W. R. Berkley (WRB) 10-K28 Feb 142013 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2013	Feb. 25, 2014	Jun. 28, 2013
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-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	128,538,265	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$4,360,513,620

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
REVENUES:	'	'	'
Net premiums written	$5,500,173	$4,898,539	$4,357,368
Change in net unearned premiums	-273,636	-225,023	-196,501
Net premiums earned	5,226,537	4,673,516	4,160,867
Net investment income	544,291	586,763	526,351
Insurance service fees	107,513	103,133	92,843
Net investment gains:	'	'	'
Net realized gains on investment sales	127,586	201,451	125,881
Other-than-temporary impairments and change in valuation allowance	-6,042	9,014	-400
Net investment gains	121,544	210,465	125,481
Revenues from wholly-owned investees	407,623	247,113	248,678
Other income	1,026	2,564	1,764
Total revenues	6,408,534	5,823,554	5,155,984
OPERATING COSTS AND EXPENSES:	'	'	'
Losses and loss expenses	3,197,024	2,948,479	2,658,365
Other operating costs and expenses	2,000,684	1,799,623	1,626,526
Expenses from wholly-owned investees	388,761	247,222	245,495
Interest expense	123,177	126,302	112,512
Total operating costs and expenses	5,709,646	5,121,626	4,642,898
Income before income taxes	698,888	701,928	513,086
Income tax expense	-193,587	-191,285	-121,945
Net income before noncontrolling interests	505,301	510,643	391,141
Noncontrolling interests	-5,376	-51	70
Net income to common stockholders	$499,925	$510,592	$391,211
NET INCOME PER SHARE:	'	'	'
Basic (dollars per share)	$3.69	$3.72	$2.80
Diluted (dollars per share)	$3.55	$3.56	$2.69

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Investments:	'	'
Fixed maturity securities	$11,616,844	$11,943,956
Equity securities available for sale	283,338	376,022
Arbitrage trading account	522,128	329,077
Investment funds	1,067,495	809,689
Loans receivable	343,583	401,961
Real estate	715,242	606,735
Total investments	14,548,630	14,467,440
Cash and cash equivalents	839,738	905,670
Premiums and fees receivable	1,557,480	1,440,752
Due from reinsurers	1,533,103	1,450,348
Accrued investment income	118,329	127,230
Prepaid reinsurance premiums	367,803	316,309
Deferred policy acquisition costs	452,101	404,047
Property, furniture and equipment	339,448	267,227
Goodwill	110,146	87,865
Trading account receivable from brokers and clearing organizations	304,936	446,873
Deferred federal and foreign income taxes	20,120	0
Current federal and foreign income taxes	24,737	0
Other assets	335,225	242,135
Total assets	20,551,796	20,155,896
Liabilities:	'	'
Reserves for losses and loss expenses	10,080,941	9,751,086
Unearned premiums	2,781,437	2,474,847
Due to reinsurers	276,755	316,388
Trading account securities sold but not yet purchased	162,278	121,487
Deferred federal and foreign income taxes	0	60,255
Other liabilities	848,749	981,626
Junior subordinated debentures	339,800	243,206
Senior notes and other debt	1,692,442	1,871,535
Total liabilities	16,182,402	15,820,430
Equity:	'	'
Preferred stock, par value $.10 per share: Authorized 5,000,000 shares; issued and outstanding - none	0	0
Common stock, par value $.20 per share: Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 132,233,167 and 136,017,732 shares, respectively	47,024	47,024
Additional paid-in capital	967,440	945,166
Retained earnings	5,265,015	4,817,807
Accumulated other comprehensive income	189,391	465,631
Treasury stock, at cost, 102,884,751 and 99,100,186 shares, respectively	-2,132,835	-1,969,411
Total common stockholdersâ€™ equity	4,336,035	4,306,217
Noncontrolling interests	33,359	29,249
Total equity	4,369,394	4,335,466
Total liabilities and equity	$20,551,796	$20,155,896

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value (dollars per share)	$0.10	$0.10
Preferred stock, authorized (shares)	5,000,000	5,000,000
Preferred stock, issued (shares)	0	0
Preferred stock, outstanding (shares)	0	0
Common stock, par value (dollars per share)	$0.20	$0.20
Common stock, authorized (shares)	500,000,000	500,000,000
Common stock, issued (shares)	132,233,167	136,017,732
Common stock, outstanding (shares)	132,233,167	136,017,732
Treasury stock, at cost (shares)	102,884,751	99,100,186

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common stocks	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Unrealized Investment gains (losses)	Currency translation adjustments	Net pension asset	Treasury Stock	Noncontrolling Interests
In Thousands, unless otherwise specified	Total	Common stocks	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Unrealized Investment gains (losses)	Currency translation adjustments	Net pension asset	Treasury Stock	Noncontrolling Interests
Beginning of period at Dec. 31, 2010	'	$47,024	$935,099	$4,143,207	'	$334,747	($42,488)	($15,696)	($1,750,494)	$6,980
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Stock options exercised and restricted units issued including tax benefit	'	'	-20,601	'	'	'	'	'	'	'
Restricted stock units expensed	'	'	26,303	'	'	'	'	'	'	'
Stock issued	'	'	308	'	'	'	'	'	564	'
Net income (loss)	391,141	'	'	391,211	'	'	'	'	'	-70
Dividends	'	'	'	-43,256	'	'	'	'	'	'
Unrealized gains (losses) on securities not other-than-temporarily impaired	95,617	'	'	'	'	98,015	'	'	'	'
Unrealized gains (losses) on other-than-temporarily impaired securities	'	'	'	'	'	-2,343	'	'	'	'
Net change in period	-18,751	'	'	'	'	'	-18,751	'	'	'
Net change in period	1,367	'	'	'	'	'	'	1,367	'	'
Stock exercised/vested	'	'	'	'	'	'	'	'	56,303	'
Stock repurchased	'	'	'	'	'	'	'	'	-187,163	'
Acquisition of noncontrolling interest	'	'	'	'	'	'	'	'	'	671
Other comprehensive income (loss), net of tax	78,233	'	'	'	'	'	'	'	'	-55
End of period at Dec. 31, 2011	'	47,024	941,109	4,491,162	354,851	430,419	-61,239	-14,329	-1,880,790	7,526
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Stock options exercised and restricted units issued including tax benefit	'	'	-22,125	'	'	'	'	'	'	'
Restricted stock units expensed	'	'	25,728	'	'	'	'	'	'	'
Stock issued	'	'	454	'	'	'	'	'	581	'
Net income (loss)	510,643	'	'	510,592	'	'	'	'	'	51
Dividends	'	'	'	-183,947	'	'	'	'	'	'
Unrealized gains (losses) on securities not other-than-temporarily impaired	87,316	'	'	'	'	84,229	'	'	'	'
Unrealized gains (losses) on other-than-temporarily impaired securities	'	'	'	'	'	3,010	'	'	'	'
Net change in period	24,563	'	'	'	'	'	24,563	'	'	'
Net change in period	-1,022	'	'	'	'	'	'	-1,022	'	'
Stock exercised/vested	'	'	'	'	'	'	'	'	45,253	'
Stock repurchased	'	'	'	'	'	'	'	'	-134,455	'
Acquisition of noncontrolling interest	'	'	'	'	'	'	'	'	'	21,595
Other comprehensive income (loss), net of tax	110,857	'	'	'	'	'	'	'	'	77
End of period at Dec. 31, 2012	4,335,466	47,024	945,166	4,817,807	465,631	517,658	-36,676	-15,351	-1,969,411	29,249
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Stock options exercised and restricted units issued including tax benefit	'	'	-1,143	'	'	'	'	'	'	'
Restricted stock units expensed	'	'	22,881	'	'	'	'	'	'	'
Stock issued	'	'	536	'	'	'	'	'	597	'
Net income (loss)	505,301	'	'	499,925	'	'	'	'	'	5,376
Dividends	'	'	'	-52,717	'	'	'	'	'	'
Unrealized gains (losses) on securities not other-than-temporarily impaired	-261,064	'	'	'	'	-261,791	'	'	'	'
Unrealized gains (losses) on other-than-temporarily impaired securities	'	'	'	'	'	699	'	'	'	'
Net change in period	-23,848	'	'	'	'	'	-23,848	'	'	'
Net change in period	8,700	'	'	'	'	'	'	8,700	'	'
Stock exercised/vested	'	'	'	'	'	'	'	'	2,452	'
Stock repurchased	'	'	'	'	'	'	'	'	-166,473	'
Acquisition of noncontrolling interest	'	'	'	'	'	'	'	'	'	-1,294
Other comprehensive income (loss), net of tax	-276,212	'	'	'	-276,212	'	-23,848	8,700	'	28
End of period at Dec. 31, 2013	$4,369,394	$47,024	$967,440	$5,265,015	$189,391	$256,566	($60,524)	($6,651)	($2,132,835)	$33,359

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'	'	'
Net income before noncontrolling interests	$505,301	$510,643	$391,141
Other comprehensive income:	'	'	'
Change in unrealized translation adjustments	-23,848	24,563	-18,751
Change in unrealized investment gains (losses), net of taxes	-261,064	87,316	95,617
Change in unrecognized pension obligation, net of taxes	8,700	-1,022	1,367
Other comprehensive income	-276,212	110,857	78,233
Comprehensive income	229,089	621,500	469,374
Comprehensive income (loss) to the noncontrolling interest	-5,404	-128	125
Comprehensive income to common shareholders	$223,685	$621,372	$469,499

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FROM OPERATING ACTIVITIES:	'	'	'
Net income to common stockholders	$499,925	$510,592	$391,211
Adjustments to reconcile net income to net cash from operating activities:	'	'	'
Net investment gains	-121,544	-210,465	-125,481
Depreciation and amortization	103,090	103,419	88,012
Noncontrolling interests	5,376	51	-70
Investment funds	-67,712	-77,015	1,751
Stock incentive plans	23,784	26,763	27,175
Change in:	'	'	'
Arbitrage trading account	-10,324	-1,424	-8,106
Premiums and fees receivable	-138,027	-228,756	-122,468
Reinsurance accounts	-171,263	-216,968	-161,070
Deferred policy acquisition costs	-52,124	-38,656	-38,541
Deferred income taxes	56,281	13,240	43,340
Reserves for losses and loss expenses	372,002	406,763	325,758
Unearned premiums	323,160	279,986	238,499
Other	-2,826	107,928	10,269
Net cash from operating activities	819,798	675,458	670,279
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:	'	'	'
Proceeds from sale of fixed maturity securities	1,344,707	838,576	1,293,876
Proceeds from sale of equity securities	267,554	409,610	159,827
Distributions from (contributions to) investment funds	-236,580	77,930	-113,913
Proceeds from maturities and prepayments of fixed maturity securities	2,718,156	2,291,105	1,697,144
Purchase of fixed maturity securities	-4,198,135	-3,617,002	-2,815,340
Purchase of equity securities	-156,557	-284,991	-97,986
Real estate purchased	-107,352	-256,386	-96,552
Change in loans receivable	-30,974	-124,776	92,176
Net additions to property, furniture and equipment	-63,150	-40,556	-45,320
Change in balances due from security brokers	-26,155	-25,799	-16,194
Payment for business purchased, net of cash acquired	-56,878	-42,779	-261,992
Net cash used investing activities	-545,364	-775,068	-204,274
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:	'	'	'
Net proceeds from issuance of debt	346,822	369,291	0
Net proceeds from stock options exercised	53	7,660	21,963
Repayment of senior notes and other debt	-465,389	0	-1,310
Cash dividends to common stockholders	-52,717	-183,947	-43,253
Purchase of common treasury shares	-166,473	-127,663	-187,163
Other	7,442	31,851	14,550
Net cash from (used in) financing activities	-330,262	97,192	-195,213
Net impact on cash due to change in foreign exchange rates	-10,104	-3,654	-2,002
Net increase (decrease) in cash and cash equivalents	-65,932	-6,072	268,790
Cash and cash equivalents at beginning of year	905,670	911,742	642,952
Cash and cash equivalents at end of year	$839,738	$905,670	$911,742

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies

	(A) Principles of consolidation and basis of presentation

	The consolidated financial statements, which include the accounts of W. R. Berkley Corporation and its subsidiaries (the "Company"), have been prepared on the basis of U.S. generally accepted accounting principles ("GAAP"). All significant intercompany transactions and balances have been eliminated. Reclassifications have been made in the 2012 and 2011 financial statements to conform to the presentation of the 2013 financial statements. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the revenues and expenses reflected during the reporting period. The most significant items on our balance sheet that involve a greater degree of accounting estimates that are subject to change in the future are the valuation of investments, other-than-temporary impairments, loss and loss adjustment expense reserves and premium estimates. Actual results could differ from those estimates.

	(B) Revenue recognition

	Insurance premiums are recognized as written at the inception of the policy. Reinsurance premiums are estimated based upon information received from ceding companies, and subsequent differences from such estimates are recorded in the period they are determined. Insurance and reinsurance premiums are primarily earned on a pro rata basis over the policy term. Fees for services are earned over the period that the services are provided.

	Audit premiums are recognized when they are reliably determinable. The change in accruals for earned but unbilled audit premiums increased net premiums written and premiums earned by $12 million, $7 million and $1 million in 2013, 2012 and 2011, respectively.

	Revenues from wholly-owned investees are derived from services provided to the general aviation market, including fuel and line service, aircraft sales and maintenance, avionics and engineering services and parts fabrication. Revenue is recognized upon delivery of aircraft, delivery of fuel, shipment of parts and upon completion of services.

	(C) Cash and cash equivalents

	Cash equivalents consist of funds invested in money market accounts and investments with an effective maturity of three months or less when purchased.

	(D) Investments

	Fixed maturity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity. Fixed maturity securities that the Company has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Investment income from fixed maturity securities is recognized based on the constant effective yield method. Premiums and discounts on mortgage-backed securities are adjusted for the effects of actual and anticipated prepayments on a retrospective basis.

	Equity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity.

	Equity securities that the Company purchased with the intent to sell in the near-term are classified as trading account securities and are reported at estimated fair value. Realized and unrealized gains and losses from trading activity are reported as net investment income and are recorded at the trade date. Short sales and short call options are presented as trading securities sold but not yet purchased. Unsettled trades and the net margin balances held by the clearing broker are presented as a trading account receivable from brokers and clearing organizations.


	Investment funds are carried under the equity method of accounting. For certain investment funds, the Company's share of the earnings or losses is reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.

	Loans receivable represent commercial real estate mortgage loans and bank loans and are carried at amortized cost. The Company monitors the performance of its loans receivable and establishes an allowance for loan losses for loans where the Company determines it is probable that the contractual terms will not be met, with a corresponding charge to earnings. For loans that are evaluated individually and deemed to be impaired, the Company establishes a specific allowance based on a discounted cash flow analysis and comparable cost and sales methodologies, if appropriate. Individual loans that are not considered impaired and smaller-balance homogeneous loans are evaluated collectively and a general allowance is established if it is considered probable that a loss has been incurred.

	The accrual of interest on loans receivable is discontinued if the loan is 90 days past due based on the contractual terms of the loan unless the loan is adequately secured and in process of collection. In general, loans are placed on non-accrual status or charged off at an earlier date if collection of principal or interest is considered doubtful. Interest on these loans is accounted for on a cash basis until qualifying for return to accrual status. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured.

	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.” Fair value of investments is determined based on a fair value hierarchy that prioritizes the use of observable inputs over the use of unobservable inputs and requires the use of observable inputs when available. (See Note 13 of the Notes to Consolidated Financial Statements.)

	Realized gains or losses represent the difference between the cost of securities sold and the proceeds realized upon sale and are recorded at the trade date. The Company uses primarily the first-in, first-out method to determine the cost of securities sold.

	The cost of securities is adjusted where appropriate to include a provision for a decline in value which is considered to be other than temporary. An other-than-temporary decline is considered to occur in investments where there has been a sustained reduction in fair value and where the Company does not expect to recover the cost basis of the investment prior to the time of sale or maturity. Since equity securities do not have a contractual cash flow or a maturity, the Company considers whether the price of an equity security is expected to recover within a reasonable period of time.

	For fixed maturity securities that the Company intends to sell or, more likely than not, would be required to sell, a decline in value below amortized cost is considered to be an other-than-temporary impairment (“OTTI”). The amount of OTTI is equal to the difference between amortized cost and fair value at the balance sheet date. For fixed maturity securities that the Company does not intend to sell or believes that it is more likely than not it would not be required to sell, a decline in value below amortized cost is considered to be an OTTI if the Company does not expect to recover the entire amortized cost basis of a security (i.e., the present value of cash flows expected to be collected is less than the amortized cost basis of the security). The portion of the decline in value considered to be a credit loss (i.e., the difference between the present value of cash flows expected to be collected and the amortized cost basis of the security) is recognized in earnings. The portion of the decline in value not considered to be a credit loss (i.e., the difference in the present value of cash flows expected to be collected and the fair value of the security) is recognized in other comprehensive income.
	Impairment assessments for structured securities, including mortgage-backed securities and asset-backed securities, collateralized debt obligations and corporate debt, are generally evaluated based on the performance of the underlying collateral under various economic and default scenarios that may involve subjective judgments and estimates by management. Modeling these securities involves various factors, such as projected default rates, the nature and realizable value of the collateral, if any, the ability of the issuer to make scheduled payments, historical performance and other relevant economic and performance factors. If an OTTI determination is made, a discounted cash flow analysis is used to ascertain the amount of the credit impairment.
	Real estate held for investment purposes is initially recorded at the purchase price, which is generally fair value, and is subsequently reported at cost less accumulated depreciation. Real estate taxes, interest and other costs incurred during development and construction are capitalized. Buildings are depreciated on a straight-line basis over the estimated useful lives of the building. Minimum rental income is recognized on a straight-line basis over the lease term. Income and expenses from real estate are reported as net investment income. The carrying value of real estate is reviewed for impairment and an impairment loss is recognized if the estimated undiscounted cash flows from the use and disposition of the property are less than the carrying value of the property.

	(E) 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 weighted average number of common shares outstanding during the year. Diluted EPS is based upon the weighted average number of common and common equivalent shares outstanding during the year 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. Stock options for which the exercise price exceeds the average market price over the period have an anti-dilutive effect on EPS and, accordingly, are excluded from the calculation.

	(F) Deferred policy acquisition costs

	Acquisition costs associated with the successful acquisition of new and renewed insurance and reinsurance contracts are deferred and amortized ratably over the terms of the related contracts. Ceding commissions received on reinsurance contracts are netted against acquisition costs and are recognized ratably over the life of the contract. Deferred policy acquisition costs are presented net of unearned ceding commissions. Deferred policy acquisition costs are comprised primarily of commissions, as well as employment-related underwriting costs and premium taxes. Deferred policy acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. The recoverability of deferred policy acquisition costs is evaluated separately by each of our operating companies for each of their major lines of business. Future investment income is taken into account in measuring the recoverability of deferred policy acquisition costs.

	(G) Reserves for losses and loss expenses

	Reserves for losses and loss expenses are an accumulation of amounts determined on the basis of (1) evaluation of claims for business written directly by the Company; (2) estimates received from other companies for reinsurance assumed by the Company; and (3) estimates for losses incurred but not reported (based on Company and industry experience). These estimates are periodically reviewed and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments are reflected in the statements of income in the period in which they are determined. The Company discounts its reserves for excess and assumed workers' compensation claims using a risk-free or statutory rate. (See Note 14 of Notes to Consolidated Financial Statements.)

	(H) Reinsurance ceded

	The unearned portion of premiums ceded to reinsurers is reported as prepaid reinsurance premiums and earned ratably over the policy term. The estimated amounts of reinsurance recoverable on unpaid losses are reported as due from reinsurers. To the extent any reinsurer does not meet its obligations under reinsurance agreements, the Company must discharge its liability. Amounts due from reinsurers are reflected net of funds held where the right of offset is present. The Company has provided reserves for estimated uncollectible reinsurance.

	(I) Deposit accounting

	Contracts that do not meet the risk transfer requirements of GAAP are accounted for using the deposit accounting method. Under this method, an asset or liability is recognized at the inception of the contract based on consideration paid or received. The amount of the deposit asset or liability is adjusted at subsequent reporting dates using the interest method with a corresponding credit or charge to interest income or expense. Deposit liabilities for assumed reinsurance contracts were $72 million and $75 million at December 31, 2013 and 2012, respectively.

(J) Federal and foreign income taxes

The Company files a consolidated income tax return in the U.S. and foreign tax returns in countries where it has overseas operations. The Company's method of accounting for income taxes is the asset and liability method. Under this method, deferred tax assets and liabilities are measured using tax rates currently in effect or expected to apply in the years in which those temporary differences are expected to reverse. Interest and penalties, if any, are reported as income tax expense. The Company believes there are no tax positions that would require disclosure under GAAP. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized.

(K) Foreign currency

Gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the entity's functional currency) are reported on the statements of income as other operating costs and expenses. Unrealized gains or losses resulting from translating the results of non-U.S. dollar denominated operations are reported in accumulated other comprehensive income. Revenues and expenses denominated in currencies other than U.S. dollars are translated at the weighted average exchange rate during the year. Assets and liabilities are translated at the rate of exchange in effect at the balance sheet date.

(L) Property, furniture and equipment

Property, furniture and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the estimated useful lives of the respective assets. Depreciation expense was $38 million, $38 million and $40 million for 2013, 2012 and 2011, respectively.

(M) Comprehensive income

Comprehensive income encompasses all changes in stockholders' equity (except those arising from transactions with stockholders) and includes net income, net unrealized holding gains or losses on available for sale securities, unrealized foreign currency translation adjustments and changes in unrecognized pension obligations.

(N) Goodwill and other intangible assets

Goodwill and other intangible assets are tested for impairment on an annual basis and at interim periods where circumstances require. The Company's impairment test as of December 31, 2013 indicated that there were no impairment losses related to goodwill and other intangible assets. Intangible assets of $72 million and $31 million are included in other assets as of December 31, 2013 and 2012, respectively.

(O) Stock options

The costs resulting from all share-based payment transactions with employees are recognized in the consolidated financial statements using a fair-value-based measurement method.

(P) Statements of cash flows

Interest payments were $125 million, $119 million and $111 million in 2013, 2012 and 2011, respectively. Income taxes paid were $186 million, $133 million and $48 million in 2013, 2012 and 2011, respectively. Other non-cash items include acquisitions, unrealized investment gains and losses and pension expense. (See Note 2, Note 11 and Note 26 of Notes to Consolidated Financial Statements.)

(Q) Change in accounting

In October 2010, the Financial Accounting Standards Board ("FASB") issued guidance regarding the treatment of costs associated with acquiring or renewing insurance contracts. This guidance modified the definition of the types of costs that can be capitalized and specifies that the costs must be directly related to the successful acquisition of a new or renewed insurance contract. The Company adopted this guidance effective January 1, 2012 and retrospectively adjusted its previously issued financial statements. The impact of applying this guidance retrospectively was a reduction in stockholders' equity of $49 million as of January 1, 2010.


A summary of the impact of the adoption of this new guidance is shown below:


(In thousands, except per share amounts)	Previously Reported			As Adjusted
For the Year Ended December 31, 2011
Other operating costs and expenses	$	1,621,329		$	1,626,526

Income before income taxes	518,283			513,086

Federal and foreign income taxes	(123,550		)	(121,945		)
Net income	394,803			391,211


Basic net income per share	$	2.83		$	2.8

Diluted net income per share	2.71			2.69

Information has been restated as a result of the adoption of this new guidance throughout these consolidated financial statements and notes, where applicable.
(R) Recent accounting pronouncements

In February 2013, the Financial Accounting Standards Board (FASB) issued guidance relating to disclosures about items reclassified out of accumulated other comprehensive income ("AOCI"). The Company’s adoption of the updated guidance effective January 1, 2013 resulted in a change in the disclosures for AOCI in the Company’s consolidated financial statements but did not have any impact on the Company’s results of operations, financial position or liquidity.

In January 2014, the FASB issued ASU 2014-01 relating to Accounting for Investments in Qualified Affordable Housing Projects. The guidance must be applied retrospectively for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. Early adoption is permitted and can be applied retrospectively in reporting periods for which financial statements have not yet been issued. The Company is currently evaluating the impact of this guidance on the Company’s results of operations, financial position and liquidity, which is not expected to be material.

All other 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.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	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.
	In 2011, the Company acquired a business that owned an office building in London for $251 million in cash and an inactive insurance company for $23 million in cash. Approximately $2 million of the aggregate purchase price for these acquisitions was allocated to intangible assets.


