$87,663	'	$87,663	'	$62,729

Realized_And_Unrealized_Invest2

Realized And Unrealized Investment Gains Realized and Unrealized Investment Gains (Loss) (Realized and unrealized investmetns gains(losses)) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'
Fixed maturity securities, gains	$1,941	$9,147	$4,003	$20,143
Fixed maturity securities, losses	-464	-5,500	-2,062	-11,466
Equity securities available for sale	23,124	18,086	29,581	33,331
Investment funds	-1,076	10,843	44,757	11,037
REal Estate Realized Gain (Loss) on Disposal	85,643	0	85,643	0
Other	0	482	0	-18
Realized Gain (Loss) on Investments, Including Equity Method Investments, Excluding Other than Temporary Impairments and Allowances	109,168	33,058	161,922	53,027
Decrease in valuation allowance	0	0	0	0
Other-than-temporary impairments	0	0	0	0
Change in valuation allowance, net of other-than-temporary impairments	0	0	0	0
Net investment gains	109,168	33,058	161,922	53,027
Income tax expense	-38,208	-11,570	-56,673	-18,559
Total after-tax realized investment gains	$70,960	$21,488	$105,249	$34,468

Recovered_Sheet2

Realized and Unrealized Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'	'
Change in unrealized gains (losses) before income taxes and noncontrolling interests	$76,390	($300,478)	$188,680	($293,662)
Income tax benefit (expense)	-28,190	103,418	-67,536	104,412
Noncontrolling interests	-19	35	-37	-5
Total change in unrealized gains	48,181	-197,025	121,107	-189,255
Debt Securities [Member]	'	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'	'
Change in unrealized gains (losses) before income taxes and noncontrolling interests	87,882	-277,791	179,520	-293,380
Debt Securities Previously Impaired [Member]	'	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'	'
Change in unrealized gains (losses) before income taxes and noncontrolling interests	194	-590	753	522
Equity securities available for sale	'	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'	'
Change in unrealized gains (losses) before income taxes and noncontrolling interests	-17,870	-16,191	8,333	8,370
Investment funds	'	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'	'
Change in unrealized gains (losses) before income taxes and noncontrolling interests	$6,184	($5,906)	$74	($9,174)

