Everest Re (EG) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Entity Registrant Name	EVEREST RE GROUP LTD
Entity Central Index Key	1,095,073
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		40,980,477

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS:
Fixed maturities - available for sale, at market value (amortized cost: 2018, $14,997,018; 2017, $14,689,598)	$ 14,844,581	$ 14,756,834
Fixed maturities - available for sale, at fair value	1,821
Equity securities - available for sale, at market value (cost: 2018, $0; 2017, $130,287)		129,530
Equity securities - available for sale, at fair value	1,169,531	963,572
Short-term investments	338,694	509,682
Other invested assets (cost: 2018, $1,527,701; 2017, $1,628,753)	1,527,701	1,631,850
Cash	700,586	635,067
Total investments and cash	18,582,914	18,626,535
Accrued investment income	100,129	97,704
Premiums receivable	1,906,427	1,844,881
Reinsurance receivables	1,356,888	1,348,226
Funds held by reinsureds	197,419	292,927
Deferred acquisition costs	420,724	411,587
Prepaid reinsurance premiums	321,203	288,211
Income taxes	265,228	299,438
Other assets	362,264	382,283
TOTAL ASSETS	23,513,196	23,591,792
LIABILITIES:
Reserve for losses and loss adjustment expenses	11,793,346	11,884,321
Future policy benefit reserve	49,106	51,014
Unearned premium reserve	2,089,628	2,000,556
Funds held under reinsurance treaties	16,965	18,030
Commission reserves	23,251	30,660
Other net payable to reinsurers	244,280	218,017
4.868% Senior notes due 6/1/2044	396,864	396,834
6.6% Long term notes due 5/1/2067	236,585	236,561
Accrued interest on debt and borrowings	7,668	2,727
Equity index put option liability	12,205	12,477
Unsettled securities payable	49,569	38,743
Other liabilities	249,549	332,620
Total liabilities	15,169,016	15,222,560
Commitments and contingencies (Note 8)
SHAREHOLDERS' EQUITY:
Preferred shares, par value: $0.01; 50,000 shares authorized; no shares issued and outstanding
Common shares, par value: $0.01; 200,000 shares authorized; (2018) 69,187 and (2017) 69,044 outstanding before treasury shares	692	691
Additional paid-in capital	2,163,519	2,165,768
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of ($11,933) at 2018 and $9,356 at 2017	(341,974)	(160,891)
Treasury shares, at cost; 28,208 shares at 2018 and 2017	(3,322,244)	(3,322,244)
Retained earnings	9,844,187	9,685,908
Total shareholders' equity	8,344,180	8,369,232
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 23,513,196	$ 23,591,792

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fixed maturities - available for sale, at market value, amortized cost	$ 14,997,018	$ 14,689,598
Equity securities - available for sale, at market value, cost	0	130,287
Other invested assets, at cost	$ 1,527,701	$ 1,628,753
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, authorized	50,000,000	50,000,000
Preferred shares, issued	0	0
Preferred shares, outstanding	0	0
Common shares, par value	$ 0.01	$ 0.01
Common shares, authorized	200,000,000	200,000,000
Common shares, outstanding	69,187,000	69,044,000
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit)	$ (11,933)	$ 9,356
Treasury shares	28,208,000	28,208,000
6.6 % Long Term Subordinated Notes [Member]
Debt instrument, stated interest rate	6.60%	6.60%
Debt instrument, maturity date	May 1, 2067
4.868% Senior notes due 6/1/2044 [Member] | Senior Notes [Member]
Debt instrument, stated interest rate	4.868%	4.868%
Debt instrument, maturity date	Jun. 1, 2044

Consolidated Statements Of Oper

Consolidated Statements Of Operations And Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
REVENUES:
Premiums earned	$ 1,619,427	$ 1,312,097
Net investment income	138,294	122,289
Net realized capital gains (losses):
Other-than-temporary impairments on fixed maturity securities	(70)	(1,229)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income (loss)
Other net realized capital gains (losses)	(24,831)	53,957
Total net realized capital gains (losses)	(24,901)	52,728
Net derivative gain (loss)	273	2,630
Other income (expense)	12,064	(4,966)
Total revenues	1,745,157	1,484,778
CLAIMS AND EXPENSES:
Incurred losses and loss adjustment expenses	1,057,177	770,788
Commission, brokerage, taxes and fees	357,639	282,269
Other underwriting expenses	96,284	75,887
Corporate expenses	8,996	8,457
Interest, fees and bond issue cost amortization expense	7,418	8,964
Total claims and expenses	1,527,514	1,146,365
INCOME (LOSS) BEFORE TAXES	217,643	338,413
Income tax expense (benefit)	7,325	46,770
NET INCOME (LOSS)	210,318	291,643
Other comprehensive income (loss), net of tax :
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period	(190,624)	19,548
Reclassification adjustment for realized losses (gains) included in net income (loss)	(8,772)	(2,199)
Total URA(D) on securities arising during the period	(199,396)	17,349
Foreign currency translation adjustments	17,699	11,893
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)	1,815	2,004
Total benefit plan net gain (loss) for the period	1,815	2,004
Total other comprehensive income (loss), net of tax	(179,882)	31,246
COMPREHENSIVE INCOME (LOSS)	$ 30,436	$ 322,889
EARNINGS PER COMMON SHARE:
Basic	$ 5.14	$ 7.12
Diluted	5.11	7.07
Dividends declared	$ 1.3	$ 1.25

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Common Shares [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Shares At Cost [Member]	Total
Balance, beginning of period, shares at Dec. 31, 2016	40,898,864
Issued during the period, shares	159,127
Balance, beginning of period at Dec. 31, 2016	$ 689	$ 2,140,783	$ (216,764)	$ 9,422,932	$ (3,272,244)
Issued during the period, net	$ 2
Share-based compensation plans		870
Net increase (decrease) during the period			31,246			$ 31,246
Net income (loss)				291,643		291,643
Dividends declared ($1.30 per share in 2018 and $1.25 per share in 2017)				(51,281)		(51,281)
Purchase of treasury shares
Balance, end of period, shares at Mar. 31, 2017	41,057,991
Balance, end of period at Mar. 31, 2017	$ 691	2,141,653	(185,518)	9,663,294	(3,272,244)	$ 8,347,876
Balance, beginning of period, shares at Dec. 31, 2016	40,898,864
Balance, beginning of period at Dec. 31, 2016	$ 689	2,140,783	(216,764)	9,422,932	(3,272,244)
Balance, end of period, shares at Dec. 31, 2017	40,835,272					69,044,000
Balance, end of period at Dec. 31, 2017	$ 691	2,165,768	(160,891)	9,685,908	(3,322,244)	$ 8,369,232
Issued during the period, shares	143,362
Issued during the period, net	$ 1
Share-based compensation plans		(2,249)
Net increase (decrease) during the period			(179,882)			(179,882)
Net income (loss)				210,318		210,318
Dividends declared ($1.30 per share in 2018 and $1.25 per share in 2017)				(53,240)		$ (53,240)
Purchase of treasury shares
Balance, end of period, shares at Mar. 31, 2018	40,978,634					69,187,000
Balance, end of period at Mar. 31, 2018	$ 692	$ 2,163,519	(341,974)	9,844,187	$ (3,322,244)	$ 8,344,180
Cumulative change due to adoption of Accounting Standards Update 2016-01			$ (1,201)	$ 1,201		$ (1,201)

Consolidated Statements Of Cha6

Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Dividends declared	$ 1.3	$ 1.25