	The following table summarizes the estimated fair value of net assets acquired and liabilities assumed at the date of acquisition:


	(In thousands)	2013			2012
	Fixed maturity securities	$	—		$	3,213

	Real estate	—			256,209

	Cash and cash equivalents	3,911			12,172

	Real estate, furniture and equipment	898			—

	Goodwill	19,664			251

	Intangible assets	44,800			—

	Other assets	60,661			6,566

	Total assets acquired	129,934			278,411

	Debt	(27,612		)	—

	Other liabilities assumed	(17,076		)	(4,247		)
	Net assets acquired	$	85,246		$	274,164

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Consolidated Statement of Comprehensive Income (Loss)	'
	Consolidated Statement of Comprehensive Income (Loss)

	The following table presents the components of the changes in accumulated other comprehensive income (loss) (AOCI) as of and for the year ended December 31, 2013:


	(In thousands)	Unrealized Investment gains (losses)				Currency translation adjustments			Net pension asset				Accumulated other comprehensive income (loss)
	Changes in AOCI
	Beginning of period	$	517,658			(36,676		)	(15,351		)		$	465,631

	Other comprehensive income (loss) before reclassifications	(193,188		)		(23,848		)	—				(217,036		)

	Amounts reclassified from AOCI	(67,876		)		—			8,700				(59,176		)

	Other comprehensive income (loss)	(261,064		)		(23,848		)	8,700				(276,212		)

	Unrealized investment gain related to non-controlling interest	(28		)		—			—				(28		)

	Ending balance	$	256,566			$	(60,524	)	$	(6,651	)		$	189,391

	Amounts reclassified from AOCI
	Pre-tax	(104,425		)	-1	—			13,387			-3	$	(91,038	)

	Tax effect	36,549			-2	—			(4,687		)	-2	31,862

	After-tax amounts reclassified	$	(67,876	)		$	—		$	8,700			$	(59,176	)

	Other comprehensive income (loss)
	Pre-tax	(401,637		)		(23,848		)	13,387				$	(412,098	)

	Tax effect	140,573				—			(4,687		)		135,886

	Other comprehensive income (loss)	$	(261,064	)		$	(23,848	)	$	8,700			$	(276,212	)

	_______________
	(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 income.

Investments_In_Fixed_Maturity_

Investments In Fixed Maturity Securities (Debt Securities)	12 Months Ended
	Dec. 31, 2012
Debt Securities	'
Schedule of Marketable Securities [Line Items]	'
Investments In Fixed Maturity Securities	'
	Investments in Fixed Maturity Securities
	At December 31, 2013 and 2012, investments in fixed maturity securities were as follows:


	(In thousands)	Amortized			Gross			Gross				Fair			Carrying
		Cost			Unrealized			Unrealized				Value			Value
					Gains			Losses
	December 31, 2013

	Held to maturity:

	State and municipal	$	68,929		$	11,172		$	—			$	80,101		$	68,929

	Residential mortgage-backed securities	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 government	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 investment in fixed maturity securities	$	11,291,631		$	451,247		$	(111,134	)		$	11,631,744		$	11,616,844



	December 31, 2012

	Held to maturity:

	State and municipal	$	65,190		$	18,529		$	—			$	83,719		$	65,190

	Residential mortgage-backed securities	32,764			5,286			—				38,050			32,764

	Corporate	4,997			605			—				5,602			4,997

	Total held to maturity	102,951			24,420			—				127,371			102,951

	Available for sale:

	U.S. government and government agency	827,591			72,532			(1,660		)		898,463			898,463

	State and municipal	4,449,238			328,974			(9,693		)		4,768,519			4,768,519

	Mortgage-backed securities:

	Residential(1)	1,395,739			53,846			(7,456		)		1,442,129			1,442,129

	Commercial	268,671			5,641			(744		)		273,568			273,568

Corporate	3,378,884			235,289			(12,525		)		3,601,648			3,601,648

Foreign government	794,880			62,380			(582		)		856,678			856,678

Total available for sale	11,115,003			758,662			(32,660		)		11,841,005			11,841,005

Total investment in fixed maturity securities	$	11,217,954		$	783,082		$	(32,660	)		$	11,968,376		$	11,943,956

_______________________________________

-1	Gross unrealized losses for mortgage-backed securities include $1,961,247 and $3,037,000, as of December 31, 2013 and 2012, respectively, related to the non-credit portion of OTTI recognized in other comprehensive income.






The amortized cost and fair value of fixed maturity securities at December 31, 2013, 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	$	926,865		$	935,322

Due after one year through five years	3,411,033			3,548,043

Due after five years through ten years	3,046,756			3,191,387

Due after ten years	2,554,437			2,596,505

Mortgage-backed securities	1,352,540			1,360,487

Total	$	11,291,631		$	11,631,744

At December 31, 2013 and 2012, there were no investments, other than investments in United States government and government agency securities, which exceeded 10% of common stockholders’ equity. At December 31, 2013, investments with a carrying value of $1,017 million were on deposit in custodial or trust accounts, of which $745 million was on deposit with state insurance departments, $211 million was on deposit in support of the Company’s underwriting activities at Lloyd’s, $48 million was on deposit as security for reinsurance clients and $13 million was on deposit as security for letters of credit issued in support of the Company’s reinsurance operations.

Investments_In_Equity_Securiti

Investments In Equity Securities Available for Sale (Equity securities available for sale)	12 Months Ended
	Dec. 31, 2012
Equity securities available for sale	'
Schedule of Available-for-sale Securities [Line Items]	'
Investments in Equity Securities	'
	Investments in Equity Securities Available for Sale
	At December 31, 2013 and 2012, investments in equity securities available for sale were as follows:


	(In thousands)	Cost		Gross		Gross			Fair		Carrying
				Unrealized		Unrealized			Value		Value
				Gains		Losses
	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


	December 31, 2012

	Common stocks	$	222,671	$	60,102	$	(707	)	$	282,066	$	282,066

	Preferred stocks	85,504		10,103		(1,651		)	93,956		93,956

	Total	$	308,175	$	70,205	$	(2,358	)	$	376,022	$	376,022

Arbitrage_Trading_Account

Arbitrage Trading Account	12 Months Ended
Arbitrage Trading Account	Dec. 31, 2012
Trading Securities and Derivative Instruments [Abstract]	'
Arbitrage Trading Account	'
	Arbitrage Trading Account
	At December 31, 2013 and 2012, the fair value and carrying value of the arbitrage trading account were $522 million and $329 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 arbitrage investments less vulnerable to changes in general financial market conditions.
	The Company uses put options, call options and swap contracts in order to mitigate the impact of potential changes in market conditions on the merger arbitrage trading account. These options and contracts are reported at fair value. As of December 31, 2013, the fair value of long option contracts outstanding was $2 million (notional amount of $28 million) and the fair value of short option contracts outstanding was $2 million (notional amount of $22 million). Other than with respect to the use of these trading account securities, the Company does not make use of derivatives.

Net_Investment_Income

Net Investment Income	12 Months Ended
	Dec. 31, 2013
Net Investment Income [Abstract]	'
Net Investment Income	'
	Net Investment Income
	Net investment income consists of the following:


	(In thousands)	2013			2012			2011
	Investment income earned on:

	Fixed maturity securities, including cash and cash equivalents and loans receivable	$	442,287		$	479,035		$	483,905

	Equity securities available for sale	11,380			16,419			12,416

	Investment funds	67,712			77,015			9,452

	Arbitrage trading account	20,431			8,286			16,576

	Real estate	12,498			12,097			7,471

	Gross investment income	554,308			592,852			529,820

	Investment expense	(10,017		)	(6,089		)	(3,469		)
	Net investment income	$	544,291		$	586,763		$	526,351

Investment_Funds

Investment Funds	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Investment Funds	'
	Investment Funds
	Investment funds consist of the following:


		Carrying Value				Income (Losses)
		as of December 31,
	(In thousands)	2013		2012		2013		2012		2011
	Real estate	$	378,435	$	373,259	$	9,315	$	30,196	$	14,527

	Energy	155,026		146,325		29,739		33,146		(6,101		)

	Hedged equity	271,575		63,920		7,655		5,912		(1,366		)

	Other funds	262,459		226,185		21,003		7,761		2,392

	Total	$	1,067,495	$	809,689	$	67,712	$	77,015	$	9,452

Real_Estate_Notes

Real Estate (Notes)	12 Months Ended
	Dec. 31, 2013
Real Estate [Abstract]	'
Real Estate	'
	Real Estate

	Investment in real estate represents directly owned property held for investment, as follows:


		As of December 31,
	(In thousands)	2013		2012
	Properties in operation	$	283,393	$	282,899

	Properties under development	431,849		323,836

	Total	$	715,242	$	606,735


	Properties in operation represent an office building in London and a long-term ground lease in Washington D.C. These properties are net of accumulated depreciation and amortization of $17,827,000 and $10,354,000, as of December 31, 2013 and 2012, respectively. Related depreciation expense was $7,474,000, $7,583,000 and $2,770,000 for the years ended December 31, 2013, 2012 and 2011, respectively. Future minimum rental income expected on operating leases relating to real estate held for investment is $1,504,000 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.

	Properties under development represent the following: an office building in London, a mixed-use project in Washington D.C. and an office complex in New York City. The Company expects to fund further development costs for these projects with a combination of its own funds and external financing.

Loans_Receivable

Loans Receivable	12 Months Ended
	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]	'
Loans Receivable	'
	Loans Receivable
	Loans receivable are as follows:


		As of December 31,
	(In thousands)	2013		2012
	Amortized cost:
	Real estate loans	$	282,357	$	336,533

	Commercial loans	61,226		65,428

	Total	$	343,583	$	401,961


	Fair value:
	Real estate loans	$	284,017	$	339,079

	Commercial loans	62,729		67,364

	Total	$	346,746	$	406,443


	Valuation allowance:
	Specific	$	—	$	3,000

	General	2,087		2,620

	Total	$	2,087	$	5,620


	Impaired loans:
	With a specific valuation allowance	$	—	$	1,775

	Without a valuation allowance	—		31,023

	Unpaid principal balance	—		35,872


		For the Year Ended December 31,
		2013		2012
	Increase (decrease) in valuation allowance	$	308	$	(14,118	)

	Loans receivable charged off	—		463

	There were no loans receivable in non-accrual status December 31, 2013, compared to $3 million at December 31, 2012. If these loans had been current at December 31, 2012, additional interest income of $498,000 would have been recognized in accordance with their original terms for the year ended December 31, 2012.
	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 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 December 31, 2013, and accordingly, the Company determined that a specific valuation allowance was not required.

Realized_And_Unrealized_Invest

Realized And Unrealized Investment Gains and Losses	12 Months Ended
	Dec. 31, 2013
Realized and Unrealized Investment Gains (Losses) [Abstract]	'
Realized and Unrealized Investment Gains and Losses	'
	Realized and Unrealized Investment Gains and Losses
	Realized and unrealized investment gains and losses are as follows:


	(In thousands)	2013			2012			2011
	Realized investment gains and losses:

	Fixed maturity securities:

	Gains	$	48,860		$	34,295		$	37,595

	Losses	(14,670		)	(6,436		)	(5,499		)
	Equity securities available for sale	70,235			97,300			90,023

	Investment funds	10,976			74,777			3,762

	Other gains	12,185			1,515			—

	Net realized gains on investments sales	127,586			201,451			125,881


	Net other-than-temporary impairments:
	Other-than-temporary impairments	(6,042		)	(4,984		)	(400		)
	Decrease in valuation allowance	—			13,998			—

	Net other-than-temporary impairments	(6,042		)	9,014			(400		)


	Total net investment gains	121,544			210,465			125,481

	Income tax expense	(47,426		)	(73,663		)	(43,834		)
		$	74,118		$	136,802		$	81,647



	Change in unrealized gains and losses of available for sales securities:

	Fixed maturity securities	$	(401,812	)	$	162,220		$	209,467

	Previously impaired fixed maturity securities	1,076			4,631			(3,604		)

	Equity securities available for sale	11,864			(33,199		)	(55,772		)

	Investment funds	(10,250		)	1,630			(2,093		)

	Total change in unrealized gains	(399,122		)	135,282			147,998

	Income tax expense	138,058			(47,966		)	(52,381		)

	Noncontrolling interests	(28		)	(77		)	55

		$	(261,092	)	$	87,239		$	95,672

Securities_In_An_Unrealized_Lo

Securities In An Unrealized Loss Position	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Securities In An Unrealized Loss Position	'
	Securities in an Unrealized Loss Position
	The following table summarizes all securities in an unrealized loss position at December 31, 2013 and 2012 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				Gross				Fair		Gross		Fair		Gross
		Value				Unrealized				Value		Unrealized		Value		Unrealized
						Losses						Losses				Losses
	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 government	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 available for sale	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


	December 31, 2012

	U.S. government and government agency	$	69,551			$	1,660			$	—	$	—	$	69,551	$	1,660

	State and municipal	152,694				1,639				135,967		8,054		288,661		9,693

	Mortgage-backed securities	484,731				3,629				58,292		4,571		543,023		8,200

	Corporate	398,595				3,406				70,537		9,119		469,132		12,525

	Foreign government	68,809				554				11,210		28		80,019		582

	Fixed maturity securities	1,174,380				10,888				276,006		21,772		1,450,386		32,660

	Common stocks	46,725				707				—		—		46,725		707

	Preferred stocks	—				—				39,812		1,651		39,812		1,651

	Equity securities available for sale	46,725				707				39,812		1,651		86,537		2,358

	Total	$	1,221,105			$	11,595			$	315,818	$	23,423	$	1,536,923	$	35,018


	Fixed Maturity Securities — A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at December 31, 2013 is presented in the table below:


	(Dollars in thousands)	Number of			Aggregate				Gross
		Securities			Fair Value				Unrealized
									Loss
	Mortgage-backed securities	13			$	66,658			$	3,748

	Corporate	9			31,579				1,005

Foreign government	2			23,603				844

Total	24			$	121,840			$	5,597



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. The table below provides a roll-forward of the portion of impairments recognized in earnings for those securities that have been impaired due to both credit factors and non-credit factors.


(In thousands)	2013				2012
Beginning balance of amounts related to credit losses	$	4,261			$	4,261

Additions for amounts related to credit losses	—				—

Deductions for amounts related to credit loss sales	—				—

Ending balance of amounts related to credit losses	$	4,261			$	4,261

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 on 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 December 31, 2013, there were three preferred stocks in an unrealized loss position, with an aggregate fair value of $33 million and a gross unrealized loss of $6 million. None of those preferred stocks are rated non-investment grade, and none are delinquent or in default. Management believes the unrealized losses are due primarily to market and sector related factors and does not consider these to be OTTI.
Common Stocks – At December 31, 2013, there were no common stocks in an unrealized loss position.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The Company’s fixed maturity, equity securities available for sale and its 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 December 31, 2013 and 2012 by level:


	(In thousands)	Total			Level 1			Level 2			Level 3
	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		$	—


	December 31, 2012

	Assets:

	Fixed maturity securities available for sale:

	U.S. government and government agency	$	898,463		$	—		$	898,463		$	—

	State and municipal	4,768,519			—			4,768,519			—

	Mortgage-backed securities	1,715,697			—			1,715,697			—

	Corporate	3,601,648			—			3,542,583			59,065

	Foreign government	856,678			—			856,678			—

	Total fixed maturity securities available for sale	11,841,005			—			11,781,940			59,065

	Equity securities available for sale:

Common stocks	282,066			280,658			—			1,408

Preferred stocks	93,956			—			93,335			621

Total equity securities available for sale	376,022			280,658			93,335			2,029

Arbitrage trading account	329,077			233,603			94,546			928

Total	$	12,546,104		$	514,261		$	11,969,821		$	62,022

Liabilities:

Securities sold but not yet purchased	$	121,487		$	114,909		$	6,558		$	20

There were no transfers between Levels 1 and 2 for the years ended December 31, 2013 and 2012.




The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2013 and 2012:


	Gains (Losses) Included in:
(In thousands)	Beginning Balance			Earnings			Other Comprehensive Income			Purchases			Sales			Paydowns/Maturities			In		Out			Ending Balance
Year ended December 31, 2013

Assets:
Fixed maturity securities 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		)	—			22		(1,329		)	1,780

Total	$	62,022		$	1,836		$	1,039		$	4,424		$	(5,776	)	$	(12,604	)	$	22	$	(1,329	)	$	49,634

Liabilities:
Securities sold but not yet purchased	20			$	(4	)	—			$	4		$	(20	)	—			—		—			$	—


Year ended December 31, 2012

Fixed maturity securities available for sale:

Corporate	$	67,828		$	(1,497	)	$	9,622		$	283		$	—		$	(17,171	)	$	—	$	—		$	59,065

Total	67,828			(1,497		)	9,622			283			—			(17,171		)	—		—			59,065

Equity securities available for sale:
Common stocks	1,559			—			—			—			(151		)	—			—		—			1,408

Preferred stocks	12,303			1,126			(1,737		)	—			(11,071		)	—			—		—			621

Total	13,862			1,126			(1,737		)	—			(11,222		)	—			—		—			2,029

Arbitrage trading account	851			(3,534		)	3,570			—			(52		)	—			93		—			928

Total	$	82,541		$	(3,905	)	$	11,455		$	283		$	(11,274	)	$	(17,171	)	$	93	$	—		$	62,022

Liabilities:
Securities sold but not yet purchased	21			(1		)	$	—		—			—			$	—		$	—	$	—		$	20


There were no significant transfers in or out of Level 3 during the years ended December 31, 2013 or 2012.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2013 and 2012:


	2013						2012
(In thousands)	Carrying Value			Fair Value			Carrying Value			Fair Value
Assets:

Fixed maturity securities	$	11,616,844		$	11,631,744		$	11,943,956		$	11,968,376

Equity securities available for sale	283,338			283,338			376,022			376,022

Arbitrage trading account	522,128			522,128			329,077			329,077

Loans receivable	343,583			346,746			401,961			406,443

Cash and cash equivalents	839,738			839,738			905,670			905,670

Trading accounts receivable from brokers and clearing organizations	304,936			304,936			446,873			446,873

Due from broker	17,735			17,735			14,449			14,449


Liabilities:
Trading account securities sold but not yet purchased	162,278			162,278			121,487			121,487

Junior subordinated debentures	339,800			288,540			243,206			252,000

Senior notes and other debt	1,692,442			1,861,898			1,871,535			2,190,173

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. 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. 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.

Reserves_For_Losses_And_Loss_E

Reserves For Losses And Loss Expenses	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Reserves For Losses And Loss Expenses	'
	Reserves for Losses and Loss Expenses
	The table below provides a reconciliation of the beginning and ending reserve balances:


	(In thousands)	2013			2012			2011
	Net reserves at beginning of year	$	8,411,851		$	8,172,112		$	7,999,521

	Net provision for losses and loss expenses:

	Claims occuring during the current year(1)	3,221,393			2,997,995			2,791,860

	Decrease in estimates for claims occurring in prior years(2)(3)	(78,810		)	(102,571		)	(181,282		)
	Loss reserve discount accretion	54,441			53,055			47,787

	Total	3,197,024			2,948,479			2,658,365

	Net payments for claims:

	Current year	822,787			698,834			765,440

	Prior year	2,055,284			2,010,101			1,721,558

	Total	2,878,071			2,708,935			2,486,998

	Foreign currency translation	(47,007		)	195			1,224

	Net reserves at end of year	8,683,797			8,411,851			8,172,112

	Ceded reserve at end of year	1,397,144			1,339,235			1,165,022

	Gross reserves at end of year	$	10,080,941		$	9,751,086		$	9,337,134

	_______________________________________

	-1	Claims occurring during the current year are net of loss reserve discounts of $22,680,000, $26,078,000 and $43,286,000 in 2013, 2012 and 2011, respectively.

	-2	The decrease in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years decreased by $77,430,000, $100,667,000 and $182,937,000 in 2013, 2012 and 2011, respectively.

	-3	For certain retrospectively rated insurance polices and reinsurance agreements, reserve development is offset by additional or return premiums. Favorable reserve development, net of additional and return premiums, was $98 million, $103 million and $182 million in 2013, 2012 and 2011, respectively.
	For the year ended December 31, 2013, estimates for claims occurring in prior years (net of additional and return premiums) decreased by $98 million. The favorable reserve development in 2013 was primarily attributable to accident years 2008 through 2010. The changes in prior year loss reserve estimates are generally the result of ongoing analysis of recent loss development trends. Original estimates are increased or decreased as additional information becomes known regarding individual claims and aggregate claim trends.
	Environmental and Asbestos — To date, known environmental and asbestos claims have not had a material impact on the Company’s operations, because its subsidiaries generally did not insure large industrial companies that are subject to significant environmental or asbestos exposures prior to 1986 when an absolute exclusion was incorporated into standard policy language.
	The Company’s net reserves for losses and loss adjustment expenses relating to asbestos and environmental claims were $36 million and $34 million at December 31, 2013 and 2012, respectively. The Company’s gross reserves for losses and loss adjustment expenses relating to asbestos and environmental claims were $59 million and $56 million at December 31, 2013 and 2012, respectively. Increases in net incurred losses and loss expenses for reported asbestos and environmental claims were approximately $5 million, $2 million and $1 million in 2013, 2012 and 2011, respectively. Net paid losses and loss expenses for asbestos and environmental claims were approximately $3 million in 2013, $2 million in 2012 and $3 million in 2011. The estimation of these liabilities is subject to significantly greater than normal variation and uncertainty because it is difficult to make an actuarial estimate of these liabilities due to the absence of a generally accepted actuarial methodology for these exposures and the potential effect of significant unresolved legal matters, including coverage issues, as well as the cost of litigating the legal issues. Additionally, the determination of ultimate damages and the final allocation of such damages to financially responsible parties are highly uncertain.
	Discounting — The Company discounts its liabilities for excess and assumed workers’ compensation business because of the long period of time over which losses are paid. Discounting is intended to appropriately match losses and loss expenses to income earned on investment securities supporting the liabilities. The expected losses and loss expense payout pattern subject to discounting was derived from the Company’s loss payout experience. For non-proportional business, reserves for losses and loss expenses have been discounted using risk-free discount rates determined by reference to the U.S. Treasury yield curve. At December 31, 2013, the discount rates by year ranged from 2.1% to 6.5% with a weighted average discount rate of 4.1%. For proportional business, reserves for losses and loss expenses have been discounted at the statutory rate permitted by the Department of Insurance of the State of Delaware of 2.2%. The aggregate net discount, after reflecting the effects of ceded reinsurance, was $837 million, $867 million and $892 million at December 31, 2013, 2012 and 2011, respectively.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2013
Reinsurance Disclosures [Abstract]	'
Reinsurance	'
	Reinsurance
	The Company reinsures a portion of its insurance exposures in order to reduce its net liability on individual risks and catastrophe losses. Reinsurance coverage and retentions vary depending on the line of business, location of the risk and nature of loss. The Company’s reinsurance purchases include the following: property reinsurance treaties that reduce exposure to large individual property losses and catastrophe events; casualty reinsurance treaties that reduce its exposure to large individual casualty losses, workers’ compensation catastrophe losses and casualty losses involving multiple claimants or insureds; and facultative reinsurance that reduces exposure on individual policies or risks for losses that exceed treaty reinsurance capacity. Depending on the operating unit, the Company purchases specific additional reinsurance to supplement the above programs.
	The following is a summary of reinsurance financial information:


	(In thousands)	2013			2012			2011
	Written premiums:

	Direct	$	5,626,172		$	4,964,069		$	4,370,092

	Assumed	884,919			815,810			707,221

	Ceded	(1,010,918		)	(881,340		)	(719,945		)
	Total net written premiums	$	5,500,173		$	4,898,539		$	4,357,368


	Earned premiums:

	Direct	$	5,328,955		$	4,723,882		$	4,164,277

	Assumed	857,119			770,981			669,593

	Ceded	(959,537		)	(821,347		)	(673,003		)
	Total net earned premiums	$	5,226,537		$	4,673,516		$	4,160,867


	Ceded losses incurred	$	556,108		$	528,018		$	458,249

	The Company reinsures a portion of its exposures principally to reduce its net liability on individual risks and to protect against catastrophic losses. Estimated amounts due from reinsurers are reported net of reserves for uncollectible reinsurance of $1,385,000, $1,680,000 and $3,169,000 as of December 31, 2013, 2012 and 2011, respectively. The following table presents the amounts due from reinsurers as of December 31, 2013:


	(In thousands)
	Munich Re	$	193,405

	Lloyd’s of London	117,059

	Swiss Re	104,096

	Alleghany Group	96,348

	Partner Re	67,116

	Axis Capital	65,580

	Berkshire Hathaway	53,118

	Ace Group	46,413

	Hannover Re Group	35,607

	Everest Re	29,253

	Arch Capital Group	25,782

	Other reinsurers less than $20,000	230,825

	Subtotal	1,064,602

	Residual market pools	468,501

	Total	$	1,533,103

Senior_Notes_And_Other_Debt

Senior Notes And Other Debt (Senior Notes and Other Debt)	12 Months Ended
	Dec. 31, 2013
Senior Notes and Other Debt	'
Debt Instrument [Line Items]	'
Senior Notes And Other Debt	'
	Senior Notes and Other Debt
	Senior notes and other debt consist of the following as of December 31, 2013 (the difference between the face value and the carrying value is unamortized discount):


	(In thousands)	Interest Rate	Face Value		2013 Carrying Value		2012 Carrying Value
	Senior notes due on:

	15-Feb-13		$	—	$	—	$	199,959

	May 15, 2015	5.60%	200,000		199,744		199,559

	August 15, 2019	6.15%	150,000		149,199		149,057

	September 15, 2019	7.38%	300,000		298,546		298,292

	September 15, 2020	5.38%	300,000		297,738		297,401

	January 1, 2022	8.70%	76,503		76,004		75,962

	15-Mar-22	4.63%	350,000		346,581		346,163

	February 15, 2037	6.25%	250,000		247,457		247,347

	Subsidiary debt (1)	Various	77,173		77,173		57,795

	Total debt		$	1,703,676	$	1,692,442	$	1,871,535

	_____________
	(1) Subsidiary debt is due as follows: $5 million in 2014, $40 million in 2015, $30 million in 2016 and $2 million thereafter.