Securities_In_An_Unrealized_Lo2

Securities In An Unrealized Loss Position Securities in an Unrealized Loss Position (Securities in an Unrealized Loss Position) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	$1,190,273	$3,085,977
Gross Unrealized Losses, Less than 12 Months	21,257	84,259
Fair Value, 12 Months or Greater	1,014,108	355,098
Gross Unrealized Losses, 12 Months or Greater	44,903	33,194
Fair Value, Total	2,204,381	3,441,075
Gross Unrealized Losses, Total	66,160	117,453
U.S. government and government agency	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	191,360	260,882
Gross Unrealized Losses, Less than 12 Months	4,176	7,927
Fair Value, 12 Months or Greater	74,427	2,163
Gross Unrealized Losses, 12 Months or Greater	3,377	55
Fair Value, Total	265,787	263,045
Gross Unrealized Losses, Total	7,553	7,982
State and municipal	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	136,081	899,613
Gross Unrealized Losses, Less than 12 Months	1,796	24,503
Fair Value, 12 Months or Greater	185,605	87,345
Gross Unrealized Losses, 12 Months or Greater	3,767	5,334
Fair Value, Total	321,686	986,958
Gross Unrealized Losses, Total	5,563	29,837
Mortgage-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	129,004	578,603
Gross Unrealized Losses, Less than 12 Months	725	17,964
Fair Value, 12 Months or Greater	341,219	140,648
Gross Unrealized Losses, 12 Months or Greater	13,087	8,965
Fair Value, Total	470,223	719,251
Gross Unrealized Losses, Total	13,812	26,929
Corporate Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	549,991	1,013,373
Gross Unrealized Losses, Less than 12 Months	7,099	17,066
Fair Value, 12 Months or Greater	285,261	105,074
Gross Unrealized Losses, 12 Months or Greater	11,393	13,034
Fair Value, Total	835,252	1,118,447
Gross Unrealized Losses, Total	18,492	30,100
Foreign government	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	183,837	320,215
Gross Unrealized Losses, Less than 12 Months	7,461	16,286
Fair Value, 12 Months or Greater	101,882	0
Gross Unrealized Losses, 12 Months or Greater	10,274	0
Fair Value, Total	285,719	320,215
Gross Unrealized Losses, Total	17,735	16,286
Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	1,190,273	3,072,686
Gross Unrealized Losses, Less than 12 Months	21,257	83,746
Fair Value, 12 Months or Greater	988,394	335,230
Gross Unrealized Losses, 12 Months or Greater	41,898	27,388
Fair Value, Total	2,178,667	3,407,916
Gross Unrealized Losses, Total	63,155	111,134
Common stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	0	0
Gross Unrealized Losses, Less than 12 Months	0	0
Fair Value, 12 Months or Greater	0	0
Gross Unrealized Losses, 12 Months or Greater	0	0
Fair Value, Total	0	0
Gross Unrealized Losses, Total	0	0
Preferred stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	0	13,291
Gross Unrealized Losses, Less than 12 Months	0	513
Fair Value, 12 Months or Greater	25,714	19,868
Gross Unrealized Losses, 12 Months or Greater	3,005	5,806
Fair Value, Total	25,714	33,159
Gross Unrealized Losses, Total	3,005	6,319
Equity securities available for sale	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair Value, Less than 12 Months	0	13,291
Gross Unrealized Losses, Less than 12 Months	0	513
Fair Value, 12 Months or Greater	25,714	19,868
Gross Unrealized Losses, 12 Months or Greater	3,005	5,806
Fair Value, Total	25,714	33,159
Gross Unrealized Losses, Total	$3,005	$6,319

Securities_In_An_Unrealized_Lo3

Securities In An Unrealized Loss Position Non-Investment Grade Fixed Maturity Securities (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	$2,204,381	$3,441,075
Mortgage-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	470,223	719,251
Corporate Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	835,252	1,118,447
State and municipal	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	321,686	986,958
Foreign government	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	285,719	320,215
Noninvestment Grade Investments at Loss Less than 5 Million	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of Securities	22	'
Aggregate fair value of securities in a continuous unrealized loss position	84,090	'
Gross Unrealized Loss	3,868	'
Noninvestment Grade Investments at Loss Less than 5 Million | Mortgage-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of Securities	11	'
Aggregate fair value of securities in a continuous unrealized loss position	44,646	'
Gross Unrealized Loss	1,772	'
Noninvestment Grade Investments at Loss Less than 5 Million | Corporate Debt Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of Securities	8	'
Aggregate fair value of securities in a continuous unrealized loss position	18,070	'
Gross Unrealized Loss	633	'
Noninvestment Grade Investments at Loss Less than 5 Million | Foreign government	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of Securities	3	'
Aggregate fair value of securities in a continuous unrealized loss position	21,374	'
Gross Unrealized Loss	$1,463	'

Securities_In_An_Unrealized_Lo4

Securities In An Unrealized Loss Position Securities In An Unrealized Loss Position (Narrative) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	$2,204,381	$3,441,075
Gross Unrealized Losses	66,160	117,453
Preferred stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	25,714	33,159
Gross Unrealized Losses	3,005	6,319
Preferred stocks | Noninvestment Grade Investments [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number of Securities	2	'
Aggregate fair value of securities in a continuous unrealized loss position	26,000	'
Gross Unrealized Losses	3,000	'
Common stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate fair value of securities in a continuous unrealized loss position	0	0
Gross Unrealized Losses	$0	$0