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 210,318	$ 291,643
Adjustments to reconcile net income to net cash provided by operating activities:
Decrease (increase) in premiums receivable	(56,826)	(220,367)
Decrease (increase) in funds held by reinsureds, net	95,416	1,211
Decrease (increase) in reinsurance receivables	236	(30,158)
Decrease (increase) in income taxes	55,905	37,010
Decrease (increase) in prepaid reinsurance premiums	(32,194)	(23,704)
Increase (decrease) in reserve for losses and loss adjustment expenses	(121,415)	99,095
Increase (decrease) in future policy benefit reserve	(1,907)	83
Increase (decrease) in unearned premiums	85,598	125,614
Increase (decrease) in other net payable to reinsurers	24,410	13,666
Increase (decrease) in losses in course of payment	45,919	113,815
Change in equity adjustments in limited partnerships	(24,596)	(10,998)
Distribution of limited partnership income	15,524	5,384
Change in other assets and liabilities, net	(142,935)	12,999
Non-cash compensation expense	8,336	7,501
Amortization of bond premium (accrual of bond discount)	8,950	11,746
Net realized capital (gains) losses	24,901	(52,728)
Net cash provided by (used in) operating activities	195,640	381,812
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from fixed maturities matured/called - available for sale, at market value	512,384	525,873
Proceeds from fixed maturities sold - available for sale, at market value	364,288	428,491
Proceeds from equity securities sold - available for sale, at market value		18,802
Proceeds from equity securities sold - available for sale, at fair value	199,875	140,315
Distributions from other invested assets	1,061,894	1,165,905
Cost of fixed maturities acquired - available for sale, at market value	(1,150,718)	(1,552,743)
Cost of fixed maturities acquired - available for sale, at fair value	(1,836)
Cost of equity securities acquired - available for sale, at market value		(1,282)
Cost of equity securities acquired - available for sale, at fair value	(310,426)	(66,902)
Cost of other invested assets acquired	(947,290)	(1,184,270)
Net change in short-term investments	169,705	(45,178)
Net change in unsettled securities transactions	46,708	236,702
Net cash provided by (used in) investing activities	(55,416)	(334,287)
CASH FLOWS FROM FINANCING ACTIVITIES:
Common shares issued during the period for share-based compensation, net of expense	(9,383)	(6,629)
Dividends paid to shareholders	(53,240)	(51,281)
Cost of shares withheld for taxes on settlements of share-based compensation awards	(14,245)	(11,517)
Net cash provided by (used in) financing activities	(76,868)	(69,427)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	2,163	8,220
Net increase (decrease) in cash	65,519	(13,682)
Cash, beginning of period	635,067	481,922
Cash, end of period	700,586	468,240
SUPPLEMENTAL CASH FLOW INFORMATION:
Income taxes paid (recovered)	(51,253)	9,593
Interest paid	$ 2,422	$ 105

General

General	3 Months Ended
	Mar. 31, 2018
General [Abstract]
General	1. GENERAL Everest Re Group, Ltd. ("Group"), a Bermuda company, through its subsidiaries, principally provides reinsurance and insurance in the U.S., Bermuda and international markets. As used in this document, "Company" means Group and its subsidiaries. During the fourth quarter of 2017, the Company established a new Irish insurance subsidiary, Everest Insurance Ireland, designated activity company ("Ireland Insurance"), which will write insurance business mainly in the European markets. During the third quarter of 2016, the Company established domestic subsidiaries, Everest Premier Insurance Company ("Everest Premier") and Everest Denali Insurance Company ("Everest Denali"), which will be used in the continued expansion of the Insurance operations. Effective July 1, 2016, the Company established a new Irish holding company, Everest Dublin Insurance Holdings Limited (Ireland) ("Everest Dublin Holdings").

Basis Of Presentation

Basis Of Presentation	3 Months Ended
	Mar. 31, 2018
Basis Of Presentation [Abstract]
Basis Of Presentation	2. BASIS OF PRESENTATION The unaudited consolidated financial statements of the Company for the three months ended March 31, 2018 and 2017 include all adjustments, consisting of normal recurring accruals, which, in the opinion of management, are necessary for a fair statement of the results on an interim basis. Certain financial information, which is normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP"), has been omitted since it is not required for interim reporting purposes. The December 31, 2017 consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for the three months ended March 31, 2018 and 2017 are not necessarily indicative of the results for a full year. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the years ended December 31, 2017, 2016 and 2015 included in the Company's most recent Form 10-K filing. The Company consolidates the results of operations and financial position of all voting interest entities ("VOE") in which the Company has a controlling financial interest and all variable interest entities ("VIE") in which the Company is considered to be the primary beneficiary. The consolidation assessment, including the determination as to whether an entity qualifies as a VIE or VOE, depends on the facts and circumstances surrounding each entity. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities (and disclosure of contingent assets and liabilities) at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Ultimate actual results could differ, possibly materially, from those estimates. All significant intercompany accounts and transactions have been eliminated. Certain reclassifications and format changes have been made to prior years' amounts to conform to the 2018 presentation. Application of Recently Issued Accounting Standard Changes. Accounting for Deferred Taxes in Accumulated Other Comprehensive Income (AOCI). 35 21 1,250 Accounting for Impact on Income Taxes due to Tax Reform. Amortization of Bond Premium. Presentation and Disclosure of Net Periodic Benefit Costs. Disclosure of Restricted Cash. In November 2016, FASB issued ASU 2016-18 and in August 2016, FASB issued ASU 2016-15 which outline guidance on the presentation in the statements of cash flows of changes in restricted cash. The new guidance requires that the statements of cash flows should reflect all changes in cash, cash equivalents and restricted cash in total and not segregated individually. The guidance is effective for annual and interim reporting periods beginning after December 15, 2017. The Company adopted the guidance effective January 1, 2018. The adoption of ASU 2016-18 and ASU 2016-15 did not have a material impact on the Company's financial statements. Intra-Entity Asset Transfers. Valuation of Financial Instruments. Accounting for Share-Based Compensation. financing activity within the Statements of Cash Flows. The Company has implemented this guidance retrospectively as of January 1, 2017. Leases. Recognition and Measurement of Financial Instruments. 1,201 Disclosures effective in the fourth quarter of 2016. Revenue Recognition. Any issued guidance and pronouncements, other than those directly referenced above, are deemed by the Company to be either not applicable or immaterial to its financial statements.