Junior_Subordinated_Debentures

Junior Subordinated Debentures (Junior Subordinated Debentures)	12 Months Ended
	Dec. 31, 2013
Junior Subordinated Debentures	'
Debt Instrument [Line Items]	'
Junior Subordinated Debentures	'
	Junior Subordinated Debentures
	In 2013, the Company issued $350,000,000 aggregate principal amount of 5.625% Subordinated Debentures due April 2053 (the “Debentures”). At December 31, 2013, the carrying value of the Debentures, net of unamortized discount, was $339,800,000. The net proceeds of the offering was primarily used to repay the $250 million aggregate principal amount of the Company's 6.750% Subordinated Debentures due 2045. The Company realized a loss from the early redemption of $7 million.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Income tax expense consists of:


	(In thousands)	Current				Deferred			Total
		Expense				Expense
	31-Dec-13

	Domestic	$	116,802			$	47,370		$	164,172

	Foreign	22,362				7,053			29,415

	Total expense	$	139,164			$	54,423		$	193,587


	31-Dec-12

	Domestic	$	156,339			$	11,448		$	167,787

	Foreign	23,029				469			23,498

	Total expense	$	179,368			$	11,917		$	191,285


	31-Dec-11

	Domestic	$	60,420			$	37,176		$	97,596

	Foreign	22,011				2,338			24,349

	Total expense	$	82,431			$	39,514		$	121,945

	Income before income taxes from domestic operations was $598 million, $624 million and $469 million for the years ended December 31, 2013, 2012 and 2011, respectively. Income before income taxes from foreign operations was $101 million, $78 million and $49 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	A reconciliation of the income tax expense and the amounts computed by applying the Federal and foreign income tax rate of 35% to pre-tax income are as follows:


	(In thousands)	2013				2012			2011
	Computed “expected” tax expense	$	244,611			$	245,675		$	179,580

	Tax-exempt investment income	(40,679		)		(50,665		)	(57,246		)
	Change in valuation allowance	—				—			(2,328		)

	Impact of lower foreign tax rates	(4,851		)		(5,234		)	(3,199		)
	State and local taxes	2,906				(753		)	2,355

	Other, net	(8,400		)		2,262			2,783

	Total expense	$	193,587			$	191,285		$	121,945

	At December 31, 2013 and 2012, the tax effects of differences that give rise to significant portions of the deferred tax asset and deferred tax liability are as follows:


	(In thousands)	2013				2012
	Deferred tax asset:

	Loss reserve discounting	$	87,394			$	119,547

	Unearned premiums	149,107				132,014

	Other-than-temporary impairments	49,483				62,187

	Restricted stock units	52,671				49,553

Other	92,698				83,740

Gross deferred tax asset	431,353				447,041

Less valuation allowance	—				—

Deferred tax asset	431,353				447,041

Deferred tax liability:

Amortization of intangibles	11,886				12,458

Deferred policy acquisition costs	136,635				120,532

Unrealized investment gains	148,215				274,497

Other	114,497				99,809

Deferred tax liability	411,233				507,296

Net deferred tax asset (liability)	$	20,120			$	(60,255	)

The Company had current tax receivables of $24,737,000 and a current tax payables of $22,546,000 at December 31, 2013 and 2012, respectively. at December 31, 2013, the Company had foreign net operating loss carryforwards of $870,000, which expire beginning in 2014. The Company had provided a valuation allowance against the unutilized foreign tax credits which were fully utilized in the 2010 federal tax return. The reduction in the valuation relates primarily to the full utilization of the foreign tax credit carryforward. At December 31, 2013 and 2012, the Company had no deferred tax assets for which a valuation allowance is required. The statute of limitations has closed for the Company’s tax returns through December 31, 2009.
The realization of the deferred tax asset is dependent upon the Company’s ability to generate sufficient taxable income in future periods. Based on historical results and the prospects for future current operations, management anticipates that it is more likely than not that future taxable income will be sufficient for the realization of this asset.

Dividends_From_Subsidiaries_An

Dividends From Subsidiaries And Statutory Financial Information	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Dividends From Subsidiaries And Statutory Financial Information (Unaudited)	'
	Dividends from Subsidiaries and Statutory Financial Information

	The Company’s insurance subsidiaries are restricted by law as to the amount of dividends they may pay without the approval of regulatory authorities. The Company’s lead insurer, Berkley Insurance Company (BIC), directly or indirectly owns all of the Company’s other insurance companies. During 2014, the maximum amount of dividends that can be paid by BIC without such approval is approximately $491 million.

	BIC’s net income and statutory capital and surplus, as determined in accordance with statutory accounting practices (SAP), are as follows:



	(In thousands)	2013		2012		2011
	Net income	$	680,418	$	490,119	$	417,441

	Statutory capital and surplus	$	4,908,010	$	4,671,922	$	4,107,745


	The significant variances between SAP and GAAP are that for statutory purposes bonds are carried at amortized cost, acquisition costs are charged to income as incurred, deferred Federal income taxes are subject to limitations, excess and assumed workers’ compensation reserves are discounted at different discount rates and certain assets designated as “non-admitted assets” are charged against surplus. The Commissioner of Insurance of the State of Delaware has allowed BIC to discount non-tabular workers' compensation loss reserves, which is a permitted practice that differs from SAP. The effect of using this permitted practice was to increase BIC’s statutory capital and surplus by $282 million at December 31, 2013.

	The National Association of Insurance Commissioners (“NAIC”) has risk-based capital (“RBC”) requirements that require insurance companies to calculate and report information under a risk-based formula which measures statutory capital and surplus needs based on a regulatory definition of risk in a company’s mix of products and its balance sheet. This guidance is used to calculate two capital measurements: Total Adjusted Capital and RBC Authorized Control Level. Total Adjusted Capital is equal to the Company’s statutory capital and surplus excluding capital and surplus derived from the use of permitted practices that differ from statutory accounting practices. RBC Authorized Control Level is the capital level used by regulatory authorities to determine whether remedial action is required. Generally, no remedial action is required if Total Adjusted Capital is 200% or more of the RBC Authorized Control Level. At December 31, 2013, BIC’s Total Adjusted Capital of 4.6 billion was 4.53% of its RBC Authorized Control Level.

	See Note 4, Investments in Fixed Maturity Securities, for a description of assets held on deposit as security.

Common_Stockholders_Equity

Common Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Common Stockholders' Equity	'
	Common Stockholders’ Equity
	The weighted average number of shares used in the computation of net income per share was as follows:


		2013		2012		2011
	Basic	135,304,752		137,097,162		139,687,546

	Diluted	140,742,922		143,314,544		145,672,211

	Treasury shares have been excluded from average outstanding shares from the date of acquisition. The difference in calculating basic and diluted net income per share is attributable entirely to the dilutive effect of stock-based compensation plans.
	Changes in shares of common stock outstanding, net of treasury shares, are presented below. Shares of common stock issued and outstanding do not include shares related to unissued restricted stock units and unexercised stock options.


		2013		2012	2011
	Balance, beginning of year	136,017,732		137,520,019	141,009,834

	Shares issued	139,790		2,114,168	2,702,303

	Shares repurchased	(3,924,355	)	-3,616,455	-6,192.12
	Balance, end of year	132,233,167		136,017,732	137,520,019


	The amount of dividends paid is dependent upon factors such as the receipt of dividends from our subsidiaries, our results of operations, cash flow, financial condition and business needs, the capital and surplus requirements of our subsidiaries, and applicable insurance regulations that limit the amount of dividends that may be paid by our regulated insurance subsidiaries.

Fair_Value_Of_Financial_Instru

Fair Value Of Financial Instruments	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Of Financial Instruments	'
	Fair Value Measurements
	The Company’s fixed maturity, equity securities available for sale and its 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 December 31, 2013 and 2012 by level:


	(In thousands)	Total			Level 1			Level 2			Level 3
	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		$	—


	December 31, 2012

	Assets:

	Fixed maturity securities available for sale:

	U.S. government and government agency	$	898,463		$	—		$	898,463		$	—

	State and municipal	4,768,519			—			4,768,519			—

	Mortgage-backed securities	1,715,697			—			1,715,697			—

	Corporate	3,601,648			—			3,542,583			59,065

	Foreign government	856,678			—			856,678			—

	Total fixed maturity securities available for sale	11,841,005			—			11,781,940			59,065

	Equity securities available for sale:

Common stocks	282,066			280,658			—			1,408

Preferred stocks	93,956			—			93,335			621

Total equity securities available for sale	376,022			280,658			93,335			2,029

Arbitrage trading account	329,077			233,603			94,546			928

Total	$	12,546,104		$	514,261		$	11,969,821		$	62,022

Liabilities:

Securities sold but not yet purchased	$	121,487		$	114,909		$	6,558		$	20

There were no transfers between Levels 1 and 2 for the years ended December 31, 2013 and 2012.




The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2013 and 2012:


	Gains (Losses) Included in:
(In thousands)	Beginning Balance			Earnings			Other Comprehensive Income			Purchases			Sales			Paydowns/Maturities			In		Out			Ending Balance
Year ended December 31, 2013

Assets:
Fixed maturity securities 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		)	—			22		(1,329		)	1,780

Total	$	62,022		$	1,836		$	1,039		$	4,424		$	(5,776	)	$	(12,604	)	$	22	$	(1,329	)	$	49,634

Liabilities:
Securities sold but not yet purchased	20			$	(4	)	—			$	4		$	(20	)	—			—		—			$	—


Year ended December 31, 2012

Fixed maturity securities available for sale:

Corporate	$	67,828		$	(1,497	)	$	9,622		$	283		$	—		$	(17,171	)	$	—	$	—		$	59,065

Total	67,828			(1,497		)	9,622			283			—			(17,171		)	—		—			59,065

Equity securities available for sale:
Common stocks	1,559			—			—			—			(151		)	—			—		—			1,408

Preferred stocks	12,303			1,126			(1,737		)	—			(11,071		)	—			—		—			621

Total	13,862			1,126			(1,737		)	—			(11,222		)	—			—		—			2,029

Arbitrage trading account	851			(3,534		)	3,570			—			(52		)	—			93		—			928

Total	$	82,541		$	(3,905	)	$	11,455		$	283		$	(11,274	)	$	(17,171	)	$	93	$	—		$	62,022

Liabilities:
Securities sold but not yet purchased	21			(1		)	$	—		—			—			$	—		$	—	$	—		$	20


There were no significant transfers in or out of Level 3 during the years ended December 31, 2013 or 2012.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2013 and 2012:


	2013						2012
(In thousands)	Carrying Value			Fair Value			Carrying Value			Fair Value
Assets:

Fixed maturity securities	$	11,616,844		$	11,631,744		$	11,943,956		$	11,968,376

Equity securities available for sale	283,338			283,338			376,022			376,022

Arbitrage trading account	522,128			522,128			329,077			329,077

Loans receivable	343,583			346,746			401,961			406,443

Cash and cash equivalents	839,738			839,738			905,670			905,670

Trading accounts receivable from brokers and clearing organizations	304,936			304,936			446,873			446,873

Due from broker	17,735			17,735			14,449			14,449


Liabilities:
Trading account securities sold but not yet purchased	162,278			162,278			121,487			121,487

Junior subordinated debentures	339,800			288,540			243,206			252,000

Senior notes and other debt	1,692,442			1,861,898			1,871,535			2,190,173

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. 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. 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.

Lease_Obligations

Lease Obligations	12 Months Ended
Lease Obligations	Dec. 31, 2013
Leases [Abstract]	'
Lease Obligations	'
	Lease Obligations

	The Company and its subsidiaries use office space and equipment under leases expiring at various dates. These leases are considered operating leases for financial reporting purposes. Some of these leases have options to extend the length of the leases and contain clauses for cost of living, operating expense and real estate tax adjustments. The Company also has an investment in a commercial office building that has a long-term land lease. Future minimum lease payments, without provision for sublease income, are: $42,586,000 in 2014; $39,218,000 in 2015; $34,009,000 in 2016; $29,573,000 in 2017 and $213,046,000 thereafter. Rental expense was $44,752,000, $38,179,000 and $33,003,000 for 2013, 2012 and 2011, respectively.

Commitments_Litigation_And_Con

Commitments, Litigation And Contingent Liabilities	12 Months Ended
Commitments, Litigation And Contingent Liabilities	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments, Litigation And Contingent Liabilities	'
	Commitments, 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.

	At December 31, 2013, the Company had commitments to invest up to $249 million in certain investment funds.

Stock_Incentive_Plan

Stock Incentive Plan	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock Incentive Plan	'
	Stock Incentive Plan

	The Company has not issued any stock options under its stock incentive plans since 2004. The following table summarizes stock option information:



		2013							2012					2011
		Shares			Price(1)				Shares			Price(1)		Shares	Price(1)
	Outstanding at beginning of year	3,375			$	15.17			1,314,057			$	11.04	3,503,384	$	10.42

	Exercised	3,375			15.17				1,310,682			11.03		2,185,952	10.05

	Canceled	—			—				—			—		3,375	10.07

	Outstanding at year end	—			$	—			3,375			$	15.17	1,314,057	$	11.04

	_______________________________________

	-1	Weighted average exercise price.
	Pursuant to the stock incentive plan, the Company may also issue restricted stock units (RSUs) to officers 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. The following table summarizes RSU information for the three years ended December 31, 2013:


		2013			2012			2011
	RSUs granted and unvested at beginning of period:	4,701,120			4,370,975			4,945,375

	Granted	108,400			2,161,220			107,500

	Vested	(146,250	)		(1,704,625	)		(576,050	)
	Cancelled	(171,750	)		(126,450	)		(105,850	)
	RSUs granted and unvested at end of period:	4,491,520			4,701,120			4,370,975

	Upon vesting, shares of the Company’s common stock equal to the number of vested RSUs are issued or deferred to a later date, depending on the terms of the specific award agreement. As of December 31, 2013, 3,643,804 shares related to vested RSUs had been deferred.
	The fair value of RSUs at the date of grant are recorded as unearned compensation, a component of stockholders’ equity, and expensed over the vesting period. Following is a summary of changes in unearned compensation for the three years ended December 31, 2013:


	(In thousands)	2013				2012				2011
	Unearned compensation at beginning of year	$	93,653			$	57,315			$	76,139

	RSUs granted, net of cancellations	4,406				73,255				2,832

	RSUs expensed	(22,881		)		(25,728		)		(26,303		)
	RSUs forfeiture adjustment	(1,973		)		(11,189		)		4,647

	Unearned compensation at end of year	$	73,205			$	93,653			$	57,315

Compensation_Plans

Compensation Plans	12 Months Ended
	Dec. 31, 2013
Compensation Related Costs [Abstract]	'
Compensation Plans	'
	Compensation Plans
	The Company and its subsidiaries have profit sharing plans in which substantially all employees participate. The plans provide for minimum annual contributions of 5% of eligible compensation; contributions above the minimum are discretionary and vary with each participating subsidiary’s profitability. Employees become eligible to participate in the profit sharing plans on the first day of the month following the first full three months in which they are employed. The plans provide that 40% of the contributions vest immediately and that the remaining 60% vest at varying percentages based upon years of service. The Company’s foreign subsidiaries provide pension benefits in accordance with local regulations. Profit sharing expense was $34 million, $31 million, and $27 million in 2013, 2012 and 2011, respectively.

	The Company has a Long-Term Incentive Compensation Plan (“LTIP”) that provides for incentive compensation to key executives based on the growth in the Company’s book value per share over a five year period. There are 211,250 units outstanding from the 2013 grant with a maximum value of $52.8 million, of which $7.4 million was earned by December 31, 2013. There are 183,100 units outstanding from the 2011 grant with a maximum value of $45.8 million, of which $19.7 million was earned by December 31, 2013. The 2008 grant, which earned $23.0 million during the five years ended December 31, 2012, was paid in 2013.
	The following table summarizes the LTIP expense for the three years ended December 31, 2013:


	(In thousands)	2013		2012		2011
	2008 grant	$	—	$	5,742	$	4,600

	2011 grant	6,741		7,365		5,620

	2013 grant	7,386		—		—

	Total	$	14,127	$	13,107	$	10,220

Retirement_Benefits

Retirement Benefits	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Retirement Benefits	'
	Retirement Benefits

	The Company has an unfunded noncontributory defined benefit plan that covers its chief executive officer and chairman of the board. The discount rate used to derive the projected benefit obligation and related retirement expense was 0% in 2013 and 3.39% in 2012. The discount rate assumption used to determine the benefit obligation is based on a yield curve approach. Under this approach, a weighted average yield is determined from a hypothetical portfolio of AA rated bonds. A summary of the change in benefit obligation, which is required to be distributed on or before March 28, 2015, is as follows:


	(In thousands)	2013			2012
	Projected benefit obligation at beginning of year	$	64,632		$	56,787

	Interest cost	2,191			2,476

	Benefits paid	(285		)	(1,426		)
	Actuarial loss	(2,221		)	6,795

	Benefit obligation at end of year	$	64,317		$	64,632


	Following is a summary of the amounts recognized in accumulated other comprehensive income as of December 31, 2013 and 2012:


	(In thousands)	2013			2012
	Net actuarial loss	$	4,242		$	14,605

	Prior service cost	5,988			9,012

	Net pension asset	$	10,230		$	23,617


	The components of net periodic pension benefit cost are as follows:


	(In thousands)	2013			2012			2011
	Components of net periodic benefit cost:

	Interest cost	$	2,191		$	2,476		$	2,716

	Amortization of unrecognized:

	Prior service costs	3,023			3,023			3,023

	Net actuarial loss	8,143			2,197			1,330

	Net periodic pension cost	$	13,357		$	7,696		$	7,069


	The changes in plan assets and projected benefit obligation recognized in other comprehensive income are as follows:


	(In thousands)	2013			2012
	Changes in plan assets and projected benefit obligation:

	Net actuarial (gain) loss	$	(2,221	)	$	6,795

	Amortization of:

	Net actuarial loss	(8,143		)	(2,197		)
	Prior service costs	(3,023		)	(3,023		)
	Total recognized in other comprehensive income	$	(13,387	)	$	1,575


	The net after tax periodic pension cost of $7 million will be amortized from accumulated other comprehensive income into periodic benefit cost during 2014.

Supplemental_Financial_Stateme

Supplemental Financial Statement Information	12 Months Ended
	Dec. 31, 2013
Other Income and Expenses [Abstract]	'
Supplemental Financial Statement Data	'
	Supplemental Financial Statement Data
	Other operating costs and expenses consist of the following:


	(In thousands)	2013			2012			2011
	Amortization of deferred policy acquisition costs	$	991,070		$	917,583		$	785,118

	Other underwriting expenses	780,058			675,163			653,011

	Service company expenses	88,662			84,986			75,231

	Net foreign currency losses	(10,120		)	(6,092		)	(1,884		)
	Other costs and expenses	151,014			127,983			115,050

	Total	$	2,000,684		$	1,799,623		$	1,626,526

Industry_Segments

Industry Segments	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Industry Segments	'
	Industry Segments
	During the first quarter of 2013, the Company changed the aggregation of its business segments. The Company’s reportable segments include the following three 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.
	All domestic insurance operating companies, previously included in the Specialty, Regional and Alternative Markets segments, were aggregated into the Insurance-Domestic segment; all reinsurance operating companies were aggregated into the Reinsurance-Global segment; and all international insurance companies were aggregated into the Insurance-International segment. The segment disclosures for prior periods have been revised to be consistent with the new reportable business segment presentation. 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 operating segments is presented in the following table. Income (loss) before income taxes by segment includes allocated investment income. Identifiable assets by segment are those assets used in or allocated to the operation of each segment.


	Revenues
	(In thousands)	Earned			Investment			Other		Total		Pre-Tax			Net
		Premiums			Income							Income			Income
												(Loss)			(Loss)
	December 31, 2013:

	Insurance-Domestic	$	3,782,416		$	404,280		$	107,517	$	4,294,213	$	648,740		$	449,981

	Insurance-International	723,151			47,039			—		770,190		56,922			40,292

	Reinsurance-Global	720,970			89,090			—		810,060		110,425			78,013

	Corporate, other and eliminations(1)	—			3,882			408,645		412,527		(238,743		)	(142,479		)

	Net investment gains	—			—			121,544		121,544		121,544			74,118

	Consolidated	$	5,226,537		$	544,291		$	637,706	$	6,408,534	$	698,888		$	499,925


	December 31, 2012:
	Insurance-Domestic	$	3,417,022		$	424,787		$	103,133	$	3,944,942	$	578,500		$	397,942

	Insurance-International	631,841			45,796			—		677,637		51,639			35,928

	Reinsurance-Global	624,653			106,932			—		731,585		103,690			72,916

	Corporate, other and eliminations(1)	—			9,248			249,677		258,925		(242,366		)	(132,996		)

	Net investment gains	—			—			210,465		210,465		210,465			136,802

	Consolidated	$	4,673,516		$	586,763		$	563,275	$	5,823,554	$	701,928		$	510,592


	December 31, 2011:
	Insurance-Domestic	$	3,121,281		$	372,053		$	92,847	$	3,586,181	$	467,126		$	345,399

	Insurance-International	508,509			36,958			—		545,467		36,912			28,142

	Reinsurance-Global	531,077			97,795			—		628,872		85,271			66,405

	Corporate, other and eliminations(1)	—			19,545			250,438		269,983		(201,704		)	(130,382		)

	Net investment gains	—			—			125,481		125,481		125,481			81,647

	Consolidated	$	4,160,867		$	526,351		$	468,766	$	5,155,984	$	513,086		$	391,211



	Identifiable Assets
(In thousands)	31-Dec-13			31-Dec-12
Insurance-Domestic	$	15,247,807		$	14,661,476

Insurance-International	1,516,310			1,541,365

Reinsurance-Global	3,103,193			3,337,937

Corporate, other and eliminations(1)	684,486			615,118

Consolidated	$	20,551,796		$	20,155,896

_______________________________________

-1	Corporate, other and eliminations represent corporate revenues and expenses and other items that are not allocated to business segments.
Net premiums earned by major line of business are as follows:


(In thousands)	2013			2012			2011
Insurance-Domestic

Other liability	$	1,259,376		$	1,104,369		$	1,003,080

Workers' compensation	995,047			869,042			785,454

Short-tail lines	774,809			733,239			665,575

Commercial automobile	486,759			455,988			437,891

Professional liability	266,425			254,384			229,281

Total Insurance-Domestic	3,782,416			3,417,022			3,121,281


Insurance-International
Other liability	65,528			44,065			49,800

Workers' compensation	84,637			82,066			73,823

Short-tail lines	336,814			276,599			183,447

Commercial automobile	130,020			125,927			110,568

Professional liability	106,152			103,184			90,871

Total Insurance-International	723,151			631,841			508,509


Reinsurance-Global
Casualty	507,790			456,376			389,557

Property	213,180			168,277			141,520

Total Reinsurance-Global	720,970			624,653			531,077

Total	$	5,226,537		$	4,673,516		$	4,160,867

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information (Unaudited)	'
	Quarterly Financial Information (Unaudited)

	The following is a summary of quarterly financial data:


	(In thousands. except per share data)	2013
	Three months ended	March 31		June 30		September 30		December 31
	Revenues	$	1,506,769	$	1,570,962	$	1,634,124	$	1,696,679

	Net income	116,615		115,957		136,974		130,379

	Net income per share(1)
	Basic	0.86		0.85		1.01		0.97

	Diluted	0.83		0.82		0.97		0.93



		2012
	Three months ended	March 31		June 30		September 30		December 31
	Revenues	$	1,378,705	$	1,415,747	$	1,420,501	$	1,608,601

	Net income	135,318		108,838		100,947		165,489

	Net income per share(1)
	Basic	0.98		0.79		0.74		1.22

	Diluted	0.94		0.76		0.71		1.17

	_______________________________________

	-1	Net income per share (“EPS”) in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Thus, the sum of the four quarters EPS does not necessarily equal the full-year EPS.

Schedule_II_Condensed_Financia

Schedule II - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2012
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Schedule II - Condensed Financial Information of Registrant	'
	Schedule II
	W. R. Berkley Corporation
	Condensed Financial Information of Registrant
	Balance Sheets (Parent Company)



		December 31,
	(In thousands)	2013				2012
	Assets:

	Cash and cash equivalents	$	17,315			$	162,972

	Fixed maturity securities available for sale at fair value (cost $61,084 and $281,708 at December 31, 2013 and 2012, respectively)	63,115				286,597

	Equity securities available for sale, at fair value (cost $4,668 in 2013 and $0 in 2012)	11,240				25,699

	Investment in subsidiaries	6,250,979				5,979,539

	Due from subsidiaries	13,648				106,334

	Deferred Federal income taxes	51,346				—

	Current Federal income taxes	17,540				—

	Property, furniture and equipment at cost, less accumulated depreciation	9,028				7,895

	Other assets	5,795				10,710

	Total assets	$	6,440,006			$	6,579,746

	Liabilities and stockholders’ equity

	Liabilities:

	Due to subsidiaries	$	—			$	—

	Other liabilities	148,903				176,416

	Current Federal income taxes	—				8,253

	Deferred Federal income taxes	—				31,914

	Junior subordinated debentures	339,800				243,206

	Senior notes	1,615,268				1,813,740

	Total liabilities	2,103,971				2,273,529

	Stockholders’ equity:

	Preferred stock	—				—

	Common stock	47,024				47,024

	Additional paid-in capital	967,440				945,166

	Retained earnings (including accumulated undistributed net income of subsidiaries of $4,393,420 and $4,023,780 at December 31, 2013 and 2012, respectively)	5,265,015				4,817,807

	Accumulated other comprehensive income	189,391				465,631

	Treasury stock, at cost	(2,132,835		)		(1,969,411		)
	Total stockholders’ equity	4,336,035				4,306,217

Total liabilities and stockholders’ equity	$	6,440,006			$	6,579,746

________________
See accompanying Report of Independent Registered Public Accounting Firm and note to condensed financial statements.

