Markel (MKL) 10-Q 1 Nov 16 2016 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 25, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Entity Registrant Name	MARKEL CORP
Entity Central Index Key	1,096,343
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		13,991,499

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
ASSETS
Fixed maturities (amortized cost of $9,563,157 in 2016 and $9,038,158 in 2015)	$ 10,318,487	$ 9,394,468
Equity securities (cost of $2,424,757 in 2016 and $2,208,834 in 2015)	4,510,427	4,074,475
Short-term investments (estimated fair value approximates cost)	1,989,305	1,642,261
Total Investments	16,818,219	15,111,204
Cash and cash equivalents	2,156,398	2,630,009
Restricted cash and cash equivalents	383,971	440,132
Receivables	1,312,685	1,113,703
Reinsurance recoverable on unpaid losses	2,041,928	2,016,665
Reinsurance recoverable on paid losses	62,254	50,123
Deferred policy acquisition costs	409,195	352,756
Prepaid reinsurance premiums	354,186	322,362
Goodwill	1,165,892	1,167,844
Intangible assets	733,415	792,372
Other assets	965,502	941,945
Total Assets	26,403,645	24,939,115
LIABILITIES AND EQUITY
Unpaid losses and loss adjustment expenses	10,258,290	10,251,953
Life and annuity benefits	1,155,672	1,123,275
Unearned premiums	2,474,277	2,166,105
Payables to insurance and reinsurance companies	256,793	224,921
Senior long-term debt and other debt (estimated fair value of $2,847,000 in 2016 and $2,403,000 in 2015)	2,589,350	2,239,271
Other liabilities	1,064,328	1,030,023
Total Liabilities	17,798,710	17,035,548
Redeemable noncontrolling interests	70,660	62,958
Commitments and contingencies
Shareholders' equity:
Common stock	3,365,750	3,342,357
Retained earnings	3,433,891	3,137,285
Accumulated other comprehensive income	1,727,642	1,354,508
Total Shareholders' Equity	8,527,283	7,834,150
Noncontrolling interests	6,992	6,459
Total Equity	8,534,275	7,840,609
Total Liabilities and Equity	$ 26,403,645	$ 24,939,115

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 9,563,157	$ 9,038,158
Equity securities, cost	2,424,757	2,208,834
Senior long-term debt and other debt, estimated fair value	$ 2,847,000	$ 2,403,000

Consolidated Statements Of Inco

Consolidated Statements Of Income And Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
OPERATING REVENUES
Earned premiums	$ 974,244	$ 963,675	$ 2,882,789	$ 2,864,882
Net investment income	93,147	87,060	279,437	270,521
Other-than-temporary impairment losses	0	(18,281)	(12,080)	(23,373)
Net realized investment gains, excluding other-than-temporary impairment losses	27,416	3,574	77,916	20,342
Net realized investment gains (losses)	27,416	(14,707)	65,836	(3,031)
Other revenues	336,475	306,736	955,339	817,151
Total Operating Revenues	1,431,282	1,342,764	4,183,401	3,949,523
OPERATING EXPENSES
Losses and loss adjustment expenses	579,405	484,737	1,564,925	1,467,926
Underwriting, acquisition and insurance expenses	372,521	365,619	1,112,789	1,085,956
Amortization of intangible assets	17,010	18,914	51,474	50,503
Other expenses	309,713	290,749	862,715	763,986
Total Operating Expenses	1,278,649	1,160,019	3,591,903	3,368,371
Operating Income	152,633	182,745	591,498	581,152
Interest expense	33,152	30,064	97,690	88,664
Loss on early extinguishment of debt	0	0	44,100	0
Income Before Income Taxes	119,481	152,681	449,708	492,488
Income tax expense	36,060	48,271	121,968	101,619
Net Income	83,421	104,410	327,740	390,869
Net income (loss) attributable to noncontrolling interests	(375)	1,891	4,777	5,989
Net Income to Shareholders	83,796	102,519	322,963	384,880
OTHER COMPREHENSIVE INCOME (LOSS)
Net holding gains (losses) arising during the period	23,098	(149,266)	411,394	(258,386)
Change in unrealized other-than-temporary impairment losses on fixed maturities arising during the period	(17)	(8)	(40)	111
Reclassification adjustments for net gains (losses) included in net income	(9,758)	6,000	(33,308)	(8,037)
Change in net unrealized gains on investments, net of taxes	13,323	(143,274)	378,046	(266,312)
Change in foreign currency translation adjustments, net of taxes	(8,349)	(10,854)	(6,141)	(22,283)
Change in net actuarial pension loss, net of taxes	390	475	1,247	1,407
Total Other Comprehensive Income (Loss)	5,364	(153,653)	373,152	(287,188)
Comprehensive Income (Loss)	88,785	(49,243)	700,892	103,681
Comprehensive income (loss) attributable to noncontrolling interests	(376)	1,900	4,795	5,942
Comprehensive Income (Loss) to Shareholders	$ 89,161	$ (51,143)	$ 696,097	$ 97,739
NET INCOME PER SHARE
Basic (in dollars per share)	$ 5.62	$ 7.43	$ 22.27	$ 27.76
Diluted (in dollars per share)	$ 5.60	$ 7.39	$ 22.16	$ 27.60

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Equity [Member]	Total Shareholders' Equity [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests [Member]
Balance at Dec. 31, 2014		$ 7,602,002	$ 7,594,818	$ 3,308,395	$ 2,581,866	$ 1,704,557	$ 7,184
Balance, shares at Dec. 31, 2014				13,962
Balance, redeemable noncontrolling interests at Dec. 31, 2014								$ 61,048
Net income	$ 390,869	385,625	384,880		384,880	0	745	5,244
Other comprehensive income (loss)	(287,188)	(287,141)	(287,141)		0	(287,141)	0	(47)
Comprehensive Income (Loss)	103,681	98,484	97,739				745	5,197
Issuance of common stock		3,971	3,971	$ 3,971	0	0	0	0
Issuance of common stock, shares				20
Repurchase of common stock		(27,262)	(27,262)	$ 0	(27,262)	0	0	0
Repurchase of common stock, shares				(32)
Restricted stock units expensed		19,983	19,983	$ 19,983	0	0	0	0
Restricted stock units expensed, shares				0
Adjustment of redeemable noncontrolling interests		3,091	3,091	$ 0	3,091	0	0	(3,091)
Adjustment of redeemable noncontrolling interests, shares				0
Purchase of noncontrolling interest		(1,447)	(1,447)	$ (1,447)	0	0	0	(8,224)
Purchase of noncontrolling interest, shares				0
Other		4,685	4,337	$ 4,306	31	0	348	(4,346)
Other, shares				0
Balance at Sep. 30, 2015		7,703,507	7,695,230	$ 3,335,208	2,942,606	1,417,416	8,277
Balance, shares at Sep. 30, 2015				13,950
Balance, redeemable noncontrolling interests at Sep. 30, 2015								50,584
Balance at Dec. 31, 2015	7,840,609	7,840,609	7,834,150	$ 3,342,357	3,137,285	1,354,508	6,459
Balance, shares at Dec. 31, 2015				13,959
Balance, redeemable noncontrolling interests at Dec. 31, 2015	62,958							62,958
Net income	327,740	323,568	322,963		322,963	0	605	4,172
Other comprehensive income (loss)	373,152	373,134	373,134		0	373,134	0	18
Comprehensive Income (Loss)	700,892	696,702	696,097				605	4,190
Issuance of common stock		4,531	4,531	$ 4,531	0	0	0	0
Issuance of common stock, shares				48
Repurchase of common stock		(15,503)	(15,503)	$ 0	(15,503)	0	0	0
Repurchase of common stock, shares				(16)
Restricted stock units expensed		18,512	18,512	$ 18,512	0	0	0	0
Restricted stock units expensed, shares				0
Adjustment of redeemable noncontrolling interests		(10,909)	(10,909)	$ 0	(10,909)	0	0	10,909
Adjustment of redeemable noncontrolling interests, shares				0
Purchase of noncontrolling interest		350	350	$ 350	0	0	0	(3,517)
Purchase of noncontrolling interest, shares				0
Other		(17)	55	$ 0	55	0	(72)	(3,880)
Other, shares				0
Balance at Sep. 30, 2016	8,534,275	$ 8,534,275	$ 8,527,283	$ 3,365,750	$ 3,433,891	$ 1,727,642	$ 6,992
Balance, shares at Sep. 30, 2016				13,991
Balance, redeemable noncontrolling interests at Sep. 30, 2016	$ 70,660							$ 70,660

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
OPERATING ACTIVITIES
Net income	$ 327,740	$ 390,869
Adjustments to reconcile net income to net cash provided by operating activities	(3,383)	159,516
Net Cash Provided By Operating Activities	324,357	550,385
INVESTING ACTIVITIES
Proceeds from sales of fixed maturities and equity securities	330,110	211,479
Proceeds from maturities, calls and prepayments of fixed maturities	734,010	1,162,500
Cost of fixed maturities and equity securities purchased	(1,728,396)	(928,601)
Net change in short-term investments	(340,742)	(687,673)
Proceeds from sales of equity method investments	9,325	22,204
Cost of equity method investments	(4,226)	(21,464)
Change in restricted cash and cash equivalents	61,071	136,203
Additions to property and equipment	(49,565)	(62,055)
Acquisitions, net of cash acquired	(5,762)	0
Other	(392)	(761)
Net Cash Used By Investing Activities	(994,567)	(168,168)
FINANCING ACTIVITIES
Additions to senior long-term debt and other debt	553,537	49,771
Repayment of senior long-term debt and other debt	(260,086)	(55,743)
Premiums and fees related to early extinguishment of debt	(43,691)	0
Repurchases of common stock	(15,503)	(27,262)
Issuance of common stock	4,531	3,971
Payment of contingent consideration	(14,219)	(9,263)
Purchase of noncontrolling interests	(3,167)	(12,474)
Distributions to noncontrolling interests	(3,931)	(3,724)
Other	(14,478)	(1,957)
Net Cash Provided (Used) By Financing Activities	202,993	(56,681)
Effect of foreign currency rate changes on cash and cash equivalents	(6,394)	(24,504)
Increase (decrease) in cash and cash equivalents	(473,611)	301,032
Cash and cash equivalents at beginning of period	2,630,009	1,960,169
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 2,156,398	$ 2,261,201