Fair_Value_Measurements_Assets

Fair Value Measurements (Assets and Liabilities Measured At Fair Value, On a Recurring Basis) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	$11,986,703	$11,515,524
Equity securities	257,059	283,338
Arbitrage trading account	732,279	522,128
Level 1 | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Equity securities	102,762	159,537
Assets, fair value disclosure	357,835	351,818
Arbitrage trading account	255,073	192,281
Securities sold but not yet purchased	111,986	162,126
Level 1 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | State and municipal	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Corporate	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Foreign government	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 1 | Fair Value, Measurements, Recurring [Member] | Common stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	102,762	159,537
Level 1 | Fair Value, Measurements, Recurring [Member] | Preferred stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 2 | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	11,949,661	11,472,660
Equity securities	149,763	118,811
Assets, fair value disclosure	12,573,948	11,919,538
Arbitrage trading account	474,524	328,067
Securities sold but not yet purchased	5	152
Level 2 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	867,127	884,859
Level 2 | Fair Value, Measurements, Recurring [Member] | State and municipal	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	4,220,740	4,218,284
Level 2 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	1,306,136	1,329,783
Level 2 | Fair Value, Measurements, Recurring [Member] | Corporate	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	4,587,282	4,159,877
Level 2 | Fair Value, Measurements, Recurring [Member] | Foreign government	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	968,376	879,857
Level 2 | Fair Value, Measurements, Recurring [Member] | Common stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 2 | Fair Value, Measurements, Recurring [Member] | Preferred stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	149,763	118,811
Level 3 | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	37,042	42,864
Equity securities	4,534	4,990
Assets, fair value disclosure	44,258	49,634
Arbitrage trading account	2,682	1,780
Securities sold but not yet purchased	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | State and municipal	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Corporate	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	37,042	42,864
Level 3 | Fair Value, Measurements, Recurring [Member] | Foreign government	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	0	0
Level 3 | Fair Value, Measurements, Recurring [Member] | Common stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	765	1,238
Level 3 | Fair Value, Measurements, Recurring [Member] | Preferred stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	3,769	3,752
Fair Value | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	11,986,703	11,515,524
Equity securities	257,059	283,338
Assets, fair value disclosure	12,976,041	12,320,990
Arbitrage trading account	732,279	522,128
Securities sold but not yet purchased	111,991	162,278
Fair Value | Fair Value, Measurements, Recurring [Member] | U.S. government and government agency	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	867,127	884,859
Fair Value | Fair Value, Measurements, Recurring [Member] | State and municipal	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	4,220,740	4,218,284
Fair Value | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	1,306,136	1,329,783
Fair Value | Fair Value, Measurements, Recurring [Member] | Corporate	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	4,624,324	4,202,741
Fair Value | Fair Value, Measurements, Recurring [Member] | Foreign government	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities	968,376	879,857
Fair Value | Fair Value, Measurements, Recurring [Member] | Common stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	103,527	160,775
Fair Value | Fair Value, Measurements, Recurring [Member] | Preferred stocks	'	'
Fair Value Measurements, Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities	$153,532	$122,563