Schedule II, Continued

W. R. Berkley Corporation
Condensed Financial Information of Registrant, Continued
Statements of Income (Parent Company)



	Years Ended December 31,
(In thousands)	2013				2012				2011
Management fees and investment income including dividends from subsidiaries of $269,626, $25,968 and $503,227 for the years ended December 31, 2013, 2012 and 2011, respectively	$	277,223			$	29,961			$	514,057

Net investment gains	24,550				71,130				45,962

Other income	223				271				96

Total revenues	301,996				101,362				560,115

Operating costs and expense	122,562				133,326				118,922

Interest expense	120,066				124,298				111,184

Income before federal income taxes	59,368				(156,262		)		330,009

Federal income taxes:

Federal income taxes provided by subsidiaries on a separate return basis	225,845				132,379				79,200

Federal income tax expense on a consolidated return basis	(154,928		)		(160,226		)		(89,144		)
Net expense	70,917				(27,847		)		(9,944		)

Income (loss) before undistributed equity in net income of subsidiaries	130,285				(184,109		)		320,065

Equity in undistributed net income of subsidiaries	369,640				694,701				71,146

Net income	$	499,925			$	510,592			$	391,211

________________
See accompanying Report of Independent Registered Public Accounting Firm and note to condensed financial statements.
Schedule II, Continued

W. R. Berkley Corporation
Condensed Financial Information of Registrant, Continued
Statements of Cash Flows (Parent Company)



	Years Ended December 31,
(In thousands)	2013				2012				2011
Cash flows (used in) from operating activities:

Net income	$	499,925			$	510,592			$	391,211

Adjustments to reconcile net income to net cash from operating activities:

Net investment gains	(24,550		)		(71,130		)		(45,962		)
Depreciation and amortization	10,397				5,624				4,905

Equity in undistributed earnings of subsidiaries	(369,640		)		(694,701		)		(71,146		)
Tax payments received from subsidiaries	77,305				125,046				139,011

Federal income taxes provided by subsidiaries on a separate return basis	(225,845		)		(132,379		)		(79,200		)
Stock incentive plans	24,594				26,763				27,176

Change in:

Federal income taxes	21,866				44,423				56,542

Other assets	(821		)		911				(542		)

Other liabilities	(16,280		)		28,017				(6,747		)

Accrued investment income	967				97				1,559

Other, net	—				(13		)		277

Net cash (used in) from operating activities	(2,082		)		(156,750		)		417,084

Cash from (used in) investing activities:

Proceeds from sales of fixed maturity securities	230,854				93,354				70,665

Proceeds from maturities and prepayments of fixed maturity securities	68,918				121,191				165,158

Proceeds from sales of equity securities	23,395				72,565				47,735

Cost of purchases of fixed maturity securities	(79,132		)		(255,885		)		(240,536		)
Cost of purchases of equity securities	(4,668		)		—				—

Investments in and advances to subsidiaries, net	(58,454		)		(16,480		)		(3,867		)
Change in balance due to security broker	6,918				(4,767		)		(5,983		)

Net additions to real estate, furniture & equipment	(1,896		)		(1,857		)		(643		)
Net cash from investing activities	185,935				8,121				32,529

Cash from (used in) financing activities:

Net proceeds from issuance of senior notes	339,627				345,823				—

Net proceeds from stock options exercised	53				13,544				21,966

Repayment of senior notes	(450,000		)		—				—

Purchase of common treasury shares	(166,473		)		(134,456		)		(187,163		)
Cash dividends to common stockholders	(52,717		)		(183,947		)		(43,255		)
Net cash from (used in) financing activities	(329,510		)		40,964				(208,452		)

Net increase (decrease) in cash and cash equivalents	(145,657		)		(107,665		)		241,161

Cash and cash equivalents at beginning of year	162,972				270,637				29,476

Cash and cash equivalents at end of year	$	17,315			$	162,972			$	270,637

________________
See accompanying Report of Independent Registered Public Accounting Firm and note to condensed financial statements.
W. R. Berkley Corporation
Condensed Financial Information of Registrant,Continued
December 31, 2013
Note to Condensed Financial Statements (Parent Company)
The accompanying condensed financial statements should be read in conjunction with the notes to consolidated financial statements included elsewhere herein. Reclassifications have been made in the 2012 and 2011 financial statements as originally reported to conform them to the presentation of the 2013 financial statements.
The Company files a consolidated federal tax return with the results of its domestic insurance subsidiaries included on a statutory basis. Under present Company policy, federal income taxes payable by subsidiary companies on a separate-return basis are paid to W. R. Berkley Corporation, and the Company pays the tax due on a consolidated return basis.

Schedule_III_Supplementary_Ins

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2013
Supplementary Insurance Information [Abstract]	'
Schedule III - Supplementary Insurance Information	'
	Schedule III

	W. R. Berkley Corporation and Subsidiaries
	Supplementary Insurance Information
	December 31, 2013, 2012 and 2011



	(In thousands)	Deferrred		Reserve for		Unearned		Net Premiums		Net		Loss and Loss		Amortization of		Other		Net
		Policy		Losses and		Premiums		Earned		Investment		Expenses		Deferred Policy		Operating Cost		Premiums
		Acquisition		Loss Expenses						Income				Acquisition		and Expenses		Written
		Cost												Cost
	December 31, 2013

	Insurance-Domestic	$	306,464	$	7,715,124	$	2,107,768	$	3,782,416	$	404,280	$	2,318,541	$	651,524	$	671,096	$	3,994,387

	Insurance-International	60,751		672,009		317,691		723,151		47,039		429,900		152,843		124,497		756,185

	Reinsurance-Global	84,886		1,693,808		355,978		720,970		89,090		448,583		186,703		64,567		749,601

	Corporate and adjustments	—		—		—		—		3,882		—		—		149,454		—

	Total	$	452,101	$	10,080,941	$	2,781,437	$	5,226,537	$	544,291	$	3,197,024	$	991,070	$	1,009,614	$	5,500,173

	December 31, 2012

	Insurance-Domestic	$	269,418	$	7,466,538	$	1,844,452	$	3,417,022	$	424,787	$	2,169,090	$	613,252	$	584,100	$	3,569,883

	Insurance-International	56,995		622,202		297,581		631,841		45,796		377,459		136,412		112,128		664,459

	Reinsurance-Global	77,634		1,662,346		332,814		624,653		106,932		401,930		167,919		58,044		664,197

	Corporate and adjustments	—		—		—		—		9,248		—		—		127,768		—

	Total	$	404,047	$	9,751,086	$	2,474,847	$	4,673,516	$	586,763	$	2,948,479	$	917,583	$	882,040	$	4,898,539

	December 31, 2011

	Insurance-Domestic	$	246,580	$	7,183,706	$	1,639,603	$	3,121,281	$	372,053	$	2,025,139	$	529,885	$	559,985	$	3,238,120

	Insurance-International	51,753		510,245		262,483		508,509		36,958		291,827		114,126		104,097		551,910

	Reinsurance-Global	66,604		1,643,183		287,489		531,077		97,795		341,399		141,107		58,449		567,338

	Corporate and adjustments	—		—		—		—		19,545		—		—		113,680		—

	Total	$	364,937	$	9,337,134	$	2,189,575	$	4,160,867	$	526,351	$	2,658,365	$	785,118	$	836,211	$	4,357,368

	See accompanying Report of Independent Registered Public Accounting Firm.

Schedule_IV_Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2013
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]	'
Schedule IV - Reinsurance	'
	Schedule IV

	W. R. Berkley Corporation and Subsidiaries
	Reinsurance
	Years ended December 31, 2013, 2012 and 2011



		Premiums Written
	(In thousands, other than percentages)	Direct		Ceded		Assumed		Net		Percentage
		Amount		to Other		from Other		Amount		of Amount
				Companies		Companies				Assumed
										to Net
	Year ended December 31, 2013:

	Insurance-Domestic	$	4,699,348	$	809,368	$	104,407	$	3,994,387	2.6	%

	Insurance-International	887,027		142,591		11,749		756,185		1.6

	Reinsurance-Global	39,797		58,959		768,763		749,601		102.6

	Total	$	5,626,172	$	1,010,918	$	884,919	$	5,500,173	16.1	%

	Year ended December 31, 2012:

	Insurance-Domestic	$	4,133,960	$	691,284	$	127,207	$	3,569,883	3.6	%

	Insurance-International	798,750		137,598		3,307		664,459		0.5

	Reinsurance-Global	31,359		52,458		685,296		664,197		103.2

	Total	$	4,964,069	$	881,340	$	815,810	$	4,898,539	16.7	%

	Year ended December 31, 2011:

	Insurance-Domestic	$	3,664,780	$	556,743	$	130,083	$	3,238,120	4.1	%

	Insurance-International	681,423		129,513		—		551,910		—

	Reinsurance-Global	23,889		33,689		577,138		567,338		101.7

	Total	$	4,370,092	$	719,945	$	707,221	$	4,357,368	16.3	%


	See accompanying Report of Independent Registered Public Accounting Firm.

Schedule_V_Valuation_and_Quali

Schedule V - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2013
Valuation and Qualifying Accounts [Abstract]	'
Schedule V - Valuation and Qualifying Accounts	'
	Schedule V

	W. R. Berkley Corporation and Subsidiaries
	Valuation and Qualifying Accounts
	Years ended December 31, 2013, 2012 and 2011



	(In thousands)	Opening		Additions-			Deduction-			Ending
		Balance		Charged to			Amounts			Balance
				Expense			Written Off
	Year ended December 31, 2013:

	Premiums and fees receivable	$	22,919	$	3,133		$	(5,101	)	$	20,951

	Due from reinsurers	1,680		186			(481		)	1,385

	Loan loss reserves	5,620		308			(3,841		)	2,087

	Total	$	30,219	$	3,627		$	(9,423	)	$	24,423

	Year ended December 31, 2012:

	Premiums and fees receivable	$	17,666	$	9,598		$	(4,345	)	$	22,919

	Due from reinsurers	3,169		22			(1,511		)	1,680

	Deferred federal and foreign income taxes	—		—			—			—

	Loan loss reserves	19,805		(13,723		)	(462		)	5,620

	Total	$	40,640	$	(4,103	)	$	(6,318	)	$	30,219

	Year ended December 31, 2011:

	Premiums and fees receivable	$	19,483	$	6,158		$	(7,975	)	$	17,666

	Due from reinsurers	3,098		71			—			3,169

	Deferred federal and foreign income taxes	2,328		—			(2,328		)	—

	Loan loss reserves	19,675		889			(759		)	19,805

	Total	$	44,584	$	7,118		$	(11,062	)	$	40,640


	See accompanying Report of Independent Registered Public Accounting Firm.

Schedule_VI_Supplementary_Info

Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2013
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]	'
Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations	'
	Schedule VI

	W. R. Berkley Corporation and Subsidiaries
	Supplementary Information Concerning Property-Casualty Insurance Operations
	Years Ended December 31, 2013, 2012 and 2011



	(In thousands)	2013			2012			2011
	Deferred policy acquisition costs	$	452,101		$	404,047		$	364,937

	Reserves for losses and loss expenses	10,080,941			9,751,086			9,337,134

	Unearned premium	2,781,437			2,474,847			2,189,575

	Net premiums earned	5,226,537			4,673,516			4,160,867

	Net investment income	544,291			586,763			526,351

	Losses and loss expenses incurred:
	Current year	3,221,393			2,997,995			2,791,860

	Prior years	(78,810		)	(102,571		)	(181,282		)
	Loss reserve discount accretion	54,441			53,055			47,787

	Amortization of deferred policy acquisition costs	991,070			917,583			785,118

	Paid losses and loss expenses	2,878,071			2,708,935			2,486,998

	Net premiums written	5,500,173			4,898,539			4,357,368


	See accompanying Report of Independent Registered Public Accounting Firm.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2013
Accounting Policies [Abstract]	'
Principles of consolidation and basis of presentation	'
	Principles of consolidation and basis of presentation

	The consolidated financial statements, which include the accounts of W. R. Berkley Corporation and its subsidiaries (the "Company"), have been prepared on the basis of U.S. generally accepted accounting principles ("GAAP"). All significant intercompany transactions and balances have been eliminated. Reclassifications have been made in the 2012 and 2011 financial statements to conform to the presentation of the 2013 financial statements. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the revenues and expenses reflected during the reporting period. The most significant items on our balance sheet that involve a greater degree of accounting estimates that are subject to change in the future are the valuation of investments, other-than-temporary impairments, loss and loss adjustment expense reserves and premium estimates. Actual results could differ from those estimates.
Revenue recognition	'
	Revenue recognition

	Insurance premiums are recognized as written at the inception of the policy. Reinsurance premiums are estimated based upon information received from ceding companies, and subsequent differences from such estimates are recorded in the period they are determined. Insurance and reinsurance premiums are primarily earned on a pro rata basis over the policy term. Fees for services are earned over the period that the services are provided.

	Audit premiums are recognized when they are reliably determinable. The change in accruals for earned but unbilled audit premiums increased net premiums written and premiums earned by $12 million, $7 million and $1 million in 2013, 2012 and 2011, respectively.

	Revenues from wholly-owned investees are derived from services provided to the general aviation market, including fuel and line service, aircraft sales and maintenance, avionics and engineering services and parts fabrication. Revenue is recognized upon delivery of aircraft, delivery of fuel, shipment of parts and upon completion of services.
Cash and cash equivalents	'
	Cash and cash equivalents

	Cash equivalents consist of funds invested in money market accounts and investments with an effective maturity of three months or less when purchased.
Investments	'
	Investments

	Fixed maturity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity. Fixed maturity securities that the Company has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Investment income from fixed maturity securities is recognized based on the constant effective yield method. Premiums and discounts on mortgage-backed securities are adjusted for the effects of actual and anticipated prepayments on a retrospective basis.

	Equity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity.

	Equity securities that the Company purchased with the intent to sell in the near-term are classified as trading account securities and are reported at estimated fair value. Realized and unrealized gains and losses from trading activity are reported as net investment income and are recorded at the trade date. Short sales and short call options are presented as trading securities sold but not yet purchased. Unsettled trades and the net margin balances held by the clearing broker are presented as a trading account receivable from brokers and clearing organizations.


	Investment funds are carried under the equity method of accounting. For certain investment funds, the Company's share of the earnings or losses is reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.

	Loans receivable represent commercial real estate mortgage loans and bank loans and are carried at amortized cost. The Company monitors the performance of its loans receivable and establishes an allowance for loan losses for loans where the Company determines it is probable that the contractual terms will not be met, with a corresponding charge to earnings. For loans that are evaluated individually and deemed to be impaired, the Company establishes a specific allowance based on a discounted cash flow analysis and comparable cost and sales methodologies, if appropriate. Individual loans that are not considered impaired and smaller-balance homogeneous loans are evaluated collectively and a general allowance is established if it is considered probable that a loss has been incurred.

	The accrual of interest on loans receivable is discontinued if the loan is 90 days past due based on the contractual terms of the loan unless the loan is adequately secured and in process of collection. In general, loans are placed on non-accrual status or charged off at an earlier date if collection of principal or interest is considered doubtful. Interest on these loans is accounted for on a cash basis until qualifying for return to accrual status. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured.

	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.” Fair value of investments is determined based on a fair value hierarchy that prioritizes the use of observable inputs over the use of unobservable inputs and requires the use of observable inputs when available. (See Note 13 of the Notes to Consolidated Financial Statements.)

	Realized gains or losses represent the difference between the cost of securities sold and the proceeds realized upon sale and are recorded at the trade date. The Company uses primarily the first-in, first-out method to determine the cost of securities sold.

	The cost of securities is adjusted where appropriate to include a provision for a decline in value which is considered to be other than temporary. An other-than-temporary decline is considered to occur in investments where there has been a sustained reduction in fair value and where the Company does not expect to recover the cost basis of the investment prior to the time of sale or maturity. Since equity securities do not have a contractual cash flow or a maturity, the Company considers whether the price of an equity security is expected to recover within a reasonable period of time.

	For fixed maturity securities that the Company intends to sell or, more likely than not, would be required to sell, a decline in value below amortized cost is considered to be an other-than-temporary impairment (“OTTI”). The amount of OTTI is equal to the difference between amortized cost and fair value at the balance sheet date. For fixed maturity securities that the Company does not intend to sell or believes that it is more likely than not it would not be required to sell, a decline in value below amortized cost is considered to be an OTTI if the Company does not expect to recover the entire amortized cost basis of a security (i.e., the present value of cash flows expected to be collected is less than the amortized cost basis of the security). The portion of the decline in value considered to be a credit loss (i.e., the difference between the present value of cash flows expected to be collected and the amortized cost basis of the security) is recognized in earnings. The portion of the decline in value not considered to be a credit loss (i.e., the difference in the present value of cash flows expected to be collected and the fair value of the security) is recognized in other comprehensive income.
	Impairment assessments for structured securities, including mortgage-backed securities and asset-backed securities, collateralized debt obligations and corporate debt, are generally evaluated based on the performance of the underlying collateral under various economic and default scenarios that may involve subjective judgments and estimates by management. Modeling these securities involves various factors, such as projected default rates, the nature and realizable value of the collateral, if any, the ability of the issuer to make scheduled payments, historical performance and other relevant economic and performance factors. If an OTTI determination is made, a discounted cash flow analysis is used to ascertain the amount of the credit impairment.
	Real estate held for investment purposes is initially recorded at the purchase price, which is generally fair value, and is subsequently reported at cost less accumulated depreciation. Real estate taxes, interest and other costs incurred during development and construction are capitalized. Buildings are depreciated on a straight-line basis over the estimated useful lives of the building. Minimum rental income is recognized on a straight-line basis over the lease term. Income and expenses from real estate are reported as net investment income. The carrying value of real estate is reviewed for impairment and an impairment loss is recognized if the estimated undiscounted cash flows from the use and disposition of the property are less than the carrying value of the property.
Per share data	'
	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 weighted average number of common shares outstanding during the year. Diluted EPS is based upon the weighted average number of common and common equivalent shares outstanding during the year 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. Stock options for which the exercise price exceeds the average market price over the period have an anti-dilutive effect on EPS and, accordingly, are excluded from the calculation.
Deferred policy acquisition costs	'
	Deferred policy acquisition costs

	Acquisition costs associated with the successful acquisition of new and renewed insurance and reinsurance contracts are deferred and amortized ratably over the terms of the related contracts. Ceding commissions received on reinsurance contracts are netted against acquisition costs and are recognized ratably over the life of the contract. Deferred policy acquisition costs are presented net of unearned ceding commissions. Deferred policy acquisition costs are comprised primarily of commissions, as well as employment-related underwriting costs and premium taxes. Deferred policy acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. The recoverability of deferred policy acquisition costs is evaluated separately by each of our operating companies for each of their major lines of business. Future investment income is taken into account in measuring the recoverability of deferred policy acquisition costs.
Reserves for losses and loss expenses	'
	Reserves for losses and loss expenses

	Reserves for losses and loss expenses are an accumulation of amounts determined on the basis of (1) evaluation of claims for business written directly by the Company; (2) estimates received from other companies for reinsurance assumed by the Company; and (3) estimates for losses incurred but not reported (based on Company and industry experience). These estimates are periodically reviewed and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments are reflected in the statements of income in the period in which they are determined. The Company discounts its reserves for excess and assumed workers' compensation claims using a risk-free or statutory rate.
Reinsurance ceded	'
	Reinsurance ceded

	The unearned portion of premiums ceded to reinsurers is reported as prepaid reinsurance premiums and earned ratably over the policy term. The estimated amounts of reinsurance recoverable on unpaid losses are reported as due from reinsurers. To the extent any reinsurer does not meet its obligations under reinsurance agreements, the Company must discharge its liability. Amounts due from reinsurers are reflected net of funds held where the right of offset is present. The Company has provided reserves for estimated uncollectible reinsurance.
Deposit accounting	'
	Deposit accounting

	Contracts that do not meet the risk transfer requirements of GAAP are accounted for using the deposit accounting method. Under this method, an asset or liability is recognized at the inception of the contract based on consideration paid or received. The amount of the deposit asset or liability is adjusted at subsequent reporting dates using the interest method with a corresponding credit or charge to interest income or expense.
Federal and foreign income taxes	'
	Federal and foreign income taxes

	The Company files a consolidated income tax return in the U.S. and foreign tax returns in countries where it has overseas operations. The Company's method of accounting for income taxes is the asset and liability method. Under this method, deferred tax assets and liabilities are measured using tax rates currently in effect or expected to apply in the years in which those temporary differences are expected to reverse. Interest and penalties, if any, are reported as income tax expense. The Company believes there are no tax positions that would require disclosure under GAAP. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized.
Foreign currency	'
	Foreign currency

	Gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the entity's functional currency) are reported on the statements of income as other operating costs and expenses. Unrealized gains or losses resulting from translating the results of non-U.S. dollar denominated operations are reported in accumulated other comprehensive income. Revenues and expenses denominated in currencies other than U.S. dollars are translated at the weighted average exchange rate during the year. Assets and liabilities are translated at the rate of exchange in effect at the balance sheet date.
Property, furniture and equipment	'
	Property, furniture and equipment

	Property, furniture and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the estimated useful lives of the respective assets.
Comprehensive income	'
	Comprehensive income

	Comprehensive income encompasses all changes in stockholders' equity (except those arising from transactions with stockholders) and includes net income, net unrealized holding gains or losses on available for sale securities, unrealized foreign currency translation adjustments and changes in unrecognized pension obligations.
Goodwill and other intangible assets	'
	Goodwill and other intangible assets

	Goodwill and other intangible assets are tested for impairment on an annual basis and at interim periods where circumstances require.
Stock options	'
	Stock options

	The costs resulting from all share-based payment transactions with employees are recognized in the consolidated financial statements using a fair-value-based measurement method.
Recent accounting pronouncements	'
	Recent accounting pronouncements

	In February 2013, the Financial Accounting Standards Board (FASB) issued guidance relating to disclosures about items reclassified out of accumulated other comprehensive income ("AOCI"). The Company’s adoption of the updated guidance effective January 1, 2013 resulted in a change in the disclosures for AOCI in the Company’s consolidated financial statements but did not have any impact on the Company’s results of operations, financial position or liquidity.

	In January 2014, the FASB issued ASU 2014-01 relating to Accounting for Investments in Qualified Affordable Housing Projects. The guidance must be applied retrospectively for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. Early adoption is permitted and can be applied retrospectively in reporting periods for which financial statements have not yet been issued. The Company is currently evaluating the impact of this guidance on the Company’s results of operations, financial position and liquidity, which is not expected to be material.