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies a) Basis of Presentation. Markel Corporation is a diverse financial holding company serving a variety of niche markets. Markel Corporation's principal business markets and underwrites specialty insurance products and programs. Through its wholly-owned subsidiary, Markel Ventures, Inc. (Markel Ventures), Markel Corporation also owns interests in various industrial and service businesses that operate outside of the specialty insurance marketplace. The consolidated balance sheet as of September 30, 2016 , the related consolidated statements of income and comprehensive income (loss) for the quarters and nine months ended September 30, 2016 and 2015 , and the consolidated statements of changes in equity and cash flows for the nine months ended September 30, 2016 and 2015 are unaudited. In the opinion of management, all adjustments necessary for fair presentation of such consolidated financial statements have been included. Such adjustments consist only of normal, recurring items. Interim results are not necessarily indicative of results of operations for the entire year. The consolidated balance sheet as of December 31, 2015 was derived from Markel Corporation's audited annual consolidated financial statements. The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and include the accounts of Markel Corporation and its consolidated subsidiaries, as well as any variable interest entities (VIEs) that meet the requirements for consolidation (the Company). All significant intercompany balances and transactions have been eliminated in consolidation. The Company consolidates the results of its Markel Ventures subsidiaries on a one-month lag. Certain prior year amounts have been reclassified to conform to the current presentation. The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results may differ materially from the estimates and assumptions used in preparing the consolidated financial statements. The consolidated financial statements and notes are presented as permitted by Form 10-Q and do not contain certain information included in the Company's annual consolidated financial statements and notes. In addition to the policies set forth below, readers are urged to review the Company's 2015 Annual Report on Form 10-K for a more complete description of the Company's business and accounting policies. b) Variable Interest Entities. The Company determines whether it has relationships with entities defined as VIEs in accordance with Accounting Standards Codification (ASC) Topic 810, Consolidation . Under this guidance, a VIE is consolidated by the variable interest holder that is determined to be the primary beneficiary. An entity in which the Company holds a variable interest is a VIE if any of the following conditions exist: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support, (b) as a group, the holders of equity investment at risk lack either the direct or indirect ability through voting rights or similar rights to make decisions about an entity's activities that most significantly impact the entity’s economic performance or the obligation to absorb the expected losses or right to receive the expected residual returns, or (c) the voting rights of some investors are disproportionate to their obligation to absorb the expected losses of the entity, their rights to receive the expected residual returns of the entity, or both and substantially all of the entity's activities either involve or are conducted on behalf of an investor with disproportionately few voting rights. The primary beneficiary is defined as the variable interest holder that is determined to have the controlling financial interest as a result of having both (a) the power to direct the activities of a VIE that most significantly impact the economic performance of the VIE and (b) the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether an entity is a VIE at the inception of our variable interest in the entity and upon the occurrence of certain reconsideration events. The Company continually reassesses whether it is the primary beneficiary of VIEs in which it holds a variable interest. c) Revenue Recognition. Investment Management and Performance Fees Investment management fee income is recognized over the period in which investment management services are provided and is calculated and billed monthly based on the net asset value of the accounts managed. Performance fee arrangements entitle the Company to participate, on a fixed-percentage basis, in any net income generated in excess of an agreed-upon threshold as established by the underlying investment management agreements. In general, net income is calculated at the end of each calendar year and performance fees are payable annually. Following the preferred method identified in the ASC Topic 605, Revenue Recognition , such performance fee income is recorded at the conclusion of the contractual performance period, when all contingencies are resolved.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Effective January 1, 2016, the Company adopted Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis , which changes the way reporting enterprises evaluate whether (a) they should consolidate limited partnerships and similar entities, (b) fees paid to a decision maker or service provider are variable interests in a VIE, and (c) variable interests in a VIE held by related parties of the reporting enterprise require the reporting enterprise to consolidate the VIE. It also eliminates the VIE consolidation model based on majority exposure to variability that applied to certain investment companies and similar entities. The ASU also significantly changes how to evaluate voting rights for entities that are not similar to limited partnerships when determining whether the entity is a VIE, which may affect entities for which the decision making rights are conveyed through a contractual arrangement. The adoption of this guidance did not result in any changes to our previous consolidation conclusions. Effective January 1, 2016, the Company adopted FASB ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs . ASU No. 2015-03 requires that debt issuance costs related to a recognized debt liability be presented on the balance sheet as a direct deduction from the debt liability, similar to the presentation of debt discounts. The cost of issuing debt is no longer recorded as a separate asset on the balance sheet. The amortization of debt issuance costs continues to be included in interest expense. ASU No. 2015-03 was applied retrospectively to all periods presented. As a result, debt issuance costs totaling $2.2 million were reclassified from other assets to senior long-term debt and other debt as of December 31, 2015. The adoption of this ASU did not have an impact on the Company's results of operations or cash flows. Effective January 1, 2016, the Company adopted FASB ASU No. 2015-05, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement , which clarifies that software licenses contained in a cloud computing arrangement should be capitalized if the customer has the right to take possession of the software and the ability to run the software outside of the cloud computing arrangement. The adoption of this ASU did not have an impact on the Company's financial position, results of operations or cash flows. Effective January 1, 2016, the Company adopted FASB ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments . ASU No. 2015-16 eliminates the requirement to retrospectively adjust the financial statements for measurement-period adjustments that occur in periods after a business combination is consummated. The adoption of this ASU did not have an impact on the Company's financial position, results of operations or cash flows and will be applied on a prospective basis, as applicable. During the second quarter of 2016, the Company early adopted FASB ASU No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting , which changes several aspects of the accounting for share-based payment award transactions. Under the new guidance, all excess tax benefits or deficiencies associated with share-based payment award transactions are required to be recognized as an income tax benefit or expense in net income when the awards vest or are settled, with the corresponding cash flows recognized as an operating activity in the statement of cash flows. Excess tax benefits and deficiencies are no longer recognized in additional paid-in-capital. The new guidance also allows an employer to repurchase more of an employee's shares for tax witholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur, rather than estimating forfeitures upon issuance of the award. Upon adoption of ASU No. 2016-09, the Company elected to account for forfeitures as they occur, which had no impact on the consolidated financial statements. The provisions of ASU No. 2016-09 were adopted as of January 1, 2016 on a prospective basis and did not have a material impact on the Company's financial position, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which creates a new comprehensive revenue recognition standard that will serve as a single source of revenue guidance for all companies in all industries. The guidance applies to all companies that either enter into contracts with customers to transfer goods or services or enter into contracts for the transfer of nonfinancial assets, unless those contracts are within the scope of other standards, such as insurance contracts. ASU No. 2014-09's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under the current guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606), Deferral of the Effective Date , which deferred the original effective date of ASU No. 2014-09 by one year. As a result, ASU No. 2014-09 becomes effective for the Company during the first quarter of 2018 and may be applied retrospectively or under a modified retrospective method where the cumulative effect is recognized at the date of initial application. Early application is permitted, but not before the first quarter of 2017. ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Consideration (Reporting Revenue Gross versus Net), ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing and ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients were issued in March, April and May 2016, respectively, as amendments to ASU No. 2014-09. These amendments will be evaluated and adopted in conjunction with ASU No. 2014-09. The Company is currently evaluating ASU No. 2014-09, and the related amendments, to determine the potential impact that adopting this standard will have on its consolidated financial statements. Adoption of this ASU is not expected to have a material impact on the Company's insurance operations, but may have a material impact on the Company's non-insurance operations. In May 2015, the FASB issued ASU No. 2015-09, Financial Services-Insurance (Topic 944): Disclosures about Short-Duration Contracts . The ASU requires significant new disclosures for insurers relating to short-duration insurance contract claims and the unpaid claims liability rollforward for long and short-duration contracts. The guidance requires annual tabular disclosure, on a disaggregated basis, of undiscounted incurred and paid claim and allocated claim adjustment expense development by accident year, on a net basis after reinsurance, for up to 10 years. Tables must also include the total incurred but not reported claims liabilities, plus expected development on reported claims, and claims frequency for each accident year. A description of estimation methodologies and any significant changes in methodologies and assumptions used to calculate the liability and frequency is also required. Based on the disaggregated claims information in the tables, disclosure of historical average annual percentage payout of incurred claims is also required. Interim period disclosures must include a tabular rollforward and related qualitative information for the liability for unpaid losses and loss adjustment expenses. Annual disclosures required by ASU No. 2015-09 become effective for the Company during 2016, with interim disclosures required beginning in the first quarter of 2017. The ASU must be applied retrospectively by providing comparative disclosures for each period presented. Early application is permitted. The adoption of this ASU will not have an impact on the Company's financial position, results of operations or cash flows, but will expand the nature and extent of its insurance contract disclosures, as described above. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory . The ASU changes the measurement principle for inventory from the lower of cost or market to lower of cost and net realizable value and eliminates the requirement to consider replacement cost or net realizable value less an approximately normal profit margin when measuring inventory. ASU No. 2015-11 becomes effective for the Company during the first quarter of 2017 and will be applied prospectively. Adoption of this ASU is not expected to have a material impact on the Company's financial position, results of operations or cash flows. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments (Topic 825): Recognition and Measurement of Financial Assets and Financial Liabilities . The ASU significantly changes the income statement impact of equity investments and the recognition of changes in fair value of financial liabilities attributable to an entity's own credit risk when the fair value option is elected. The ASU requires equity instruments that do not result in consolidation and are not accounted for under the equity method to be measured at fair value and to recognize any changes in fair value in net income rather than other comprehensive income (loss). ASU No. 2016-01 becomes effective for the Company during the first quarter of 2018 and will be applied using a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The provisions related to equity investments without a readily determinable fair value will be applied prospectively to equity investments as of the adoption date. Early adoption is permitted for certain provisions of the ASU. The Company is currently evaluating ASU No. 2016-01 to determine the potential impact that adopting this standard will have on the consolidated financial statements. Adoption of this ASU is not expected to have a material impact on the Company's financial position, cash flows, or total comprehensive income (loss), but will have a significant impact on the Company's results of operations as changes in fair value will be presented in net income rather than other comprehensive income (loss). In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . The ASU requires lessees to put most leases on their balance sheets as a lease liability with a corresponding right-of-use asset, but continue to recognize the related leasing expense within net income. The guidance also eliminates the real estate-specific provisions for all entities. For lessors, the guidance modifies the classification criteria and the accounting for sales-type and direct financing leases. ASU No. 2016-02 becomes effective for the Company during the first quarter of 2019 and will be applied under a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. Early adoption is permitted. The Company is currently evaluating ASU No. 2016-02 to determine the potential impact that adopting this standard will have on the consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-07, Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting. The ASU eliminates the requirement for an investor to retroactively apply the equity method when its increase in ownership interest or degree of influence in an investee triggers equity method accounting. ASU No. 2016-07 becomes effective for the Company during the first quarter of 2017 and will be applied prospectively. Early adoption is permitted. Adoption of this ASU is not expected to have an impact on the Company's financial position, results of operations or cash flows. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU replaces the current incurred loss model used to measure impairment losses with an expected loss model for trade, reinsurance, and other receivables as well as financial instruments measured at amortized cost. For available-for-sale debt securities, the ASU requires entities to record impairments as an allowance, rather than a reduction of the amortized cost, as is currently required under the other-than-temporary impairment model. ASU No. 2016-13 becomes effective for the Company during the first quarter of 2020 and will be applied using a modified-retrospective approach through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The Company is currently evaluating ASU No. 2016-13 to determine the potential impact that adopting this standard will have on the consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. Some of the topics covered by the ASU include the classification of debt prepayment and extinguishment costs, contingent consideration payments made after a business combination and distributions from equity method investees. ASU No. 2016-15 becomes effective for the Company during the first quarter of 2018 and will be applied using a retrospective transition approach. Early adoption is permitted. The Company is currently evaluating ASU No. 2016-15 to determine the potential impact that adopting this standard will have on the consolidated statements of cash flows. Adoption of this ASU will not impact the Company's financial position or results of operations and is not expected to have a material impact on the Company's consolidated statements of cash flows.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Acquisitions	Acquisitions In December 2015, the Company acquired 80% of the outstanding shares of CapTech Ventures, Inc. (CapTech), a privately held company headquartered in Richmond, Virginia. CapTech is a management and IT consulting firm, providing services and solutions to a wide array of customers. Total consideration for the CapTech acquisition was $60.6 million , which included the estimated fair value of contingent consideration the Company expected to pay based on CapTech's earnings, as defined in the stock purchase agreement, through 2018. As of December 31, 2015, the purchase price was preliminarily allocated to the acquired assets and liabilities based on the estimated fair values at the acquisition date. During the first quarter of 2016, the Company completed the process of determining the fair value of the assets and liabilities acquired with CapTech. There were no material adjustments to the provisional estimates recorded as of December 31, 2015. However, during the third quarter of 2016, the Company increased its estimate of the contingent consideration it expects to pay based on an increase in the estimate of CapTech's earnings beyond the initial projection, which resulted in a charge to other expenses of $10.3 million . Results attributable to this acquisition are included with the Company's non-insurance operations, which are not included in a reportable segment.