Investments

Investments	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Investments	3. INVESTMENTS The amortized cost, market value and gross unrealized appreciation and depreciation of available for sale, fixed maturity, equity security investments, carried at market value and other-than-temporary impairments ("OTTI") in accumulated other comprehensive income ("AOCI") are as follows for the periods indicated: At March 31, 2018 Amortized Unrealized Unrealized Market OTTI in AOCI (Dollars in thousands) Cost Appreciation Depreciation Value (a) Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,516,251 $ 7,019 $ (25,857 ) $ 1,497,413 $ - Obligations of U.S. states and political subdivisions 523,611 14,630 (1,694 ) 536,547 165 Corporate securities 5,834,818 50,974 (108,045 ) 5,777,747 2,481 Asset-backed securities 511,328 409 (5,307 ) 506,430 - Mortgage-backed securities Commercial 232,693 2 (5,396 ) 227,299 - Agency residential 2,272,215 8,860 (58,080 ) 2,222,995 - Non-agency residential 478 42 (44 ) 476 - Foreign government securities 1,283,177 35,703 (44,558 ) 1,274,322 163 Foreign corporate securities 2,822,447 54,062 (75,157 ) 2,801,352 618 Total fixed maturity securities $ 14,997,018 $ 171,701 $ (324,138 ) $ 14,844,581 $ 3,427 Equity securities $ - $ - $ - $ - $ - At December 31, 2017 Amortized Unrealized Unrealized Market OTTI in AOCI (Dollars in thousands) Cost Appreciation Depreciation Value (a) Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,540,952 $ 9,816 $ (14,076 ) $ 1,536,692 $ - Obligations of U.S. states and political subdivisions 563,790 22,123 (444 ) 585,469 - Corporate securities 5,658,456 81,724 (41,175 ) 5,699,005 2,488 Asset-backed securities 532,473 869 (1,982 ) 531,360 - Mortgage-backed securities Commercial 235,794 616 (2,369 ) 234,041 - Agency residential 2,236,361 10,379 (35,838 ) 2,210,902 - Non-agency residential 497 41 (44 ) 494 - Foreign government securities 1,305,070 43,804 (34,847 ) 1,314,027 178 Foreign corporate securities 2,616,205 77,045 (48,406 ) 2,644,844 950 Total fixed maturity securities $ 14,689,598 $ 246,417 $ (179,181 ) $ 14,756,834 $ 3,616 Equity securities $ 130,287 $ 2,615 $ (3,372 ) $ 129,530 $ - (a) Represents the amount of OTTI recognized in AOCI. Amount includes unrealized gains and losses on impaired securities relating to changes in the value of such securities subsequent to the impairment measurement date Effective January 1, 2018, the Company adopted ASU 2016-01, which requires equity investments in unconsolidated entities to be measured at fair value, with any change in value being recorded within net realized capital gains/(losses) as part of the consolidated statements of operations and comprehensive income (loss). Previously, changes in the market value had been recorded within AOCI as part of the consolidated balance sheets. Therefore, effective January 1, 2018, equity security investments no longer have an impact upon the AOCI balance. The amortized cost and market value of fixed maturity securities are shown in the following table by contractual maturity. Mortgage-backed securities are generally more likely to be prepaid than other fixed maturity securities. As the stated maturity of such securities may not be indicative of actual maturities, the totals for mortgage-backed and asset-backed securities are shown separately. At March 31, 2018 At December 31, 2017 Amortized Market Amortized Market (Dollars in thousands) Cost Value Cost Value Fixed maturity securities – available for sale: Due in one year or less $ 1,593,546 $ 1,592,697 $ 1,041,885 $ 1,050,094 Due after one year through five years 7,197,033 7,097,641 7,545,731 7,554,248 Due after five years through ten years 2,314,395 2,283,642 2,214,473 2,231,456 Due after ten years 875,330 913,401 882,384 944,239 Asset-backed securities 511,328 506,430 532,473 531,360 Mortgage-backed securities: Commercial 232,693 227,299 235,794 234,041 Agency residential 2,272,215 2,222,995 2,236,361 2,210,902 Non-agency residential 478 476 497 494 Total fixed maturity securities $ 14,997,018 $ 14,844,581 $ 14,689,598 $ 14,756,834 The changes in net unrealized appreciation (depreciation) for the Company's investments are derived from the following sources for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Increase (decrease) during the period between the market value and cost of investments carried at market value, and deferred taxes thereon: Fixed maturity securities $ (219,485 ) $ 18,055 Fixed maturity securities, other-than-temporary impairment (189 ) (4,501 ) Equity securities - 5,999 Other invested assets - 444 Change in unrealized appreciation (depreciation), pre-tax (219,674 ) 19,997 Deferred tax benefit (expense) 20,299 (3,873 ) Deferred tax benefit (expense), other-than-temporary impairment (21) 1,225 Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders' equity $ (199,396 ) $ 17,349 The Company frequently reviews all of its fixed maturity, available for sale securities for declines in market value and focuses its attention on securities whose fair value has fallen below 80 The Company's assessments are based on the issuers' current and expected future financial position, timeliness with respect to interest and/or principal payments, speed of repayments and any applicable credit enhancements or breakeven constant default rates on mortgage-backed and asset-backed securities, as well as relevant information provided by rating agencies, investment advisors and analysts. Upon the adoption of ASU 2016-01 as of January 1, 2018, all equity investments in unconsolidated entities are recorded at fair value. Prior to the adoption of ASU 2016-01, the Company classified certain equity securities as available for sale at market value. The majority of the Company's equity securities classified as available for sale at market value prior to January 1, 2018 were primarily comprised of mutual fund investments whose underlying securities consisted of fixed maturity securities. When a fund's value reflected an unrealized loss, the Company assessed whether the decline in value was temporary or other-than-temporary. In making its assessment, the Company considered the composition of its portfolios and their related markets, reports received from the portfolio managers and discussions with portfolio managers. If the Company determined that the declines were temporary and it had the ability and intent to continue to hold the investments, then the declines were recorded as unrealized losses in accumulated other comprehensive income (loss). If declines were deemed to be other-than-temporary, then the carrying value of the investment was written down to fair value and recorded in net realized capital gains (losses) in the Company's consolidated statements of operations and comprehensive income (loss). Retrospective adjustments are employed to recalculate the values of asset-backed securities. All of the Company's asset-backed and mortgage-backed securities have a pass-through structure. Each acquisition lot is reviewed to recalculate the effective yield. The recalculated effective yield is used to derive a book value as if the new yield were applied at the time of acquisition. Outstanding principal factors from the time of acquisition to the adjustment date are used to calculate the prepayment history for all applicable securities. Conditional prepayment rates, computed with life to date factor histories and weighted average maturities, are used in the calculation of projected prepayments for pass-through security types. The tables below display the aggregate market value and gross unrealized depreciation of fixed maturity and equity securities, by security type and contractual maturity, in each case subdivided according to length of time that individual securities had been in a continuous unrealized loss position for the periods indicated: Duration of Unrealized Loss at March 31, 2018 By Security Type Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities - available for sale U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,193,463 $ (17,432 ) $ 225,194 $ (8,425 ) $ 1,418,657 $ (25,857 ) Obligations of U.S. states and political subdivisions 48,613 (383 ) 36,392 (1,311 ) 85,005 (1,694 ) Corporate securities 3,466,924 (77,213 ) 674,674 (30,832 ) 4,141,598 (108,045 ) Asset-backed securities 337,232 (4,400 ) 74,603 (907 ) 411,835 (5,307 ) Mortgage-backed securities Commercial 164,758 (2,555 ) 62,303 (2,841 ) 227,061 (5,396 ) Agency residential 683,971 (12,440 ) 1,285,758 (45,640 ) 1,969,729 (58,080 ) Non-agency residential - - 13 (44 ) 13 (44 ) Foreign government securities 300,778 (12,541 ) 351,734 (32,017 ) 652,512 (44,558 ) Foreign corporate securities 1,308,105 (38,136 ) 468,241 (37,021 ) 1,776,346 (75,157 ) Total fixed maturity securities $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) Equity securities - - - - - - Total $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) Duration of Unrealized Loss at March 31, 2018 By Maturity Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities Due in one year or less $ 952,178 $ (3,382 ) $ 197,004 $ (9,958 ) $ 1,149,182 $ (13,340 ) Due in one year through five years 4,143,873 (95,121 ) 1,208,285 (74,158 ) 5,352,158 (169,279 ) Due in five years through ten years 1,021,638 (40,701 ) 309,198 (23,485 ) 1,330,836 (64,186 ) Due after ten years 200,194 (6,501 ) 41,748 (2,005 ) 241,942 (8,506 ) Asset-backed securities 337,232 (4,400 ) 74,603 (907 ) 411,835 (5,307 ) Mortgage-backed securities 848,729 (14,995 ) 1,348,074 (48,525 ) 2,196,803 (63,520 ) Total fixed maturity securities $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) The aggregate market value and gross unrealized losses related to investments in an unrealized loss position at March 31, 2018 were $ 10,682,756 324,138 9.6 1.1 165,100 155,350 159,038 153,293 The Company, given the size of its investment portfolio and capital position, does not have the intent to sell these securities; and it is more likely than not that the Company will not have to sell the security before recovery of its cost basis. In addition, all securities currently in an unrealized loss position are current with respect to principal and interest payments. The tables below display the aggregate market value and gross unrealized depreciation of fixed maturity and equity securities, by security type and contractual maturity, in each case subdivided according to length of time that individual securities had been in a continuous unrealized loss position for the periods indicated: Duration of Unrealized Loss at December 31, 2017 By Security Type Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities - available for sale U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,077,051 $ (8,380 ) $ 224,189 $ (5,696 ) $ 1,301,240 $ (14,076 ) Obligations of U.S. states and political subdivisions 4,400 (27 ) 37,886 (417 ) 42,286 (444 ) Corporate securities 1,779,292 (24,942 ) 700,098 (16,233 ) 2,479,390 (41,175 ) Asset-backed securities 301,316 (1,467 ) 72,780 (515 ) 374,096 (1,982 ) Mortgage-backed securities Commercial 101,821 (572 ) 64,272 (1,797 ) 166,093 (2,369 ) Agency residential 610,941 (4,836 ) 1,343,547 (31,002 ) 1,954,488 (35,838 ) Non-agency residential - - 69 (44 ) 69 (44 ) Foreign government securities 327,790 (12,811 ) 331,432 (22,036 ) 659,222 (34,847 ) Foreign corporate securities 691,865 (19,381 ) 450,860 (29,025 ) 1,142,725 (48,406 ) Total fixed maturity securities $ 4,894,476 $ (72,416 ) $ 3,225,133 $ (106,765 ) $ 8,119,609 $ (179,181 ) Equity securities - - 113,506 (3,372 ) 113,506 (3,372 ) Total $ 4,894,476 $ (72,416 ) $ 3,338,639 $ (110,137 ) $ 8,233,115 $ (182,553 ) Duration of Unrealized Loss at December 31, 2017 By Maturity Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities Due in one year or less $ 247,927 $ (962 ) $ 206,113 $ (7,643 ) $ 454,040 $ (8,605 ) Due in one year through five years 2,930,977 (42,480 ) 1,200,414 (52,143 ) 4,131,391 (94,623 ) Due in five years through ten years 612,702 (20,154 ) 292,245 (12,680 ) 904,947 (32,834 ) Due after ten years 88,792 (1,945 ) 45,693 (941 ) 134,485 (2,886 ) Asset-backed securities 301,316 (1,467 ) 72,780 (515 ) 374,096 (1,982 ) Mortgage-backed securities 712,762 (5,408 ) 1,407,888 (32,843 ) 2,120,650 (38,251 ) Total fixed maturity securities $ 4,894,476 $ (72,416 ) $ 3,225,133 $ (106,765 ) $ 8,119,609 $ (179,181 ) The aggregate market value and gross unrealized losses related to investments in an unrealized loss position at December 31, 2017 were $ 8,233,115 182,553 8.9 1.1 72,416 68,107 106,765 103,739 no interest obligations. The mortgage-backed securities still have excess credit coverage and are current on interest and principal payments. The components of net investment income are presented in the table below for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Fixed maturities $ 108,682 $ 103,245 Equity securities 6,827 8,745 Short-term investments and cash 1,732 630 Other invested assets Limited partnerships 23,381 10,998 Other 4,325 2,272 Gross investment income before adjustments 144,947 125,890 Funds held interest income (expense) 3,630 3,148 Future policy benefit reserve income (expense) (209 ) (319 ) Gross investment income 148,368 128,719 Investment expenses (10,074 ) (6,430 ) Net investment income $ 138,294 $ 122,289 The Company records results from limited partnership investments on the equity method of accounting with changes in value reported through net investment income. Due to the timing of receiving financial information from these partnerships, the results are generally reported on a one month or quarter lag. If the Company determines there has been a significant decline in value of a limited partnership during this lag period, a loss will be recorded in the period in which the Company identifies the decline. The Company had contractual commitments to invest up to an additional $ 777,058 The Company's other invested assets at March 31, 2018 and December 31, 2017 included $ 220,241 447,915 The components of net realized capital gains (losses) are presented in the table below for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Fixed maturity securities, market value: Other-than-temporary impairments $ (70 ) $ (1,229 ) Gains (losses) from sales 10,392 11,373 Fixed maturity securities, fair value: Gains (losses) from sales (14 ) - Equity securities, market value: Gains (losses) from sales - (3,436 ) Equity securities, fair value: Gains (losses) from sales 40 4,516 Gains (losses) from fair value adjustments (35,253 ) 41,507 Other invested assets 3 1 Short-term investments gain (loss) 1 (4 ) Total net realized capital gains (losses) $ (24,901 ) $ 52,728 The Company recorded as net realized capital gains (losses) in the consolidated statements of operations and comprehensive income (loss) both fair value re-measurements and write-downs in the value of securities deemed to be impaired on an other-than-temporary basis as displayed in the table above. The Company had no other-than-temporary impaired securities where the impairment had both a credit and non-credit component. The proceeds and split between gross gains and losses, from sales of fixed maturity and equity securities, are presented in the table below for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Proceeds from sales of fixed maturity securities $ 364,288 $ 428,491 Gross gains from sales 13,002 15,473 Gross losses from sales (2,624 ) (4,100 ) Proceeds from sales of equity securities $ 199,875 $ 159,117 Gross gains from sales 6,687 8,208 Gross losses from sales (6,647 ) (7,128 )