	All other 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.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	'
	A summary of the impact of the adoption of this new guidance is shown below:


	(In thousands, except per share amounts)	Previously Reported			As Adjusted
	For the Year Ended December 31, 2011
	Other operating costs and expenses	$	1,621,329		$	1,626,526

	Income before income taxes	518,283			513,086

	Federal and foreign income taxes	(123,550		)	(121,945		)
	Net income	394,803			391,211


	Basic net income per share	$	2.83		$	2.8

	Diluted net income per share	2.71			2.69

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Schedule of estimated 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)	2013			2012
	Fixed maturity securities	$	—		$	3,213

	Real estate	—			256,209

	Cash and cash equivalents	3,911			12,172

	Real estate, furniture and equipment	898			—

	Goodwill	19,664			251

	Intangible assets	44,800			—

	Other assets	60,661			6,566

	Total assets acquired	129,934			278,411

	Debt	(27,612		)	—

	Other liabilities assumed	(17,076		)	(4,247		)
	Net assets acquired	$	85,246		$	274,164

Consolidated_Statement_of_Comp1

Consolidated Statement of Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Components of Changes in Accumulated Other Comprehensive Income (Loss) (AOCI)	'
	The following table presents the components of the changes in accumulated other comprehensive income (loss) (AOCI) as of and for the year ended December 31, 2013:


	(In thousands)	Unrealized Investment gains (losses)				Currency translation adjustments			Net pension asset				Accumulated other comprehensive income (loss)
	Changes in AOCI
	Beginning of period	$	517,658			(36,676		)	(15,351		)		$	465,631

	Other comprehensive income (loss) before reclassifications	(193,188		)		(23,848		)	—				(217,036		)

	Amounts reclassified from AOCI	(67,876		)		—			8,700				(59,176		)

	Other comprehensive income (loss)	(261,064		)		(23,848		)	8,700				(276,212		)

	Unrealized investment gain related to non-controlling interest	(28		)		—			—				(28		)

	Ending balance	$	256,566			$	(60,524	)	$	(6,651	)		$	189,391

	Amounts reclassified from AOCI
	Pre-tax	(104,425		)	-1	—			13,387			-3	$	(91,038	)

	Tax effect	36,549			-2	—			(4,687		)	-2	31,862

	After-tax amounts reclassified	$	(67,876	)		$	—		$	8,700			$	(59,176	)

	Other comprehensive income (loss)
	Pre-tax	(401,637		)		(23,848		)	13,387				$	(412,098	)

	Tax effect	140,573				—			(4,687		)		135,886

	Other comprehensive income (loss)	$	(261,064	)		$	(23,848	)	$	8,700			$	(276,212	)

	_______________
	(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 income.

Investments_In_Fixed_Maturity_1

Investments In Fixed Maturity Securities (Tables) (Debt Securities)	12 Months Ended
	Dec. 31, 2012
Debt Securities	'
Schedule of Marketable Securities [Line Items]	'
Investments In Fixed Maturity Securities	'
	At December 31, 2013 and 2012, investments in fixed maturity securities were as follows:


	(In thousands)	Amortized			Gross			Gross				Fair			Carrying
		Cost			Unrealized			Unrealized				Value			Value
					Gains			Losses
	December 31, 2013

	Held to maturity:

	State and municipal	$	68,929		$	11,172		$	—			$	80,101		$	68,929

	Residential mortgage-backed securities	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 government	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 investment in fixed maturity securities	$	11,291,631		$	451,247		$	(111,134	)		$	11,631,744		$	11,616,844



	December 31, 2012

	Held to maturity:

	State and municipal	$	65,190		$	18,529		$	—			$	83,719		$	65,190

	Residential mortgage-backed securities	32,764			5,286			—				38,050			32,764

	Corporate	4,997			605			—				5,602			4,997

	Total held to maturity	102,951			24,420			—				127,371			102,951

	Available for sale:

	U.S. government and government agency	827,591			72,532			(1,660		)		898,463			898,463

	State and municipal	4,449,238			328,974			(9,693		)		4,768,519			4,768,519

	Mortgage-backed securities:

	Residential(1)	1,395,739			53,846			(7,456		)		1,442,129			1,442,129

	Commercial	268,671			5,641			(744		)		273,568			273,568

	Corporate	3,378,884			235,289			(12,525		)		3,601,648			3,601,648

Foreign government	794,880			62,380			(582		)		856,678			856,678

Total available for sale	11,115,003			758,662			(32,660		)		11,841,005			11,841,005

Total investment in fixed maturity securities	$	11,217,954		$	783,082		$	(32,660	)		$	11,968,376		$	11,943,956

_______________________________________

-1	Gross unrealized losses for mortgage-backed securities include $1,961,247 and $3,037,000, as of December 31, 2013 and 2012, respectively, related to the non-credit portion of OTTI recognized in other comprehensive income.
The Amortized Cost And Fair Value of Fixed Maturity Securities	'
	The amortized cost and fair value of fixed maturity securities at December 31, 2013, 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	$	926,865		$	935,322

	Due after one year through five years	3,411,033			3,548,043

	Due after five years through ten years	3,046,756			3,191,387

	Due after ten years	2,554,437			2,596,505

	Mortgage-backed securities	1,352,540			1,360,487

	Total	$	11,291,631		$	11,631,744

Investments_In_Equity_Securiti1

Investments In Equity Securities Available For Sale (Tables) (Equity securities available for sale)	12 Months Ended
	Dec. 31, 2012
Equity securities available for sale	'
Schedule of Available-for-sale Securities [Line Items]	'
Schedule of Investments in Equity Securities	'
	At December 31, 2013 and 2012, investments in equity securities available for sale were as follows:


	(In thousands)	Cost		Gross		Gross			Fair		Carrying
				Unrealized		Unrealized			Value		Value
				Gains		Losses
	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


	December 31, 2012

	Common stocks	$	222,671	$	60,102	$	(707	)	$	282,066	$	282,066

	Preferred stocks	85,504		10,103		(1,651		)	93,956		93,956

	Total	$	308,175	$	70,205	$	(2,358	)	$	376,022	$	376,022

Net_Investment_Income_Tables

Net Investment Income (Tables)	12 Months Ended
	Dec. 31, 2013
Net Investment Income [Abstract]	'
Net Investment Income	'
	Net investment income consists of the following:


	(In thousands)	2013			2012			2011
	Investment income earned on:

	Fixed maturity securities, including cash and cash equivalents and loans receivable	$	442,287		$	479,035		$	483,905

	Equity securities available for sale	11,380			16,419			12,416

	Investment funds	67,712			77,015			9,452

	Arbitrage trading account	20,431			8,286			16,576

	Real estate	12,498			12,097			7,471

	Gross investment income	554,308			592,852			529,820

	Investment expense	(10,017		)	(6,089		)	(3,469		)
	Net investment income	$	544,291		$	586,763		$	526,351

Investment_Funds_Tables

Investment Funds (Tables)	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Schedule of Investment Funds	'
	Investment funds consist of the following:


		Carrying Value				Income (Losses)
		as of December 31,
	(In thousands)	2013		2012		2013		2012		2011
	Real estate	$	378,435	$	373,259	$	9,315	$	30,196	$	14,527

	Energy	155,026		146,325		29,739		33,146		(6,101		)

	Hedged equity	271,575		63,920		7,655		5,912		(1,366		)

	Other funds	262,459		226,185		21,003		7,761		2,392

	Total	$	1,067,495	$	809,689	$	67,712	$	77,015	$	9,452

Real_Estate_Tables

Real Estate (Tables)	12 Months Ended
	Dec. 31, 2013
Real Estate [Abstract]	'
Schedule of real estate properties	'
	Investment in real estate represents directly owned property held for investment, as follows:


		As of December 31,
	(In thousands)	2013		2012
	Properties in operation	$	283,393	$	282,899

	Properties under development	431,849		323,836

	Total	$	715,242	$	606,735

Loans_Receivable_Tables

Loans Receivable (Tables)	12 Months Ended
	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]	'
Schedule of Loans Receivable	'
	Loans receivable are as follows:


		As of December 31,
	(In thousands)	2013		2012
	Amortized cost:
	Real estate loans	$	282,357	$	336,533

	Commercial loans	61,226		65,428

	Total	$	343,583	$	401,961


	Fair value:
	Real estate loans	$	284,017	$	339,079

	Commercial loans	62,729		67,364

	Total	$	346,746	$	406,443


	Valuation allowance:
	Specific	$	—	$	3,000

	General	2,087		2,620

	Total	$	2,087	$	5,620


	Impaired loans:
	With a specific valuation allowance	$	—	$	1,775

	Without a valuation allowance	—		31,023

	Unpaid principal balance	—		35,872


		For the Year Ended December 31,
		2013		2012
	Increase (decrease) in valuation allowance	$	308	$	(14,118	)

	Loans receivable charged off	—		463

Realized_And_Unrealized_Invest1

Realized And Unrealized Investment Gains and Losses (Tables)	12 Months Ended
	Dec. 31, 2013
Realized and Unrealized Investment Gains (Losses) [Abstract]	'
Realized and Unrealized Investment Gains (Losses)	'
	Realized and unrealized investment gains and losses are as follows:


	(In thousands)	2013			2012			2011
	Realized investment gains and losses:

	Fixed maturity securities:

	Gains	$	48,860		$	34,295		$	37,595

	Losses	(14,670		)	(6,436		)	(5,499		)
	Equity securities available for sale	70,235			97,300			90,023

	Investment funds	10,976			74,777			3,762

	Other gains	12,185			1,515			—

	Net realized gains on investments sales	127,586			201,451			125,881


	Net other-than-temporary impairments:
	Other-than-temporary impairments	(6,042		)	(4,984		)	(400		)
	Decrease in valuation allowance	—			13,998			—

	Net other-than-temporary impairments	(6,042		)	9,014			(400		)


	Total net investment gains	121,544			210,465			125,481

	Income tax expense	(47,426		)	(73,663		)	(43,834		)
		$	74,118		$	136,802		$	81,647

Change In Unrealized Gains (Losses)	'


	Change in unrealized gains and losses of available for sales securities:

	Fixed maturity securities	$	(401,812	)	$	162,220		$	209,467

	Previously impaired fixed maturity securities	1,076			4,631			(3,604		)

	Equity securities available for sale	11,864			(33,199		)	(55,772		)

	Investment funds	(10,250		)	1,630			(2,093		)

	Total change in unrealized gains	(399,122		)	135,282			147,998

	Income tax expense	138,058			(47,966		)	(52,381		)

	Noncontrolling interests	(28		)	(77		)	55

		$	(261,092	)	$	87,239		$	95,672

Securities_In_An_Unrealized_Lo1

Securities In An Unrealized Loss Position (Tables)	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Securities In An Unrealized Loss Position	'
	The following table summarizes all securities in an unrealized loss position at December 31, 2013 and 2012 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			Gross			Fair		Gross		Fair		Gross
		Value			Unrealized			Value		Unrealized		Value		Unrealized
					Losses					Losses				Losses
	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 government	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 available for sale	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


	December 31, 2012

	U.S. government and government agency	$	69,551		$	1,660		$	—	$	—	$	69,551	$	1,660

	State and municipal	152,694			1,639			135,967		8,054		288,661		9,693

	Mortgage-backed securities	484,731			3,629			58,292		4,571		543,023		8,200

	Corporate	398,595			3,406			70,537		9,119		469,132		12,525

	Foreign government	68,809			554			11,210		28		80,019		582

	Fixed maturity securities	1,174,380			10,888			276,006		21,772		1,450,386		32,660

	Common stocks	46,725			707			—		—		46,725		707

	Preferred stocks	—			—			39,812		1,651		39,812		1,651

	Equity securities available for sale	46,725			707			39,812		1,651		86,537		2,358

	Total	$	1,221,105		$	11,595		$	315,818	$	23,423	$	1,536,923	$	35,018

Non-Investment Grade Fixed Maturity Securities	'
	A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at December 31, 2013 is presented in the table below:


	(Dollars in thousands)	Number of		Aggregate			Gross
		Securities		Fair Value			Unrealized
							Loss
	Mortgage-backed securities	13		$	66,658		$	3,748

	Corporate	9		31,579			1,005

	Foreign government	2		23,603			844

	Total	24		$	121,840		$	5,597

Roll-Forward Of Portion Of Impairments	'


	(In thousands)	2013			2012
	Beginning balance of amounts related to credit losses	$	4,261		$	4,261

	Additions for amounts related to credit losses	—			—

	Deductions for amounts related to credit loss sales	—			—

	Ending balance of amounts related to credit losses	$	4,261		$	4,261

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012 by level:


	(In thousands)	Total			Level 1				Level 2				Level 3
	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			$	—


	December 31, 2012

	Assets:

	Fixed maturity securities available for sale:

	U.S. government and government agency	$	898,463		$	—			$	898,463			$	—

	State and municipal	4,768,519			—				4,768,519				—

	Mortgage-backed securities	1,715,697			—				1,715,697				—

	Corporate	3,601,648			—				3,542,583				59,065

	Foreign government	856,678			—				856,678				—

	Total fixed maturity securities available for sale	11,841,005			—				11,781,940				59,065

	Equity securities available for sale:

	Common stocks	282,066			280,658				—				1,408

	Preferred stocks	93,956			—				93,335				621

Total equity securities available for sale	376,022			280,658				93,335				2,029

Arbitrage trading account	329,077			233,603				94,546				928

Total	$	12,546,104		$	514,261			$	11,969,821			$	62,022

Liabilities:

Securities sold but not yet purchased	$	121,487		$	114,909			$	6,558			$	20

Summarize Changes In Level 3 Assets and Liabilities	'
	The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2013 and 2012:


		Gains (Losses) Included in:
	(In thousands)	Beginning Balance			Earnings				Other Comprehensive Income				Purchases		Sales			Paydowns/Maturities			In		Out			Ending Balance
	Year ended December 31, 2013

	Assets:
	Fixed maturity securities 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		)	—			22		(1,329		)	1,780

	Total	$	62,022		$	1,836			$	1,039			$	4,424	$	(5,776	)	$	(12,604	)	$	22	$	(1,329	)	$	49,634

	Liabilities:
	Securities sold but not yet purchased	20			$	(4	)		—				$	4	$	(20	)	—			—		—			$	—


	Year ended December 31, 2012

	Fixed maturity securities available for sale:

	Corporate	$	67,828		$	(1,497	)		$	9,622			$	283	$	—		$	(17,171	)	$	—	$	—		$	59,065

	Total	67,828			(1,497		)		9,622				283		—			(17,171		)	—		—			59,065

	Equity securities available for sale:
	Common stocks	1,559			—				—				—		(151		)	—			—		—			1,408

	Preferred stocks	12,303			1,126				(1,737		)		—		(11,071		)	—			—		—			621

	Total	13,862			1,126				(1,737		)		—		(11,222		)	—			—		—			2,029

	Arbitrage trading account	851			(3,534		)		3,570				—		(52		)	—			93		—			928

	Total	$	82,541		$	(3,905	)		$	11,455			$	283	$	(11,274	)	$	(17,171	)	$	93	$	—		$	62,022

	Liabilities:
	Securities sold but not yet purchased	21			(1		)		$	—			—		—			$	—		$	—	$	—		$	20

Reserves_For_Losses_And_Loss_E1

Reserves For Losses And Loss Expenses (Tables)	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	'
	The table below provides a reconciliation of the beginning and ending reserve balances:


	(In thousands)	2013			2012			2011
	Net reserves at beginning of year	$	8,411,851		$	8,172,112		$	7,999,521

	Net provision for losses and loss expenses:

	Claims occuring during the current year(1)	3,221,393			2,997,995			2,791,860

	Decrease in estimates for claims occurring in prior years(2)(3)	(78,810		)	(102,571		)	(181,282		)
	Loss reserve discount accretion	54,441			53,055			47,787

	Total	3,197,024			2,948,479			2,658,365

	Net payments for claims:

	Current year	822,787			698,834			765,440

	Prior year	2,055,284			2,010,101			1,721,558

	Total	2,878,071			2,708,935			2,486,998

	Foreign currency translation	(47,007		)	195			1,224

	Net reserves at end of year	8,683,797			8,411,851			8,172,112

	Ceded reserve at end of year	1,397,144			1,339,235			1,165,022

	Gross reserves at end of year	$	10,080,941		$	9,751,086		$	9,337,134

	_______________________________________

	-1	Claims occurring during the current year are net of loss reserve discounts of $22,680,000, $26,078,000 and $43,286,000 in 2013, 2012 and 2011, respectively.

	-2	The decrease in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years decreased by $77,430,000, $100,667,000 and $182,937,000 in 2013, 2012 and 2011, respectively.

	-3	For certain retrospectively rated insurance polices and reinsurance agreements, reserve development is offset by additional or return premiums. Favorable reserve development, net of additional and return premiums, was $98 million, $103 million and $182 million in 2013, 2012 and 2011, respectively.

Reinsurance_Tables

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2013
Reinsurance Disclosures [Abstract]	'
Reinsurance Financial Information	'
	The following is a summary of reinsurance financial information:


	(In thousands)	2013			2012			2011
	Written premiums:

	Direct	$	5,626,172		$	4,964,069		$	4,370,092

	Assumed	884,919			815,810			707,221

	Ceded	(1,010,918		)	(881,340		)	(719,945		)
	Total net written premiums	$	5,500,173		$	4,898,539		$	4,357,368


	Earned premiums:

	Direct	$	5,328,955		$	4,723,882		$	4,164,277

	Assumed	857,119			770,981			669,593

	Ceded	(959,537		)	(821,347		)	(673,003		)
	Total net earned premiums	$	5,226,537		$	4,673,516		$	4,160,867


	Ceded losses incurred	$	556,108		$	528,018		$	458,249

Schedule of Ceded Credit Risk by Reinsurer	'
	The following table presents the amounts due from reinsurers as of December 31, 2013:


	(In thousands)
	Munich Re	$	193,405

	Lloyd’s of London	117,059

	Swiss Re	104,096

	Alleghany Group	96,348

	Partner Re	67,116

	Axis Capital	65,580

	Berkshire Hathaway	53,118

	Ace Group	46,413

	Hannover Re Group	35,607

	Everest Re	29,253

	Arch Capital Group	25,782

	Other reinsurers less than $20,000	230,825

	Subtotal	1,064,602

	Residual market pools	468,501

	Total	$	1,533,103

Senior_Notes_And_Other_Debt_Ta

Senior Notes And Other Debt (Tables) (Senior Notes and Other Debt)	12 Months Ended
	Dec. 31, 2013
Senior Notes and Other Debt	'
Debt Instrument [Line Items]	'
Schedule of Debt	'
	Senior notes and other debt consist of the following as of December 31, 2013 (the difference between the face value and the carrying value is unamortized discount):


	(In thousands)	Interest Rate	Face Value		2013 Carrying Value		2012 Carrying Value
	Senior notes due on:

	15-Feb-13		$	—	$	—	$	199,959

	May 15, 2015	5.60%	200,000		199,744		199,559

	August 15, 2019	6.15%	150,000		149,199		149,057

	September 15, 2019	7.38%	300,000		298,546		298,292

	September 15, 2020	5.38%	300,000		297,738		297,401

	January 1, 2022	8.70%	76,503		76,004		75,962

	15-Mar-22	4.63%	350,000		346,581		346,163

	February 15, 2037	6.25%	250,000		247,457		247,347

	Subsidiary debt (1)	Various	77,173		77,173		57,795

	Total debt		$	1,703,676	$	1,692,442	$	1,871,535

	_____________
	(1) Subsidiary debt is due as follows: $5 million in 2014, $40 million in 2015, $30 million in 2016 and $2 million thereafter.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit)	'
	Income tax expense consists of:


	(In thousands)	Current			Deferred			Total
		Expense			Expense
	31-Dec-13

	Domestic	$	116,802		$	47,370		$	164,172

	Foreign	22,362			7,053			29,415

	Total expense	$	139,164		$	54,423		$	193,587


	31-Dec-12

	Domestic	$	156,339		$	11,448		$	167,787

	Foreign	23,029			469			23,498

	Total expense	$	179,368		$	11,917		$	191,285


	31-Dec-11

	Domestic	$	60,420		$	37,176		$	97,596

	Foreign	22,011			2,338			24,349

	Total expense	$	82,431		$	39,514		$	121,945

Schedule of Effective Income Tax Rate Reconciliation	'
	A reconciliation of the income tax expense and the amounts computed by applying the Federal and foreign income tax rate of 35% to pre-tax income are as follows:


	(In thousands)	2013			2012			2011
	Computed “expected” tax expense	$	244,611		$	245,675		$	179,580

	Tax-exempt investment income	(40,679		)	(50,665		)	(57,246		)
	Change in valuation allowance	—			—			(2,328		)

	Impact of lower foreign tax rates	(4,851		)	(5,234		)	(3,199		)
	State and local taxes	2,906			(753		)	2,355

	Other, net	(8,400		)	2,262			2,783

	Total expense	$	193,587		$	191,285		$	121,945

Schedule of Deferred Tax Assets and Liabilities	'


	(In thousands)	2013			2012			2011
	Computed “expected” tax expense	$	244,611		$	245,675		$	179,580

	Tax-exempt investment income	(40,679		)	(50,665		)	(57,246		)
	Change in valuation allowance	—			—			(2,328		)

	Impact of lower foreign tax rates	(4,851		)	(5,234		)	(3,199		)
	State and local taxes	2,906			(753		)	2,355

	Other, net	(8,400		)	2,262			2,783

	Total expense	$	193,587		$	191,285		$	121,945

	At December 31, 2013 and 2012, the tax effects of differences that give rise to significant portions of the deferred tax asset and deferred tax liability are as follows:


	(In thousands)	2013			2012
	Deferred tax asset:

	Loss reserve discounting	$	87,394		$	119,547

	Unearned premiums	149,107			132,014

	Other-than-temporary impairments	49,483			62,187

	Restricted stock units	52,671			49,553

	Other	92,698			83,740

	Gross deferred tax asset	431,353			447,041

	Less valuation allowance	—			—

	Deferred tax asset	431,353			447,041

	Deferred tax liability:

	Amortization of intangibles	11,886			12,458

	Deferred policy acquisition costs	136,635			120,532

	Unrealized investment gains	148,215			274,497

	Other	114,497			99,809

	Deferred tax liability	411,233			507,296

	Net deferred tax asset (liability)	$	20,120		$	(60,255	)

Dividends_From_Subsidiaries_An1

Dividends From Subsidiaries And Statutory Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
Insurance [Abstract]	'
Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices	'
	BIC’s net income and statutory capital and surplus, as determined in accordance with statutory accounting practices (SAP), are as follows:



	(In thousands)	2013		2012		2011
	Net income	$	680,418	$	490,119	$	417,441

	Statutory capital and surplus	$	4,908,010	$	4,671,922	$	4,107,745

Common_Stockholders_Equity_Tab

Common Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share	'
	The weighted average number of shares used in the computation of net income per share was as follows:


		2013		2012		2011
	Basic	135,304,752		137,097,162		139,687,546

	Diluted	140,742,922		143,314,544		145,672,211

Schedule of Changes in Shares of Common Stock Outstanding	'
	Changes in shares of common stock outstanding, net of treasury shares, are presented below. Shares of common stock issued and outstanding do not include shares related to unissued restricted stock units and unexercised stock options.


		2013		2012	2011
	Balance, beginning of year	136,017,732		137,520,019	141,009,834

	Shares issued	139,790		2,114,168	2,702,303

	Shares repurchased	(3,924,355	)	-3,616,455	-6,192.12
	Balance, end of year	132,233,167		136,017,732	137,520,019

Recovered_Sheet1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Carrying Amounts and Estimated Fair Values of Financial Insruments	'
	The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2013 and 2012:


		2013				2012
	(In thousands)	Carrying Value		Fair Value		Carrying Value		Fair Value
	Assets:

	Fixed maturity securities	$	11,616,844	$	11,631,744	$	11,943,956	$	11,968,376

	Equity securities available for sale	283,338		283,338		376,022		376,022

	Arbitrage trading account	522,128		522,128		329,077		329,077

	Loans receivable	343,583		346,746		401,961		406,443

	Cash and cash equivalents	839,738		839,738		905,670		905,670

	Trading accounts receivable from brokers and clearing organizations	304,936		304,936		446,873		446,873

	Due from broker	17,735		17,735		14,449		14,449


	Liabilities:
	Trading account securities sold but not yet purchased	162,278		162,278		121,487		121,487

	Junior subordinated debentures	339,800		288,540		243,206		252,000

	Senior notes and other debt	1,692,442		1,861,898		1,871,535		2,190,173

Stock_Incentive_Plan_Tables

Stock Incentive Plan (Tables)	12 Months Ended
	Dec. 31, 2013												Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'												'
Schedule of Share-based Compensation, Stock Options, Activity	'												'
	The following table summarizes stock option information:



		2013					2012			2011
		Shares		Price(1)			Shares	Price(1)		Shares	Price(1)
	Outstanding at beginning of year	3,375		$	15.17		1,314,057	$	11.04	3,503,384	$	10.42

	Exercised	3,375		15.17			1,310,682	11.03		2,185,952	10.05

	Canceled	—		—			—	—		3,375	10.07

	Outstanding at year end	—		$	—		3,375	$	15.17	1,314,057	$	11.04

	_______________________________________

	-1	Weighted average exercise price.
Schedule of Nonvested Restricted Stock Units Activity	'												'
	The following table summarizes RSU information for the three years ended December 31, 2013:


		2013		2012		2011
	RSUs granted and unvested at beginning of period:	4,701,120		4,370,975		4,945,375

	Granted	108,400		2,161,220		107,500

	Vested	(146,250	)	(1,704,625	)	(576,050	)
	Cancelled	(171,750	)	(126,450	)	(105,850	)
	RSUs granted and unvested at end of period:	4,491,520		4,701,120		4,370,975

Schedule of Share-based Compensation, Unearned Compensation Related to RSU's	'												'
													The fair value of RSUs at the date of grant are recorded as unearned compensation, a component of stockholders’ equity, and expensed over the vesting period. Following is a summary of changes in unearned compensation for the three years ended December 31, 2013:


													(In thousands)	2013			2012			2011
													Unearned compensation at beginning of year	$	93,653		$	57,315		$	76,139

													RSUs granted, net of cancellations	4,406			73,255			2,832

													RSUs expensed	(22,881		)	(25,728		)	(26,303		)
													RSUs forfeiture adjustment	(1,973		)	(11,189		)	4,647

													Unearned compensation at end of year	$	73,205		$	93,653		$	57,315

Compensation_Plans_Tables

Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Compensation Related Costs [Abstract]	'
Long-Term Incentive Compensation Plan Expense	'
	The following table summarizes the LTIP expense for the three years ended December 31, 2013:


	(In thousands)	2013		2012		2011
	2008 grant	$	—	$	5,742	$	4,600

	2011 grant	6,741		7,365		5,620

	2013 grant	7,386		—		—

	Total	$	14,127	$	13,107	$	10,220

Retirement_Benefits_Tables

Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Schedule of Changes in Projected Benefit Obligations	'
	benefit obligation, which is required to be distributed on or before March 28, 2015, is as follows:


	(In thousands)	2013			2012
	Projected benefit obligation at beginning of year	$	64,632		$	56,787

	Interest cost	2,191			2,476

	Benefits paid	(285		)	(1,426		)
	Actuarial loss	(2,221		)	6,795

	Benefit obligation at end of year	$	64,317		$	64,632

Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	'
	Following is a summary of the amounts recognized in accumulated other comprehensive income as of December 31, 2013 and 2012:


	(In thousands)	2013			2012
	Net actuarial loss	$	4,242		$	14,605

	Prior service cost	5,988			9,012

	Net pension asset	$	10,230		$	23,617

Schedule of Net Benefit Costs	'
	The components of net periodic pension benefit cost are as follows:


	(In thousands)	2013			2012			2011
	Components of net periodic benefit cost:

	Interest cost	$	2,191		$	2,476		$	2,716

	Amortization of unrecognized:

	Prior service costs	3,023			3,023			3,023

	Net actuarial loss	8,143			2,197			1,330

	Net periodic pension cost	$	13,357		$	7,696		$	7,069

Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	'
	The changes in plan assets and projected benefit obligation recognized in other comprehensive income are as follows:


	(In thousands)	2013			2012
	Changes in plan assets and projected benefit obligation:

	Net actuarial (gain) loss	$	(2,221	)	$	6,795

	Amortization of:

	Net actuarial loss	(8,143		)	(2,197		)
	Prior service costs	(3,023		)	(3,023		)
	Total recognized in other comprehensive income	$	(13,387	)	$	1,575

Supplemental_Financial_Stateme1

Supplemental Financial Statement Information (Tables)	12 Months Ended
	Dec. 31, 2013
Other Income and Expenses [Abstract]	'
Schedule of Other Operating Cost and Expense, by Component	'
	Other operating costs and expenses consist of the following:


	(In thousands)	2013			2012			2011
	Amortization of deferred policy acquisition costs	$	991,070		$	917,583		$	785,118

	Other underwriting expenses	780,058			675,163			653,011

	Service company expenses	88,662			84,986			75,231

	Net foreign currency losses	(10,120		)	(6,092		)	(1,884		)
	Other costs and expenses	151,014			127,983			115,050

	Total	$	2,000,684		$	1,799,623		$	1,626,526

Industry_Segments_Tables

Industry Segments (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Financial Information Of Company Operating Segments	'
	Summary financial information about the Company’s operating segments is presented in the following table. Income (loss) before income taxes by segment includes allocated investment income. Identifiable assets by segment are those assets used in or allocated to the operation of each segment.