Investments

Investments	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Investments	Investments a) The following tables summarize the Company's available-for-sale investments. September 30, 2016 (dollars in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Unrealized Other-Than- Temporary Impairment Losses Estimated Fair Value Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 659,539 $ 24,943 $ (99 ) $ — $ 684,383 Obligations of states, municipalities and political subdivisions 4,259,553 318,183 (3,081 ) — 4,574,655 Foreign governments 1,334,364 237,498 (15 ) — 1,571,847 Commercial mortgage-backed securities 981,613 46,791 (396 ) — 1,028,008 Residential mortgage-backed securities 780,631 49,568 (586 ) (2,258 ) 827,355 Asset-backed securities 27,911 83 (16 ) — 27,978 Corporate bonds 1,519,546 87,459 (1,071 ) (1,673 ) 1,604,261 Total fixed maturities 9,563,157 764,525 (5,264 ) (3,931 ) 10,318,487 Equity securities: Insurance, banks and other financial institutions 841,416 807,430 (9,770 ) — 1,639,076 Industrial, consumer and all other 1,583,341 1,295,784 (7,774 ) — 2,871,351 Total equity securities 2,424,757 2,103,214 (17,544 ) — 4,510,427 Short-term investments 1,989,124 181 — — 1,989,305 Investments, available-for-sale $ 13,977,038 $ 2,867,920 $ (22,808 ) $ (3,931 ) $ 16,818,219 December 31, 2015 (dollars in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Unrealized Other-Than- Temporary Impairment Losses Estimated Fair Value Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 695,652 $ 9,836 $ (4,781 ) $ — $ 700,707 Obligations of states, municipalities and political subdivisions 3,817,136 204,302 (8,225 ) — 4,013,213 Foreign governments 1,302,329 115,809 (1,681 ) — 1,416,457 Commercial mortgage-backed securities 657,670 6,867 (4,999 ) — 659,538 Residential mortgage-backed securities 837,964 22,563 (4,022 ) (2,258 ) 854,247 Asset-backed securities 36,462 15 (406 ) — 36,071 Corporate bonds 1,690,945 41,123 (16,209 ) (1,624 ) 1,714,235 Total fixed maturities 9,038,158 400,515 (40,323 ) (3,882 ) 9,394,468 Equity securities: Insurance, banks and other financial institutions 651,002 690,271 (6,551 ) — 1,334,722 Industrial, consumer and all other 1,557,832 1,227,052 (45,131 ) — 2,739,753 Total equity securities 2,208,834 1,917,323 (51,682 ) — 4,074,475 Short-term investments 1,642,103 167 (9 ) — 1,642,261 Investments, available-for-sale $ 12,889,095 $ 2,318,005 $ (92,014 ) $ (3,882 ) $ 15,111,204 b) The following tables summarize gross unrealized investment losses by the length of time that securities have continuously been in an unrealized loss position. September 30, 2016 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 26,599 $ (96 ) $ 7,700 $ (3 ) $ 34,299 $ (99 ) Obligations of states, municipalities and political subdivisions 156,618 (1,404 ) 42,834 (1,677 ) 199,452 (3,081 ) Foreign governments 7,159 (10 ) 5,015 (5 ) 12,174 (15 ) Commercial mortgage-backed securities 14,318 (45 ) 43,475 (351 ) 57,793 (396 ) Residential mortgage-backed securities 7,473 (2,311 ) 85,864 (533 ) 93,337 (2,844 ) Asset-backed securities 6,312 (5 ) 6,236 (11 ) 12,548 (16 ) Corporate bonds 73,320 (1,736 ) 95,302 (1,008 ) 168,622 (2,744 ) Total fixed maturities 291,799 (5,607 ) 286,426 (3,588 ) 578,225 (9,195 ) Equity securities: Insurance, banks and other financial institutions 22,769 (1,456 ) 37,751 (8,314 ) 60,520 (9,770 ) Industrial, consumer and all other 23,713 (2,315 ) 138,245 (5,459 ) 161,958 (7,774 ) Total equity securities 46,482 (3,771 ) 175,996 (13,773 ) 222,478 (17,544 ) Total $ 338,281 $ (9,378 ) $ 462,422 $ (17,361 ) $ 800,703 $ (26,739 ) At September 30, 2016 , the Company held 220 securities with a total estimated fair value of $800.7 million and gross unrealized losses of $26.7 million . Of these 220 securities, 118 securities had been in a continuous unrealized loss position for one year or longer and had a total estimated fair value of $462.4 million and gross unrealized losses of $17.4 million . Of these securities, 101 securities were fixed maturities and 17 were equity securities. The Company does not intend to sell or believe it will be required to sell these fixed maturities before recovery of their amortized cost. The Company has the ability and intent to hold these equity securities for a period of time sufficient to allow for the anticipated recovery of their fair value. December 31, 2015 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 427,003 $ (3,648 ) $ 92,552 $ (1,133 ) $ 519,555 $ (4,781 ) Obligations of states, municipalities and political subdivisions 169,362 (4,864 ) 70,101 (3,361 ) 239,463 (8,225 ) Foreign governments 51,328 (249 ) 40,345 (1,432 ) 91,673 (1,681 ) Commercial mortgage-backed securities 289,058 (3,600 ) 95,843 (1,399 ) 384,901 (4,999 ) Residential mortgage-backed securities 78,814 (2,858 ) 137,100 (3,422 ) 215,914 (6,280 ) Asset-backed securities 6,228 (54 ) 24,315 (352 ) 30,543 (406 ) Corporate bonds 470,694 (9,509 ) 343,737 (8,324 ) 814,431 (17,833 ) Total fixed maturities 1,492,487 (24,782 ) 803,993 (19,423 ) 2,296,480 (44,205 ) Equity securities: Insurance, banks and other financial institutions 63,873 (6,384 ) 6,247 (167 ) 70,120 (6,551 ) Industrial, consumer and all other 344,857 (44,879 ) 2,907 (252 ) 347,764 (45,131 ) Total equity securities 408,730 (51,263 ) 9,154 (419 ) 417,884 (51,682 ) Short-term investments 129,473 (9 ) — — 129,473 (9 ) Total $ 2,030,690 $ (76,054 ) $ 813,147 $ (19,842 ) $ 2,843,837 $ (95,896 ) At December 31, 2015 , the Company held 659 securities with a total estimated fair value of $2.8 billion and gross unrealized losses of $95.9 million . Of these 659 securities, 271 securities had been in a continuous unrealized loss position for one year or longer and had a total estimated fair value of $813.1 million and gross unrealized losses of $19.8 million . Of these securities, 264 securities were fixed maturities and seven were equity securities. The Company completes a detailed analysis each quarter to assess whether the decline in the fair value of any investment below its cost basis is deemed other-than-temporary. All securities with unrealized losses are reviewed. The Company considers many factors in completing its quarterly review of securities with unrealized losses for other-than-temporary impairment, including the length of time and the extent to which fair value has been below cost and the financial condition and near-term prospects of the issuer. For equity securities, the ability and intent to hold the security for a period of time sufficient to allow for anticipated recovery is considered. For fixed maturities, the Company considers whether it intends to sell the security or if it is more likely than not that it will be required to sell the security before recovery, the implied yield-to-maturity, the credit quality of the issuer and the ability to recover all amounts outstanding when contractually due. For equity securities, a decline in fair value that is considered to be other-than-temporary is recognized in net income based on the fair value of the security at the time of assessment, resulting in a new cost basis for the security. For fixed maturities where the Company intends to sell the security or it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost, a decline in fair value is considered to be other-than-temporary and is recognized in net income based on the fair value of the security at the time of assessment, resulting in a new cost basis for the security. If the decline in fair value of a fixed maturity below its amortized cost is considered to be other-than-temporary based upon other considerations, the Company compares the estimated present value of the cash flows expected to be collected to the amortized cost of the security. The extent to which the estimated present value of the cash flows expected to be collected is less than the amortized cost of the security represents the credit-related portion of the other-than-temporary impairment, which is recognized in net income, resulting in a new cost basis for the security. Any remaining decline in fair value represents the non-credit portion of the other-than-temporary impairment, which is recognized in other comprehensive income (loss). The discount rate used to calculate the estimated present value of the cash flows expected to be collected is the effective interest rate implicit for the security at the date of purchase. When assessing whether it intends to sell a fixed maturity or if it is likely to be required to sell a fixed maturity before recovery of its amortized cost, the Company evaluates facts and circumstances including decisions to reposition the investment portfolio, potential sales of investments to meet cash flow needs and, ultimately, current market prices. c) The amortized cost and estimated fair value of fixed maturities at September 30, 2016 are shown below by contractual maturity. (dollars in thousands) Amortized Cost Estimated Fair Value Due in one year or less $ 798,670 $ 803,039 Due after one year through five years 1,292,802 1,349,605 Due after five years through ten years 1,650,289 1,791,219 Due after ten years 4,031,241 4,491,283 7,773,002 8,435,146 Commercial mortgage-backed securities 981,613 1,028,008 Residential mortgage-backed securities 780,631 827,355 Asset-backed securities 27,911 27,978 Total fixed maturities $ 9,563,157 $ 10,318,487 d) The following table presents the components of net investment income. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Interest: Municipal bonds (tax-exempt) $ 22,136 $ 21,979 $ 66,621 $ 72,124 Municipal bonds (taxable) 16,710 14,667 48,820 42,917 Other taxable bonds 36,697 34,368 108,975 103,519 Short-term investments, including overnight deposits 2,878 1,287 7,823 3,654 Dividends on equity securities 17,308 17,887 51,718 55,544 Income (loss) from equity method investments 1,232 (4 ) 4,900 3,052 Other (60 ) 37 2,614 577 96,901 90,221 291,471 281,387 Investment expenses (3,754 ) (3,161 ) (12,034 ) (10,866 ) Net investment income $ 93,147 $ 87,060 $ 279,437 $ 270,521 e) The following table presents net realized investment gains (losses) and the change in net unrealized gains on investments. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Realized gains: Sales of fixed maturities $ 3,698 $ 435 $ 4,658 $ 2,769 Sales of equity securities 18,418 11,329 63,931 34,285 Other 423 1,026 1,117 3,297 Total realized gains 22,539 12,790 69,706 40,351 Realized losses: Sales of fixed maturities (60 ) (3,730 ) (608 ) (3,947 ) Sales of equity securities (4,187 ) (400 ) (6,672 ) (672 ) Other-than-temporary impairments — (18,281 ) (12,080 ) (23,373 ) Other (55 ) (279 ) (2,972 ) (364 ) Total realized losses (4,302 ) (22,690 ) (22,332 ) (28,356 ) Gains (losses) on securities measured at fair value through net income 9,179 (4,807 ) 18,462 (15,026 ) Net realized investment gains (losses) $ 27,416 $ (14,707 ) $ 65,836 $ (3,031 ) Change in net unrealized gains on investments included in other comprehensive income (loss): Fixed maturities $ (53,962 ) $ 102,844 $ 399,020 $ (77,369 ) Equity securities 80,285 (313,075 ) 220,029 (319,522 ) Short-term investments 58 45 23 36 Net increase (decrease) $ 26,381 $ (210,186 ) $ 619,072 $ (396,855 ) There were no write downs for other-than-temporary declines in the estimated fair value of investments for the quarter ended September 30, 2016. For the nine months ended September 30, 2016 , other-than-temporary impairment losses recognized in net income and included in net realized investment gains totaled $12.1 million and were attributable to 21 equity securities. The write downs for the nine-month period included $10.8 million related to equities in industrial, consumer, or other types of businesses and $1.3 million related to equities in insurance, banks, and other financial institutions. For the quarter ended September 30, 2015 , other-than-temporary impairment losses recognized in net income and included in net realized investment losses totaled $18.3 million and were attributable to eight equity securities. The write downs for the quarter included $14.3 million related to equities in industrial, consumer, or other types of businesses and $4.0 million related to equities in insurance, banks, and other financial institutions. For the nine months ended September 30, 2015 , other-than-temporary impairment losses recognized in net income and included in net realized investment losses totaled $23.4 million and were attributable to 16 equity securities. The write downs for the nine-month period included $18.8 million related to equities in industrial, consumer, or other types of businesses and $4.6 million related to equities in insurance, banks, and other financial institutions.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements FASB ASC 820-10, Fair Value Measurements and Disclosures, establishes a three-level hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure the assets or liabilities fall within different levels of the hierarchy, the classification is based on the lowest level input that is significant to the fair value measurement of the asset or liability. Classification of assets and liabilities within the hierarchy considers the markets in which the assets and liabilities are traded and the reliability and transparency of the assumptions used to determine fair value. The hierarchy requires the use of observable market data when available. The levels of the hierarchy are defined as follows: Level 1 – Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities traded in active markets. Level 2 – Inputs to the valuation methodology include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and market-corroborated inputs. Level 3 – Inputs to the valuation methodology are unobservable for the asset or liability and are significant to the fair value measurement. In accordance with FASB ASC 820, the Company determines fair value based on 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. In determining fair value, the Company uses various methods, including the market, income and cost approaches. The Company uses valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The following section describes the valuation methodologies used by the Company to measure assets and liabilities at fair value, including an indication of the level within the fair value hierarchy in which each asset or liability is generally classified. Investments available-for-sale. Investments available-for-sale are recorded at fair value on a recurring basis and include fixed maturities, equity securities and short-term investments. Short-term investments include certificates of deposit, commercial paper, discount notes and treasury bills with original maturities of one year or less. Fair value for investments available-for-sale is determined by the Company after considering various sources of information, including information provided by a third party pricing service. The pricing service provides prices for substantially all of the Company's fixed maturities and equity securities. In determining fair value, the Company generally does not adjust the prices obtained from the pricing service. The Company obtains an understanding of the pricing service's valuation methodologies and related inputs, which include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers, duration, credit ratings, estimated cash flows and prepayment speeds. The Company validates prices provided by the pricing service by reviewing prices from other pricing sources and analyzing pricing data in certain instances. The Company has evaluated the various types of securities in its investment portfolio to determine an appropriate fair value hierarchy level based upon trading activity and the observability of market inputs. Level 1 investments include those traded on an active exchange, such as the New York Stock Exchange. Level 2 investments include U.S. Treasury securities and obligations of U.S. government agencies, municipal bonds, foreign government bonds, commercial mortgage-backed securities, residential mortgage-backed securities, asset-backed securities and corporate debt securities. Level 3 investments include the Company's investments in insurance-linked securities funds (the ILS Funds), as further described in note 12 , which are not traded on an active exchange and are valued using unobservable inputs. Fair value for investments available-for-sale is measured based upon quoted prices in active markets, if available. Due to variations in trading volumes and the lack of quoted market prices, fixed maturities are classified as Level 2 investments. The fair value of fixed maturities is normally derived through recent reported trades for identical or similar securities, making adjustments through the reporting date based upon available market observable data described above. If there are no recent reported trades, the fair value of fixed maturities may be derived through the use of matrix pricing or model processes, where future cash flow expectations are developed based upon collateral performance and discounted at an estimated market rate. Significant inputs used to determine the fair value of obligations of states, municipalities and political subdivisions, corporate bonds and obligations of foreign governments include reported trades, benchmark yields, issuer spreads, bids, offers, credit information and estimated cash flows. Significant inputs used to determine the fair value of commercial mortgage-backed securities, residential mortgage-backed securities and asset-backed securities include the type of underlying assets, benchmark yields, prepayment speeds, collateral information, tranche type and volatility, estimated cash flows, credit information, default rates, recovery rates, issuer spreads and the year of issue. Due to the significance of unobservable inputs required in measuring the fair value of the Company's investments in the ILS Funds, these investments are classified as Level 3 within the fair value hierarchy. Changes in fair value of the ILS Funds are included in net realized gains (losses) in net income. The fair value of the securities are derived using their reported net asset value (NAV) as the primary input, as well as other observable and unobservable inputs as deemed necessary by management. Management has obtained an understanding of the inputs, assumptions, process, and controls used to determine NAV, which is calculated by an independent third party. Unobservable inputs to the NAV calculations include assumptions around premium earnings patterns and loss reserve estimates for the underlying securitized reinsurance contracts in which the ILS Funds invest. Significant unobservable inputs used in the valuation of these investments include an adjustment to include the fair value of the equity that was issued by one of the ILS Funds in exchange for notes receivable, rather than cash, which is excluded from NAV. The Company's investments in the ILS Funds are redeemable annually as of January 1 st of each calendar year. The Company's valuation policies and procedures for Level 3 investments are determined by management. Fair value measurements are analyzed quarterly to ensure the change in fair value from prior periods is reasonable relative to management's understanding of the underlying investments, recent market trends and external market data, which includes the price of a comparable security and an insurance-linked security index. Senior long-term debt and other debt. Senior long-term debt and other debt is carried at amortized cost with the estimated fair value disclosed on the consolidated balance sheets. Senior long-term debt and other debt is classified as Level 2 within the fair value hierarchy due to variations in trading volumes and the lack of quoted market prices. Fair value for senior long-term debt and other debt is generally derived through recent reported trades for identical securities, making adjustments through the reporting date, if necessary, based upon available market observable data including U.S. Treasury securities and implied credit spreads. Significant inputs used to determine the fair value of senior long-term debt and other debt include reported trades, benchmark yields, issuer spreads, bids and offers. The following tables present the balances of assets measured at fair value on a recurring basis by level within the fair value hierarchy. September 30, 2016 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments available-for-sale: Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ 684,383 $ — $ 684,383 Obligations of states, municipalities and political subdivisions — 4,574,655 — 4,574,655 Foreign governments — 1,571,847 — 1,571,847 Commercial mortgage-backed securities — 1,028,008 — 1,028,008 Residential mortgage-backed securities — 827,355 — 827,355 Asset-backed securities — 27,978 — 27,978 Corporate bonds — 1,604,261 — 1,604,261 Total fixed maturities — 10,318,487 — 10,318,487 Equity securities: Insurance, banks and other financial institutions 1,448,672 — 190,404 1,639,076 Industrial, consumer and all other 2,871,351 — — 2,871,351 Total equity securities 4,320,023 — 190,404 4,510,427 Short-term investments 1,903,399 85,906 — 1,989,305 Total investments available-for-sale $ 6,223,422 $ 10,404,393 $ 190,404 $ 16,818,219 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments available-for-sale: Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ 700,707 $ — $ 700,707 Obligations of states, municipalities and political subdivisions — 4,013,213 — 4,013,213 Foreign governments — 1,416,457 — 1,416,457 Commercial mortgage-backed securities — 659,538 — 659,538 Residential mortgage-backed securities — 854,247 — 854,247 Asset-backed securities — 36,071 — 36,071 Corporate bonds — 1,714,235 — 1,714,235 Total fixed maturities — 9,394,468 — 9,394,468 Equity securities: Insurance, banks and other financial institutions 1,334,722 — — 1,334,722 Industrial, consumer and all other 2,739,753 — — 2,739,753 Total equity securities 4,074,475 — — 4,074,475 Short-term investments 1,529,924 112,337 — 1,642,261 Total investments available-for-sale $ 5,604,399 $ 9,506,805 $ — $ 15,111,204 The following table summarizes changes in Level 3 investments measured at fair value on a recurring basis. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Equity securities, beginning of period $ 183,523 $ — $ — $ — Purchases — — 195,250 — Sales — — (25,000 ) — Total gains included in: Net income 6,881 — 20,154 — Other comprehensive income (loss) — — — — Transfers into Level 3 — — — — Transfers out of Level 3 — — — — Equity securities, end of period $ 190,404 $ — $ 190,404 $ — Net unrealized gains included in net income relating to assets held at September 30, 2016 and 2015 (1) $ 6,881 $ — $ 20,154 $ — (1) Included in net realized investment gains in the consolidated statements of income and comprehensive income (loss). There were no transfers into or out of Level 1 and Level 2 during the quarter and nine months ended September 30, 2016 and 2015 . The Company did not have any assets or liabilities measured at fair value on a non-recurring basis during the nine months ended September 30, 2016 and 2015 .

Segment Reporting Disclosures

Segment Reporting Disclosures	9 Months Ended
	Sep. 30, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Segment Reporting Disclosures	Segment Reporting Disclosures The Company monitors and reports its ongoing underwriting operations in the following three segments: U.S. Insurance, International Insurance and Reinsurance. In determining how to aggregate and monitor its underwriting results, the Company considers many factors, including the geographic location and regulatory environment of the insurance entity underwriting the risk, the nature of the insurance product sold, the type of account written and the type of customer served. The U.S. Insurance segment includes all direct business and facultative placements written by the Company's insurance subsidiaries domiciled in the United States. The International Insurance segment includes all direct business and facultative placements written by the Company's insurance subsidiaries domiciled outside of the United States, including the Company's syndicate at Lloyd's of London. The Reinsurance segment includes all treaty reinsurance written across the Company. Results for lines of business discontinued prior to, or in conjunction with, acquisitions, including the results attributable to the run-off of life and annuity reinsurance business, are reported in the Other Insurance (Discontinued Lines) segment. All investing activities related to the Company's insurance operations are included in the Investing segment. The Company's non-insurance operations include the Company's Markel Ventures operations, which primarily consist of controlling interests in various industrial and service businesses. The Company's non-insurance operations also include the results of the Company's legal and professional consulting services, and, effective December 8, 2015, the results of the Company's investment management services attributable to Markel CATCo Investment Management Ltd. For purposes of segment reporting, the Company's non-insurance operations are not considered to be a reportable segment. Segment profit for the Investing segment is measured by net investment income and net realized investment gains or losses. Segment profit or loss for each of the Company's underwriting segments is measured by underwriting profit or loss. The property and casualty insurance industry commonly defines underwriting profit or loss as earned premiums net of losses and loss adjustment expenses and underwriting, acquisition and insurance expenses. Underwriting profit or loss does not replace operating income or net income computed in accordance with U.S. GAAP as a measure of profitability. Underwriting profit or loss provides a basis for management to evaluate the Company's underwriting performance. Segment profit or loss for the Company's underwriting segments also includes other revenues and other expenses, primarily related to the run-off of managing general agent operations that were discontinued in conjunction with acquisitions. Other revenues and other expenses in the Other Insurance (Discontinued Lines) segment are comprised of the results attributable to the run-off of life and annuity reinsurance business. For management reporting purposes, the Company allocates assets to its underwriting, investing and non-insurance operations. Underwriting assets are all assets not specifically allocated to the Investing segment or to the Company's non-insurance operations. Underwriting and investing assets are not allocated to the U.S. Insurance, International Insurance, Reinsurance or Other Insurance (Discontinued Lines) segments since the Company does not manage its assets by underwriting segment. The Company does not allocate capital expenditures for long-lived assets to any of its underwriting segments for management reporting purposes. a) The following tables summarize the Company's segment disclosures. Quarter Ended September 30, 2016 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 663,196 $ 269,093 $ 196,948 $ 536 $ — $ 1,129,773 Net written premiums 562,215 209,656 157,043 469 — 929,383 Earned premiums 548,792 218,968 206,018 466 — 974,244 Losses and loss adjustment expenses: Current accident year (370,435 ) (159,812 ) (129,875 ) — — (660,122 ) Prior accident years 21,471 42,705 19,135 (2,594 ) — 80,717 Underwriting, acquisition and insurance expenses (206,628 ) (82,791 ) (82,490 ) (612 ) — (372,521 ) Underwriting profit (loss) (6,800 ) 19,070 12,788 (2,740 ) — 22,318 Net investment income — — — — 93,147 93,147 Net realized investment gains — — — — 27,416 27,416 Other revenues (insurance) 1,285 419 — 466 — 2,170 Other expenses (insurance) (670 ) (677 ) — (4,232 ) — (5,579 ) Segment profit (loss) $ (6,185 ) $ 18,812 $ 12,788 $ (6,506 ) $ 120,563 $ 139,472 Other revenues (non-insurance) 334,305 Other expenses (non-insurance) (304,134 ) Amortization of intangible assets (17,010 ) Interest expense (33,152 ) Income before income taxes $ 119,481 U.S. GAAP combined ratio (1) 101 % 91 % 94 % NM (2) 98 % Quarter Ended September 30, 2015 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 635,926 $ 284,576 $ 239,094 $ (1,232 ) $ — $ 1,158,364 Net written premiums 536,285 213,423 204,336 (860 ) — 953,184 Earned premiums 534,615 225,034 204,825 (799 ) — 963,675 Losses and loss adjustment expenses: Current accident year (357,400 ) (162,024 ) (128,428 ) — — (647,852 ) Prior accident years 74,976 57,860 24,241 6,038 — 163,115 Underwriting, acquisition and insurance expenses (200,272 ) (92,680 ) (72,449 ) (218 ) — (365,619 ) Underwriting profit 51,919 28,190 28,189 5,021 — 113,319 Net investment income — — — — 87,060 87,060 Net realized investment losses — — — — (14,707 ) (14,707 ) Other revenues (insurance) (41 ) 1,096 246 42 — 1,343 Other expenses (insurance) (960 ) (1,379 ) — (6,913 ) — (9,252 ) Segment profit (loss) $ 50,918 $ 27,907 $ 28,435 $ (1,850 ) $ 72,353 $ 177,763 Other revenues (non-insurance) 305,393 Other expenses (non-insurance) (281,497 ) Amortization of intangible assets (18,914 ) Interest expense (30,064 ) Income before income taxes $ 152,681 U.S. GAAP combined ratio (1) 90 % 87 % 86 % NM (2) 88 % (1) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (2) NM – Ratio is not meaningful. Nine Months Ended September 30, 2016 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 2,000,454 $ 879,078 $ 920,038 $ 515 $ — $ 3,800,085 Net written premiums 1,694,193 680,691 786,450 555 — 3,161,889 Earned premiums 1,614,588 637,365 630,151 685 — 2,882,789 Losses and loss adjustment expenses: Current accident year (1,038,860 ) (451,741 ) (413,044 ) — — (1,903,645 ) Prior accident years 126,457 111,359 90,140 10,764 — 338,720 Underwriting, acquisition and insurance expenses (617,006 ) (267,959 ) (227,138 ) (686 ) — (1,112,789 ) Underwriting profit 85,179 29,024 80,109 10,763 — 205,075 Net investment income — — — — 279,437 279,437 Net realized investment gains — — — — 65,836 65,836 Other revenues (insurance) 3,662 5,149 — 1,407 — 10,218 Other expenses (insurance) (2,078 ) (4,368 ) — (19,432 ) — (25,878 ) Segment profit (loss) $ 86,763 $ 29,805 $ 80,109 $ (7,262 ) $ 345,273 $ 534,688 Other revenues (non-insurance) 945,121 Other expenses (non-insurance) (836,837 ) Amortization of intangible assets (51,474 ) Interest expense (97,690 ) Loss on early extinguishment of debt (44,100 ) Income before income taxes $ 449,708 U.S. GAAP combined ratio (1) 95 % 95 % 87 % NM (2) 93 % Nine Months Ended September 30, 2015 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 1,890,144 $ 911,962 $ 875,676 $ (1,159 ) $ — $ 3,676,623 Net written premiums 1,587,092 700,260 736,068 (462 ) — 3,022,958 Earned premiums 1,569,615 654,936 640,719 (388 ) — 2,864,882 Losses and loss adjustment expenses: Current accident year (1,015,492 ) (479,764 ) (431,791 ) — — (1,927,047 ) Prior accident years 211,177 177,883 65,746 4,315 — 459,121 Underwriting, acquisition and insurance expenses (597,388 ) (266,091 ) (222,172 ) (305 ) — (1,085,956 ) Underwriting profit 167,912 86,964 52,502 3,622 — 311,000 Net investment income — — — — 270,521 270,521 Net realized investment losses — — — — (3,031 ) (3,031 ) Other revenues (insurance) 3,564 7,398 1,138 369 — 12,469 Other expenses (insurance) (3,149 ) (4,101 ) — (17,610 ) — (24,860 ) Segment profit (loss) $ 168,327 $ 90,261 $ 53,640 $ (13,619 ) $ 267,490 $ 566,099 Other revenues (non-insurance) 804,682 Other expenses (non-insurance) (739,126 ) Amortization of intangible assets (50,503 ) Interest expense (88,664 ) Income before income taxes $ 492,488 U.S. GAAP combined ratio (1) 89 % 87 % 92 % NM (2) 89 % (1) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (2) NM – Ratio is not meaningful. b) The following table reconciles segment assets to the Company's consolidated balance sheets. (dollars in thousands) September 30, 2016 December 31, 2015 Segment assets: Investing $ 19,235,156 $ 18,056,947 Underwriting 5,681,650 5,385,126 Total segment assets 24,916,806 23,442,073 Non-insurance operations 1,486,839 1,497,042 Total assets $ 26,403,645 $ 24,939,115