Fair_Value_Measurements_Fair_V1

Fair Value Measurements Fair Value Measurements (Summarize Changes in Level 3 Assets) (Details) (Level 3, USD $)	6 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	$49,634	$62,022
Assets, earnings	-1,347	1,836
Assets, other comprehensive income	144	1,039
Assets, purchases	2,623	4,424
Assets, (sales)	-14,972	-5,776
Assets, maturities	846	12,604
Assets, transfers in	9,022	-1,307
Assets, ending balance	44,258	49,634
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Liabilities, beginning balance	0	20
Liabilities, earnings	'	-4
Liabilities, other comprehensive income	'	0
Liabilities, purchases	'	4
Liabilities, (sales)	'	-20
Liabilities, maturities	'	0
Liabilities, transfers in	'	0
Liabilities, ending balance	'	0
Equity securities available for sale	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	4,990	2,029
Assets, earnings	39	-299
Assets, other comprehensive income	0	0
Assets, purchases	0	3,430
Assets, (sales)	-495	-170
Assets, maturities	'	'
Assets, transfers in	0	0
Assets, ending balance	4,534	4,990
Preferred stocks	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	3,752	621
Assets, earnings	39	-299
Assets, other comprehensive income	0	0
Assets, purchases	0	3,430
Assets, (sales)	-22	0
Assets, maturities	'	'
Assets, transfers in	0	0
Assets, ending balance	3,769	3,752
Common stocks	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	1,238	1,408
Assets, earnings	0	0
Assets, other comprehensive income	0	0
Assets, purchases	0	0
Assets, (sales)	-473	-170
Assets, maturities	'	'
Assets, transfers in	0	0
Assets, ending balance	765	1,238
Debt Securities [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	42,864	59,065
Assets, earnings	43	677
Assets, other comprehensive income	144	309
Assets, purchases	84	170
Assets, (sales)	-5,247	-4,753
Assets, maturities	846	12,604
Assets, transfers in	0	0
Assets, ending balance	37,042	42,864
Corporate Debt Securities [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	42,864	59,065
Assets, earnings	43	677
Assets, other comprehensive income	144	309
Assets, purchases	84	170
Assets, (sales)	-5,247	-4,753
Assets, maturities	846	12,604
Assets, transfers in	0	0
Assets, ending balance	37,042	42,864
Trading Assets, Excluding Debt and Equity Securities [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Assets, beginning balance	1,780	928
Assets, earnings	-1,429	1,458
Assets, other comprehensive income	0	730
Assets, purchases	2,539	824
Assets, (sales)	-9,230	-853
Assets, maturities	'	'
Assets, transfers in	9,022	-1,307
Assets, ending balance	$2,682	$1,780

Reinsurance_Reinsurance_Detail

Reinsurance Reinsurance (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Premiums Written	'	'	'	'	'
Written premiums, direct	$1,580,639,000	$1,405,183,000	$3,145,827,000	$2,805,595,000	'
Written premiums, assumed	191,762,000	212,753,000	431,841,000	443,962,000	'
Written premiums, ceded	-282,625,000	-276,038,000	-562,012,000	-530,693,000	'
Total net premiums written	1,489,776,000	1,341,898,000	3,015,656,000	2,718,864,000	'
Premiums Earned	'	'	'	'	'
Earned premiums, direct	1,449,152,000	1,301,702,000	2,830,724,000	2,542,264,000	'
Earned premiums, assumed	224,916,000	217,517,000	450,678,000	431,533,000	'
Earned premiums, ceded	-256,423,000	-236,704,000	-500,145,000	-459,163,000	'
Net premiums earned	1,417,645,000	1,282,515,000	2,781,257,000	2,514,634,000	'
Ceded losses incurred	89,569,000	142,360,000	190,253,000	252,911,000	'
Uncollectible reinsurance	$2,000,000	'	$2,000,000	'	$1,000,000

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:	'	'
Arbitrage trading account	$732,279	$522,128
Loans receivable	659,183	346,746
Carrying Value	'	'
Assets:	'	'
Fixed maturity securities	12,088,055	11,616,844
Equity securities available for sale	257,059	283,338
Arbitrage trading account	732,279	522,128
Loans receivable	655,691	343,583
Cash and cash equivalents	842,671	839,738
Trading account receivables from brokers and clearing organizations	57,454	304,936
Due from broker	0	17,735
Due from broker fair value	18,850	8,273
Liabilities:	'	'
Trading account securities sold but not yet purchased	111,991	162,278
Junior subordinated debentures	339,930	339,800
Senior notes and other debt	1,697,037	1,692,442
Fair Value	'	'
Assets:	'	'
Fixed maturity securities	12,107,686	11,631,744
Equity securities available for sale	257,059	283,338
Arbitrage trading account	732,279	522,128
Loans receivable	659,183	346,746
Cash and cash equivalents	842,671	839,738
Trading account receivables from brokers and clearing organizations	57,454	304,936
Due from broker	0	17,735
Liabilities:	'	'
Trading account securities sold but not yet purchased	111,991	162,278
Junior subordinated debentures	325,500	288,540
Senior notes and other debt	$1,939,000	$1,861,898