Reserve For Losses, LAE And Fut

Reserve For Losses, LAE And Future Policy Benefit Reserve	3 Months Ended
	Mar. 31, 2018
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Reserve For Losses LAE And Future Policy Benefit Reserve	4. RESERVE FOR LOSSES, LAE AND FUTURE POLICY BENEFIT RESERVE Activity in the reserve for losses and LAE is summarized for the periods indicated: Three Months Ended Twelve Months Ended March 31, December 31, (Dollars in thousands) 2018 2017 Gross reserves at beginning of period $ 11,884,321 $ 10,312,313 Less reinsurance recoverables (1,212,649 ) (990,862 ) Net reserves at beginning of period 10,671,672 9,321,451 Incurred related to: Current year 957,177 4,815,967 Prior years 100,000 (293,386 ) Total incurred losses and LAE 1,057,177 4,522,581 Paid related to: Current year 140,761 1,280,605 Prior years 1,055,225 2,062,634 Total paid losses and LAE 1,195,986 3,343,239 Foreign exchange/translation adjustment 25,512 170,879 Net reserves at end of period 10,558,375 10,671,672 Plus reinsurance recoverables 1,234,971 1,212,649 Gross reserves at end of period $ 11,793,346 $ 11,884,321 Incurred prior years' reserves increased by $100,000 thousand for the three months ended March 31, 2018 and decreased by $293,386 thousand for the twelve months ended December 31, 2017. The increase for the three months ended March 31, 2018, related primarily to unfavorable development on prior year catastrophes, notably the 2017 California wildfires. The decrease for 2017 was attributable to favorable development in the reinsurance segments of $ 238,378 37,137 55,007

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2018
Derivatives [Abstract]
Derivatives	5. DERIVATIVES The Company sold seven two One no The Company has five 2 zero 403,464 2,640.87 no The Company has one 17 zero 3 42,531 7,056.61 no At March 31, 2018 and December 31, 2017, the fair value for these equity put options was $ 12,205 12,477 The fair value of the equity index put options can be found in the Company's consolidated balance sheets as follows: (Dollars in thousands) Derivatives not designated as Location of fair value At At hedging instruments in balance sheets March 31, 2018 December 31, 2017 Equity index put option contracts Equity index put option liability $ 12,205 $ 12,477 Total $ 12,205 $ 12,477 The change in fair value of the equity index put option contracts can be found in the Company's statement of operations and comprehensive income (loss) as follows: (Dollars in thousands) For the Three Months Ended Derivatives not designated as Location of gain (loss) in statements of March 31, hedging instruments operations and comprehensive income (loss) 2018 2017 Equity index put option contracts Net derivative gain (loss) $ 273 $ 2,630 Total $ 273 $ 2,630