Senior Long-Term Debt

Senior Long-Term Debt	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Senior Long-Term Debt	Senior Long-Term Debt In the second quarter of 2016, the Company issued $500 million of 5.0% unsecured senior notes due April 5, 2046. Net proceeds to the Company were $493.1 million . The Company used a portion of these proceeds to purchase $70.2 million of principal on its 7.35% Senior Notes due 2034 and $108.8 million of principal on its 7.125% Senior Notes due 2019 through a tender offer at a total purchase price of $95.0 million and $126.4 million , respectively. The Company also expects to use the proceeds from this issuance to retire its 7.20% unsecured senior notes, when they come due April 14, 2017 ( $90.6 million aggregate principal amount of those notes was outstanding at September 30, 2016 ), and the remainder for general corporate purposes. In connection with the tender offer and purchase, the Company recognized a loss on early extinguishment of debt of $44.1 million during the nine months ended September 30, 2016.

Other Revenues And Other Expens

Other Revenues And Other Expenses	9 Months Ended
	Sep. 30, 2016
Other Income and Expenses [Abstract]
Other Revenues And Other Expenses	Other Revenues and Other Expenses The following tables summarize the components of other revenues and other expenses. Quarter Ended September 30, 2016 2015 (dollars in thousands) Other Revenues Other Expenses Other Revenues Other Expenses Insurance: Managing general agent operations $ 1,704 $ 1,347 $ 1,055 $ 2,339 Life and annuity 466 4,232 42 6,913 Other — — 246 — 2,170 5,579 1,343 9,252 Non-Insurance: Markel Ventures: Manufacturing 203,909 171,595 216,057 192,707 Markel Ventures: Non-Manufacturing 117,433 115,529 83,098 83,104 Investment management 8,297 10,385 — — Other 4,666 6,625 6,238 5,686 334,305 304,134 305,393 281,497 Total $ 336,475 $ 309,713 $ 306,736 $ 290,749 Nine Months Ended September 30, 2016 2015 (dollars in thousands) Other Revenues Other Expenses Other Revenues Other Expenses Insurance: Managing general agent operations $ 8,811 $ 6,446 $ 10,043 $ 7,250 Life and annuity 1,407 19,432 369 17,610 Other — — 2,057 — 10,218 25,878 12,469 24,860 Non-Insurance: Markel Ventures: Manufacturing 589,752 491,188 567,960 513,087 Markel Ventures: Non-Manufacturing 315,863 295,647 216,191 209,947 Investment management 22,820 31,151 — — Other 16,686 18,851 20,531 16,092 945,121 836,837 804,682 739,126 Total $ 955,339 $ 862,715 $ 817,151 $ 763,986 The Company's Markel Ventures operations primarily consist of controlling interests in various industrial and service businesses and are viewed by management as separate and distinct from the Company's insurance operations. While each of the companies is operated independently from one another, management aggregates financial results into two industry groups: manufacturing and non-manufacturing.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2016
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The following tables summarize the effect of reinsurance and retrocessional reinsurance on premiums written and earned. Quarter Ended September 30, 2016 2015 (dollars in thousands) Written Earned Written Earned Direct $ 888,009 $ 883,687 $ 878,269 $ 881,512 Assumed 241,764 292,951 280,095 293,481 Ceded (200,390 ) (202,394 ) (205,180 ) (211,318 ) Net premiums $ 929,383 $ 974,244 $ 953,184 $ 963,675 Nine Months Ended September 30, 2016 2015 (dollars in thousands) Written Earned Written Earned Direct $ 2,724,341 $ 2,617,074 $ 2,631,734 $ 2,601,458 Assumed 1,075,744 878,882 1,044,889 910,640 Ceded (638,196 ) (613,167 ) (653,665 ) (647,216 ) Net premiums $ 3,161,889 $ 2,882,789 $ 3,022,958 $ 2,864,882 The percentage of ceded earned premiums to gross earned premiums was 17% and 18% , respectively, for the quarters ended September 30, 2016 and 2015 and 18% for the nine months ended September 30, 2016 and 2015 . The percentage of assumed earned premiums to net earned premiums was 30% for the quarters ended September 30, 2016 and 2015 and 30% and 32% , respectively, for the nine months ended September 30, 2016 and 2015 . Incurred losses and loss adjustment expenses were net of reinsurance recoverables (ceded incurred losses and loss adjustment expenses) of $83.3 million and $53.8 million , respectively, for the quarters ended September 30, 2016 and 2015 and $289.4 million and $285.9 million , respectively, for the nine months ended September 30, 2016 and 2015 .

Life And Annuity Benefits

Life And Annuity Benefits	9 Months Ended
	Sep. 30, 2016
Liability for Future Policy Benefits [Abstract]
Life And Annuity Benefits	Life and Annuity Benefits Life and annuity benefits are compiled on a reinsurance contract-by-contract basis and are discounted using standard actuarial techniques and cash flow models. Since the development of the life and annuity reinsurance reserves is based upon cash flow projection models, the Company must make estimates and assumptions based on cedent experience, industry mortality tables, and expense and investment experience, including a provision for adverse deviation. The assumptions used to determine policy benefit reserves are generally locked-in for the life of the contract unless an unlocking event occurs. Loss recognition testing is performed to determine if existing policy benefit reserves, together with the present value of future gross premiums and expected investment income earned thereon, are adequate to cover the present value of future benefits, settlement and maintenance costs. If the existing policy benefit reserves are not sufficient, the locked-in assumptions are revised to current best estimate assumptions and a charge to earnings for life and annuity benefits is recognized at that time. Life and annuity benefits are also adjusted to the extent unrealized gains on the investments supporting the policy benefit reserves would result in a reserve deficiency if those gains were realized. During the quarter and nine months ended September 30, 2016, the Company recognized a reserve deficiency resulting from decreases in the market yield on the investment portfolio supporting the policy benefit reserves by increasing life and annuity benefits by $9.6 million and $57.5 million , respectively, and decreasing the change in net unrealized holding gains included in other comprehensive income by a corresponding amount. As of September 30, 2016, the cumulative adjustment to life and annuity benefits attributable to unrealized gains on the underlying investment portfolio totaled $57.5 million .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective tax rate was 27% and 21% for the nine months ended September 30, 2016 and 2015 , respectively. For the nine months ended September 30, 2016 , the effective tax rate differs from the U.S. statutory tax rate of 35% primarily as a result of tax-exempt investment income. For the nine months ended September 30, 2015 , the effective tax rate differs from the U.S. statutory tax rate of 35% primarily as a result of foreign tax credits for foreign taxes paid and tax-exempt investment income. The Company's recognition of foreign tax credits in 2015 had a favorable impact on its effective tax rate for the nine months ended September 30, 2015 of 8% . The increase in the effective tax rate in 2016 compared to 2015 was primarily due to the 2015 impact of foreign tax credits described above and a decrease in estimated annual earnings attributable to foreign operations that are taxed at a lower rate in 2016 compared to 2015. During the first quarter of 2016, the Internal Revenue Service completed its examination of the Company’s 2012 federal income tax return. There were no adjustments to our income tax liabilities as a result of this examination.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities In December 2015, the Company formed Markel CATCo Investment Management Ltd. (MCIM), a wholly-owned consolidated subsidiary. MCIM is an insurance-linked securities investment fund manager and insurance manager headquartered in Bermuda. Results attributable to MCIM are included with the Company's non-insurance operations, which are not included in a reportable segment. In December 2015, the Company also formed a mutual fund company and reinsurance company, both of which were organized under Bermuda law and are managed by MCIM. The mutual fund company issues multiple classes of nonvoting, redeemable preference shares to investors through its funds (the Funds) and the Funds are primarily invested in nonvoting shares of the reinsurance company. The underwriting results of the reinsurance company are attributed to the Funds through the issuance of nonvoting preference shares. The Funds and the reinsurance company are considered VIEs, as their preference shareholders have no voting rights. MCIM has the power to direct the activities that most significantly impact the economic performance of these entities, but does not have a variable interest in any of the entities. Except as described below, the Company is not the primary beneficiary of the Funds or the reinsurance company, as the Company’s involvement is generally limited to that of an investment or insurance manager, receiving fees that are at market and commensurate with the level of effort required. The Company is the sole investor in one of the Funds, the Markel Diversified Fund, and consolidates that fund as its primary beneficiary. The Company also holds an investment in another one of the Funds ( $26.0 million as of September 30, 2016 ) but does not have the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE, and therefore does not consolidate that Fund. As of September 30, 2016 , total assets of the Markel Diversified Fund were $166.9 million and total liabilities were $63.8 million . The assets of the Markel Diversified Fund are available for use only by the Markel Diversified Fund, and are not available for use by the Company. Total assets of the Markel Diversified Fund include an investment in one of the unconsolidated Funds totaling $164.4 million as of September 30, 2016 , which represents 6% of the outstanding preference shares of that fund. This investment is included in equity securities (available-for-sale) on the Company’s consolidated balance sheet. Total liabilities of the Markel Diversified Fund include a $62.5 million note payable delivered as part of the consideration provided for its investment. This note payable is included in senior long-term debt and other debt on the Company’s consolidated balance sheet. Other than the note payable, any liabilities held by the Markel Diversified Fund have no recourse to the Company’s general credit. The Company’s exposure to risk from the unconsolidated Funds and reinsurance company is generally limited to its investment and any earned but uncollected fees. The Company has not issued any investment performance guarantees to these VIEs or their investors. As of September 30, 2016 , total investment and insurance assets under management of MCIM for unconsolidated VIEs were $3.4 billion .

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Net Income Per Share	Net Income per Share Net income per share was determined by dividing adjusted net income to shareholders by the applicable weighted average shares outstanding. Diluted net income per share is computed by dividing adjusted net income to shareholders by the weighted average number of common shares and dilutive potential common shares outstanding during the period. Quarter Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2016 2015 2016 2015 Net income to shareholders $ 83,796 $ 102,519 $ 322,963 $ 384,880 Adjustment of redeemable noncontrolling interests (4,928 ) 1,376 (10,909 ) 3,091 Adjusted net income to shareholders $ 78,868 $ 103,895 $ 312,054 $ 387,971 Basic common shares outstanding 14,033 13,983 14,013 13,977 Dilutive potential common shares from conversion of options 3 8 4 9 Dilutive potential common shares from conversion of restricted stock 49 71 62 70 Diluted shares outstanding 14,085 14,062 14,079 14,056 Basic net income per share $ 5.62 $ 7.43 $ 22.27 $ 27.76 Diluted net income per share $ 5.60 $ 7.39 $ 22.16 $ 27.60

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2016
Other Comprehensive Income (Loss), Tax [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) Other comprehensive income (loss) includes net holding gains (losses) arising during the period, changes in unrealized other-than-temporary impairment losses on fixed maturities arising during the period and reclassification adjustments for net gains included in net income. Other comprehensive income (loss) also includes changes in foreign currency translation adjustments and changes in net actuarial pension loss. The following table presents the change in accumulated other comprehensive income by component, net of taxes and noncontrolling interests, for the nine months ended September 30, 2016 and 2015 . (dollars in thousands) Unrealized Holding Gains on Available-for-Sale Securities Foreign Currency Net Actuarial Pension Loss Total December 31, 2014 $ 1,793,254 $ (43,491 ) $ (45,206 ) $ 1,704,557 Other comprehensive loss before reclassifications (258,275 ) (22,236 ) — (280,511 ) Amounts reclassified from accumulated other comprehensive income (8,037 ) — 1,407 (6,630 ) Total other comprehensive income (loss) (266,312 ) (22,236 ) 1,407 (287,141 ) September 30, 2015 $ 1,526,942 $ (65,727 ) $ (43,799 ) $ 1,417,416 December 31, 2015 $ 1,472,762 $ (72,696 ) $ (45,558 ) $ 1,354,508 Other comprehensive income (loss) before reclassifications 411,354 (6,159 ) — 405,195 Amounts reclassified from accumulated other comprehensive income (33,308 ) — 1,247 (32,061 ) Total other comprehensive income (loss) 378,046 (6,159 ) 1,247 373,134 September 30, 2016 $ 1,850,808 $ (78,855 ) $ (44,311 ) $ 1,727,642 The following table summarizes the tax expense (benefit) associated with each component of other comprehensive income (loss). Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Change in net unrealized gains on investments: Net holding gains (losses) arising during the period $ 8,309 $ (71,549 ) $ 196,189 $ (129,546 ) Change in unrealized other-than-temporary impairment losses on fixed maturities arising during the period (3 ) (10 ) (9 ) 28 Reclassification adjustments for net gains (losses) included in net income (4,811 ) 4,647 (12,621 ) (1,025 ) Change in net unrealized gains on investments 3,495 (66,912 ) 183,559 (130,543 ) Change in foreign currency translation adjustments 2,847 829 1,152 1,662 Change in net actuarial pension loss 86 119 274 352 Total $ 6,428 $ (65,964 ) $ 184,985 $ (128,529 ) The following table presents the details of amounts reclassified from accumulated other comprehensive income into income, by component. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Unrealized holding gains on available-for-sale securities: Other-than-temporary impairment losses $ — $ (18,281 ) $ (12,080 ) $ (23,373 ) Net realized investment gains, excluding other-than-temporary impairment losses 14,569 7,634 58,009 32,435 Total before taxes 14,569 (10,647 ) 45,929 9,062 Income taxes (4,811 ) 4,647 (12,621 ) (1,025 ) Reclassification of unrealized holding gains (losses), net of taxes $ 9,758 $ (6,000 ) $ 33,308 $ 8,037 Net actuarial pension loss: Underwriting, acquisition and insurance expenses $ (476 ) $ (594 ) $ (1,521 ) $ (1,759 ) Income taxes 86 119 274 352 Reclassification of net actuarial pension loss, net of taxes $ (390 ) $ (475 ) $ (1,247 ) $ (1,407 )

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2016
Loss Contingency [Abstract]
Contingencies	Contingencies Contingencies arise in the normal course of the Company's operations and are not expected to have a material impact on the Company's financial condition or results of operations.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events After the end of the third quarter of 2016, the Caribbean and southeastern and mid-Atlantic regions of the United States sustained losses from Hurricane Matthew. Based on information currently available, the Company estimates its range of net incurred losses on this event is between $40 million and $100 million before income taxes. This estimated range of losses was derived based on preliminary industry loss estimates, policy level reviews and direct contact with insureds and brokers when possible. However, we are still gathering loss data from our policy holders and cedents and do not expect that all losses have been reported at this time. Potential losses associated with business interruption are also not yet clear. The Company continues to closely monitor reported claims to refine its estimate of losses, which will be recorded in the fourth quarter of 2016.