	Revenues
	(In thousands)	Earned		Investment		Other		Total		Pre-Tax			Net
		Premiums		Income						Income			Income
										(Loss)			(Loss)
	December 31, 2013:

	Insurance-Domestic	$	3,782,416	$	404,280	$	107,517	$	4,294,213	$	648,740		$	449,981

	Insurance-International	723,151		47,039		—		770,190		56,922			40,292

	Reinsurance-Global	720,970		89,090		—		810,060		110,425			78,013

	Corporate, other and eliminations(1)	—		3,882		408,645		412,527		(238,743		)	(142,479		)

	Net investment gains	—		—		121,544		121,544		121,544			74,118

	Consolidated	$	5,226,537	$	544,291	$	637,706	$	6,408,534	$	698,888		$	499,925


	December 31, 2012:
	Insurance-Domestic	$	3,417,022	$	424,787	$	103,133	$	3,944,942	$	578,500		$	397,942

	Insurance-International	631,841		45,796		—		677,637		51,639			35,928

	Reinsurance-Global	624,653		106,932		—		731,585		103,690			72,916

	Corporate, other and eliminations(1)	—		9,248		249,677		258,925		(242,366		)	(132,996		)

	Net investment gains	—		—		210,465		210,465		210,465			136,802

	Consolidated	$	4,673,516	$	586,763	$	563,275	$	5,823,554	$	701,928		$	510,592


	December 31, 2011:
	Insurance-Domestic	$	3,121,281	$	372,053	$	92,847	$	3,586,181	$	467,126		$	345,399

	Insurance-International	508,509		36,958		—		545,467		36,912			28,142

	Reinsurance-Global	531,077		97,795		—		628,872		85,271			66,405

	Corporate, other and eliminations(1)	—		19,545		250,438		269,983		(201,704		)	(130,382		)

	Net investment gains	—		—		125,481		125,481		125,481			81,647

	Consolidated	$	4,160,867	$	526,351	$	468,766	$	5,155,984	$	513,086		$	391,211

Identifiable Assets by Segments	'


	Identifiable Assets
	(In thousands)	31-Dec-13		31-Dec-12
	Insurance-Domestic	$	15,247,807	$	14,661,476

	Insurance-International	1,516,310		1,541,365

	Reinsurance-Global	3,103,193		3,337,937

	Corporate, other and eliminations(1)	684,486		615,118

	Consolidated	$	20,551,796	$	20,155,896

	_______________________________________

	-1	Corporate, other and eliminations represent corporate revenues and expenses and other items that are not allocated to business segments.
Net Premiums Earned By Major Line Of Business	'
	Net premiums earned by major line of business are as follows:


	(In thousands)	2013		2012		2011
	Insurance-Domestic

	Other liability	$	1,259,376	$	1,104,369	$	1,003,080

	Workers' compensation	995,047		869,042		785,454

	Short-tail lines	774,809		733,239		665,575

	Commercial automobile	486,759		455,988		437,891

	Professional liability	266,425		254,384		229,281

	Total Insurance-Domestic	3,782,416		3,417,022		3,121,281


	Insurance-International
	Other liability	65,528		44,065		49,800

	Workers' compensation	84,637		82,066		73,823

	Short-tail lines	336,814		276,599		183,447

	Commercial automobile	130,020		125,927		110,568

	Professional liability	106,152		103,184		90,871

	Total Insurance-International	723,151		631,841		508,509


	Reinsurance-Global
	Casualty	507,790		456,376		389,557

	Property	213,180		168,277		141,520

	Total Reinsurance-Global	720,970		624,653		531,077

	Total	$	5,226,537	$	4,673,516	$	4,160,867

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	The following is a summary of quarterly financial data:


	(In thousands. except per share data)	2013
	Three months ended	March 31		June 30		September 30		December 31
	Revenues	$	1,506,769	$	1,570,962	$	1,634,124	$	1,696,679

	Net income	116,615		115,957		136,974		130,379

	Net income per share(1)
	Basic	0.86		0.85		1.01		0.97

	Diluted	0.83		0.82		0.97		0.93



		2012
	Three months ended	March 31		June 30		September 30		December 31
	Revenues	$	1,378,705	$	1,415,747	$	1,420,501	$	1,608,601

	Net income	135,318		108,838		100,947		165,489

	Net income per share(1)
	Basic	0.98		0.79		0.74		1.22

	Diluted	0.94		0.76		0.71		1.17

	_______________________________________

	-1	Net income per share (“EPS”) in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Thus, the sum of the four quarters EPS does not necessarily equal the full-year EPS.

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]	'	'	'
Unbilled Audit Premiums	$12,000,000	$7,000,000	$1,000,000
Deposit contracts, liabilities	72,000,000	75,000,000	'
Depreciation	38,000,000	38,000,000	40,000,000
Goodwill and intangible asset impairment	0	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'	'
Interest payments	125,000,000	119,000,000	111,000,000
Income taxes paid	186,000,000	133,000,000	48,000,000
Other Assets	'	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'	'
Intangible assets, net (excluding goodwill)	$72,000,000	$31,000,000	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Recent accounting change) (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2009

Accounting Standards Update 2010-26 [Member]

Previously Reported

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Stockholders' Equity, Period Increase (Decrease)

$49,000,000

Other operating costs and expenses

2,000,684,000

1,799,623,000

1,626,526,000

1,621,329,000

Income before income taxes

698,888,000

701,928,000

513,086,000

518,283,000

Federal and foreign income taxes

-193,587,000

-191,285,000

-121,945,000

-123,550,000

Net income

$130,379,000

$136,974,000

$115,957,000

$116,615,000

$165,489,000

$100,947,000

$108,838,000

$135,318,000

$499,925,000

$510,592,000

$391,211,000

$394,803,000

Basic net income per share (dollars per share)

$0.97

[1]

$1.01

[1]

$0.85

[1]

$0.86

[1]

$1.22

[1]

$0.74

[1]

$0.79

[1]

$0.98

[1]

$3.69

$3.72

$2.80

$2.83

Diluted net income per share (dollars per share)

$0.93

[1]

$0.97

[1]

$0.82

[1]

$0.83

[1]

$1.17

[1]

$0.71

[1]

$0.76

[1]

$0.94

[1]

$3.55

$3.56

$2.69

$2.71

[1]

Net income per share (â€œEPSâ€) in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Thus, the sum of the four quarters EPS does not necessarily equal the full-year EPS.

Acquisitions_Details

Acquisitions (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Jan. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Worldwide Supplier of After-market (OEM) Parts [Member]

London Acquisition, Inactive insurance Company, and Worldwide Supplier of After-market (OEM) Parts [Member]

London Acquisition [Member]

Inactive Insurance Company [Member]

London Acquisition and Inactive Insurance Company [Member]

Minimum

Maximum

Worldwide Supplier of After-market (OEM) Parts [Member]

Business Acquisition [Line Items]

Business acquisition, cost of acquired entity, cash paid

$43,000,000

$251,000,000

$23,000,000

Business Acquisition, Percentage of Voting Interests Acquired

51.00%

49.00%

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

'2 years

'15 years

Indefinite-lived Intangible Assets Acquired

3,000,000

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]

Fixed maturity securities

3,213,000

Real estate

256,209,000

Cash and cash equivalents

3,911,000

12,172,000

Real estate, furniture and equipment

898,000

Goodwill

110,146,000

87,865,000

19,664,000

251,000

Intangible assets

44,800,000

2,000,000

Other assets

60,661,000

6,566,000

Total assets acquired

129,934,000

278,411,000

Debt

-27,612,000

Other liabilities assumed

-17,076,000

-4,247,000

Net assets acquired

$85,246,000

$274,164,000

Consolidated_Statement_of_Comp2

Consolidated Statement of Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Beginning of period	$465,631		'	'
Other comprehensive income	-276,212		110,857	78,233
Ending balance	189,391		465,631	'
Income before income taxes	698,888		701,928	513,086
Other operating costs and expenses	2,000,684		1,799,623	1,626,526
Federal and foreign income taxes	-193,587		-191,285	-121,945
Net income before noncontrolling interests	505,301		510,643	391,141
Unrealized investment gains, before tax	-401,637		'	'
Currency translation adjustments, before tax	-23,848		'	'
Net pension asset, before tax	13,387		-1,575	'
Other comprehensive income (loss), before tax	-412,098		'	'
Unrealized investment gains, tax	140,573		'	'
Currency translation adjustments, tax	0		'	'
Net pension asset, tax	-4,687		'	'
Other comprehensive income (loss), tax	135,886		'	'
Unrealized investment gains, net of tax	-261,064		'	'
Change in unrealized translation adjustments	-23,848		24,563	-18,751
Net pension asset, net of tax	8,700		'	'
Unrealized Investment gains (losses)	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Beginning of period	517,658		'	'
Other comprehensive income (loss) before reclassifications	-193,188		'	'
Amounts reclassified from AOCI	-67,876		'	'
Other comprehensive income	-261,064		'	'
Unrealized investment gain related to non-controlling interest	-28		'	'
Ending balance	256,566		'	'
Unrealized Investment gains (losses) \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Net investment gains	-104,425	[1]	'	'
Federal and foreign income taxes	36,549	[2]	'	'
Net income before noncontrolling interests	-67,876		'	'
Currency translation adjustments	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Beginning of period	-36,676		'	'
Other comprehensive income (loss) before reclassifications	-23,848		'	'
Amounts reclassified from AOCI	0		'	'
Other comprehensive income	-23,848		'	'
Ending balance	-60,524		-36,676	'
Change in unrealized translation adjustments	-23,848		24,563	-18,751
Currency translation adjustments \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Income before income taxes	0		'	'
Federal and foreign income taxes	0		'	'
Net income before noncontrolling interests	0		'	'
Net pension asset	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Beginning of period	-15,351		'	'
Other comprehensive income (loss) before reclassifications	0		'	'
Amounts reclassified from AOCI	8,700		'	'
Other comprehensive income	8,700		'	'
Ending balance	-6,651		'	'
Net pension asset \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Other operating costs and expenses	13,387	[3]	'	'
Federal and foreign income taxes	-4,687	[2]	'	'
Net income before noncontrolling interests	8,700		'	'
Accumulated other comprehensive income (loss)	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Beginning of period	465,631		'	'
Other comprehensive income (loss) before reclassifications	-217,036		'	'
Amounts reclassified from AOCI	-59,176		'	'
Other comprehensive income	-276,212		'	'
Unrealized investment gain related to non-controlling interest	-28		'	'
Ending balance	189,391		'	'
Accumulated other comprehensive income (loss) \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'		'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'	'
Income before income taxes	-91,038		'	'
Federal and foreign income taxes	31,862		'	'
Net income before noncontrolling interests	($59,176)		'	'

[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 income.

Recovered_Sheet2

Investments in Fixed Maturity Securities (Investments in Fixed Maturity Securities) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total held to maturity, Amortized Cost	$101,320,000		$102,951,000
Total held to maturity, Gross Unrealized Gains	14,900,000		24,420,000
Total held to maturity, Gross Unrealized Losses	0		0
Total held to maturity, Fair Value	116,220,000		127,371,000
Total held to maturity, Carrying Value	101,320,000		102,951,000
Total available for sale, Amortized Cost	11,190,311,000		11,115,003,000
Total available for sale, Gross Unrealized Gains	436,347,000		758,662,000
Total available for sale, Gross Unrealized Losses	-111,134,000		-32,660,000
Total available for sale, Fair Value	11,515,524,000		11,841,005,000
Total available for sale, Carrying Value	11,515,524,000		11,841,005,000
Total investment in fixed maturity securities, Amortized Cost	11,291,631,000		11,217,954,000
Total investments in fixed maturity securities, Gross Unrealized Gains	451,247,000		783,082,000
Total investments in fixed maturity securities, Gross Unrealized Losses	-111,134,000		-32,660,000
Total investments in fixed maturity securities, Fair Value	11,631,744,000		11,968,376,000
Total investments in fixed maturity securities, carrying value	11,616,844,000		11,943,956,000
U.S. government and government agency	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	858,319,000		827,591,000
Total available for sale, Gross Unrealized Gains	34,522,000		72,532,000
Total available for sale, Gross Unrealized Losses	-7,982,000		-1,660,000
Total available for sale, Fair Value	884,859,000		898,463,000
Total available for sale, Carrying Value	884,859,000		898,463,000
State and municipal	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	4,085,791,000		4,449,238,000
Total available for sale, Gross Unrealized Gains	162,330,000		328,974,000
Total available for sale, Gross Unrealized Losses	-29,837,000		-9,693,000
Total available for sale, Fair Value	4,218,284,000		4,768,519,000
Total available for sale, Carrying Value	4,218,284,000		4,768,519,000
Residential mortgage-backed securities	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	1,248,693,000	[1]	1,395,739,000	[1]
Total available for sale, Gross Unrealized Gains	25,895,000	[1]	53,846,000	[1]
Total available for sale, Gross Unrealized Losses	-25,941,000	[1]	-7,456,000	[1]
Total available for sale, Fair Value	1,248,647,000	[1]	1,442,129,000	[1]
Total available for sale, Carrying Value	1,248,647,000	[1]	1,442,129,000	[1]
Non-credit portion of other-than-temporary impairments ("OTTI")	1,961,247		3,037,000
Commercial	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	76,454,000		268,671,000
Total available for sale, Gross Unrealized Gains	5,670,000		5,641,000
Total available for sale, Gross Unrealized Losses	-988,000		-744,000
Total available for sale, Fair Value	81,136,000		273,568,000
Total available for sale, Carrying Value	81,136,000		273,568,000
Corporate	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	4,076,585,000		3,378,884,000
Total available for sale, Gross Unrealized Gains	156,256,000		235,289,000
Total available for sale, Gross Unrealized Losses	-30,100,000		-12,525,000
Total available for sale, Fair Value	4,202,741,000		3,601,648,000
Total available for sale, Carrying Value	4,202,741,000		3,601,648,000
Foreign government	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total available for sale, Amortized Cost	844,469,000		794,880,000
Total available for sale, Gross Unrealized Gains	51,674,000		62,380,000
Total available for sale, Gross Unrealized Losses	-16,286,000		-582,000
Total available for sale, Fair Value	879,857,000		856,678,000
Total available for sale, Carrying Value	879,857,000		856,678,000
State and municipal	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total held to maturity, Amortized Cost	68,929,000		65,190,000
Total held to maturity, Gross Unrealized Gains	11,172,000		18,529,000
Total held to maturity, Gross Unrealized Losses	0		0
Total held to maturity, Fair Value	80,101,000		83,719,000
Total held to maturity, Carrying Value	68,929,000		65,190,000
Residential mortgage-backed securities	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total held to maturity, Amortized Cost	27,393,000		32,764,000
Total held to maturity, Gross Unrealized Gains	3,311,000		5,286,000
Total held to maturity, Gross Unrealized Losses	0		0
Total held to maturity, Fair Value	30,704,000		38,050,000
Total held to maturity, Carrying Value	27,393,000		32,764,000
Corporate	'		'
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]	'		'
Total held to maturity, Amortized Cost	4,998,000		4,997,000
Total held to maturity, Gross Unrealized Gains	417,000		605,000
Total held to maturity, Gross Unrealized Losses	0		0
Total held to maturity, Fair Value	5,415,000		5,602,000
Total held to maturity, Carrying Value	$4,998,000		$4,997,000

[1]	Gross unrealized losses for mortgage-backed securities include $1,961,247 and $3,037,000, as of DecemberÂ 31, 2013 and 2012, respectively, related to the non-credit portion of OTTI recognized in other comprehensive income.

Recovered_Sheet3

Investments in Fixed Maturity Securities (The Amortized Cost and Fair Value of Fixed Maturity Securities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]	'	'
Amortized Cost, Due in one year or less	$926,865	'
Amortized Cost, Due after one year through five years	3,411,033	'
Amortized Cost, Due after five years through ten years	3,046,756	'
Amortized Cost, Due after ten years	2,554,437	'
Amortized Cost, Mortgage-backed securities	1,352,540	'
Total investment in fixed maturity securities, Amortized Cost	11,291,631	11,217,954
Fair Value, Due in one year or less	935,322	'
Fair Value, Due after one year through five years	3,548,043	'
Fair Value, Due after five years through ten years	3,191,387	'
Fair Value, Due after ten years	2,596,505	'
Fair Value, Mortgage-backed securities	1,360,487	'
Total investments in fixed maturity securities, Fair Value	$11,631,744	$11,968,376

Investments_in_Fixed_Maturity_2

Investments in Fixed Maturity Securities (Narrative) (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Minimum ownership of Common stockholders equity	10.00%
Investments on deposit in custodial or trust accounts, carrying value	$1,017
Assets on deposit with state insurance departments	745
Assets on deposit in support of underwriting activities	211
Funds on deposit as security for reinsurance clients	48
Funds on deposit as security for letters of credit issued in support of reinsurance operations	$13

Recovered_Sheet4

Investments in Equity Securities Available for Sale (Investments in Equity Securities Available for Sale) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	$203,627	$308,175
Gross Unrealized, Gains	86,030	70,205
Gross Unrealized, Losses	-6,319	-2,358
Carrying value and fair value of equity securities	283,338	376,022
Common stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	118,536	222,671
Gross Unrealized, Gains	42,239	60,102
Gross Unrealized, Losses	0	-707
Carrying value and fair value of equity securities	160,775	282,066
Preferred stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	85,091	85,504
Gross Unrealized, Gains	43,791	10,103
Gross Unrealized, Losses	-6,319	-1,651
Carrying value and fair value of equity securities	$122,563	$93,956

Arbitrage_Trading_Account_Deta

Arbitrage Trading Account (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Trading Securities and Derivative Instruments [Abstract]	'	'
Arbitrage trading account	$522,128,000	$329,077,000
Options Held \| Long	'	'
Derivative [Line Items]	'	'
Other derivatives not designated as hedging instruments at fair value, net	2,000,000	'
Derivative, notional amount	28,000,000	'
Options Held \| Short	'	'
Derivative [Line Items]	'	'
Other derivatives not designated as hedging instruments at fair value, net	2,000,000	'
Derivative, notional amount	$22,000,000	'

Net_Investment_Income_Net_Inve

Net Investment Income (Net Investment Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Investment Income [Line Items]	'	'	'
Gross investment income	$554,308	$592,852	$529,820
Investment expense	-10,017	-6,089	-3,469
Net investment income	544,291	586,763	526,351
Fixed maturity securities, including cash and cash equivalents and loans receivable	'	'	'
Net Investment Income [Line Items]	'	'	'
Gross investment income	442,287	479,035	483,905
Equity securities available for sale	'	'	'
Net Investment Income [Line Items]	'	'	'
Gross investment income	11,380	16,419	12,416
Investment funds	'	'	'
Net Investment Income [Line Items]	'	'	'
Gross investment income	67,712	77,015	9,452
Arbitrage trading account	'	'	'
Net Investment Income [Line Items]	'	'	'
Gross investment income	20,431	8,286	16,576
Real estate	'	'	'
Net Investment Income [Line Items]	'	'	'
Gross investment income	$12,498	$12,097	$7,471

Investment_Funds_Schedule_of_I

Investment Funds (Schedule of Investment Funds) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	$1,067,495	$809,689	'
Income (Losses)	67,712	77,015	9,452
Real estate	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	378,435	373,259	'
Income (Losses)	9,315	30,196	14,527
Energy	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	155,026	146,325	'
Income (Losses)	29,739	33,146	-6,101
Hedged equity	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	271,575	63,920	'
Income (Losses)	7,655	5,912	-1,366
Other funds	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Investment funds	262,459	226,185	'
Income (Losses)	$21,003	$7,761	$2,392

Real_Estate_Details

Real Estate (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Real Estate [Abstract]	'	'
Properties in operation	$283,393	$282,899
Properties under development	431,849	323,836
Total	$715,242	$606,735

Real_Estate_Narrative_Details

Real Estate (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate [Abstract]	'	'	'
Accumulated depreciation and amortization on properites	$17,827	$10,354	'
Depreciation	7,474	7,583	2,770
Lease future minimum payments 2014	1,504	'	'
Lease future minimum payments 2015	1,549	'	'
Lease future minimum payments 2016	1,596	'	'
Lease future minimum payments 2017	1,644	'	'
Lease future minimum payments 2018	1,693	'	'
Lease future minimum payments after 2018	$327,320	'	'

Loans_Receivable_Details

Loans Receivable (Details) (USD $)	12 Months Ended
Loans Receivable (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Loans Receivable [Line Items]	'	'
Loans and Leases Receivable, Gross	$343,583,000	$401,961,000
Loans receivable	346,746,000	406,443,000
Debt Instrument, Term	'10 years	'
Total loans receivable	343,583,000	401,961,000
Valuation allowance, Specific	0	3,000,000
Valuation allowance, General	2,087,000	2,620,000
Valuation allowance	2,087,000	5,620,000
Impaired loans, With a specific valuation allowance	0	1,775,000
Impaired loans, Without a valuation allowance	0	31,023,000
Impaired loans, Unpaid principal balance	0	35,872,000
Increase (decrease) in valuation allowance	308,000	-14,118,000
Loans receivable charged off	0	463,000
Loans in nonaccrual status	'	3,000,000
Interest lost on nonaccrual loans	'	0
Real Estate	'	'
Loans Receivable [Line Items]	'	'
Loans and Leases Receivable, Gross	282,357,000	336,533,000
Loans receivable	284,017,000	339,079,000
Commercial	'	'
Loans Receivable [Line Items]	'	'
Loans and Leases Receivable, Gross	61,226,000	65,428,000
Loans receivable	$62,729,000	$67,364,000

Recovered_Sheet5

Realized and Unrealized Investment Gains and Losses (Realized and Unrealized Investment Gains (Losses) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Realized and Unrealized Investment Gains (Losses) [Abstract]	'	'	'
Fixed maturity securities, Gains	$48,860	$34,295	$37,595
Fixed maturity securities, Losses	-14,670	-6,436	-5,499
Equity securities available for sale	70,235	97,300	90,023
Investment funds	10,976	74,777	3,762
Other gains	12,185	1,515	0
Net realized gains on investments sales	127,586	201,451	125,881
Other-than-temporary impairments	-6,042	-4,984	-400
Decrease in valuation allowance	0	13,998	0
Net other-than-temporary impairments	-6,042	9,014	-400
Net investment gains	121,544	210,465	125,481
Income tax expense	-47,426	-73,663	-43,834
Total after-tax investment gains	$74,118	$136,802	$81,647

Recovered_Sheet6

Realized and Unrealized Investment Gains and Losses (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'
Total change in unrealized gains (losses) before income taxes and noncontrolling interests	($399,122)	$135,282	$147,998
Income tax expense	138,058	-47,966	-52,381
Noncontrolling interests	-28	-77	55
Total change in unrealized gains and losses	-261,092	87,239	95,672
Debt Securities	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'
Total change in unrealized gains (losses) before income taxes and noncontrolling interests	-401,812	162,220	209,467
Debt Securities Previously Impaired	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'
Total change in unrealized gains (losses) before income taxes and noncontrolling interests	1,076	4,631	-3,604
Equity securities available for sale	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'
Total change in unrealized gains (losses) before income taxes and noncontrolling interests	11,864	-33,199	-55,772
Investment funds	'	'	'
Realized and Unrealized Investment Gains Losses [Line Items]	'	'	'
Total change in unrealized gains (losses) before income taxes and noncontrolling interests	($10,250)	$1,630	($2,093)

Recovered_Sheet7

Securities in an Unrealized Loss Position (Securities in an Unrealized Loss Position) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	$3,085,977	$1,221,105
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	84,259	11,595
Available-for-sale Securities, 12 Months or Greater, Fair Value	355,098	315,818
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	33,194	23,423
Available-for-sale Securities, Fair Value	3,441,075	1,536,923
Available For Sale Securities, Gross Unrealized Losses	117,453	35,018
U.S. government and government agency	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	260,882	69,551
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	7,927	1,660
Available-for-sale Securities, 12 Months or Greater, Fair Value	2,163	0
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	55	0
Available-for-sale Securities, Fair Value	263,045	69,551
Available For Sale Securities, Gross Unrealized Losses	7,982	1,660
State and municipal	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	899,613	152,694
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	24,503	1,639
Available-for-sale Securities, 12 Months or Greater, Fair Value	87,345	135,967
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	5,334	8,054
Available-for-sale Securities, Fair Value	986,958	288,661
Available For Sale Securities, Gross Unrealized Losses	29,837	9,693
Mortgage-backed securities	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	578,603	484,731
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	17,964	3,629
Available-for-sale Securities, 12 Months or Greater, Fair Value	140,648	58,292
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	8,965	4,571
Available-for-sale Securities, Fair Value	719,251	543,023
Available For Sale Securities, Gross Unrealized Losses	26,929	8,200
Corporate	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	1,013,373	398,595
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	17,066	3,406
Available-for-sale Securities, 12 Months or Greater, Fair Value	105,074	70,537
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	13,034	9,119
Available-for-sale Securities, Fair Value	1,118,447	469,132
Available For Sale Securities, Gross Unrealized Losses	30,100	12,525
Foreign government	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	320,215	68,809
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	16,286	554
Available-for-sale Securities, 12 Months or Greater, Fair Value	0	11,210
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	28
Available-for-sale Securities, Fair Value	320,215	80,019
Available For Sale Securities, Gross Unrealized Losses	16,286	582
Fixed maturity securities	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	3,072,686	1,174,380
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	83,746	10,888
Available-for-sale Securities, 12 Months or Greater, Fair Value	335,230	276,006
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	27,388	21,772
Available-for-sale Securities, Fair Value	3,407,916	1,450,386
Available For Sale Securities, Gross Unrealized Losses	111,134	32,660
Common stocks	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	0	46,725
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	707
Available-for-sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	0	46,725
Available For Sale Securities, Gross Unrealized Losses	0	707
Preferred stocks	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	13,291	0
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	513	0
Available-for-sale Securities, 12 Months or Greater, Fair Value	19,868	39,812
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	5,806	1,651
Available-for-sale Securities, Fair Value	33,159	39,812
Available For Sale Securities, Gross Unrealized Losses	6,319	1,651
Equity securities available for sale	'	'
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]	'	'
Available-for-sale Securities, Less Than 12 Months, Fair Value	13,291	46,725
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses	513	707
Available-for-sale Securities, 12 Months or Greater, Fair Value	19,868	39,812
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses	5,806	1,651
Available-for-sale Securities, Fair Value	33,159	86,537
Available For Sale Securities, Gross Unrealized Losses	$6,319	$2,358