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2018
Fair Value [Abstract]
Fair Value	6. FAIR VALUE GAAP guidance regarding fair value measurements address how companies should measure fair value when they are required to use fair value measures for recognition or disclosure purposes under GAAP and provides a common definition of fair value to be used throughout GAAP. It defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly fashion between market participants at the measurement date. In addition, it establishes a three-level valuation hierarchy for the disclosure of fair value measurements. The valuation hierarchy is based on the transparency of inputs to the valuation of an asset or liability. The level in the hierarchy within which a given fair value measurement falls is determined based on the lowest level input that is significant to the measurement, with Level 1 being the highest priority and Level 3 being the lowest priority. The levels in the hierarchy are defined as follows: Level 1: Inputs to the valuation methodology are observable inputs that reflect unadjusted quoted prices for identical assets or liabilities in an active market; Level 2: Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument; Level 3: Inputs to the valuation methodology are unobservable and significant to the fair value measurement. The Company's fixed maturity and equity securities are primarily managed by third party investment asset managers. The investment asset managers obtain prices from nationally recognized pricing services. These services seek to utilize market data and observations in their evaluation process. They use pricing applications that vary by asset class and incorporate available market information and when fixed maturity securities do not trade on a daily basis the services will apply available information through processes such as benchmark curves, benchmarking of like securities, sector groupings and matrix pricing. In addition, they use model processes, such as the Option Adjusted Spread model to develop prepayment and interest rate scenarios for securities that have prepayment features. In limited instances where prices are not provided by pricing services or in rare instances when a manager may not agree with the pricing service, price quotes on a non-binding basis are obtained from investment brokers. The investment asset managers do not make any changes to prices received from either the pricing services or the investment brokers. In addition, the investment asset managers have procedures in place to review the reasonableness of the prices from the service providers and may request verification of the prices. In addition, the Company continually performs analytical reviews of price changes and tests the prices on a random basis to an independent pricing source. No material variances were noted during these price validation procedures. In limited situations, where financial markets are inactive or illiquid, the Company may use its own assumptions about future cash flows and risk-adjusted discount rates to determine fair value. Due to the unavailability of prices for seventy-five seventy-three 164,818 two 68,927 sixty-six sixty-five 165,173 one 51,965 The Company internally manages a public equity portfolio which had a fair value at March 31, 2018 and December 31, 2017 of $ 500,330 386,241 Equity securities denominated in U.S. currency with quoted prices in active markets for identical assets are categorized as level 1 since the quoted prices are directly observable. Equity securities traded on foreign exchanges are categorized as level 2 due to the added input of a foreign exchange conversion rate to determine fair or market value. The Company uses foreign currency exchange rates published by nationally recognized sources. All categories of fixed maturity securities listed in the tables below are generally categorized as level 2, since a particular security may not have traded but the pricing services are able to use valuation models with observable market inputs such as interest rate yield curves and prices for similar fixed maturity securities in terms of issuer, maturity and seniority. For foreign government securities and foreign corporate securities, the fair values provided by the third party pricing services in local currencies, and where applicable, are converted to U.S. dollars using currency exchange rates from nationally recognized sources. The fixed maturities with fair values categorized as level 3 result when prices are not available from the nationally recognized pricing services. The asset managers will then obtain non-binding price quotes for the securities from brokers. The single broker quotes are provided by market makers or broker-dealers who are recognized as market participants in the markets in which they are providing the quotes. The prices received from brokers are reviewed for reasonableness by the third party asset managers and the Company. If the broker quotes are for foreign denominated securities, the quotes are converted to U.S. dollars using currency exchange rates from nationally recognized sources. In limited circumstances when broker prices are not available for private placements, the Company will value the securities using comparable market information or receive fair values from investment managers. The composition and valuation inputs for the presented fixed maturities categories are as follows: · U.S. Treasury securities and obligations of U.S. government agencies and corporations are primarily comprised of U.S. Treasury bonds and the fair value is based on observable market inputs such as quoted prices, reported trades, quoted prices for similar issuances or benchmark yields; · Obligations of U.S. states and political subdivisions are comprised of state and municipal bond issuances and the fair values are based on observable market inputs such as quoted market prices, quoted prices for similar securities, benchmark yields and credit spreads; · Corporate securities are primarily comprised of U.S. corporate and public utility bond issuances and the fair values are based on observable market inputs such as quoted market prices, quoted prices for similar securities, benchmark yields and credit spreads; · Asset-backed and mortgage-backed securities fair values are based on observable inputs such as quoted prices, reported trades, quoted prices for similar issuances or benchmark yields and cash flow models using observable inputs such as prepayment speeds, collateral performance and default spreads; · Foreign government securities are comprised of global non-U.S. sovereign bond issuances and the fair values are based on observable market inputs such as quoted market prices, quoted prices for similar securities and models with observable inputs such as benchmark yields and credit spreads and then, where applicable, converted to U.S. dollars using an exchange rate from a nationally recognized source; · Foreign corporate securities are comprised of global non-U.S. corporate bond issuances and the fair values are based on observable market inputs such as quoted market prices, quoted prices for similar securities and models with observable inputs such as benchmark yields and credit spreads and then, where applicable, converted to U.S. dollars using an exchange rate from a nationally recognized source. The Company sold seven two recorded in the consolidated statements of operations and comprehensive income (loss). One of these contracts expired on June 9, 2017, with no liability due under the terms of the contract. The Company's liability for equity index put options is categorized as level 3 since there is no active market for these equity put options. The fair values for these options are calculated by the Company using an industry accepted pricing model, Black-Scholes. The model inputs and assumptions are: risk free interest rates, equity market indexes values, volatilities and dividend yields and duration. The model results are then adjusted for the Company's credit default swap rate. All of these inputs and assumptions are updated quarterly. One of the option contacts is in British Pound Sterling so the fair value for this contract is converted to U.S. dollars using an exchange rate from a nationally recognized source. The following table presents the fair value measurement levels for all assets and liabilities, which the Company has recorded at fair value (fair and market value) as of the periods indicated: Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) March 31, 2018 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,497,413 $ - $ 1,497,413 $ - Obligations of U.S. States and political subdivisions 536,547 - 536,547 - Corporate securities 5,777,747 - 5,557,192 220,555 Asset-backed securities 506,430 - 506,430 - Mortgage-backed securities Commercial 227,299 - 227,299 - Agency residential 2,222,995 - 2,222,995 - Non-agency residential 476 - 476 - Foreign government securities 1,274,322 - 1,274,322 - Foreign corporate securities 2,801,352 - 2,789,984 11,368 Total fixed maturities, market value 14,844,581 - 14,612,658 231,923 Fixed maturities, fair value 1,821 - - 1,821 Equity securities, fair value 1,169,531 1,123,632 45,899 - Liabilities: Equity index put option contracts $ 12,205 $ - $ - $ 12,205 There were no The following table presents the fair value measurement levels for all assets and liabilities, which the Company has recorded at fair value (fair and market value) as of the periods indicated: Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2017 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,536,692 $ - $ 1,536,692 $ - Obligations of U.S. States and political subdivisions 585,469 - 585,469 - Corporate securities 5,699,005 - 5,488,819 210,186 Asset-backed securities 531,360 - 531,360 - Mortgage-backed securities Commercial 234,041 - 234,041 - Agency residential 2,210,902 - 2,210,902 - Non-agency residential 494 - 494 - Foreign government securities 1,314,027 - 1,314,027 - Foreign corporate securities 2,644,844 - 2,637,892 6,952 Total fixed maturities, market value 14,756,834 - 14,539,696 217,138 Equity securities, market value 129,530 113,506 16,024 - Equity securities, fair value 963,572 941,739 21,833 - Liabilities: Equity index put option contracts $ 12,477 $ - $ - $ 12,477 In addition, $ 82,902 79,505 The following tables present the activity under Level 3, fair value measurements using significant unobservable inputs by asset type, for the periods indicated: Total Fixed Maturities, Market Value Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Corporate Foreign Corporate Foreign (Dollars in thousands) Securities Corporate Total Securities Corporate Total Beginning balance fixed maturities at market value $ 210,186 $ 6,952 $ 217,138 $ 65,197 $ 2,538 $ 67,735 Total gains or (losses) (realized/unrealized) Included in earnings 722 94 816 214 (24 ) 190 Included in other comprehensive income (loss) 235 - 235 (29 ) - (29 ) Purchases, issuances and settlements 9,412 4,322 13,734 18,940 288 19,228 Transfers in and/or (out) of Level 3 - - - - - - Ending balance $ 220,555 $ 11,368 $ 231,923 $ 84,322 $ 2,802 $ 87,124 The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ - $ - $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.) Total Fixed Maturities, Fair Value Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Foreign Foreign (Dollars in thousands) Corporate Total Corporate Total Beginning balance fixed maturities at fair value $ - $ - $ - $ - Total gains or (losses) (realized/unrealized) Included in earnings (14 ) (14 ) - - Included in other comprehensive income (loss) - - - - Purchases, issuances and settlements 1,835 1,835 - - Transfers in and/or (out) of Level 3 - - - - Ending balance $ 1,821 $ 1,821 $ - $ - The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.) There were no The following table presents the activity under Level 3, fair value measurements using significant unobservable inputs for equity index put option contracts, for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Liabilities: Balance, beginning of period $ 12,477 $ 22,059 Total (gains) or losses (realized/unrealized) Included in earnings (273 ) (2,630 ) Included in other comprehensive income (loss) - - Purchases, issuances and settlements - - Transfers in and/or (out) of Level 3 - - Balance, end of period $ 12,205 $ 19,429 The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to liabilities still held at the reporting date $ - $ - (Some amounts may not reconcile due to rounding.)

Earnings Per Common Share

Earnings Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Common Share [Abstract]
Earnings Per Common Share	7. EARNINGS PER COMMON SHARE Basic earnings per share are calculated by dividing net income by the weighted average number of common shares outstanding. Diluted earnings per share reflect the potential dilution that would occur if options granted under various share-based compensation plans were exercised resulting in the issuance of common shares that would participate in the earnings of the entity. Net income (loss) per common share has been computed as per below, based upon weighted average common basic and dilutive shares outstanding. Three Months Ended March 31, (Dollars in thousands, except per share amounts) 2018 2017 Net income (loss) per share: Numerator Net income (loss) $ 210,318 $ 291,643 Less: dividends declared-common shares and nonvested common shares (53,240 ) (51,281 ) Undistributed earnings 157,078 240,362 Percentage allocated to common shareholders (1) 98.9 % 98.9 % 155,410 237,754 Add: dividends declared-common shareholders 52,697 50,753 Numerator for basic and diluted earnings per common share $ 208,107 $ 288,507 Denominator Denominator for basic earnings per weighted-average common shares 40,469 40,529 Effect of dilutive securities: Options 220 267 Denominator for diluted earnings per adjusted weighted-average common shares 40,689 40,796 Per common share net income (loss) Basic $ 5.14 $ 7.12 Diluted $ 5.11 $ 7.07 (1) Basic weighted-average common shares outstanding 40,469 40,529 Basic weighted-average common shares outstanding and nonvested common shares expected to vest 40,903 40,973 Percentage allocated to common shareholders 98.9 % 98.9 % (Some amounts may not reconcile due to rounding.) There were no All outstanding options expire on or between February 18, 2019 September 19, 2022

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies [Abstract]
Commitments And Contingencies	8. COMMITMENTS AND CONTINGENCIES In the ordinary course of business, the Company is involved in lawsuits, arbitrations and other formal and informal dispute resolution procedures, the outcomes of which will determine the Company's rights and obligations under insurance and reinsurance agreements. In some disputes, the Company seeks to enforce its rights under an agreement or to collect funds owing to it. In other matters, the Company is resisting attempts by others to collect funds or enforce alleged rights. These disputes arise from time to time and are ultimately resolved through both informal and formal means, including negotiated resolution, arbitration and litigation. In all such matters, the Company believes that its positions are legally and commercially reasonable. The Company considers the statuses of these proceedings when determining its reserves for unpaid loss and loss adjustment expenses. Aside from litigation and arbitrations related to these insurance and reinsurance agreements, the Company is not a party to any other material litigation or arbitration. The Company has entered into separate annuity agreements with The Prudential Insurance Company of America ("The Prudential") and an additional unaffiliated life insurance company in which the Company has either purchased annuity contracts or become the assignee of annuity proceeds that are meant to settle claim payment obligations in the future. In both instances, the Company would become contingently liable if either The Prudential or the unaffiliated life insurance company were unable to make payments related to the respective annuity contract. The table below presents the estimated cost to replace all such annuities for which the Company was contingently liable for the periods indicated: At March 31, At December 31, (Dollars in thousands) 2018 2017 The Prudential $ 144,516 $ 144,618 Unaffiliated life insurance company 32,718 34,444