Summary Of Significant Accoun23

Summary Of Significant Accounting Policies (Policy)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation. Markel Corporation is a diverse financial holding company serving a variety of niche markets. Markel Corporation's principal business markets and underwrites specialty insurance products and programs. Through its wholly-owned subsidiary, Markel Ventures, Inc. (Markel Ventures), Markel Corporation also owns interests in various industrial and service businesses that operate outside of the specialty insurance marketplace. The consolidated balance sheet as of September 30, 2016 , the related consolidated statements of income and comprehensive income (loss) for the quarters and nine months ended September 30, 2016 and 2015 , and the consolidated statements of changes in equity and cash flows for the nine months ended September 30, 2016 and 2015 are unaudited. In the opinion of management, all adjustments necessary for fair presentation of such consolidated financial statements have been included. Such adjustments consist only of normal, recurring items. Interim results are not necessarily indicative of results of operations for the entire year. The consolidated balance sheet as of December 31, 2015 was derived from Markel Corporation's audited annual consolidated financial statements. The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and include the accounts of Markel Corporation and its consolidated subsidiaries, as well as any variable interest entities (VIEs) that meet the requirements for consolidation (the Company). All significant intercompany balances and transactions have been eliminated in consolidation. The Company consolidates the results of its Markel Ventures subsidiaries on a one-month lag. Certain prior year amounts have been reclassified to conform to the current presentation. The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results may differ materially from the estimates and assumptions used in preparing the consolidated financial statements. The consolidated financial statements and notes are presented as permitted by Form 10-Q and do not contain certain information included in the Company's annual consolidated financial statements and notes. In addition to the policies set forth below, readers are urged to review the Company's 2015 Annual Report on Form 10-K for a more complete description of the Company's business and accounting policies.
Variable Interest Entities	Variable Interest Entities. The Company determines whether it has relationships with entities defined as VIEs in accordance with Accounting Standards Codification (ASC) Topic 810, Consolidation . Under this guidance, a VIE is consolidated by the variable interest holder that is determined to be the primary beneficiary. An entity in which the Company holds a variable interest is a VIE if any of the following conditions exist: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support, (b) as a group, the holders of equity investment at risk lack either the direct or indirect ability through voting rights or similar rights to make decisions about an entity's activities that most significantly impact the entity’s economic performance or the obligation to absorb the expected losses or right to receive the expected residual returns, or (c) the voting rights of some investors are disproportionate to their obligation to absorb the expected losses of the entity, their rights to receive the expected residual returns of the entity, or both and substantially all of the entity's activities either involve or are conducted on behalf of an investor with disproportionately few voting rights. The primary beneficiary is defined as the variable interest holder that is determined to have the controlling financial interest as a result of having both (a) the power to direct the activities of a VIE that most significantly impact the economic performance of the VIE and (b) the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether an entity is a VIE at the inception of our variable interest in the entity and upon the occurrence of certain reconsideration events. The Company continually reassesses whether it is the primary beneficiary of VIEs in which it holds a variable interest.
Revenue Recognition	Revenue Recognition. Investment Management and Performance Fees Investment management fee income is recognized over the period in which investment management services are provided and is calculated and billed monthly based on the net asset value of the accounts managed. Performance fee arrangements entitle the Company to participate, on a fixed-percentage basis, in any net income generated in excess of an agreed-upon threshold as established by the underlying investment management agreements. In general, net income is calculated at the end of each calendar year and performance fees are payable annually. Following the preferred method identified in the ASC Topic 605, Revenue Recognition , such performance fee income is recorded at the conclusion of the contractual performance period, when all contingencies are resolved.

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Available-For-Sale Investments	The following tables summarize the Company's available-for-sale investments. September 30, 2016 (dollars in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Unrealized Other-Than- Temporary Impairment Losses Estimated Fair Value Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 659,539 $ 24,943 $ (99 ) $ — $ 684,383 Obligations of states, municipalities and political subdivisions 4,259,553 318,183 (3,081 ) — 4,574,655 Foreign governments 1,334,364 237,498 (15 ) — 1,571,847 Commercial mortgage-backed securities 981,613 46,791 (396 ) — 1,028,008 Residential mortgage-backed securities 780,631 49,568 (586 ) (2,258 ) 827,355 Asset-backed securities 27,911 83 (16 ) — 27,978 Corporate bonds 1,519,546 87,459 (1,071 ) (1,673 ) 1,604,261 Total fixed maturities 9,563,157 764,525 (5,264 ) (3,931 ) 10,318,487 Equity securities: Insurance, banks and other financial institutions 841,416 807,430 (9,770 ) — 1,639,076 Industrial, consumer and all other 1,583,341 1,295,784 (7,774 ) — 2,871,351 Total equity securities 2,424,757 2,103,214 (17,544 ) — 4,510,427 Short-term investments 1,989,124 181 — — 1,989,305 Investments, available-for-sale $ 13,977,038 $ 2,867,920 $ (22,808 ) $ (3,931 ) $ 16,818,219 December 31, 2015 (dollars in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Unrealized Other-Than- Temporary Impairment Losses Estimated Fair Value Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 695,652 $ 9,836 $ (4,781 ) $ — $ 700,707 Obligations of states, municipalities and political subdivisions 3,817,136 204,302 (8,225 ) — 4,013,213 Foreign governments 1,302,329 115,809 (1,681 ) — 1,416,457 Commercial mortgage-backed securities 657,670 6,867 (4,999 ) — 659,538 Residential mortgage-backed securities 837,964 22,563 (4,022 ) (2,258 ) 854,247 Asset-backed securities 36,462 15 (406 ) — 36,071 Corporate bonds 1,690,945 41,123 (16,209 ) (1,624 ) 1,714,235 Total fixed maturities 9,038,158 400,515 (40,323 ) (3,882 ) 9,394,468 Equity securities: Insurance, banks and other financial institutions 651,002 690,271 (6,551 ) — 1,334,722 Industrial, consumer and all other 1,557,832 1,227,052 (45,131 ) — 2,739,753 Total equity securities 2,208,834 1,917,323 (51,682 ) — 4,074,475 Short-term investments 1,642,103 167 (9 ) — 1,642,261 Investments, available-for-sale $ 12,889,095 $ 2,318,005 $ (92,014 ) $ (3,882 ) $ 15,111,204
Summary Of Gross Unrealized Investment Losses By Length Of Time That Securities Have Continuously Been In An Unrealized Loss Position	The following tables summarize gross unrealized investment losses by the length of time that securities have continuously been in an unrealized loss position. September 30, 2016 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 26,599 $ (96 ) $ 7,700 $ (3 ) $ 34,299 $ (99 ) Obligations of states, municipalities and political subdivisions 156,618 (1,404 ) 42,834 (1,677 ) 199,452 (3,081 ) Foreign governments 7,159 (10 ) 5,015 (5 ) 12,174 (15 ) Commercial mortgage-backed securities 14,318 (45 ) 43,475 (351 ) 57,793 (396 ) Residential mortgage-backed securities 7,473 (2,311 ) 85,864 (533 ) 93,337 (2,844 ) Asset-backed securities 6,312 (5 ) 6,236 (11 ) 12,548 (16 ) Corporate bonds 73,320 (1,736 ) 95,302 (1,008 ) 168,622 (2,744 ) Total fixed maturities 291,799 (5,607 ) 286,426 (3,588 ) 578,225 (9,195 ) Equity securities: Insurance, banks and other financial institutions 22,769 (1,456 ) 37,751 (8,314 ) 60,520 (9,770 ) Industrial, consumer and all other 23,713 (2,315 ) 138,245 (5,459 ) 161,958 (7,774 ) Total equity securities 46,482 (3,771 ) 175,996 (13,773 ) 222,478 (17,544 ) Total $ 338,281 $ (9,378 ) $ 462,422 $ (17,361 ) $ 800,703 $ (26,739 ) December 31, 2015 Less than 12 months 12 months or longer Total (dollars in thousands) Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Estimated Fair Value Gross Unrealized Holding and Other-Than- Temporary Impairment Losses Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 427,003 $ (3,648 ) $ 92,552 $ (1,133 ) $ 519,555 $ (4,781 ) Obligations of states, municipalities and political subdivisions 169,362 (4,864 ) 70,101 (3,361 ) 239,463 (8,225 ) Foreign governments 51,328 (249 ) 40,345 (1,432 ) 91,673 (1,681 ) Commercial mortgage-backed securities 289,058 (3,600 ) 95,843 (1,399 ) 384,901 (4,999 ) Residential mortgage-backed securities 78,814 (2,858 ) 137,100 (3,422 ) 215,914 (6,280 ) Asset-backed securities 6,228 (54 ) 24,315 (352 ) 30,543 (406 ) Corporate bonds 470,694 (9,509 ) 343,737 (8,324 ) 814,431 (17,833 ) Total fixed maturities 1,492,487 (24,782 ) 803,993 (19,423 ) 2,296,480 (44,205 ) Equity securities: Insurance, banks and other financial institutions 63,873 (6,384 ) 6,247 (167 ) 70,120 (6,551 ) Industrial, consumer and all other 344,857 (44,879 ) 2,907 (252 ) 347,764 (45,131 ) Total equity securities 408,730 (51,263 ) 9,154 (419 ) 417,884 (51,682 ) Short-term investments 129,473 (9 ) — — 129,473 (9 ) Total $ 2,030,690 $ (76,054 ) $ 813,147 $ (19,842 ) $ 2,843,837 $ (95,896 )
Schedule Of Amortized Cost And Estimated Fair Value Of Fixed Maturities By Contractual Maturity Date	The amortized cost and estimated fair value of fixed maturities at September 30, 2016 are shown below by contractual maturity. (dollars in thousands) Amortized Cost Estimated Fair Value Due in one year or less $ 798,670 $ 803,039 Due after one year through five years 1,292,802 1,349,605 Due after five years through ten years 1,650,289 1,791,219 Due after ten years 4,031,241 4,491,283 7,773,002 8,435,146 Commercial mortgage-backed securities 981,613 1,028,008 Residential mortgage-backed securities 780,631 827,355 Asset-backed securities 27,911 27,978 Total fixed maturities $ 9,563,157 $ 10,318,487
Components Of Net Investment Income	The following table presents the components of net investment income. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Interest: Municipal bonds (tax-exempt) $ 22,136 $ 21,979 $ 66,621 $ 72,124 Municipal bonds (taxable) 16,710 14,667 48,820 42,917 Other taxable bonds 36,697 34,368 108,975 103,519 Short-term investments, including overnight deposits 2,878 1,287 7,823 3,654 Dividends on equity securities 17,308 17,887 51,718 55,544 Income (loss) from equity method investments 1,232 (4 ) 4,900 3,052 Other (60 ) 37 2,614 577 96,901 90,221 291,471 281,387 Investment expenses (3,754 ) (3,161 ) (12,034 ) (10,866 ) Net investment income $ 93,147 $ 87,060 $ 279,437 $ 270,521
Summary Of Net Realized Investment Gains (Losses) And The Change In Net Unrealized Gains On Investments	The following table presents net realized investment gains (losses) and the change in net unrealized gains on investments. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Realized gains: Sales of fixed maturities $ 3,698 $ 435 $ 4,658 $ 2,769 Sales of equity securities 18,418 11,329 63,931 34,285 Other 423 1,026 1,117 3,297 Total realized gains 22,539 12,790 69,706 40,351 Realized losses: Sales of fixed maturities (60 ) (3,730 ) (608 ) (3,947 ) Sales of equity securities (4,187 ) (400 ) (6,672 ) (672 ) Other-than-temporary impairments — (18,281 ) (12,080 ) (23,373 ) Other (55 ) (279 ) (2,972 ) (364 ) Total realized losses (4,302 ) (22,690 ) (22,332 ) (28,356 ) Gains (losses) on securities measured at fair value through net income 9,179 (4,807 ) 18,462 (15,026 ) Net realized investment gains (losses) $ 27,416 $ (14,707 ) $ 65,836 $ (3,031 ) Change in net unrealized gains on investments included in other comprehensive income (loss): Fixed maturities $ (53,962 ) $ 102,844 $ 399,020 $ (77,369 ) Equity securities 80,285 (313,075 ) 220,029 (319,522 ) Short-term investments 58 45 23 36 Net increase (decrease) $ 26,381 $ (210,186 ) $ 619,072 $ (396,855 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Balances Of Assets Measured At Fair Value On A Recurring Basis	The following tables present the balances of assets measured at fair value on a recurring basis by level within the fair value hierarchy. September 30, 2016 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments available-for-sale: Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ 684,383 $ — $ 684,383 Obligations of states, municipalities and political subdivisions — 4,574,655 — 4,574,655 Foreign governments — 1,571,847 — 1,571,847 Commercial mortgage-backed securities — 1,028,008 — 1,028,008 Residential mortgage-backed securities — 827,355 — 827,355 Asset-backed securities — 27,978 — 27,978 Corporate bonds — 1,604,261 — 1,604,261 Total fixed maturities — 10,318,487 — 10,318,487 Equity securities: Insurance, banks and other financial institutions 1,448,672 — 190,404 1,639,076 Industrial, consumer and all other 2,871,351 — — 2,871,351 Total equity securities 4,320,023 — 190,404 4,510,427 Short-term investments 1,903,399 85,906 — 1,989,305 Total investments available-for-sale $ 6,223,422 $ 10,404,393 $ 190,404 $ 16,818,219 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total Assets: Investments available-for-sale: Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ 700,707 $ — $ 700,707 Obligations of states, municipalities and political subdivisions — 4,013,213 — 4,013,213 Foreign governments — 1,416,457 — 1,416,457 Commercial mortgage-backed securities — 659,538 — 659,538 Residential mortgage-backed securities — 854,247 — 854,247 Asset-backed securities — 36,071 — 36,071 Corporate bonds — 1,714,235 — 1,714,235 Total fixed maturities — 9,394,468 — 9,394,468 Equity securities: Insurance, banks and other financial institutions 1,334,722 — — 1,334,722 Industrial, consumer and all other 2,739,753 — — 2,739,753 Total equity securities 4,074,475 — — 4,074,475 Short-term investments 1,529,924 112,337 — 1,642,261 Total investments available-for-sale $ 5,604,399 $ 9,506,805 $ — $ 15,111,204
Summary Of Changes In Level 3 Investments Measured At Fair Value On A Recurring Basis	The following table summarizes changes in Level 3 investments measured at fair value on a recurring basis. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Equity securities, beginning of period $ 183,523 $ — $ — $ — Purchases — — 195,250 — Sales — — (25,000 ) — Total gains included in: Net income 6,881 — 20,154 — Other comprehensive income (loss) — — — — Transfers into Level 3 — — — — Transfers out of Level 3 — — — — Equity securities, end of period $ 190,404 $ — $ 190,404 $ — Net unrealized gains included in net income relating to assets held at September 30, 2016 and 2015 (1) $ 6,881 $ — $ 20,154 $ — (1) Included in net realized investment gains in the consolidated statements of income and comprehensive income (loss).