Recovered_Sheet8

Securities in an Unrealized Loss Position (Non-Investment Grade Fixed Maturity Securities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate Fair Value	$3,441,075	$1,536,923
Mortgage-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate Fair Value	719,251	543,023
Corporate	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate Fair Value	1,118,447	469,132
Debt Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Aggregate Fair Value	3,407,916	1,450,386
Unrealized Loss Less than 5 Million \| Mortgage-backed securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number Of Securities	13	'
Aggregate Fair Value	66,658	'
Gross Unrealized Loss	3,748	'
Unrealized Loss Less than 5 Million \| Corporate	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number Of Securities	9	'
Aggregate Fair Value	31,579	'
Gross Unrealized Loss	1,005	'
Unrealized Loss Less than 5 Million \| State and Municipal	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number Of Securities	2	'
Aggregate Fair Value	23,603	'
Gross Unrealized Loss	844	'
Unrealized Loss Less than 5 Million \| Debt Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Number Of Securities	24	'
Aggregate Fair Value	121,840	'
Gross Unrealized Loss	$5,597	'

Securities_in_an_Unrealized_Lo2

Securities in an Unrealized Loss Position (Roll-Forward of Portion of Impairments) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]	'	'
Beginning balance of amounts related to credit losses	$4,261	$4,261
Additions for amounts related to credit losses	0	0
Deductions for amounts related to credit loss sales	0	0
Ending balance of amounts related to credit losses	$4,261	$4,261

Securities_in_an_Unrealized_Lo3

Securities in an Unrealized Loss Position (Narrative) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities in continuous unrealized loss position fair value	$3,441,075	$1,536,923
Securities in continuous unrealized loss position, aggregate losses accumulated In AOCI	117,453	35,018
Preferred stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities in unrealized loss positions	3	'
Securities in continuous unrealized loss position fair value	33,159	39,812
Securities in continuous unrealized loss position, aggregate losses accumulated In AOCI	6,319	1,651
Common stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities in unrealized loss positions	0	'
Securities in continuous unrealized loss position fair value	0	46,725
Securities in continuous unrealized loss position, aggregate losses accumulated In AOCI	$0	$707

Fair_Value_Measurements_Assets

Fair Value Measurements (Assets and Liabilities Measured At Fair Value, On a Recurring Basis) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	$11,515,524	$11,841,005
Equity securities available for sale	283,338	376,022
Arbitrage trading account	522,128	329,077
Recurring \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	11,515,524	11,841,005
Equity securities available for sale	283,338	376,022
Arbitrage trading account	522,128	329,077
Total assets	12,320,990	12,546,104
Securities sold but not yet purchased	162,278	121,487
Recurring \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Equity securities available for sale	159,537	280,658
Arbitrage trading account	192,281	233,603
Total assets	351,818	514,261
Securities sold but not yet purchased	162,126	114,909
Recurring \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	11,472,660	11,781,940
Equity securities available for sale	118,811	93,335
Arbitrage trading account	328,067	94,546
Total assets	11,919,538	11,969,821
Securities sold but not yet purchased	152	6,558
Recurring \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	42,864	59,065
Equity securities available for sale	4,990	2,029
Arbitrage trading account	1,780	928
Total assets	49,634	62,022
Securities sold but not yet purchased	0	20
Recurring \| U.S. government and government agency \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	884,859	898,463
Recurring \| U.S. government and government agency \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| U.S. government and government agency \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	884,859	898,463
Recurring \| U.S. government and government agency \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| State and municipal \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	4,218,284	4,768,519
Recurring \| State and municipal \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| State and municipal \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	4,218,284	4,768,519
Recurring \| State and municipal \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Mortgage-backed securities \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	1,329,783	1,715,697
Recurring \| Mortgage-backed securities \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Mortgage-backed securities \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	1,329,783	1,715,697
Recurring \| Mortgage-backed securities \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Corporate \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	4,202,741	3,601,648
Recurring \| Corporate \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Corporate \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	4,159,877	3,542,583
Recurring \| Corporate \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	42,864	59,065
Recurring \| Foreign government \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	879,857	856,678
Recurring \| Foreign government \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Foreign government \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	879,857	856,678
Recurring \| Foreign government \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturity securities available for sale	0	0
Recurring \| Common stocks \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	160,775	282,066
Recurring \| Common stocks \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	159,537	280,658
Recurring \| Common stocks \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	0	0
Recurring \| Common stocks \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	1,238	1,408
Recurring \| Preferred stocks \| Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	122,563	93,956
Recurring \| Preferred stocks \| Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	0	0
Recurring \| Preferred stocks \| Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	118,811	93,335
Recurring \| Preferred stocks \| Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities available for sale	$3,752	$621

Fair_Value_Measurements_Summar

Fair Value Measurements (Summarize Changes in Level 3 Assets and Liabilities) (Details) (Level 3, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	$20,000	$21,000
Earnings	-4,000	-1,000
Other Comprehensive Income	0	0
Purchases	4,000	0
Sales	-20,000	0
Paydown/Maturities	0	0
In	0	0
Out	0	0
Ending balance	0	20,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	62,022,000	82,541,000
Earnings	1,836,000	-3,905,000
Other Comprehensive Income	1,039,000	11,455,000
Purchases	4,424,000	283,000
Sales	-5,776,000	-11,274,000
Paydowns / Maturities	-12,604,000	-17,171,000
In	22,000	93,000
Out	-1,329,000	0
Ending Balance	49,634,000	62,022,000
Corporate	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	59,065,000	67,828,000
Earnings	677,000	-1,497,000
Other Comprehensive Income	309,000	9,622,000
Purchases	170,000	283,000
Sales	-4,753,000	0
Paydowns / Maturities	-12,604,000	-17,171,000
In	0	0
Out	0	0
Ending Balance	42,864,000	59,065,000
Fixed maturity securities	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	59,065,000	67,828,000
Earnings	677,000	-1,497,000
Other Comprehensive Income	309,000	9,622,000
Purchases	170,000	283,000
Sales	-4,753,000	0
Paydowns / Maturities	-12,604,000	-17,171,000
In	0	0
Out	0	0
Ending Balance	42,864,000	59,065,000
Common stocks	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	1,408,000	1,559,000
Earnings	0	0
Other Comprehensive Income	0	0
Purchases	0	0
Sales	-170,000	-151,000
Paydowns / Maturities	0	0
In	0	0
Out	0	0
Ending Balance	1,238,000	1,408,000
Preferred stocks	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	621,000	12,303,000
Earnings	-299,000	1,126,000
Other Comprehensive Income	0	-1,737,000
Purchases	3,430,000	0
Sales	0	-11,071,000
Paydowns / Maturities	0	0
In	0	0
Out	0	0
Ending Balance	3,752,000	621,000
Equity securities available for sale	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	2,029,000	13,862,000
Earnings	-299,000	1,126,000
Other Comprehensive Income	0	-1,737,000
Purchases	3,430,000	0
Sales	-170,000	-11,222,000
Paydowns / Maturities	0	0
In	0	0
Out	0	0
Ending Balance	4,990,000	2,029,000
Trading account	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning Balance	928,000	851,000
Earnings	1,458,000	-3,534,000
Other Comprehensive Income	730,000	3,570,000
Purchases	824,000	0
Sales	-853,000	-52,000
Paydowns / Maturities	0	0
In	22,000	93,000
Out	-1,329,000	0
Ending Balance	$1,780,000	$928,000

Reserves_For_Losses_And_Loss_E2

Reserves For Losses And Loss Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]	'		'		'
Net reserves at beginning of year	$8,411,851,000		$8,172,112,000		$7,999,521,000
Net provision for losses and loss expenses:	'		'		'
Claims occuring during the current year	3,221,393,000	[1]	2,997,995,000	[1]	2,791,860,000	[1]
Decrease in estimates for claims occurring in prior years	-78,810,000	[2],[3]	-102,571,000	[2],[3]	-181,282,000	[2],[3]
Loss reserve discount accretion	54,441,000		53,055,000		47,787,000
Total	3,197,024,000		2,948,479,000		2,658,365,000
Net payments for claims:	'		'		'
Current year	822,787,000		698,834,000		765,440,000
Prior year	2,055,284,000		2,010,101,000		1,721,558,000
Total	2,878,071,000		2,708,935,000		2,486,998,000
Foreign currency translation	-47,007,000		195,000		1,224,000
Net reserves at end of year	8,683,797,000		8,411,851,000		8,172,112,000
Ceded reserve at end of year	1,397,144,000		1,339,235,000		1,165,022,000
Gross reserves at end of year	10,080,941,000		9,751,086,000		9,337,134,000
Workers' Compensation Discount, Current Year Amount	22,680,000		26,078,000		43,286,000
Decrease in estimates for claims occurring in prior years, undiscounted basis	77,430,000		100,667,000		182,937,000
Favorable reserve development and return premiums	$98,000,000		$103,000,000		$182,000,000

[1]	Claims occurring during the current year are net of loss reserve discounts of $22,680,000, $26,078,000 and $43,286,000Â in 2013, 2012 and 2011, respectively.
[2]	For certain retrospectively rated insurance polices and reinsurance agreements, reserve development is offset by additional or return premiums. Favorable reserve development, net of additional and return premiums, was $98 million, $103 million and $182 million in 2013, 2012 and 2011, respectively.
[3]	The decrease in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years decreased by $77,430,000, $100,667,000 and $182,937,000 in 2013, 2012 and 2011, respectively.

Reserves_For_Losses_And_Loss_E3

Reserves For Losses And Loss Expenses (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reserves For Losses And Loss Expenses [Line Items]	'	'	'
Reserve for losses and loss adjustment expenses relating to asbestos and environmental claims, net	$36	$34	'
Reserve for losses and loss adjustment expenses relating to asbestos and environmental claims, gross	59	56	'
Increase (decrease) in net incurred losses and loss expenses relating to asbestos and environmental claims	5	2	1
Net paid losses and loss expenses for asbestos and environmental claims	3	2	3
Workers' compensation discount after effects of ceded reinsurance, amount	$837	$867	$892
Non-Proportional Reinsurance	'	'	'
Reserves For Losses And Loss Expenses [Line Items]	'	'	'
Workers' compensation weighted average discount rate, percent	4.10%	'	'
Non-Proportional Reinsurance \| Minimum	'	'	'
Reserves For Losses And Loss Expenses [Line Items]	'	'	'
Workers' compensation discount, percent	2.10%	'	'
Non-Proportional Reinsurance \| Maximum	'	'	'
Reserves For Losses And Loss Expenses [Line Items]	'	'	'
Workers' compensation discount, percent	6.50%	'	'
Proportional Reinsurance	'	'	'
Reserves For Losses And Loss Expenses [Line Items]	'	'	'
Workers' compensation discount, percent	2.20%	'	'

Reinsurance_Reinsurance_Financ

Reinsurance (Reinsurance Financial Information) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reinsurance Disclosures [Abstract]	'	'	'
Written premiums, Direct	$5,626,172	$4,964,069	$4,370,092
Written premiums, Assumed	884,919	815,810	707,221
Written premiums, Ceded	-1,010,918	-881,340	-719,945
Total net premiums written	5,500,173	4,898,539	4,357,368
Earned premiums, Direct	5,328,955	4,723,882	4,164,277
Earned premiums, Assumed	857,119	770,981	669,593
Earned premiums, Ceded	-959,537	-821,347	-673,003
Net premiums earned	5,226,537	4,673,516	4,160,867
Ceded losses incurred	556,108	528,018	458,249
Uncollectible reinsurance	$1,385	$1,680	$3,169

Reinsurance_Schedule_Of_Ceded_

Reinsurance (Schedule Of Ceded Credit Risk by Reinsurer) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	$1,533,103	$1,450,348
Credit Risk Reinsurers, Subtotal, Excluding Residual Market Pools [Member]	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	1,064,602	'
Munich Re	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	193,405	'
Lloyds of London	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	117,059	'
Swiss Re	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	104,096	'
Alleghany Group	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	96,348	'
Partner Re	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	67,116	'
Axis Capital	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	65,580	'
Berkshire Hathaway	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	53,118	'
Ace Group	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	46,413	'
Hannover Re Group	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	35,607	'
Everest Re	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	29,253	'
Arch Capital Group	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	25,782	'
Other Reinsurers	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	230,825	'
Residual Market Pools	'	'
Ceded Credit Risk [Line Items]	'	'
Ceded reserve at end of year	$468,501	'

Senior_Notes_And_Other_Debt_Sc

Senior Notes And Other Debt (Schedule of Debt) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Subsidiary Debt	'		'
Debt Instrument [Line Items]	'		'
Face Value	$77,173,000	[1]	'
Carrying Value	77,173,000	[1]	57,795,000	[1]
Repayments in 2014	5,000,000		'
Repayments in 2015	40,000,000		'
Repayments in 2016	30,000,000		'
Repayments thereafter	2,000,000		'
Senior Notes and Other Debt	'		'
Debt Instrument [Line Items]	'		'
Face Value	1,703,676,000		'
Carrying Value	1,692,442,000		1,871,535,000
Senior Notes \| Senior Notes due May 15, 2015	'		'
Debt Instrument [Line Items]	'		'
Rate	5.60%		'
Face Value	200,000,000		'
Carrying Value	199,744,000		199,559,000
Senior Notes \| Senior Notes due August 15, 2019	'		'
Debt Instrument [Line Items]	'		'
Rate	6.15%		'
Face Value	150,000,000		'
Carrying Value	149,199,000		149,057,000
Senior Notes \| Senior Notes due September 15, 2019	'		'
Debt Instrument [Line Items]	'		'
Rate	7.38%		'
Face Value	300,000,000		'
Carrying Value	298,546,000		298,292,000
Senior Notes \| Senior Notes due September 15, 2020	'		'
Debt Instrument [Line Items]	'		'
Rate	5.38%		'
Face Value	300,000,000		'
Carrying Value	297,738,000		297,401,000
Senior Notes \| Senior Notes due January 1, 2022	'		'
Debt Instrument [Line Items]	'		'
Rate	8.70%		'
Face Value	76,503,000		'
Carrying Value	76,004,000		75,962,000
Senior Notes \| Senior Notes due March 15, 2022	'		'
Debt Instrument [Line Items]	'		'
Rate	4.63%		'
Face Value	350,000,000		'
Carrying Value	346,581,000		346,163,000
Senior Notes \| Senior Notes due February 15, 2037	'		'
Debt Instrument [Line Items]	'		'
Rate	6.25%		'
Face Value	250,000,000		'
Carrying Value	$247,457,000		$247,347,000

[1]	Subsidiary debt is due as follows: $5 million in 2014, $40 million in 2015, $30 million in 2016 and $2 million thereafter.

Junior_Subordinated_Debentures1

Junior Subordinated Debentures (Narrative) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013
			Five Point Six Two Five Percent Subordinated Debentures [Member]	Six Point Seven Five Zero Percent Subordinated Debentures [Member]
			Junior Subordinated Debentures	Junior Subordinated Debentures
Debt Instrument [Line Items]	'	'	'	'
Junior subordinated debentures, aggregate principal amount	'	'	$350,000,000	$250,000,000
Junior subordinated debentures, interest rate, stated percentage	'	'	5.63%	6.75%
Junior subordinated debentures	339,800,000	243,206,000	339,800,000	'
Gains (Losses) on Extinguishment of Debt	'	'	'	$7,000,000

Income_Taxes_Schedule_of_Compo

Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Current Expense, Domestic	$116,802,000	$156,339,000	$60,420,000
Deferred Expense (Benefit), Domestic	47,370,000	11,448,000	37,176,000
Domestic, Total	164,172,000	167,787,000	97,596,000
Current Expense, Foreign	22,362,000	23,029,000	22,011,000
Deferred Expense (Benefit), Foreign	7,053,000	469,000	2,338,000
Foreign, Total	29,415,000	23,498,000	24,349,000
Current Expense, Total	139,164,000	179,368,000	82,431,000
Deferred Expense (Benefit), Total	54,423,000	11,917,000	39,514,000
Total expense	193,587,000	191,285,000	121,945,000
Income (Loss) from Continuing Operations before Income Taxes, Domestic	598,000,000	624,000,000	469,000,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign	$101,000,000	$78,000,000	$49,000,000

Income_Taxes_Schedule_of_Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Statutory federal income tax rate	35.00%	'	'
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]	'	'	'
Computed â€œexpectedâ€ tax expense	$244,611	$245,675	$179,580
Tax-exempt investment income	-40,679	-50,665	-57,246
Change in valuation allowance	0	0	-2,328
Impact of lower foreign tax rates	-4,851	-5,234	-3,199
State and local taxes	2,906	-753	2,355
Other, net	-8,400	2,262	2,783
Total expense	$193,587	$191,285	$121,945

Income_Taxes_Schedule_of_Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax asset:	'	'
Loss reserve discounting	$87,394	$119,547
Unearned premiums	149,107	132,014
Other-than-temporary impairments	49,483	62,187
Restricted stock units	52,671	49,553
Other	92,698	83,740
Gross deferred tax asset	431,353	447,041
Less valuation allowance	0	0
Deferred tax asset	431,353	447,041
Deferred tax liability:	'	'
Amortization of intangibles	11,886	12,458
Deferred policy acquisition costs	136,635	120,532
Unrealized investment gains	148,215	274,497
Other	114,497	99,809
Deferred tax liability	411,233	507,296
Net deferred tax asset (liability)	20,120	-60,255
Current taxes payables	'	22,546
Current Federal income taxes	24,737	0
Foreign Tax Authority	'	'
Operating Loss Carryforwards [Line Items]	'	'
Operating loss carryforwards	$870	'

Dividends_From_Subsidiaries_An2

Dividends From Subsidiaries And Statutory Financial Information (Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Insurance [Abstract]	'	'	'
Amount available for dividend distribution without prior approval from regulatory authorities	$491,000,000	'	'
Net income	680,418,000	490,119,000	417,441,000
Policyholders' surplus	4,908,010,000	4,671,922,000	4,107,745,000
Increase in BIC's statutory capital and surplus	282,000,000	'	'
Total Adjusted Capital percentage threshold	200.00%	'	'
BIC's Total Adjusted Capital balance	$4,600,000,000	'	'
BIC's Total Adjusted Capital balance as percentage of RBC Authorized Control Level	5.00%	'	'

Common_Stockholders_Equity_Wei

Common Stockholders' Equity (Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Abstract]	'	'	'
Basic	135,304,752	137,097,162	139,687,546
Diluted	140,742,922	143,314,544	145,672,211

Common_Stockholders_Equity_Sch

Common Stockholders' Equity (Schedule of Changes in Shares of Common Stock Outstanding) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Stock Shares Outstanding [Roll Forward]	'	'	'
Balance, beginning of year	136,017,732	137,520,019	141,009,834
Shares issued	139,790	2,114,168	2,702,303
Shares repurchased	-3,924,355	-3,616,455	-6,192,118
Balance, end of year	132,233,167	136,017,732	137,520,019

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets:	'	'
Arbitrage trading account	$522,128	$329,077
Loans receivable	346,746	406,443
Carrying Value	'	'
Assets:	'	'
Fixed maturity securities	11,616,844	11,943,956
Equity securities available for sale	283,338	376,022
Arbitrage trading account	522,128	329,077
Loans receivable	343,583	401,961
Cash and cash equivalents	839,738	905,670
Trading accounts receivable from brokers and clearing organizations	304,936	446,873
Due from broker	17,735	14,449
Liabilities:	'	'
Trading account securities sold but not yet purchased	162,278	121,487
Junior subordinated debentures	339,800	243,206
Senior notes and other debt	1,692,442	1,871,535
Fair Value	'	'
Assets:	'	'
Fixed maturity securities	11,631,744	11,968,376
Equity securities available for sale	283,338	376,022
Arbitrage trading account	522,128	329,077
Loans receivable	346,746	406,443
Cash and cash equivalents	839,738	905,670
Trading accounts receivable from brokers and clearing organizations	304,936	446,873
Due from broker	17,735	14,449
Liabilities:	'	'
Trading account securities sold but not yet purchased	162,278	121,487
Junior subordinated debentures	288,540	252,000
Senior notes and other debt	$1,861,898	$2,190,173

Lease_Obligations_Details

Lease Obligations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Leases [Abstract]	'	'	'
Future minimum lease payment - due in 2014	$42,586	'	'
Future minimum lease payment - due in 2015	39,218	'	'
Future minimum lease payment - due in 2016	34,009	'	'
Future minimum lease payment - due in 2017	29,573	'	'
Future minimum lease payment - due after 2017	213,046	'	'
Rental expense	$44,752	$38,179	$33,003

Commitments_Litigation_And_Con1

Commitments, Litigation And Contingent Liabilities (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Maximum commitments to invest	$249

Stock_Incentive_Plan_Schedule_

Stock Incentive Plan (Schedule of Share-based Compensation, Stock Options, Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'		'		'
Number of outstanding options - vested and exercisable	3,375		3,375		1,314,057
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'		'		'
Outstanding at beginning of year (in shares)	3,375		1,314,057		3,503,384
Exercised (in shares)	3,375		1,310,682		2,185,952
Canceled (in shares)	0		0		3,375
Outstanding at year end (in shares)	0		3,375		1,314,057
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]	'		'		'
Oustanding at beginning of year (Price) (in dollars per share)	$15.17	[1]	$11.04	[1]	$10.42	[1]
Exercised (Price) (in dollars per share)	$15.17	[1]	$11.03	[1]	$10.05	[1]
Canceled (Price) (in dollars per share)	$0	[1]	$0	[1]	$10.07	[1]
Outstanding at end of year (Price) (in dollars per share)	$0	[1]	$15.17	[1]	$11.04	[1]

[1]	Weighted average exercise price.