Restricted_Stock_Units_Summary

Restricted Stock Units (Summary of Restricted Stock Units Issued) (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]	'	'
Share based compensation expense	$12,000,000	$11,000,000
Restricted Stock [Member]	'	'
Share-Based Compensation Arrangement by Share-based Payment Award [Line Item]	'	'
Award vesting period	'5 years	'
Restricted Stock Units	25,950	55,150
Restricted Stock Units, Fair Value	$1,079,000	$2,312,000

Industry_Segments_Financial_In

Industry Segments (Financial Information of Company Operating Segments) (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	$1,417,645		$1,282,515		$2,781,257		$2,514,634
Investment Income and Funds	138,729		143,737		307,440		279,666
Other Revenues	240,615		144,710		415,198		283,431
Total revenues	1,796,989		1,570,962		3,503,895		3,077,731
Pre-Tax Income (Loss)	263,454		158,706		511,039		318,929
Net Income (Loss)	179,961		115,957		349,634		232,572
Net investment gains	109,168		33,058		161,922		53,027
Net investment gains, net of tax	70,959		21,488		105,249		34,468
Intersegment Eliminations and Corporate, Non-Segment [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	0	[1]	0	[1]	0	[1]	0	[1]
Investment Income and Funds	6,772	[1]	-32	[1]	13,116	[1]	3,540	[1]
Other Revenues	104,462	[1]	84,000	[1]	197,525	[1]	176,016	[1]
Total revenues	111,234	[1]	83,968	[1]	210,641	[1]	179,556	[1]
Pre-Tax Income (Loss)	-59,945	[1]	-64,021	[1]	-117,120	[1]	-125,440	[1]
Net Income (Loss)	-39,110	[1]	-38,782	[1]	-76,623	[1]	-76,426	[1]
Insurance-Domestic Segment [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	1,041,745		925,997		2,045,252		1,810,375
Insurance-Domestic Segment [Member] | Operating Segments [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	1,041,745		925,997		2,045,252		1,810,375
Investment Income and Funds	103,073		107,562		221,210		205,359
Other Revenues	26,985		27,652		55,751		54,388
Total revenues	1,171,803		1,061,211		2,322,213		2,070,122
Pre-Tax Income (Loss)	176,855		152,334		379,040		293,684
Net Income (Loss)	121,834		106,478		259,870		205,886
Insurance-International Segment [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	201,868		180,192		387,192		351,311
Insurance-International Segment [Member] | Operating Segments [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	201,868		180,192		387,192		351,311
Investment Income and Funds	11,276		13,171		27,928		25,232
Other Revenues	0		0		0		0
Total revenues	213,144		193,363		415,120		376,543
Pre-Tax Income (Loss)	11,510		12,583		29,257		34,965
Net Income (Loss)	8,253		9,092		20,721		24,569
Reinsurance-Global Segment [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	174,032		176,326		348,813		352,948
Reinsurance-Global Segment [Member] | Operating Segments [Member]	'		'		'		'
Segment Reporting Information [Line Items]	'		'		'		'
Earned Premiums	174,032		176,326		348,813		352,948
Investment Income and Funds	17,608		23,036		45,186		45,535
Other Revenues	0		0		0		0
Total revenues	191,640		199,362		393,999		398,483
Pre-Tax Income (Loss)	25,866		24,752		57,940		62,693
Net Income (Loss)	$18,025		$17,681		$40,417		$44,075
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Industry_Segments_Identifiable