Segment Reporting Disclosures (

Segment Reporting Disclosures (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Company's Segment Disclosures	The following tables summarize the Company's segment disclosures. Quarter Ended September 30, 2016 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 663,196 $ 269,093 $ 196,948 $ 536 $ — $ 1,129,773 Net written premiums 562,215 209,656 157,043 469 — 929,383 Earned premiums 548,792 218,968 206,018 466 — 974,244 Losses and loss adjustment expenses: Current accident year (370,435 ) (159,812 ) (129,875 ) — — (660,122 ) Prior accident years 21,471 42,705 19,135 (2,594 ) — 80,717 Underwriting, acquisition and insurance expenses (206,628 ) (82,791 ) (82,490 ) (612 ) — (372,521 ) Underwriting profit (loss) (6,800 ) 19,070 12,788 (2,740 ) — 22,318 Net investment income — — — — 93,147 93,147 Net realized investment gains — — — — 27,416 27,416 Other revenues (insurance) 1,285 419 — 466 — 2,170 Other expenses (insurance) (670 ) (677 ) — (4,232 ) — (5,579 ) Segment profit (loss) $ (6,185 ) $ 18,812 $ 12,788 $ (6,506 ) $ 120,563 $ 139,472 Other revenues (non-insurance) 334,305 Other expenses (non-insurance) (304,134 ) Amortization of intangible assets (17,010 ) Interest expense (33,152 ) Income before income taxes $ 119,481 U.S. GAAP combined ratio (1) 101 % 91 % 94 % NM (2) 98 % Quarter Ended September 30, 2015 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 635,926 $ 284,576 $ 239,094 $ (1,232 ) $ — $ 1,158,364 Net written premiums 536,285 213,423 204,336 (860 ) — 953,184 Earned premiums 534,615 225,034 204,825 (799 ) — 963,675 Losses and loss adjustment expenses: Current accident year (357,400 ) (162,024 ) (128,428 ) — — (647,852 ) Prior accident years 74,976 57,860 24,241 6,038 — 163,115 Underwriting, acquisition and insurance expenses (200,272 ) (92,680 ) (72,449 ) (218 ) — (365,619 ) Underwriting profit 51,919 28,190 28,189 5,021 — 113,319 Net investment income — — — — 87,060 87,060 Net realized investment losses — — — — (14,707 ) (14,707 ) Other revenues (insurance) (41 ) 1,096 246 42 — 1,343 Other expenses (insurance) (960 ) (1,379 ) — (6,913 ) — (9,252 ) Segment profit (loss) $ 50,918 $ 27,907 $ 28,435 $ (1,850 ) $ 72,353 $ 177,763 Other revenues (non-insurance) 305,393 Other expenses (non-insurance) (281,497 ) Amortization of intangible assets (18,914 ) Interest expense (30,064 ) Income before income taxes $ 152,681 U.S. GAAP combined ratio (1) 90 % 87 % 86 % NM (2) 88 % (1) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (2) NM – Ratio is not meaningful. Nine Months Ended September 30, 2016 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 2,000,454 $ 879,078 $ 920,038 $ 515 $ — $ 3,800,085 Net written premiums 1,694,193 680,691 786,450 555 — 3,161,889 Earned premiums 1,614,588 637,365 630,151 685 — 2,882,789 Losses and loss adjustment expenses: Current accident year (1,038,860 ) (451,741 ) (413,044 ) — — (1,903,645 ) Prior accident years 126,457 111,359 90,140 10,764 — 338,720 Underwriting, acquisition and insurance expenses (617,006 ) (267,959 ) (227,138 ) (686 ) — (1,112,789 ) Underwriting profit 85,179 29,024 80,109 10,763 — 205,075 Net investment income — — — — 279,437 279,437 Net realized investment gains — — — — 65,836 65,836 Other revenues (insurance) 3,662 5,149 — 1,407 — 10,218 Other expenses (insurance) (2,078 ) (4,368 ) — (19,432 ) — (25,878 ) Segment profit (loss) $ 86,763 $ 29,805 $ 80,109 $ (7,262 ) $ 345,273 $ 534,688 Other revenues (non-insurance) 945,121 Other expenses (non-insurance) (836,837 ) Amortization of intangible assets (51,474 ) Interest expense (97,690 ) Loss on early extinguishment of debt (44,100 ) Income before income taxes $ 449,708 U.S. GAAP combined ratio (1) 95 % 95 % 87 % NM (2) 93 % Nine Months Ended September 30, 2015 (dollars in thousands) U.S. Insurance International Insurance Reinsurance Other Insurance (Discontinued Lines) Investing Consolidated Gross premium volume $ 1,890,144 $ 911,962 $ 875,676 $ (1,159 ) $ — $ 3,676,623 Net written premiums 1,587,092 700,260 736,068 (462 ) — 3,022,958 Earned premiums 1,569,615 654,936 640,719 (388 ) — 2,864,882 Losses and loss adjustment expenses: Current accident year (1,015,492 ) (479,764 ) (431,791 ) — — (1,927,047 ) Prior accident years 211,177 177,883 65,746 4,315 — 459,121 Underwriting, acquisition and insurance expenses (597,388 ) (266,091 ) (222,172 ) (305 ) — (1,085,956 ) Underwriting profit 167,912 86,964 52,502 3,622 — 311,000 Net investment income — — — — 270,521 270,521 Net realized investment losses — — — — (3,031 ) (3,031 ) Other revenues (insurance) 3,564 7,398 1,138 369 — 12,469 Other expenses (insurance) (3,149 ) (4,101 ) — (17,610 ) — (24,860 ) Segment profit (loss) $ 168,327 $ 90,261 $ 53,640 $ (13,619 ) $ 267,490 $ 566,099 Other revenues (non-insurance) 804,682 Other expenses (non-insurance) (739,126 ) Amortization of intangible assets (50,503 ) Interest expense (88,664 ) Income before income taxes $ 492,488 U.S. GAAP combined ratio (1) 89 % 87 % 92 % NM (2) 89 % (1) The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums. (2) NM – Ratio is not meaningful.
Reconciliation Of Segment Assets To The Company's Consolidated Balance Sheets	The following table reconciles segment assets to the Company's consolidated balance sheets. (dollars in thousands) September 30, 2016 December 31, 2015 Segment assets: Investing $ 19,235,156 $ 18,056,947 Underwriting 5,681,650 5,385,126 Total segment assets 24,916,806 23,442,073 Non-insurance operations 1,486,839 1,497,042 Total assets $ 26,403,645 $ 24,939,115

Other Revenues And Other Expe27

Other Revenues And Other Expenses (Tables)	9 Months Ended
	Sep. 30, 2016
Other Income and Expenses [Abstract]
Summary Of Other Revenues And Other Expenses By Component	The following tables summarize the components of other revenues and other expenses. Quarter Ended September 30, 2016 2015 (dollars in thousands) Other Revenues Other Expenses Other Revenues Other Expenses Insurance: Managing general agent operations $ 1,704 $ 1,347 $ 1,055 $ 2,339 Life and annuity 466 4,232 42 6,913 Other — — 246 — 2,170 5,579 1,343 9,252 Non-Insurance: Markel Ventures: Manufacturing 203,909 171,595 216,057 192,707 Markel Ventures: Non-Manufacturing 117,433 115,529 83,098 83,104 Investment management 8,297 10,385 — — Other 4,666 6,625 6,238 5,686 334,305 304,134 305,393 281,497 Total $ 336,475 $ 309,713 $ 306,736 $ 290,749 Nine Months Ended September 30, 2016 2015 (dollars in thousands) Other Revenues Other Expenses Other Revenues Other Expenses Insurance: Managing general agent operations $ 8,811 $ 6,446 $ 10,043 $ 7,250 Life and annuity 1,407 19,432 369 17,610 Other — — 2,057 — 10,218 25,878 12,469 24,860 Non-Insurance: Markel Ventures: Manufacturing 589,752 491,188 567,960 513,087 Markel Ventures: Non-Manufacturing 315,863 295,647 216,191 209,947 Investment management 22,820 31,151 — — Other 16,686 18,851 20,531 16,092 945,121 836,837 804,682 739,126 Total $ 955,339 $ 862,715 $ 817,151 $ 763,986

Reinsurance (Tables)

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2016
Reinsurance Disclosures [Abstract]
Effect Of Reinsurance And Retrocessional Reinsurance On Premiums Written And Earned	The following tables summarize the effect of reinsurance and retrocessional reinsurance on premiums written and earned. Quarter Ended September 30, 2016 2015 (dollars in thousands) Written Earned Written Earned Direct $ 888,009 $ 883,687 $ 878,269 $ 881,512 Assumed 241,764 292,951 280,095 293,481 Ceded (200,390 ) (202,394 ) (205,180 ) (211,318 ) Net premiums $ 929,383 $ 974,244 $ 953,184 $ 963,675 Nine Months Ended September 30, 2016 2015 (dollars in thousands) Written Earned Written Earned Direct $ 2,724,341 $ 2,617,074 $ 2,631,734 $ 2,601,458 Assumed 1,075,744 878,882 1,044,889 910,640 Ceded (638,196 ) (613,167 ) (653,665 ) (647,216 ) Net premiums $ 3,161,889 $ 2,882,789 $ 3,022,958 $ 2,864,882

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Schedule Of Net Income Per Share	Net income per share was determined by dividing adjusted net income to shareholders by the applicable weighted average shares outstanding. Diluted net income per share is computed by dividing adjusted net income to shareholders by the weighted average number of common shares and dilutive potential common shares outstanding during the period. Quarter Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2016 2015 2016 2015 Net income to shareholders $ 83,796 $ 102,519 $ 322,963 $ 384,880 Adjustment of redeemable noncontrolling interests (4,928 ) 1,376 (10,909 ) 3,091 Adjusted net income to shareholders $ 78,868 $ 103,895 $ 312,054 $ 387,971 Basic common shares outstanding 14,033 13,983 14,013 13,977 Dilutive potential common shares from conversion of options 3 8 4 9 Dilutive potential common shares from conversion of restricted stock 49 71 62 70 Diluted shares outstanding 14,085 14,062 14,079 14,056 Basic net income per share $ 5.62 $ 7.43 $ 22.27 $ 27.76 Diluted net income per share $ 5.60 $ 7.39 $ 22.16 $ 27.60

Other Comprehensive Income (L30

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2016
Other Comprehensive Income (Loss), Tax [Abstract]
Change In Accumulated Other Comprehensive Income By Component, Net Of Taxes And Noncontrolling Interest	The following table presents the change in accumulated other comprehensive income by component, net of taxes and noncontrolling interests, for the nine months ended September 30, 2016 and 2015 . (dollars in thousands) Unrealized Holding Gains on Available-for-Sale Securities Foreign Currency Net Actuarial Pension Loss Total December 31, 2014 $ 1,793,254 $ (43,491 ) $ (45,206 ) $ 1,704,557 Other comprehensive loss before reclassifications (258,275 ) (22,236 ) — (280,511 ) Amounts reclassified from accumulated other comprehensive income (8,037 ) — 1,407 (6,630 ) Total other comprehensive income (loss) (266,312 ) (22,236 ) 1,407 (287,141 ) September 30, 2015 $ 1,526,942 $ (65,727 ) $ (43,799 ) $ 1,417,416 December 31, 2015 $ 1,472,762 $ (72,696 ) $ (45,558 ) $ 1,354,508 Other comprehensive income (loss) before reclassifications 411,354 (6,159 ) — 405,195 Amounts reclassified from accumulated other comprehensive income (33,308 ) — 1,247 (32,061 ) Total other comprehensive income (loss) 378,046 (6,159 ) 1,247 373,134 September 30, 2016 $ 1,850,808 $ (78,855 ) $ (44,311 ) $ 1,727,642
Summary Of Tax Expense (Benefit) Of Other Comprehensive Income (Loss)	The following table summarizes the tax expense (benefit) associated with each component of other comprehensive income (loss). Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Change in net unrealized gains on investments: Net holding gains (losses) arising during the period $ 8,309 $ (71,549 ) $ 196,189 $ (129,546 ) Change in unrealized other-than-temporary impairment losses on fixed maturities arising during the period (3 ) (10 ) (9 ) 28 Reclassification adjustments for net gains (losses) included in net income (4,811 ) 4,647 (12,621 ) (1,025 ) Change in net unrealized gains on investments 3,495 (66,912 ) 183,559 (130,543 ) Change in foreign currency translation adjustments 2,847 829 1,152 1,662 Change in net actuarial pension loss 86 119 274 352 Total $ 6,428 $ (65,964 ) $ 184,985 $ (128,529 )
Reclassifications From Accumulated Other Comprehensive Income Into Income, By Component	The following table presents the details of amounts reclassified from accumulated other comprehensive income into income, by component. Quarter Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Unrealized holding gains on available-for-sale securities: Other-than-temporary impairment losses $ — $ (18,281 ) $ (12,080 ) $ (23,373 ) Net realized investment gains, excluding other-than-temporary impairment losses 14,569 7,634 58,009 32,435 Total before taxes 14,569 (10,647 ) 45,929 9,062 Income taxes (4,811 ) 4,647 (12,621 ) (1,025 ) Reclassification of unrealized holding gains (losses), net of taxes $ 9,758 $ (6,000 ) $ 33,308 $ 8,037 Net actuarial pension loss: Underwriting, acquisition and insurance expenses $ (476 ) $ (594 ) $ (1,521 ) $ (1,759 ) Income taxes 86 119 274 352 Reclassification of net actuarial pension loss, net of taxes $ (390 ) $ (475 ) $ (1,247 ) $ (1,407 )

Recent Accounting Pronounceme31

Recent Accounting Pronouncements (Narrative) (Details) $ in Millions	Dec. 31, 2015USD ($)
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs reclassified from other assets to senior long-term debt and other debt	$ 2.2

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) - CapTech Ventures Inc [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2016	Mar. 31, 2016
Business Acquisition [Line Items]
Percentage acquired	80.00%
Total consideration	$ 60.6
Material adjustments to the provisional estimates recorded			$ 0
Increase in estimate of contingent consideration		$ 10.3

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)securities	Sep. 30, 2015USD ($)securities	Sep. 30, 2016USD ($)securities	Sep. 30, 2015USD ($)securities	Dec. 31, 2015USD ($)securities
Schedule of Investments [Line Items]
Available-for-sale securities in unrealized loss position, number of positions | securities	220		220		659
Available-for-sale securities, estimated fair value	$ 800,703		$ 800,703		$ 2,843,837
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	$ (26,739)		$ (26,739)		$ (95,896)
Number of available-for-sale securities positions in a continuous unrealized loss position for one year or longer at period end | securities	118		118		271
Available-for-sale securities, estimated fair value, 12 months or longer	$ 462,422		$ 462,422		$ 813,147
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(17,361)		(17,361)		(19,842)
Other-than-temporary impairment losses recognized in net income	0	$ (18,281)	(12,080)	$ (23,373)
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, estimated fair value	578,225		578,225		2,296,480
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	$ (9,195)		$ (9,195)		$ (44,205)
Number of available-for-sale securities positions in a continuous unrealized loss position for one year or longer at period end | securities	101		101		264
Available-for-sale securities, estimated fair value, 12 months or longer	$ 286,426		$ 286,426		$ 803,993
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(3,588)		(3,588)		(19,423)
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, estimated fair value	222,478		222,478		417,884
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	$ (17,544)		$ (17,544)		$ (51,682)
Number of available-for-sale securities positions in a continuous unrealized loss position for one year or longer at period end | securities	17		17		7
Available-for-sale securities, estimated fair value, 12 months or longer	$ 175,996		$ 175,996		$ 9,154
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(13,773)		(13,773)		(419)
Other-than-temporary impairment losses recognized in net income		$ (18,300)	$ (12,100)	$ (23,400)
Other than temporary impairment losses recognized in earnings, number of investment positions | securities		8	21	16
Industrial, Consumer And All Other [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, estimated fair value	161,958		$ 161,958		347,764
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(7,774)		(7,774)		(45,131)
Available-for-sale securities, estimated fair value, 12 months or longer	138,245		138,245		2,907
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(5,459)		(5,459)		(252)
Other-than-temporary impairment losses recognized in net income		$ (14,300)	(10,800)	$ (18,800)
Insurance, Banks And Other Financial Institutions [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, estimated fair value	60,520		60,520		70,120
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(9,770)		(9,770)		(6,551)
Available-for-sale securities, estimated fair value, 12 months or longer	37,751		37,751		6,247
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	$ (8,314)		(8,314)		$ (167)
Other-than-temporary impairment losses recognized in net income		$ (4,000)	$ (1,300)	$ (4,600)