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Other Comprehensive Income (Loss) [Abstract]
Other Comprehensive Income (Loss)	9. OTHER COMPREHENSIVE INCOME (LOSS) The following tables present the components of comprehensive income (loss) in the consolidated statements of operations for the periods indicated: Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 (Dollars in thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized appreciation (depreciation) ("URA(D)") on securities - temporary $ (209,160 ) $ 18,746 $ (190,414 ) $ 31,206 $ (8,382 ) $ 22,824 URA(D) on securities - OTTI (189 ) (21 ) (210 ) (4,501 ) 1,225 (3,276 ) Reclassification of net realized losses (gains) included in net income (loss) (10,325 ) 1,553 (8,772 ) (6,708 ) 4,509 (2,199 ) Foreign currency translation adjustments 17,345 354 17,699 13,813 (1,920 ) 11,893 Reclassification of benefit plan liability amortization included in net income (loss) 2,298 (483 ) 1,815 3,083 (1,079 ) 2,004 Total other comprehensive income (loss) $ (200,031 ) $ 20,149 $ (179,882 ) $ 36,893 $ (5,647 ) $ 31,246 22 The following table presents details of the amounts reclassified from AOCI for the periods indicated: Three Months Ended March 31, Affected line item within the statements of AOCI component 2018 2017 operations and comprehensive income (loss) (Dollars in thousands) URA(D) on securities $ (10,325 ) $ (6,708 ) Other net realized capital gains (losses) 1,553 4,509 Income tax expense (benefit) $ (8,772 ) $ (2,199 ) Net income (loss) Benefit plan net gain (loss) $ 2,298 $ 3,083 Other underwriting expenses (483 ) (1,079 ) Income tax expense (benefit) $ 1,815 $ 2,004 Net income (loss) The following table presents the components of accumulated other comprehensive income (loss), net of tax, in the consolidated balance sheets for the periods indicated: Three Months Ended Twelve Months Ended March 31, December 31, (Dollars in thousands) 2018 2017 Beginning balance of URA (D) on securities $ 49,969 $ 115,558 Current period change in URA (D) of investments - temporary (199,186 ) (67,268 ) Current period change in URA (D) of investments - non-credit OTTI (210 ) (4,030 ) Reclass due to early adoption of ASU 2018-02 - 5,709 Cumulative change due to ASU 2016-01 (1,201 ) - Ending balance of URA (D) on securities (150,628 ) 49,969 Beginning balance of foreign currency translation adjustments (138,931 ) (266,818 ) Current period change in foreign currency translation adjustments 17,699 121,917 Reclass due to early adoption of ASU 2018-02 - 5,970 Ending balance of foreign currency translation adjustments (121,232 ) (138,931 ) Beginning balance of benefit plan net gain (loss) (71,929 ) (65,504 ) Current period change in benefit plan net gain (loss) 1,815 6,504 Reclass due to early adoption of ASU 2018-02 - (12,929 ) Ending balance of benefit plan net gain (loss) (70,114 ) (71,929 ) Ending balance of accumulated other comprehensive income (loss) $ (341,974 ) $ (160,891 ) (Some amounts may not reconcile due to rounding.)

Credit Facilities

Credit Facilities	3 Months Ended
	Mar. 31, 2018
Credit Facilities [Abstract]
Credit Facilities	10. CREDIT FACILITIES The Company has two 1,050,000 Three Months Ended March 31, (Dollars in thousands) 2018 2017 Credit facility interest and fees incurred $ 105 $ 104 The terms and outstanding amounts for each facility are discussed below: Group Credit Facility Effective May 26, 2016, Group, Everest Reinsurance (Bermuda), Ltd. ("Bermuda Re") and Everest International Reinsurance, Ltd. ("Everest International"), both direct subsidiaries of Group, entered into a five year, $ 800,000 800,000 two 200,000 0.5 1.0 600,000 The Group Credit Facility requires Group to maintain a debt to capital ratio of not greater than 0.35 5,370,979 25 25 5,919,732 (Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Wells Fargo Bank Group Credit Facility Tranche One $ 200,000 $ - $ 200,000 $ - Tranche Two 600,000 564,638 12/31/2018 600,000 538,214 12/31/2018 Total Wells Fargo Bank Group Credit Facility $ 800,000 $ 564,638 $ 800,000 $ 538,214 Bermuda Re Letter of Credit Facility Effective December 29, 2017, Bermuda Re renewed its letter of credit issuance facility with Citibank N.A. referred to as the "Bermuda Re Letter of Credit Facility", which commitment is reconfirmed annually with updated fees. The current renewal of the Bermuda Re Letter of Credit Facility provides for the issuance of up to $ 250,000 0.35 0.45 60 0.15 The following table summarizes the outstanding letters of credit for the periods indicated: (Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Citibank Bilateral Letter of Credit Agreement $ 250,000 $ 3,672 11/24/2018 $ 250,000 $ 3,297 2/28/2018 108,875 12/31/2018 3,672 11/24/2018 3,297 2/28/2019 73,626 12/31/2018 346 8/30/2019 344 8/30/2019 3,599 12/31/2019 93,855 12/30/2021 95,667 3/30/2022 - Total Citibank Bilateral Agreement $ 250,000 $ 215,456 $ 250,000 $ 174,794 Everest International Credit Facility Effective November 9, 2016 four 145,000 0.1 0.35 The Everest International Credit Facility requires Group to maintain a debt to capital ratio of not greater than 0.35 5,326,009 70 25 25 5,919,732 The following table summarizes the outstanding letters of credit for the periods indicated: (Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Lloyd's Bank plc £ 145,000 £ - £ 145,000 £ - - - - - Total Lloyd's Bank Credit Facility £ 145,000 £ - £ 145,000 £ -

Collateralized Reinsurance And

Collateralized Reinsurance And Trust Agreements	3 Months Ended
	Mar. 31, 2018
Collateralized Reinsurance And Trust Agreements [Abstract]
Collateralized Reinsurance And Trust Agreements	11. COLLATERALIZED REINSURANCE AND TRUST AGREEMENTS Certain subsidiaries of Group have established trust agreements, which effectively use the Company's investments as collateral, as security for assumed losses payable to certain non-affiliated ceding companies. At March 31, 2018, the total amount on deposit in trust accounts was $ 862,629 The Company reinsures some of its catastrophe exposures with the segregated accounts of Mt. Logan Re. Mt. Logan Re is a Class 3 insurer registered in Bermuda effective February 27, 2013 under The Segregated Accounts Companies Act 2000 and 100 The following table summarizes the premiums and losses that are ceded by the Company to Mt. Logan Re segregated accounts and assumed by the Company from Mt. Logan Re segregated accounts. Three Months Ended March 31, Mt. Logan Re Segregated Accounts 2018 2017 (Dollars in thousands) Ceded written premiums 81,036 54,218 Ceded earned premiums 61,409 40,597 Ceded losses and LAE 21,069 19,585 Assumed written premiums 3,043 2,732 Assumed earned premiums 3,043 2,732 Assumed losses and LAE - - Each segregated account is permitted to assume net risk exposures equal to the amount of its available posted collateral, which in the aggregate was $ 1,077,895 837,202 51,564 50,373 On April 24, 2014, the Company entered into two 250,000 200,000 On November 18, 2014, the Company entered into a collateralized reinsurance agreement with Kilimanjaro to provide the Company with catastrophe reinsurance coverage. This agreement is a multi-year reinsurance contract which covers specified earthquake events. The agreement provides up to $ 500,000 On December 1, 2015 the Company entered into two 300,000 325,000 On April 13, 2017 the Company entered into six three four 225,000 400,000 325,000 three five 50,000 75,000 175,000 On April 30, 2018 the Company entered into four two four 62,500 200,000 two five 62,500 200,000 Recoveries under these collateralized reinsurance agreements with Kilimanjaro are primarily dependent on estimated industry level insured losses from covered events, as well as, the geographic location of the events. The estimated industry level of insured losses is obtained from published estimates by an independent recognized authority on insured property losses. As of December 31, 2017, none of the published insured loss estimates for the 2017 catastrophe events have exceeded the single event retentions under the terms of the agreements that would result in a recovery. In addition, the aggregation of the to-date published insured loss estimates for the 2017 covered events have not exceeded the aggregated retentions for recovery. However, if the published estimates for insured losses for the covered 2017 events increase, the aggregate losses may exceed the aggregate event retentions under the agreements resulting in a recovery. Kilimanjaro has financed the various property catastrophe reinsurance coverages by issuing catastrophe bonds to unrelated, external investors. On April 24, 2014, Kilimanjaro issued $ 450,000 450,000 500,000 625,000 950,000 300,000 262,500 -1 262,500