Industry Segments (Identifiable Assets by Segment) (Details) (USD $)	Jun. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	$21,167,194		$20,551,796
Operating Segments [Member] | Reinsurance-Global Segment [Member]	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	2,767,108		3,103,193
Operating Segments [Member] | Insurance-International Segment [Member]	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	1,963,689		1,516,310
Operating Segments [Member] | Insurance-Domestic Segment [Member]	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	15,565,600		15,247,807
Intersegment Eliminations and Corporate, Non-Segment [Member]	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	$870,797	[1]	$684,486	[1]
[1]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmU4MGE2OGM2MmFlYTQxMzliN2Y4ZmNjY2U4MTM2NjM1fFRleHRTZWxlY3Rpb246NUYwOTAzRjFFMUMyNUI0Qzk2QUM0RUUxRENENDkxMDAM}

Industry_Segments_Industry_Seg

Industry Segments Industry Segments (Net Premiums Earned By Major Line of Business) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	$1,417,645	$1,282,515	$2,781,257		$2,514,634
Insurance-Domestic Segment [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	1,041,745	925,997	2,045,252		1,810,375
Insurance-Domestic Segment [Member] | Other Insurance Liabilities [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	362,074	307,444	701,707		603,032
Insurance-Domestic Segment [Member] | Workers' Compensation [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	270,212	241,191	533,244		470,202
Insurance-Domestic Segment [Member] | Property [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	215,506	192,938	420,272	[1]	371,687	[1]
Insurance-Domestic Segment [Member] | Commercial Automobile [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	127,102	119,900	251,470		236,022
Insurance-Domestic Segment [Member] | Products Liability [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	66,851	64,524	138,559		129,432
Insurance-International Segment [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	201,868	180,192	387,192		351,311
Insurance-International Segment [Member] | Other Insurance Liabilities [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	22,956	15,070	42,331		30,288
Insurance-International Segment [Member] | Workers' Compensation [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	17,241	21,746	34,566		44,635
Insurance-International Segment [Member] | Property [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	106,428	84,301	202,702	[1]	156,424	[1]
Insurance-International Segment [Member] | Commercial Automobile [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	29,649	32,392	57,242		67,031
Insurance-International Segment [Member] | Products Liability [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	25,594	26,683	50,351		52,933
Reinsurance-Global Segment [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	174,032	176,326	348,813		352,948
Reinsurance-Global Segment [Member] | Property [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	49,482	54,209	98,660		109,504
Reinsurance-Global Segment [Member] | Casualty [Member]	'	'	'		'
Revenue from External Customer [Line Items]	'	'	'		'
Premiums Earned, Net	$124,550	$122,117	$250,153		$243,444
[1]	For the Three MonthsFor the Six Months Ended June 30,Ended June 30,(In thousands)2014 20132014 2013 Insurance-Domestic: Other liability$362,074$307,444$701,707 $603,032Workers’ compensation270,212241,191533,244 470,202Short-tail lines 215,506192,938420,272 371,687Commercial automobile127,102119,900251,470 236,022Professional liability66,85164,524138,559 129,432Total1,041,745925,9972,045,252 1,810,375 Insurance-International: Other liability22,95615,07042,331 30,288Workers’ compensation17,24121,74634,566 44,635Short-tail lines106,42884,301202,702 156,424Commercial automobile29,64932,39257,242 67,031Professional liability25,59426,68350,351 52,933Total201,868180,192387,192 351,311 Reinsurance-Global: Casualty124,550122,117250,153 243,444Property49,48254,20998,660 109,504Total174,032176,326348,813 352,948 Total$1,417,645 $1,282,515$2,781,257 $2,514,634

Subsequent_Event_Subsequent_Ev1

Subsequent Event Subsequent Event (Details) (Subsequent Event [Member], USD $)	Aug. 06, 2014
In Millions, unless otherwise specified
Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Debt Instrument, Face Amount	$350