Stock_Incentive_Plan_Schedule_1

Stock Incentive Plan (Schedule of Nonvested Restricted Stock Units Activity) (Details) (Restricted Stock Units (RSUs))	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Units (RSUs)	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period	'5 years	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]	'	'	'
RSUs granted and unvested at beginning of period:	4,701,120	4,370,975	4,945,375
Granted	108,400	2,161,220	107,500
Vested	-146,250	-1,704,625	-576,050
Cancelled	-171,750	-126,450	-105,850
RSUs granted and unvested at end of period:	4,491,520	4,701,120	4,370,975
Deferred	3,643,804	'	'

Stock_Incentive_Plan_Schedule_2

Stock Incentive Plan (Schedule of Share-based Compensation, Unearned Compensation Related to RSU's) (Details) (Restricted Stock Units (RSUs), USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Units (RSUs)	'	'	'
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Changes In Unearned Compensation [Roll Forward]	'	'	'
Unearned compensation at beginning of year	$93,653	$57,315	$76,139
RSUs granted, net of cancellations	4,406	73,255	2,832
RSUs expensed	-22,881	-25,728	-26,303
RSUs forfeiture adjustment	-1,973	-11,189	4,647
Unearned compensation at end of year	$73,205	$93,653	$57,315

Compensation_Plans_Details

Compensation Plans (Details) (USD $)	12 Months Ended
Compensation Plans (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Period of Measurement for Book Value Per Share	'5 years	'	'
LTIP Expense	$14,127,000	$13,107,000	$10,220,000
Deferred Profit Sharing	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Profit Sharing Plan Minimum Contribution, Percent	5.00%	'	'
Profit Sharing Plan, Contributions Vesting Immediately, Percent	40.00%	'	'
Profit Sharing Plan, Contributions Vesting Based on Years of Service, Percent	60.00%	'	'
Profit sharing expense	34,000,000	31,000,000	27,000,000
2011 grant	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Long-Term Incentive Compensation Plan, Number of Units Oustanding	183,100	'	'
Long-Term Incentive Compensation Plan, Maximum Value	45,800,000	'	'
Long-Term Incentive Compensation Plan, Earned	19,700,000	'	'
LTIP Expense	6,741,000	7,365,000	5,620,000
2008 grant	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Long-Term Incentive Compensation Plan, Earned	23,000,000	'	'
LTIP Expense	0	5,742,000	4,600,000
Number Of Years Long Term Compensation Was Earned	'	'5 years	'
2013 grant	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Long-Term Incentive Compensation Plan, Number of Units Oustanding	211,250	'	'
Long-Term Incentive Compensation Plan, Maximum Value	52,800,000	'	'
Long-Term Incentive Compensation Plan, Earned	7,400,000	'	'
LTIP Expense	$7,386,000	$0	$0

Retirement_Benefits_Schedule_o

Retirement Benefits (Schedule of Changes in Projected Benefit Obligations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]	'	'	'
Benefit obligation, discount rate	0.00%	3.39%	'
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]	'	'	'
Projected benefit obligation at beginning of year	$64,632	$56,787	'
Interest cost	2,191	2,476	2,716
Benefits paid	-285	-1,426	'
Actuarial loss	-2,221	6,795	'
Benefit obligation at end of year	$64,317	$64,632	$56,787

Retirement_Benefits_Schedule_o1

Retirement Benefits (Schedule of Amounts Recognized in Other Comprehensive Income (Loss)) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]	'	'
Net actuarial loss	$4,242	$14,605
Prior service cost	5,988	9,012
Net pension asset	$10,230	$23,617

Retirement_Benefits_Schedule_o2

Retirement Benefits (Schedule of Net Benefit Costs) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]	'	'	'
Interest cost	$2,191	$2,476	$2,716
Amortization of unrecognized:	'	'	'
Prior service costs	3,023	3,023	3,023
Net actuarial loss	8,143	2,197	1,330
Net periodic pension cost	$13,357	$7,696	$7,069

Retirement_Benefits_Schedule_o3

Retirement Benefits (Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
	Dec. 31, 2013	Dec. 31, 2012	Net pension asset	Net pension asset	Net pension asset	Net pension asset
Amortization of:	'	'	'	'	'	'
Net actuarial (gain) loss	($2,221)	$6,795	'	'	'	'
Net actuarial loss	-8,143	-2,197	'	'	'	'
Prior service costs	-3,023	-3,023	'	'	'	'
Total recognized in other comprehensive income	-13,387	1,575	'	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'	'	'
Net after tax unamortized periodic pension cost	($4,369,394)	($4,335,466)	$6,651	$15,351	$14,329	$15,696

Supplemental_Financial_Stateme2

Supplemental Financial Statement Information (Schedule of Other Operating Cost and Expense, by Component) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Income and Expenses [Abstract]	'	'	'
Amortization of deferred policy acquisition costs	$991,070	$917,583	$785,118
Other underwriting expenses	780,058	675,163	653,011
Service company expenses	88,662	84,986	75,231
Net foreign currency losses	-10,120	-6,092	-1,884
Other costs and expenses	151,014	127,983	115,050
Total	$2,000,684	$1,799,623	$1,626,526

Industry_Segments_Financial_In

Industry Segments (Financial Information of Company Operating Segments) (Details) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Segment Reporting Information [Line Items]

Earned Premiums

$5,226,537

$4,673,516

$4,160,867

Investment Income

544,291

586,763

526,351

Other Revenues

637,706

563,275

468,766

Total revenues

1,696,679

1,634,124

1,570,962

1,506,769

1,608,601

1,420,501

1,415,747

1,378,705

6,408,534

5,823,554

5,155,984

Pre-Tax Income (Loss)

698,888

701,928

513,086

Net income to common stockholders

130,379

136,974

115,957

116,615

165,489

100,947

108,838

135,318

499,925

510,592

391,211

Net investment gains, before tax

121,544

210,465

125,481

Net investment gains, net of tax

74,118

136,802

81,647

Insurance-Domestic

Segment Reporting Information [Line Items]

Earned Premiums

3,782,416

3,417,022

3,121,281

Insurance-International

Segment Reporting Information [Line Items]

Earned Premiums

723,151

631,841

508,509

Reinsurance-Global

Segment Reporting Information [Line Items]

Earned Premiums

720,970

624,653

531,077

Operating Segments | Insurance-Domestic

Segment Reporting Information [Line Items]

Earned Premiums

3,782,416

3,417,022

3,121,281

Investment Income

404,280

424,787

372,053

Other Revenues

107,517

103,133

92,847

Total revenues

4,294,213

3,944,942

3,586,181

Pre-Tax Income (Loss)

648,740

578,500

467,126

Net income to common stockholders

449,981

397,942

345,399

Operating Segments | Insurance-International

Segment Reporting Information [Line Items]

Earned Premiums

723,151

631,841

508,509

Investment Income

47,039

45,796

36,958

Other Revenues

Total revenues

770,190

677,637

545,467

Pre-Tax Income (Loss)

56,922

51,639

36,912

Net income to common stockholders

40,292

35,928

28,142

Operating Segments | Reinsurance-Global

Segment Reporting Information [Line Items]

Earned Premiums

720,970

624,653

531,077

Investment Income

89,090

106,932

97,795

Other Revenues

Total revenues

810,060

731,585

628,872

Pre-Tax Income (Loss)

110,425

103,690

85,271

Net income to common stockholders

78,013

72,916

66,405

Corporate, Other and Eliminations Segment

Segment Reporting Information [Line Items]

Earned Premiums

[1]

Investment Income

3,882

[1]

9,248

[1]

19,545

[1]

Other Revenues

408,645

[1]

249,677

[1]

250,438

[1]

Total revenues

412,527

[1]

258,925

[1]

269,983

[1]

Pre-Tax Income (Loss)

-238,743

[1]

-242,366

[1]

-201,704

[1]

Net income to common stockholders

($142,479)

[1]

($132,996)

[1]

($130,382)

[1]

Corporate, other and eliminations represent corporate revenues and expenses and other items that are not allocated to business segments.

Industry_Segments_Identifiable

Industry Segments (Identifiable Assets by Segment) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	$20,551,796		$20,155,896
Operating Segments \| Insurance-Domestic	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	15,247,807		14,661,476
Operating Segments \| Insurance-International	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	1,516,310		1,541,365
Operating Segments \| Reinsurance-Global	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	3,103,193		3,337,937
Corporate, Other and Eliminations Segment	'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'
Consolidated Assets	$684,486	[1]	$615,118	[1]

[1]	Corporate, other and eliminations represent corporate revenues and expenses and other items that are not allocated to business segments.

Industry_Segments_Net_Premiums

Industry Segments (Net Premiums Earned By Major Line of Business) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	$5,226,537	$4,673,516	$4,160,867
Insurance-Domestic	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	3,782,416	3,417,022	3,121,281
Insurance-Domestic \| Other Liability [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	1,259,376	1,104,369	1,003,080
Insurance-Domestic \| Workers' Compensation [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	995,047	869,042	785,454
Insurance-Domestic \| Short-tail Lines [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	774,809	733,239	665,575
Insurance-Domestic \| Commercial Automobile [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	486,759	455,988	437,891
Insurance-Domestic \| Professional Liability [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	266,425	254,384	229,281
Insurance-International	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	723,151	631,841	508,509
Insurance-International \| Other Liability [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	65,528	44,065	49,800
Insurance-International \| Workers' Compensation [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	84,637	82,066	73,823
Insurance-International \| Short-tail Lines [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	336,814	276,599	183,447
Insurance-International \| Commercial Automobile [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	130,020	125,927	110,568
Insurance-International \| Professional Liability [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	106,152	103,184	90,871
Reinsurance-Global	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	720,970	624,653	531,077
Reinsurance-Global \| Casualty [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	507,790	456,376	389,557
Reinsurance-Global \| Property [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net premiums earned	$213,180	$168,277	$141,520

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Schedule of Quarterly Financial Information) (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]	'		'		'		'		'		'		'		'		'	'	'
Revenues	$1,696,679		$1,634,124		$1,570,962		$1,506,769		$1,608,601		$1,420,501		$1,415,747		$1,378,705		$6,408,534	$5,823,554	$5,155,984
Net income	$130,379		$136,974		$115,957		$116,615		$165,489		$100,947		$108,838		$135,318		$499,925	$510,592	$391,211
Net income per share	'		'		'		'		'		'		'		'		'	'	'
Basic (dollars per share)	$0.97	[1]	$1.01	[1]	$0.85	[1]	$0.86	[1]	$1.22	[1]	$0.74	[1]	$0.79	[1]	$0.98	[1]	$3.69	$3.72	$2.80
Diluted (dollars per share)	$0.93	[1]	$0.97	[1]	$0.82	[1]	$0.83	[1]	$1.17	[1]	$0.71	[1]	$0.76	[1]	$0.94	[1]	$3.55	$3.56	$2.69

[1]	Net income per share (â€œEPSâ€) in each quarter is computed using the weighted-average number of shares outstanding during that quarter, while EPS for the full year is computed using the weighted-average number of shares outstanding during the year. Thus, the sum of the four quarters EPS does not necessarily equal the full-year EPS.

Schedule_II_Condensed_Financia1

Schedule II - Condensed Financial Information of Registrant (Balance Sheets (Parent Company)) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets:	'	'	'	'
Cash and cash equivalents	$839,738	$905,670	$911,742	$642,952
Fixed maturity securities available for sale at fair value (cost $61,084 and $281,708 at December 31, 2013 and 2012, respectively)	11,616,844	11,943,956	'	'
Equity securities available for sale, at fair value (cost $4,668 in 2013 and $0 in 2012)	283,338	376,022	'	'
Deferred Federal income taxes	20,120	0	'	'
Current Federal income taxes	24,737	0	'	'
Property, furniture and equipment at cost, less accumulated depreciation	339,448	267,227	'	'
Other assets	335,225	242,135	'	'
Total assets	20,551,796	20,155,896	'	'
Liabilities:	'	'	'	'
Other liabilities	848,749	981,626	'	'
Current Federal income taxes	'	22,546	'	'
Deferred Federal income taxes	0	60,255	'	'
Junior subordinated debentures	339,800	243,206	'	'
Total liabilities	16,182,402	15,820,430	'	'
Stockholders' equity:	'	'	'	'
Preferred stock	0	0	'	'
Common stock	47,024	47,024	'	'
Additional paid-in capital	967,440	945,166	'	'
Retained earnings (including accumulated undistributed net income of subsidiaries of $4,393,420 and $4,023,780 at December 31, 2013 and 2012, respectively)	5,265,015	4,817,807	'	'
Accumulated other comprehensive income	189,391	465,631	'	'
Treasury stock, at cost	-2,132,835	-1,969,411	'	'
Total common stockholdersâ€™ equity	4,336,035	4,306,217	'	'
Total liabilities and equity	20,551,796	20,155,896	'	'
Equity securities available for sale at cost	203,627	308,175	'	'
Parent Company	'	'	'	'
Assets:	'	'	'	'
Cash and cash equivalents	17,315	162,972	270,637	29,476
Fixed maturity securities available for sale at fair value (cost $61,084 and $281,708 at December 31, 2013 and 2012, respectively)	63,115	286,597	'	'
Equity securities available for sale, at fair value (cost $4,668 in 2013 and $0 in 2012)	11,240	25,699	'	'
Investment in subsidiaries	6,250,979	5,979,539	'	'
Due from subsidiaries	13,648	106,334	'	'
Deferred Federal income taxes	51,346	0	'	'
Current Federal income taxes	17,540	0	'	'
Property, furniture and equipment at cost, less accumulated depreciation	9,028	7,895	'	'
Other assets	5,795	10,710	'	'
Total assets	6,440,006	6,579,746	'	'
Liabilities:	'	'	'	'
Due to subsidiaries	0	0	'	'
Other liabilities	148,903	176,416	'	'
Current Federal income taxes	0	8,253	'	'
Deferred Federal income taxes	0	31,914	'	'
Junior subordinated debentures	339,800	243,206	'	'
Senior notes	1,615,268	1,813,740	'	'
Total liabilities	2,103,971	2,273,529	'	'
Stockholders' equity:	'	'	'	'
Preferred stock	0	0	'	'
Common stock	47,024	47,024	'	'
Additional paid-in capital	967,440	945,166	'	'
Retained earnings (including accumulated undistributed net income of subsidiaries of $4,393,420 and $4,023,780 at December 31, 2013 and 2012, respectively)	5,265,015	4,817,807	'	'
Accumulated other comprehensive income	189,391	465,631	'	'
Treasury stock, at cost	-2,132,835	-1,969,411	'	'
Total common stockholdersâ€™ equity	4,336,035	4,306,217	'	'
Total liabilities and equity	6,440,006	6,579,746	'	'
Fixed maturity securities available for sale at cost	61,084	281,708	'	'
Equity securities available for sale at cost	4,668	0	'	'
Accumulated undistributed net income of subsidiaries	$4,393,420	$4,023,780	'	'

Schedule_II_Condensed_Financia2

Schedule II - Condensed Financial Information of Registrant (Statements of Income (Parent Company)) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Other income	'	'	'	'	'	'	'	'	$1,026	$2,564	$1,764
Total revenues	1,696,679	1,634,124	1,570,962	1,506,769	1,608,601	1,420,501	1,415,747	1,378,705	6,408,534	5,823,554	5,155,984
Operating costs and expense	'	'	'	'	'	'	'	'	5,709,646	5,121,626	4,642,898
Income before income taxes	'	'	'	'	'	'	'	'	698,888	701,928	513,086
Federal income taxes:	'	'	'	'	'	'	'	'	'	'	'
Net expense	'	'	'	'	'	'	'	'	-193,587	-191,285	-121,945
Net income to common stockholders	130,379	136,974	115,957	116,615	165,489	100,947	108,838	135,318	499,925	510,592	391,211
Dividends from subsidiaries	'	'	'	'	'	'	'	'	269,626	25,968	503,227
Parent Company	'	'	'	'	'	'	'	'	'	'	'
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Management fees and investment income including dividends from subsidiaries of $269,626, $25,968 and $503,227 for the years ended December 31, 2013, 2012 and 2011, respectively	'	'	'	'	'	'	'	'	277,223	29,961	514,057
Net investment gains	'	'	'	'	'	'	'	'	24,550	71,130	45,962
Other income	'	'	'	'	'	'	'	'	223	271	96
Total revenues	'	'	'	'	'	'	'	'	301,996	101,362	560,115
Operating costs and expense	'	'	'	'	'	'	'	'	122,562	133,326	118,922
Interest expense	'	'	'	'	'	'	'	'	120,066	124,298	111,184
Income before income taxes	'	'	'	'	'	'	'	'	59,368	-156,262	330,009
Federal income taxes:	'	'	'	'	'	'	'	'	'	'	'
Federal income taxes provided by subsidiaries on a separate return basis	'	'	'	'	'	'	'	'	225,845	132,379	79,200
Federal income tax expense on a consolidated return basis	'	'	'	'	'	'	'	'	-154,928	-160,226	-89,144
Net expense	'	'	'	'	'	'	'	'	70,917	-27,847	-9,944
Income (loss) before undistributed equity in net income of subsidiaries	'	'	'	'	'	'	'	'	130,285	-184,109	320,065
Equity in undistributed net income of subsidiaries	'	'	'	'	'	'	'	'	369,640	694,701	71,146
Net income to common stockholders	'	'	'	'	'	'	'	'	$499,925	$510,592	$391,211

Schedule_II_Condensed_Financia3

Schedule II - Condensed Financial Information of Registrant (Statements of Cash Flows (Parent Company)) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Fixed maturity securities available for sale at fair value (cost $61,084 and $281,708 at December 31, 2013 and 2012, respectively)	$11,616,844	$11,943,956	'
Cash flows from operating activities:	'	'	'
Net income	499,925	510,592	391,211
Adjustments to reconcile net income to net cash from operating activities:	'	'	'
Net investment gains	-121,544	-210,465	-125,481
Depreciation and amortization	103,090	103,419	88,012
Stock incentive plans	23,784	26,763	27,175
Change in:	'	'	'
Other liabilities	-2,826	107,928	10,269
Net cash from operating activities	819,798	675,458	670,279
Cash from (used in) investing activities:	'	'	'
Proceeds from sale of fixed maturity securities	1,344,707	838,576	1,293,876
Proceeds from maturities and prepayments of fixed maturity securities	2,718,156	2,291,105	1,697,144
Proceeds from sales of equity securities	267,554	409,610	159,827
Cost of purchases of fixed maturity securities	-4,198,135	-3,617,002	-2,815,340
Payments to Acquire Available-for-sale Securities, Equity	-156,557	-284,991	-97,986
Change in balance due to security broker	-26,155	-25,799	-16,194
Net additions to real estate, furniture & equipment	-63,150	-40,556	-45,320
Net cash used investing activities	-545,364	-775,068	-204,274
Cash from (used in) financing activities:	'	'	'
Net proceeds from stock options exercised	53	7,660	21,963
Purchase of common treasury shares	-166,473	-127,663	-187,163
Cash dividends to common stockholders	-52,717	-183,947	-43,253
Net cash from (used in) financing activities	-330,262	97,192	-195,213
Net increase (decrease) in cash and cash equivalents	-65,932	-6,072	268,790
Cash and cash equivalents at beginning of year	905,670	911,742	642,952
Cash and cash equivalents at end of year	839,738	905,670	911,742
Parent Company	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Fixed maturity securities available for sale at fair value (cost $61,084 and $281,708 at December 31, 2013 and 2012, respectively)	63,115	286,597	'
Cash flows from operating activities:	'	'	'
Net income	499,925	510,592	391,211
Adjustments to reconcile net income to net cash from operating activities:	'	'	'
Net investment gains	-24,550	-71,130	-45,962
Depreciation and amortization	10,397	5,624	4,905
Equity in undistributed earnings of subsidiaries	-369,640	-694,701	-71,146
Tax payments received from subsidiaries	77,305	125,046	139,011
Federal income taxes provided by subsidiaries on a separate return basis	-225,845	-132,379	-79,200
Stock incentive plans	24,594	26,763	27,176
Change in:	'	'	'
Federal income taxes	21,866	44,423	56,542
Other assets	-821	911	-542
Other liabilities	-16,280	28,017	-6,747
Accrued investment income	967	97	1,559
Other, net	0	-13	277
Net cash from operating activities	-2,082	-156,750	417,084
Cash from (used in) investing activities:	'	'	'
Proceeds from sale of fixed maturity securities	230,854	93,354	70,665
Proceeds from maturities and prepayments of fixed maturity securities	68,918	121,191	165,158
Proceeds from sales of equity securities	23,395	72,565	47,735
Cost of purchases of fixed maturity securities	-79,132	-255,885	-240,536
Payments to Acquire Available-for-sale Securities, Equity	-4,668	0	0
Investments in and advances to subsidiaries, net	-58,454	-16,480	-3,867
Change in balance due to security broker	6,918	-4,767	-5,983
Net additions to real estate, furniture & equipment	-1,896	-1,857	-643
Net cash used investing activities	185,935	8,121	32,529
Cash from (used in) financing activities:	'	'	'
Net proceeds from issuance of senior notes	339,627	345,823	0
Net proceeds from stock options exercised	53	13,544	21,966
Repayment of senior notes	-450,000	0	0
Purchase of common treasury shares	-166,473	-134,456	-187,163
Cash dividends to common stockholders	-52,717	-183,947	-43,255
Net cash from (used in) financing activities	-329,510	40,964	-208,452
Net increase (decrease) in cash and cash equivalents	-145,657	-107,665	241,161
Cash and cash equivalents at beginning of year	162,972	270,637	29,476
Cash and cash equivalents at end of year	$17,315	$162,972	$270,637

Schedule_III_Supplementary_Ins1

Schedule III - Supplementary Insurance Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplementary Insurance Information, by Segment [Line Items]	'	'	'
Deferrred Policy Acquisition Cost	$452,101	$404,047	$364,937
Reserve for Losses and Loss Expenses	10,080,941	9,751,086	9,337,134
Unearned Premiums	2,781,437	2,474,847	2,189,575
Net Premiums Earned	5,226,537	4,673,516	4,160,867
Net Investment Income	544,291	586,763	526,351
Loss and Loss Expenses	3,197,024	2,948,479	2,658,365
Amortization of Deferred Policy Acquisition Cost	991,070	917,583	785,118
Other Operating Cost and Expenses	1,009,614	882,040	836,211
Net Premiums Written	5,500,173	4,898,539	4,357,368
Operating Segments \| Insurance-Domestic	'	'	'
Supplementary Insurance Information, by Segment [Line Items]	'	'	'
Deferrred Policy Acquisition Cost	306,464	269,418	246,580
Reserve for Losses and Loss Expenses	7,715,124	7,466,538	7,183,706
Unearned Premiums	2,107,768	1,844,452	1,639,603
Net Premiums Earned	3,782,416	3,417,022	3,121,281
Net Investment Income	404,280	424,787	372,053
Loss and Loss Expenses	2,318,541	2,169,090	2,025,139
Amortization of Deferred Policy Acquisition Cost	651,524	613,252	529,885
Other Operating Cost and Expenses	671,096	584,100	559,985
Net Premiums Written	3,994,387	3,569,883	3,238,120
Operating Segments \| Insurance-International	'	'	'
Supplementary Insurance Information, by Segment [Line Items]	'	'	'
Deferrred Policy Acquisition Cost	60,751	56,995	51,753
Reserve for Losses and Loss Expenses	672,009	622,202	510,245
Unearned Premiums	317,691	297,581	262,483
Net Premiums Earned	723,151	631,841	508,509
Net Investment Income	47,039	45,796	36,958
Loss and Loss Expenses	429,900	377,459	291,827
Amortization of Deferred Policy Acquisition Cost	152,843	136,412	114,126
Other Operating Cost and Expenses	124,497	112,128	104,097
Net Premiums Written	756,185	664,459	551,910
Operating Segments \| Reinsurance-Global	'	'	'
Supplementary Insurance Information, by Segment [Line Items]	'	'	'
Deferrred Policy Acquisition Cost	84,886	77,634	66,604
Reserve for Losses and Loss Expenses	1,693,808	1,662,346	1,643,183
Unearned Premiums	355,978	332,814	287,489
Net Premiums Earned	720,970	624,653	531,077
Net Investment Income	89,090	106,932	97,795
Loss and Loss Expenses	448,583	401,930	341,399
Amortization of Deferred Policy Acquisition Cost	186,703	167,919	141,107
Other Operating Cost and Expenses	64,567	58,044	58,449
Net Premiums Written	749,601	664,197	567,338
Corporate and adjustments	'	'	'
Supplementary Insurance Information, by Segment [Line Items]	'	'	'
Deferrred Policy Acquisition Cost	0	0	0
Reserve for Losses and Loss Expenses	0	0	0
Unearned Premiums	0	0	0
Net Premiums Earned	0	0	0
Net Investment Income	3,882	9,248	19,545
Loss and Loss Expenses	0	0	0
Amortization of Deferred Policy Acquisition Cost	0	0	0
Other Operating Cost and Expenses	149,454	127,768	113,680
Net Premiums Written	$0	$0	$0

Schedule_IV_Reinsurance_Detail

Schedule IV - Reinsurance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'	'
Direct Amount	$5,626,172	$4,964,069	$4,370,092
Ceded to Other Companies	1,010,918	881,340	719,945
Assumed from Other Companies	884,919	815,810	707,221
Total net premiums written	5,500,173	4,898,539	4,357,368
Percentage of Amount Assumed to Net	16.10%	16.70%	16.30%
Insurance-Domestic	'	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'	'
Direct Amount	4,699,348	4,133,960	3,664,780
Ceded to Other Companies	809,368	691,284	556,743
Assumed from Other Companies	104,407	127,207	130,083
Total net premiums written	3,994,387	3,569,883	3,238,120
Percentage of Amount Assumed to Net	2.60%	3.60%	4.10%
Insurance-International	'	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'	'
Direct Amount	887,027	798,750	681,423
Ceded to Other Companies	142,591	137,598	129,513
Assumed from Other Companies	11,749	3,307	0
Total net premiums written	756,185	664,459	551,910
Percentage of Amount Assumed to Net	1.60%	0.50%	0.00%
Reinsurance-Global	'	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'	'
Direct Amount	39,797	31,359	23,889
Ceded to Other Companies	58,959	52,458	33,689
Assumed from Other Companies	768,763	685,296	577,138
Total net premiums written	$749,601	$664,197	$567,338
Percentage of Amount Assumed to Net	102.60%	103.20%	101.70%

Schedule_V_Valuation_and_Quali1

Schedule V - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Opening Balance	$30,219	$40,640	$44,584
Additions - Charged to Expense	3,627	-4,103	7,118
Deductions - Amounts Written Off	-9,423	-6,318	-11,062
Ending Balance	24,423	30,219	40,640
Premiums and fees receivable	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Opening Balance	22,919	17,666	19,483
Additions - Charged to Expense	3,133	9,598	6,158
Deductions - Amounts Written Off	-5,101	-4,345	-7,975
Ending Balance	20,951	22,919	17,666
Due from reinsurers	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Opening Balance	1,680	3,169	3,098
Additions - Charged to Expense	186	22	71
Deductions - Amounts Written Off	-481	-1,511	0
Ending Balance	1,385	1,680	3,169
Deferred federal and foreign income taxes	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Opening Balance	'	0	2,328
Additions - Charged to Expense	'	0	0
Deductions - Amounts Written Off	'	0	-2,328
Ending Balance	'	0	0
Loan loss reserves	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'
Opening Balance	5,620	19,805	19,675
Additions - Charged to Expense	308	-13,723	889
Deductions - Amounts Written Off	-3,841	-462	-759
Ending Balance	$2,087	$5,620	$19,805

Schedule_VI_Supplementary_Info1

Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]	'	'	'
Deferred policy acquisition costs	$452,101	$404,047	$364,937
Reserves for losses and loss expenses	10,080,941	9,751,086	9,337,134
Unearned premium	2,781,437	2,474,847	2,189,575
Net premiums earned	5,226,537	4,673,516	4,160,867
Net investment income	544,291	586,763	526,351
Losses and loss expenses incurred:	'	'	'
Current year	3,221,393	2,997,995	2,791,860
Prior years	-78,810	-102,571	-181,282
Loss reserve discount accretion	54,441	53,055	47,787
Amortization of deferred policy acquisition costs	991,070	917,583	785,118
Paid losses and loss expenses	2,878,071	2,708,935	2,486,998
Net premiums written	$5,500,173	$4,898,539	$4,357,368