Investments (Available-For-Sale

Investments (Available-For-Sale Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	$ 13,977,038	$ 12,889,095
Available-for-sale investments, gross unrealized holding gains	2,867,920	2,318,005
Available-for-sale investments, gross unrealized holding losses	(22,808)	(92,014)
Available-for-sale investments, unrealized other-than-temporary impairment losses	(3,931)	(3,882)
Available-for-sale investments, estimated fair value	16,818,219	15,111,204
U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	659,539	695,652
Available-for-sale investments, gross unrealized holding gains	24,943	9,836
Available-for-sale investments, gross unrealized holding losses	(99)	(4,781)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	684,383	700,707
Obligations Of States, Municipalities And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	4,259,553	3,817,136
Available-for-sale investments, gross unrealized holding gains	318,183	204,302
Available-for-sale investments, gross unrealized holding losses	(3,081)	(8,225)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	4,574,655	4,013,213
Foreign Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	1,334,364	1,302,329
Available-for-sale investments, gross unrealized holding gains	237,498	115,809
Available-for-sale investments, gross unrealized holding losses	(15)	(1,681)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	1,571,847	1,416,457
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	981,613	657,670
Available-for-sale investments, gross unrealized holding gains	46,791	6,867
Available-for-sale investments, gross unrealized holding losses	(396)	(4,999)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	1,028,008	659,538
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	780,631	837,964
Available-for-sale investments, gross unrealized holding gains	49,568	22,563
Available-for-sale investments, gross unrealized holding losses	(586)	(4,022)
Available-for-sale investments, unrealized other-than-temporary impairment losses	(2,258)	(2,258)
Available-for-sale investments, estimated fair value	827,355	854,247
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	27,911	36,462
Available-for-sale investments, gross unrealized holding gains	83	15
Available-for-sale investments, gross unrealized holding losses	(16)	(406)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	27,978	36,071
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	1,519,546	1,690,945
Available-for-sale investments, gross unrealized holding gains	87,459	41,123
Available-for-sale investments, gross unrealized holding losses	(1,071)	(16,209)
Available-for-sale investments, unrealized other-than-temporary impairment losses	(1,673)	(1,624)
Available-for-sale investments, estimated fair value	1,604,261	1,714,235
Total Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	9,563,157	9,038,158
Available-for-sale investments, gross unrealized holding gains	764,525	400,515
Available-for-sale investments, gross unrealized holding losses	(5,264)	(40,323)
Available-for-sale investments, unrealized other-than-temporary impairment losses	(3,931)	(3,882)
Available-for-sale investments, estimated fair value	10,318,487	9,394,468
Insurance, Banks And Other Financial Institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	841,416	651,002
Available-for-sale investments, gross unrealized holding gains	807,430	690,271
Available-for-sale investments, gross unrealized holding losses	(9,770)	(6,551)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	1,639,076	1,334,722
Industrial, Consumer And All Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	1,583,341	1,557,832
Available-for-sale investments, gross unrealized holding gains	1,295,784	1,227,052
Available-for-sale investments, gross unrealized holding losses	(7,774)	(45,131)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	2,871,351	2,739,753
Total Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	2,424,757	2,208,834
Available-for-sale investments, gross unrealized holding gains	2,103,214	1,917,323
Available-for-sale investments, gross unrealized holding losses	(17,544)	(51,682)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	4,510,427	4,074,475
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments, amortized cost	1,989,124	1,642,103
Available-for-sale investments, gross unrealized holding gains	181	167
Available-for-sale investments, gross unrealized holding losses	0	(9)
Available-for-sale investments, unrealized other-than-temporary impairment losses	0	0
Available-for-sale investments, estimated fair value	$ 1,989,305	$ 1,642,261

Investments (Summary Of Gross U

Investments (Summary Of Gross Unrealized Investment Losses By Length Of Time That Securities Have Continuously Been In An Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	$ 338,281	$ 2,030,690
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(9,378)	(76,054)
Available-for-sale securities, estimated fair value, 12 months or longer	462,422	813,147
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(17,361)	(19,842)
Available-for-sale securities, estimated fair value	800,703	2,843,837
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(26,739)	(95,896)
U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	26,599	427,003
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(96)	(3,648)
Available-for-sale securities, estimated fair value, 12 months or longer	7,700	92,552
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(3)	(1,133)
Available-for-sale securities, estimated fair value	34,299	519,555
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(99)	(4,781)
Obligations Of States, Municipalities And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	156,618	169,362
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(1,404)	(4,864)
Available-for-sale securities, estimated fair value, 12 months or longer	42,834	70,101
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(1,677)	(3,361)
Available-for-sale securities, estimated fair value	199,452	239,463
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(3,081)	(8,225)
Foreign Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	7,159	51,328
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(10)	(249)
Available-for-sale securities, estimated fair value, 12 months or longer	5,015	40,345
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(5)	(1,432)
Available-for-sale securities, estimated fair value	12,174	91,673
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(15)	(1,681)
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	14,318	289,058
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(45)	(3,600)
Available-for-sale securities, estimated fair value, 12 months or longer	43,475	95,843
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(351)	(1,399)
Available-for-sale securities, estimated fair value	57,793	384,901
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(396)	(4,999)
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	7,473	78,814
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(2,311)	(2,858)
Available-for-sale securities, estimated fair value, 12 months or longer	85,864	137,100
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(533)	(3,422)
Available-for-sale securities, estimated fair value	93,337	215,914
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(2,844)	(6,280)
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	6,312	6,228
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(5)	(54)
Available-for-sale securities, estimated fair value, 12 months or longer	6,236	24,315
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(11)	(352)
Available-for-sale securities, estimated fair value	12,548	30,543
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(16)	(406)
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	73,320	470,694
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(1,736)	(9,509)
Available-for-sale securities, estimated fair value, 12 months or longer	95,302	343,737
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(1,008)	(8,324)
Available-for-sale securities, estimated fair value	168,622	814,431
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(2,744)	(17,833)
Total Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	291,799	1,492,487
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(5,607)	(24,782)
Available-for-sale securities, estimated fair value, 12 months or longer	286,426	803,993
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(3,588)	(19,423)
Available-for-sale securities, estimated fair value	578,225	2,296,480
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(9,195)	(44,205)
Insurance, Banks And Other Financial Institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	22,769	63,873
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(1,456)	(6,384)
Available-for-sale securities, estimated fair value, 12 months or longer	37,751	6,247
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(8,314)	(167)
Available-for-sale securities, estimated fair value	60,520	70,120
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(9,770)	(6,551)
Industrial, Consumer And All Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	23,713	344,857
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(2,315)	(44,879)
Available-for-sale securities, estimated fair value, 12 months or longer	138,245	2,907
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(5,459)	(252)
Available-for-sale securities, estimated fair value	161,958	347,764
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	(7,774)	(45,131)
Total Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months	46,482	408,730
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months	(3,771)	(51,263)
Available-for-sale securities, estimated fair value, 12 months or longer	175,996	9,154
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer	(13,773)	(419)
Available-for-sale securities, estimated fair value	222,478	417,884
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses	$ (17,544)	(51,682)
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, estimated fair value, less than 12 months		129,473
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, less than 12 months		(9)
Available-for-sale securities, estimated fair value, 12 months or longer		0
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses, 12 months or longer		0
Available-for-sale securities, estimated fair value		129,473
Available-for-sale securities, gross unrealized holding and other-than-temporary impairment losses		$ (9)

Investments (Schedule Of Amorti

Investments (Schedule Of Amortized Cost And Estimated Fair Value Of Fixed Maturities By Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, amortized cost	$ 798,670
Due after one year through five years, amortized cost	1,292,802
Due after five years through ten years, amortized cost	1,650,289
Due after ten years, amortized cost	4,031,241
Amortized cost, sub-total	7,773,002
Total fixed maturities, amortized cost	9,563,157	$ 9,038,158
Due in one year or less, estimated fair value	803,039
Due after one year through five years, estimated fair value	1,349,605
Due after five years through ten years, estimated fair value	1,791,219
Due after ten years, estimated fair value	4,491,283
Estimated fair value, sub-total	8,435,146
Total fixed maturities, estimated fair value	10,318,487	$ 9,394,468
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturities, amortized cost	981,613
Fixed maturities, estimated fair value	1,028,008
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturities, amortized cost	780,631
Fixed maturities, estimated fair value	827,355
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturities, amortized cost	27,911
Fixed maturities, estimated fair value	$ 27,978

Investments (Components Of Net

Investments (Components Of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Municipal bonds (tax-exempt)	$ 22,136	$ 21,979	$ 66,621	$ 72,124
Short-term investments, including overnight deposits	2,878	1,287	7,823	3,654
Dividends on equity securities	17,308	17,887	51,718	55,544
Income (loss) from equity method investments	1,232	(4)	4,900	3,052
Other	(60)	37	2,614	577
Total investment income	96,901	90,221	291,471	281,387
Investment expenses	(3,754)	(3,161)	(12,034)	(10,866)
Net investment income	93,147	87,060	279,437	270,521
Taxable Municipal Bonds [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Taxable bonds	16,710	14,667	48,820	42,917
Other Taxable Bonds [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Taxable bonds	$ 36,697	$ 34,368	$ 108,975	$ 103,519

Investments (Summary Of Net Rea

Investments (Summary Of Net Realized Investment Gains (Losses) And The Change In Net Unrealized Gains On Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Investments [Line Items]
Realized gains	$ 22,539	$ 12,790	$ 69,706	$ 40,351
Realized losses	(4,302)	(22,690)	(22,332)	(28,356)
Gains (losses) on securities measured at fair value through net income	9,179	(4,807)	18,462	(15,026)
Other-than-temporary impairment losses recognized in net income	0	(18,281)	(12,080)	(23,373)
Net realized investment gains (losses)	27,416	(14,707)	65,836	(3,031)
Change in net unrealized gains on investments included in other comprehensive income (loss)	26,381	(210,186)	619,072	(396,855)
Sales Of Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Realized gains	3,698	435	4,658	2,769
Realized losses	(60)	(3,730)	(608)	(3,947)
Sales Of Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Realized gains	18,418	11,329	63,931	34,285
Realized losses	(4,187)	(400)	(6,672)	(672)
Other [Member]
Gain (Loss) on Investments [Line Items]
Realized gains	423	1,026	1,117	3,297
Realized losses	(55)	(279)	(2,972)	(364)
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Change in net unrealized gains on investments included in other comprehensive income (loss)	(53,962)	102,844	399,020	(77,369)
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses recognized in net income		(18,300)	(12,100)	(23,400)
Change in net unrealized gains on investments included in other comprehensive income (loss)	80,285	(313,075)	220,029	(319,522)
Short-Term Investments [Member]
Gain (Loss) on Investments [Line Items]
Change in net unrealized gains on investments included in other comprehensive income (loss)	$ 58	$ 45	$ 23	$ 36

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair value, level 1 to level 2 transfers, amount	$ 0	$ 0	$ 0	$ 0
Fair value, level 2 to level 1 transfers, amount	0	0	0	0
Assets measured at fair value on a nonrecurring basis	0	0	0	0
Liabilities measured at fair value on a nonrecurring basis	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements (Balanc

Fair Value Measurements (Balances Of Assets Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 10,318,487	$ 9,394,468
Total equity securities	4,510,427	4,074,475
Short-term investments	1,989,305	1,642,261
Available-for-sale investments, estimated fair value	16,818,219	15,111,204
Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	10,318,487	9,394,468
U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	684,383	700,707
Obligations Of States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	4,574,655	4,013,213
Foreign Governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	1,571,847	1,416,457
Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	1,028,008	659,538
Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	827,355	854,247
Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	27,978	36,071
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	1,604,261	1,714,235
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	4,510,427	4,074,475
Insurance, Banks And Other Financial Institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	1,639,076	1,334,722
Industrial, Consumer And All Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments, estimated fair value	2,871,351	2,739,753
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	10,318,487	9,394,468
Total equity securities	4,510,427	4,074,475
Short-term investments	1,989,305	1,642,261
Available-for-sale investments, estimated fair value	16,818,219	15,111,204
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Total equity securities	4,320,023	4,074,475
Short-term investments	1,903,399	1,529,924
Available-for-sale investments, estimated fair value	6,223,422	5,604,399
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	10,318,487	9,394,468
Total equity securities	0	0
Short-term investments	85,906	112,337
Available-for-sale investments, estimated fair value	10,404,393	9,506,805
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Total equity securities	190,404	0
Short-term investments	0	0
Available-for-sale investments, estimated fair value	190,404	0
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	684,383	700,707
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	684,383	700,707
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities And Obligations Of U.S. Government Agencies [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Obligations Of States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	4,574,655	4,013,213
Fair Value, Measurements, Recurring [Member] | Obligations Of States, Municipalities And Political Subdivisions [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Obligations Of States, Municipalities And Political Subdivisions [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	4,574,655	4,013,213
Fair Value, Measurements, Recurring [Member] | Obligations Of States, Municipalities And Political Subdivisions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Foreign Governments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,571,847	1,416,457
Fair Value, Measurements, Recurring [Member] | Foreign Governments [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Foreign Governments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,571,847	1,416,457
Fair Value, Measurements, Recurring [Member] | Foreign Governments [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,028,008	659,538
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,028,008	659,538
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	827,355	854,247
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	827,355	854,247
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	27,978	36,071
Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	27,978	36,071
Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,604,261	1,714,235
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	1,604,261	1,714,235
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	0	0
Fair Value, Measurements, Recurring [Member] | Insurance, Banks And Other Financial Institutions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	1,639,076	1,334,722
Fair Value, Measurements, Recurring [Member] | Insurance, Banks And Other Financial Institutions [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	1,448,672	1,334,722
Fair Value, Measurements, Recurring [Member] | Insurance, Banks And Other Financial Institutions [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	0	0
Fair Value, Measurements, Recurring [Member] | Insurance, Banks And Other Financial Institutions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	190,404	0
Fair Value, Measurements, Recurring [Member] | Industrial, Consumer And All Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	2,871,351	2,739,753
Fair Value, Measurements, Recurring [Member] | Industrial, Consumer And All Other [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	2,871,351	2,739,753
Fair Value, Measurements, Recurring [Member] | Industrial, Consumer And All Other [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	0	0
Fair Value, Measurements, Recurring [Member] | Industrial, Consumer And All Other [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	$ 0	$ 0

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Changes In Level 3 Investments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Equity securities, beginning of period		$ 183,523	$ 0	$ 0	$ 0
Purchases		0	0	195,250	0
Sales		0	0	(25,000)	0
Total gains included in net income		6,881	0	20,154	0
Total gains included in other comprehensive income (loss)		0	0	0	0
Transfers into level 3		0	0	0	0
Transfers out of level 3		0	0	0	0
Equity securities, end of period		190,404	0	190,404	0
Net unrealized gains included in net income relating to assets held at September 30, 2016 and 2015	[1]	$ 6,881	$ 0	$ 20,154	$ 0
[1]	Included in net realized investment gains in the consolidated statements of income and comprehensive income (loss).