Senior Notes

Senior Notes	3 Months Ended
	Mar. 31, 2018
Senior Notes [Abstract]
Senior Notes	12. SENIOR NOTES The table below displays Holdings' outstanding senior notes. Market value is based on quoted market prices, but due to limited trading activity, these senior notes are considered Level 2 in the fair value hierarchy. March 31, 2018 December 31, 2017 Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Date Due Principal Amounts Sheet Amount Market Value Sheet Amount Market Value 4.868 06/05/2014 06/01/2044 400,000 $ 396,864 $ 399,080 $ 396,834 $ 420,340 On June 5, 2014, Holdings issued $400,000 thousand of 30 Interest expense incurred in connection with these senior notes is as follows for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Interest expense incurred $ 4,868 $ 4,868

Long Term Subordinated Notes

Long Term Subordinated Notes	3 Months Ended
	Mar. 31, 2018
Long Term Subordinated Notes [Abstract]
Long Term Subordinated Notes	13. LONG TERM SUBORDINATED NOTES The table below displays Holdings' outstanding fixed to floating rate long term subordinated notes. Market value is based on quoted market prices, but due to limited trading activity, these subordinated notes are considered Level 2 in the fair value hierarchy. Maturity Date March 31, 2018 December 31, 2017 Original Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Principal Amount Scheduled Final Sheet Amount Market Value Sheet Amount Market Value 6.6 04/26/2007 $ 400,000 05/15/2037 05/01/2067 $ 236,585 $ 238,421 $ 236,561 $ 233,072 During the fixed rate interest period from May 3, 2007 May 14, 2017 6.6 November 15, 2007 4.22 Holdings may redeem the long term subordinated notes on or after May 15, 2017, in whole or in part at 100 May 1, 2047 5.40 October 15, 2014 4.868 June 1, 2044 On March 19, 2009, Group announced the commencement of a cash tender offer for any and all of the 6.60% fixed to floating rate long term subordinated notes. Upon expiration of the tender offer, the Company had reduced its outstanding debt by $ 161,441 Interest expense incurred in connection with these long term subordinated notes is as follows for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Interest expense incurred $ 2,391 $ 3,937

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	14. SEGMENT REPORTING The U.S. Reinsurance operation writes property and casualty reinsurance and specialty lines of business, including Marine, Aviation, Surety and Accident and Health ("A&H") business, on both a treaty and facultative basis, through reinsurance brokers, as well as directly with ceding companies primarily within the U.S. The International operation writes non-U.S. property and casualty reinsurance through Everest Re's branches in Canada and Singapore and through offices in Brazil, Miami and New Jersey. The Bermuda operation provides reinsurance and insurance to worldwide property and casualty markets through brokers and directly with ceding companies from its Bermuda office and reinsurance to the United Kingdom and European markets through its UK branch and Ireland Re. The Insurance operation writes property and casualty insurance directly and through brokers, surplus lines brokers and general agents within the U.S., Canada and Europe. These segments are managed independently, but conform with corporate guidelines with respect to pricing, risk management, control of aggregate catastrophe exposures, capital, investments and support operations. Management generally monitors and evaluates the financial performance of these operating segments based upon their underwriting results. Underwriting results include earned premium less losses and loss adjustment expenses ("LAE") incurred, commission and brokerage expenses and other underwriting expenses. We measure our underwriting results using ratios, in particular loss, commission and brokerage and other underwriting expense ratios, which, respectively, divide incurred losses, commissions and brokerage and other underwriting expenses by premiums earned. For inter-affiliate reinsurance and business written through the Lloyd's Syndicate, business is generally reported within the segment in which the business was first produced, consistent with how the business is managed. The Company does not maintain separate balance sheet data for its operating segments. Accordingly, the Company does not review and evaluate the financial results of its operating segments based upon balance sheet data. The following tables present the underwriting results for the operating segments for the periods indicated: Three Months Ended U.S. Reinsurance March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 644,222 $ 578,958 Net written premiums 545,831 517,369 Premiums earned $ 563,385 $ 481,524 Incurred losses and LAE 545,193 262,066 Commission and brokerage 127,320 102,358 Other underwriting expenses 16,886 14,251 Underwriting gain (loss) $ (126,014 ) $ 102,849 Three Months Ended International March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 366,724 $ 266,417 Net written premiums 345,155 245,662 Premiums earned $ 343,604 $ 271,581 Incurred losses and LAE 127,024 159,501 Commission and brokerage 82,177 66,150 Other underwriting expenses 10,576 9,480 Underwriting gain (loss) $ 123,827 $ 36,450 Three Months Ended Bermuda March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 415,686 $ 321,122 Net written premiums 394,968 305,032 Premiums earned $ 319,134 $ 235,106 Incurred losses and LAE 129,513 128,432 Commission and brokerage 81,487 58,423 Other underwriting expenses 10,133 9,480 Underwriting gain (loss) $ 98,001 $ 38,771 Three Months Ended Insurance March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 504,975 $ 434,447 Net written premiums 386,252 345,751 Premiums earned $ 393,304 $ 323,886 Incurred losses and LAE 255,447 220,789 Commission and brokerage 66,655 55,338 Other underwriting expenses 58,689 42,676 Underwriting gain (loss) $ 12,513 $ 5,083 The following table reconciles the underwriting results for the operating segments to income before taxes as reported in the consolidated statements of operations and comprehensive income (loss) for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 Underwriting gain (loss) $ 108,327 $ 183,153 Net investment income 138,294 122,289 Net realized capital gains (losses) (24,901 ) 52,728 Net derivative gain (loss) 273 2,630 Corporate expenses (8,996 ) (8,457 ) Interest, fee and bond issue cost amortization expense (7,418 ) (8,964 ) Other income (expense) 12,064 (4,966 ) Income (loss) before taxes $ 217,643 $ 338,413 The Company produces business in the U.S., Bermuda and internationally. The net income deriving from and assets residing in the individual foreign countries in which the Company writes business are not identifiable in the Company's financial records. Based on gross written premium, the table below presents the largest country, other than the U.S., in which the Company writes business, for the periods indicated: Three Months Ended March 31, (Dollars in thousands) 2018 2017 United Kingdom gross written premium $ 258,259 $ 170,820 No other country represented more than 5

Share-Based Compensation Plans

Share-Based Compensation Plans	3 Months Ended
	Mar. 31, 2018
Share-Based Compensation Plans [Abstract]
Share-Based Compensation Plans	15. SHARE-BASED COMPENSATION PLANS For the three months ended March 31, 2018, share-based compensation awards granted were 160,645 February 21, 2018 242.39 13,325 February 21, 2018 242.39

Retirement Benefits

Retirement Benefits	3 Months Ended
	Mar. 31, 2018
Retirement Benefits [Abstract]
Retirement Benefits	16. RETIREMENT BENEFITS The Company maintains both qualified and non-qualified defined benefit pension plans and a retiree health plan for its U.S. employees employed prior to April 1, 2010. Net periodic benefit cost for U.S. employees included the following components for the periods indicated: Pension Benefits Three Months Ended March 31, (Dollars in thousands) 2018 2017 Service cost $ 2,977 $ 3,299 Interest cost 2,585 2,276 Expected return on plan assets (3,670 ) (3,155 ) Amortization of net (income) loss 2,237 3,040 Net periodic benefit cost $ 4,128 $ 5,460 Other Benefits Three Months Ended March 31, (Dollars in thousands) 2018 2017 Service cost $ 446 $ 440 Interest cost 307 249 Amortization of prior service cost (33 ) (33 ) Amortization of net (income) loss 94 76 Net periodic benefit cost $ 814 $ 732 (Some amounts may not reconcile due to rounding.) The service cost component of net periodic benefit costs is included within other underwriting expenses on the consolidated statement of operations and comprehensive income (loss). In accordance with ASU 2017-07, other staff compensation costs are also primarily recorded within this line item. The Company did no