Segment Reporting Disclosures42

Segment Reporting Disclosures (Company's Segment Disclosures) (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)segment	Sep. 30, 2015USD ($)
Segment Reporting Information [Line Items]
Number of reportable ongoing underwriting segments | segment				3
Gross premium volume		$ 1,129,773	$ 1,158,364	$ 3,800,085	$ 3,676,623
Net written premiums		929,383	953,184	3,161,889	3,022,958
Earned premiums		974,244	963,675	2,882,789	2,864,882
Losses and loss adjustment expenses, current accident year		(660,122)	(647,852)	(1,903,645)	(1,927,047)
Losses and loss adjustment expenses, prior accident years		80,717	163,115	338,720	459,121
Underwriting, acquisition and insurance expenses		(372,521)	(365,619)	(1,112,789)	(1,085,956)
Underwriting profit (loss)		22,318	113,319	205,075	311,000
Net investment income		93,147	87,060	279,437	270,521
Net realized investment gains (losses)		27,416	(14,707)	65,836	(3,031)
Other revenues (insurance)		2,170	1,343	10,218	12,469
Other expenses (insurance)		(5,579)	(9,252)	(25,878)	(24,860)
Segment profit (loss)		139,472	177,763	534,688	566,099
Other revenues (non-insurance)		334,305	305,393	945,121	804,682
Other expenses (non-insurance)		(304,134)	(281,497)	(836,837)	(739,126)
Amortization of intangible assets		(17,010)	(18,914)	(51,474)	(50,503)
Interest expense		(33,152)	(30,064)	(97,690)	(88,664)
Loss on early extinguishment of debt		0	0	(44,100)	0
Income Before Income Taxes		$ 119,481	$ 152,681	$ 449,708	$ 492,488
U.S. GAAP combined ratio	[1]	98.00%	88.00%	93.00%	89.00%
U.S. Insurance [Member]
Segment Reporting Information [Line Items]
Gross premium volume		$ 663,196	$ 635,926	$ 2,000,454	$ 1,890,144
Net written premiums		562,215	536,285	1,694,193	1,587,092
Earned premiums		548,792	534,615	1,614,588	1,569,615
Losses and loss adjustment expenses, current accident year		(370,435)	(357,400)	(1,038,860)	(1,015,492)
Losses and loss adjustment expenses, prior accident years		21,471	74,976	126,457	211,177
Underwriting, acquisition and insurance expenses		(206,628)	(200,272)	(617,006)	(597,388)
Underwriting profit (loss)		(6,800)	51,919	85,179	167,912
Net investment income		0	0	0	0
Net realized investment gains (losses)		0	0	0	0
Other revenues (insurance)		1,285	(41)	3,662	3,564
Other expenses (insurance)		(670)	(960)	(2,078)	(3,149)
Segment profit (loss)		$ (6,185)	$ 50,918	$ 86,763	$ 168,327
U.S. GAAP combined ratio	[1]	101.00%	90.00%	95.00%	89.00%
International Insurance [Member]
Segment Reporting Information [Line Items]
Gross premium volume		$ 269,093	$ 284,576	$ 879,078	$ 911,962
Net written premiums		209,656	213,423	680,691	700,260
Earned premiums		218,968	225,034	637,365	654,936
Losses and loss adjustment expenses, current accident year		(159,812)	(162,024)	(451,741)	(479,764)
Losses and loss adjustment expenses, prior accident years		42,705	57,860	111,359	177,883
Underwriting, acquisition and insurance expenses		(82,791)	(92,680)	(267,959)	(266,091)
Underwriting profit (loss)		19,070	28,190	29,024	86,964
Net investment income		0	0	0	0
Net realized investment gains (losses)		0	0	0	0
Other revenues (insurance)		419	1,096	5,149	7,398
Other expenses (insurance)		(677)	(1,379)	(4,368)	(4,101)
Segment profit (loss)		$ 18,812	$ 27,907	$ 29,805	$ 90,261
U.S. GAAP combined ratio	[1]	91.00%	87.00%	95.00%	87.00%
Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross premium volume		$ 196,948	$ 239,094	$ 920,038	$ 875,676
Net written premiums		157,043	204,336	786,450	736,068
Earned premiums		206,018	204,825	630,151	640,719
Losses and loss adjustment expenses, current accident year		(129,875)	(128,428)	(413,044)	(431,791)
Losses and loss adjustment expenses, prior accident years		19,135	24,241	90,140	65,746
Underwriting, acquisition and insurance expenses		(82,490)	(72,449)	(227,138)	(222,172)
Underwriting profit (loss)		12,788	28,189	80,109	52,502
Net investment income		0	0	0	0
Net realized investment gains (losses)		0	0	0	0
Other revenues (insurance)		0	246	0	1,138
Other expenses (insurance)		0	0	0	0
Segment profit (loss)		$ 12,788	$ 28,435	$ 80,109	$ 53,640
U.S. GAAP combined ratio	[1]	94.00%	86.00%	87.00%	92.00%
Other Insurance (Discontinued Lines) [Member]
Segment Reporting Information [Line Items]
Gross premium volume		$ 536	$ (1,232)	$ 515	$ (1,159)
Net written premiums		469	(860)	555	(462)
Earned premiums		466	(799)	685	(388)
Losses and loss adjustment expenses, current accident year		0	0	0	0
Losses and loss adjustment expenses, prior accident years		(2,594)	6,038	10,764	4,315
Underwriting, acquisition and insurance expenses		(612)	(218)	(686)	(305)
Underwriting profit (loss)		(2,740)	5,021	10,763	3,622
Net investment income		0	0	0	0
Net realized investment gains (losses)		0	0	0	0
Other revenues (insurance)		466	42	1,407	369
Other expenses (insurance)		(4,232)	(6,913)	(19,432)	(17,610)
Segment profit (loss)		$ (6,506)	$ (1,850)	$ (7,262)	$ (13,619)
U.S. GAAP combined ratio - not meaniningful	[1],[2]	NM	NM	NM	NM
Investing [Member]
Segment Reporting Information [Line Items]
Gross premium volume		$ 0	$ 0	$ 0	$ 0
Net written premiums		0	0	0	0
Earned premiums		0	0	0	0
Losses and loss adjustment expenses, current accident year		0	0	0	0
Losses and loss adjustment expenses, prior accident years		0	0	0	0
Underwriting, acquisition and insurance expenses		0	0	0	0
Underwriting profit (loss)		0	0	0	0
Net investment income		93,147	87,060	279,437	270,521
Net realized investment gains (losses)		27,416	(14,707)	65,836	(3,031)
Other revenues (insurance)		0	0	0	0
Other expenses (insurance)		0	0	0	0
Segment profit (loss)		$ 120,563	$ 72,353	$ 345,273	$ 267,490
[1]	The U.S. GAAP combined ratio is a measure of underwriting performance and represents the relationship of incurred losses, loss adjustment expenses and underwriting, acquisition and insurance expenses to earned premiums.
[2]	NM – Ratio is not meaningful.

Segment Reporting Disclosures43

Segment Reporting Disclosures (Reconciliation Of Segment Assets To The Company's Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Assets	$ 26,403,645	$ 24,939,115
Non-Insurance Operations [Member]
Segment Reporting Information [Line Items]
Assets	1,486,839	1,497,042
Segment Assets [Member]
Segment Reporting Information [Line Items]
Assets	24,916,806	23,442,073
Segment Assets [Member] | Investing [Member]
Segment Reporting Information [Line Items]
Assets	19,235,156	18,056,947
Segment Assets [Member] | Underwriting [Member]
Segment Reporting Information [Line Items]
Assets	$ 5,681,650	$ 5,385,126

Senior Long-Term Debt (Narrativ

Senior Long-Term Debt (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Loss on early extinguishment of debt	$ 0		$ 0	$ (44,100)	$ 0
5.0% Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 500,000
Debt instrument, interest rate		5.00%
Net proceeds from issuance of unsecured senior notes		$ 493,100
7.35% Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate		7.35%
Debt instrument, repurchased face amount		$ 70,200
Early repayment of senior debt		$ 95,000
7.125% Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate		7.125%
Debt instrument, repurchased face amount		$ 108,800
Early repayment of senior debt		$ 126,400
7.20% Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	7.20%			7.20%
Debt instrument, principal amount outstanding	$ 90,600			$ 90,600

Other Revenues And Other Expe45

Other Revenues And Other Expenses (Summary Of Other Revenues And Other Expenses By Component) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Revenues and Other Expenses [Line Items]
Other revenues	$ 336,475	$ 306,736	$ 955,339	$ 817,151
Other expenses	309,713	290,749	862,715	763,986
Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	2,170	1,343	10,218	12,469
Other expenses	5,579	9,252	25,878	24,860
Non-Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	334,305	305,393	945,121	804,682
Other expenses	304,134	281,497	836,837	739,126
Managing General Agent Operations [Member] | Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	1,704	1,055	8,811	10,043
Other expenses	1,347	2,339	6,446	7,250
Life And Annuity [Member] | Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	466	42	1,407	369
Other expenses	4,232	6,913	19,432	17,610
Other Insurance [Member] | Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	0	246	0	2,057
Other expenses	0	0	0	0
Manufacturing [Member] | Non-Insurance Operations [Member] | Markel Ventures Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	203,909	216,057	589,752	567,960
Other expenses	171,595	192,707	491,188	513,087
Non-Manufacturing [Member] | Non-Insurance Operations [Member] | Markel Ventures Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	117,433	83,098	315,863	216,191
Other expenses	115,529	83,104	295,647	209,947
Investment Management [Member] | Non-Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	8,297	0	22,820	0
Other expenses	10,385	0	31,151	0
Other Non-Insurance [Member] | Non-Insurance Operations [Member]
Other Revenues and Other Expenses [Line Items]
Other revenues	4,666	6,238	16,686	20,531
Other expenses	$ 6,625	$ 5,686	$ 18,851	$ 16,092

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reinsurance Disclosures [Abstract]
Percentage of ceded earned premiums to gross earned premiums	17.00%	18.00%	18.00%	18.00%
Percentage of assumed earned premiums to net earned premiums	30.00%	30.00%	30.00%	32.00%
Reinsurance recoverables	$ 83.3	$ 53.8	$ 289.4	$ 285.9

Reinsurance (Effect Of Reinsura

Reinsurance (Effect Of Reinsurance And Retrocessional Reinsurance On Premiums Written And Earned) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reinsurance Disclosures [Abstract]
Direct premiums written	$ 888,009	$ 878,269	$ 2,724,341	$ 2,631,734
Direct premiums earned	883,687	881,512	2,617,074	2,601,458
Assumed premiums written	241,764	280,095	1,075,744	1,044,889
Assumed premiums earned	292,951	293,481	878,882	910,640
Ceded premiums written	(200,390)	(205,180)	(638,196)	(653,665)
Ceded premiums earned	(202,394)	(211,318)	(613,167)	(647,216)
Net premiums written	929,383	953,184	3,161,889	3,022,958
Net premiums earned	$ 974,244	$ 963,675	$ 2,882,789	$ 2,864,882

Life And Annuity Benefits (Narr

Life And Annuity Benefits (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2016USD ($)
Liability for Future Policy Benefits [Abstract]
Increase in life and annuity benefits	$ 9.6	$ 57.5
Cumulative adjustment to life and annuity benefits	$ 57.5	$ 57.5

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Effective tax rate	27.00%	21.00%
U.S. statutory tax rate	35.00%	35.00%
Favorable impact due to recognition of foreign tax credits		8.00%

Variable Interest Entities (Nar

Variable Interest Entities (Narrative) (Details) $ in Millions	Sep. 30, 2016USD ($)
Variable Interest Entity [Line Items]
Total investment and insurance assets under management of MCIM for unconsolidated VIEs	$ 3,400
Other Fund [Member]
Variable Interest Entity [Line Items]
Investment in one of the unconsolidated Funds	26
Markel Diversified Fund [Member]
Variable Interest Entity [Line Items]
Investment in one of the unconsolidated Funds	164.4
Total assets of the Markel Diversified Fund	166.9
Total liabilities of the Markel Diversified Fund	$ 63.8
Percentage of total assets of the Markel Diversified Fund invested in one of the unconsolidated Funds	6.00%
Note payable included in total liabilities of the Markel Diversified Fund delivered as part of the consideration provided for its investment	$ 62.5

Net Income Per Share (Schedule

Net Income Per Share (Schedule Of Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Line Items]
Net income to shareholders	$ 83,796	$ 102,519	$ 322,963	$ 384,880
Adjustment of redeemable noncontrolling interests	(4,928)	1,376	(10,909)	3,091
Adjusted net income to shareholders	$ 78,868	$ 103,895	$ 312,054	$ 387,971
Basic common shares outstanding	14,033	13,983	14,013	13,977
Diluted shares outstanding	14,085	14,062	14,079	14,056
Basic net income per share	$ 5.62	$ 7.43	$ 22.27	$ 27.76
Diluted net income per share	$ 5.60	$ 7.39	$ 22.16	$ 27.60
Stock Options [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares	3	8	4	9
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Dilutive potential common shares	49	71	62	70

Other Comprehensive Income (L52

Other Comprehensive Income (Loss) (Change In Accumulated Other Comprehensive Income By Component, Net Of Taxes And Noncontrolling Interest) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income, beginning balance	$ 1,354,508	$ 1,704,557
Other comprehensive income (loss) before reclassifications	405,195	(280,511)
Amounts reclassified from accumulated other comprehensive income	(32,061)	(6,630)
Total other comprehensive income (loss)	373,134	(287,141)
Accumulated other comprehensive income, ending balance	1,727,642	1,417,416
Unrealized Holding Gains On Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income, beginning balance	1,472,762	1,793,254
Other comprehensive income (loss) before reclassifications	411,354	(258,275)
Amounts reclassified from accumulated other comprehensive income	(33,308)	(8,037)
Total other comprehensive income (loss)	378,046	(266,312)
Accumulated other comprehensive income, ending balance	1,850,808	1,526,942
Foreign Currency [Member]
Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income, beginning balance	(72,696)	(43,491)
Other comprehensive income (loss) before reclassifications	(6,159)	(22,236)
Amounts reclassified from accumulated other comprehensive income	0	0
Total other comprehensive income (loss)	(6,159)	(22,236)
Accumulated other comprehensive income, ending balance	(78,855)	(65,727)
Net Actuarial Pension Loss [Member]
Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income, beginning balance	(45,558)	(45,206)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	1,247	1,407
Total other comprehensive income (loss)	1,247	1,407
Accumulated other comprehensive income, ending balance	$ (44,311)	$ (43,799)

Other Comprehensive Income (L53

Other Comprehensive Income (Loss) (Summary Of Tax Expense (Benefit) Of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Comprehensive Income (Loss), Tax [Abstract]
Net holding gains (losses) arising during the period	$ 8,309	$ (71,549)	$ 196,189	$ (129,546)
Change in unrealized other-than-temporary impairment losses on fixed maturities arising during the period	(3)	(10)	(9)	28
Reclassification adjustments for net gains (losses) included in net income	(4,811)	4,647	(12,621)	(1,025)
Change in net unrealized gains on investments	3,495	(66,912)	183,559	(130,543)
Change in foreign currency translation adjustments	2,847	829	1,152	1,662
Change in net actuarial pension loss	86	119	274	352
Total	$ 6,428	$ (65,964)	$ 184,985	$ (128,529)

Other Comprehensive Income (L54

Other Comprehensive Income (Loss) (Reclassifications From Accumulated Other Comprehensive Income Into Income, By Component) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Other-than-temporary impairment losses recognized in net income	$ 0	$ (18,281)	$ (12,080)	$ (23,373)
Net realized investment gains, excluding other-than-temporary impairment losses	27,416	3,574	77,916	20,342
Income Before Income Taxes	119,481	152,681	449,708	492,488
Underwriting, acquisition and insurance expenses	(372,521)	(365,619)	(1,112,789)	(1,085,956)
Income taxes	(36,060)	(48,271)	(121,968)	(101,619)
Net Income	83,421	104,410	327,740	390,869
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Unrealized Holding Gains On Available-For-Sale Securities [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Other-than-temporary impairment losses recognized in net income	0	(18,281)	(12,080)	(23,373)
Net realized investment gains, excluding other-than-temporary impairment losses	14,569	7,634	58,009	32,435
Income Before Income Taxes	14,569	(10,647)	45,929	9,062
Income taxes	(4,811)	4,647	(12,621)	(1,025)
Net Income	9,758	(6,000)	33,308	8,037
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Net Actuarial Pension Loss [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Underwriting, acquisition and insurance expenses	(476)	(594)	(1,521)	(1,759)
Income taxes	86	119	274	352
Net Income	$ (390)	$ (475)	$ (1,247)	$ (1,407)

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 01, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Subsequent Event [Line Items]
Net incurred losses		$ 579,405	$ 484,737	$ 1,564,925	$ 1,467,926
Subsequent Event [Member] | Hurricane Matthew [Member] | Minimum [Member]
Subsequent Event [Line Items]
Net incurred losses	$ 40,000
Subsequent Event [Member] | Hurricane Matthew [Member] | Maximum [Member]
Subsequent Event [Line Items]
Net incurred losses	$ 100,000