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Taxes [Abstract]
Income Taxes	17. INCOME TAXES The Company is domiciled in Bermuda and has significant subsidiaries and/or branches in Canada, Ireland, Singapore, the United Kingdom, and the United States. The Company's Bermuda domiciled subsidiaries are exempt from income taxation under Bermuda law until 2035. The Company's non-Bermudian subsidiaries and branches are subject to income taxation at varying rates in their respective domiciles. The Company generally applies the estimated annual effective tax rate approach for calculating its tax provision for interim periods as prescribed by ASC 740-270, Interim Reporting. Under the estimated annual effective tax rate approach, the estimated annual effective tax rate is applied to the interim year-to-date pre-tax income/loss to determine the income tax expense or benefit for the year-to-date period. If the annual effective tax rate approach produces a year-to-date tax benefit which exceeds the amount which is estimated to be recoverable for the full year, then the tax benefit for the interim reporting period will be limited as prescribed under ASC 740-270 to the estimated recoverable based on the year-to-date result. The tax expense or benefit for the quarter represents the difference between the year-to-date tax expense or benefit for the current year-to-date period less such amount for the immediately preceding year-to-date period. Management considers the impact of all known events in its estimation of the Company's annual pre-tax income/loss and effective tax rate.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	18. SUBSEQUENT EVENTS On April 30, 2018, the Company entered into four 525,000

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Summary Of Unrealized Appreciation (Depreciation) Of Available For Sale, Fixed Maturity And Equity Security Investments	At March 31, 2018 Amortized Unrealized Unrealized Market OTTI in AOCI (Dollars in thousands) Cost Appreciation Depreciation Value (a) Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,516,251 $ 7,019 $ (25,857 ) $ 1,497,413 $ - Obligations of U.S. states and political subdivisions 523,611 14,630 (1,694 ) 536,547 165 Corporate securities 5,834,818 50,974 (108,045 ) 5,777,747 2,481 Asset-backed securities 511,328 409 (5,307 ) 506,430 - Mortgage-backed securities Commercial 232,693 2 (5,396 ) 227,299 - Agency residential 2,272,215 8,860 (58,080 ) 2,222,995 - Non-agency residential 478 42 (44 ) 476 - Foreign government securities 1,283,177 35,703 (44,558 ) 1,274,322 163 Foreign corporate securities 2,822,447 54,062 (75,157 ) 2,801,352 618 Total fixed maturity securities $ 14,997,018 $ 171,701 $ (324,138 ) $ 14,844,581 $ 3,427 Equity securities $ - $ - $ - $ - $ - At December 31, 2017 Amortized Unrealized Unrealized Market OTTI in AOCI (Dollars in thousands) Cost Appreciation Depreciation Value (a) Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,540,952 $ 9,816 $ (14,076 ) $ 1,536,692 $ - Obligations of U.S. states and political subdivisions 563,790 22,123 (444 ) 585,469 - Corporate securities 5,658,456 81,724 (41,175 ) 5,699,005 2,488 Asset-backed securities 532,473 869 (1,982 ) 531,360 - Mortgage-backed securities Commercial 235,794 616 (2,369 ) 234,041 - Agency residential 2,236,361 10,379 (35,838 ) 2,210,902 - Non-agency residential 497 41 (44 ) 494 - Foreign government securities 1,305,070 43,804 (34,847 ) 1,314,027 178 Foreign corporate securities 2,616,205 77,045 (48,406 ) 2,644,844 950 Total fixed maturity securities $ 14,689,598 $ 246,417 $ (179,181 ) $ 14,756,834 $ 3,616 Equity securities $ 130,287 $ 2,615 $ (3,372 ) $ 129,530 $ - (a)
Summary Of Amortized Cost And Market Value Of Fixed Maturity Securities, By Contractual Maturity	At March 31, 2018 At December 31, 2017 Amortized Market Amortized Market (Dollars in thousands) Cost Value Cost Value Fixed maturity securities – available for sale: Due in one year or less $ 1,593,546 $ 1,592,697 $ 1,041,885 $ 1,050,094 Due after one year through five years 7,197,033 7,097,641 7,545,731 7,554,248 Due after five years through ten years 2,314,395 2,283,642 2,214,473 2,231,456 Due after ten years 875,330 913,401 882,384 944,239 Asset-backed securities 511,328 506,430 532,473 531,360 Mortgage-backed securities: Commercial 232,693 227,299 235,794 234,041 Agency residential 2,272,215 2,222,995 2,236,361 2,210,902 Non-agency residential 478 476 497 494 Total fixed maturity securities $ 14,997,018 $ 14,844,581 $ 14,689,598 $ 14,756,834
Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Increase (decrease) during the period between the market value and cost of investments carried at market value, and deferred taxes thereon: Fixed maturity securities $ (219,485 ) $ 18,055 Fixed maturity securities, other-than-temporary impairment (189 ) (4,501 ) Equity securities - 5,999 Other invested assets - 444 Change in unrealized appreciation (depreciation), pre-tax (219,674 ) 19,997 Deferred tax benefit (expense) 20,299 (3,873 ) Deferred tax benefit (expense), other-than-temporary impairment (21) 1,225 Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders' equity $ (199,396 ) $ 17,349
Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Security Type	Duration of Unrealized Loss at March 31, 2018 By Security Type Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities - available for sale U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,193,463 $ (17,432 ) $ 225,194 $ (8,425 ) $ 1,418,657 $ (25,857 ) Obligations of U.S. states and political subdivisions 48,613 (383 ) 36,392 (1,311 ) 85,005 (1,694 ) Corporate securities 3,466,924 (77,213 ) 674,674 (30,832 ) 4,141,598 (108,045 ) Asset-backed securities 337,232 (4,400 ) 74,603 (907 ) 411,835 (5,307 ) Mortgage-backed securities Commercial 164,758 (2,555 ) 62,303 (2,841 ) 227,061 (5,396 ) Agency residential 683,971 (12,440 ) 1,285,758 (45,640 ) 1,969,729 (58,080 ) Non-agency residential - - 13 (44 ) 13 (44 ) Foreign government securities 300,778 (12,541 ) 351,734 (32,017 ) 652,512 (44,558 ) Foreign corporate securities 1,308,105 (38,136 ) 468,241 (37,021 ) 1,776,346 (75,157 ) Total fixed maturity securities $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) Equity securities - - - - - - Total $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) Duration of Unrealized Loss at December 31, 2017 By Security Type Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities - available for sale U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,077,051 $ (8,380 ) $ 224,189 $ (5,696 ) $ 1,301,240 $ (14,076 ) Obligations of U.S. states and political subdivisions 4,400 (27 ) 37,886 (417 ) 42,286 (444 ) Corporate securities 1,779,292 (24,942 ) 700,098 (16,233 ) 2,479,390 (41,175 ) Asset-backed securities 301,316 (1,467 ) 72,780 (515 ) 374,096 (1,982 ) Mortgage-backed securities Commercial 101,821 (572 ) 64,272 (1,797 ) 166,093 (2,369 ) Agency residential 610,941 (4,836 ) 1,343,547 (31,002 ) 1,954,488 (35,838 ) Non-agency residential - - 69 (44 ) 69 (44 ) Foreign government securities 327,790 (12,811 ) 331,432 (22,036 ) 659,222 (34,847 ) Foreign corporate securities 691,865 (19,381 ) 450,860 (29,025 ) 1,142,725 (48,406 ) Total fixed maturity securities $ 4,894,476 $ (72,416 ) $ 3,225,133 $ (106,765 ) $ 8,119,609 $ (179,181 ) Equity securities - - 113,506 (3,372 ) 113,506 (3,372 ) Total $ 4,894,476 $ (72,416 ) $ 3,338,639 $ (110,137 ) $ 8,233,115 $ (182,553 )
Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity	Duration of Unrealized Loss at March 31, 2018 By Maturity Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities Due in one year or less $ 952,178 $ (3,382 ) $ 197,004 $ (9,958 ) $ 1,149,182 $ (13,340 ) Due in one year through five years 4,143,873 (95,121 ) 1,208,285 (74,158 ) 5,352,158 (169,279 ) Due in five years through ten years 1,021,638 (40,701 ) 309,198 (23,485 ) 1,330,836 (64,186 ) Due after ten years 200,194 (6,501 ) 41,748 (2,005 ) 241,942 (8,506 ) Asset-backed securities 337,232 (4,400 ) 74,603 (907 ) 411,835 (5,307 ) Mortgage-backed securities 848,729 (14,995 ) 1,348,074 (48,525 ) 2,196,803 (63,520 ) Total fixed maturity securities $ 7,503,844 $ (165,100 ) $ 3,178,912 $ (159,038 ) $ 10,682,756 $ (324,138 ) Duration of Unrealized Loss at December 31, 2017 By Maturity Less than 12 months Greater than 12 months Total Gross Gross Gross Unrealized Unrealized Unrealized (Dollars in thousands) Market Value Depreciation Market Value Depreciation Market Value Depreciation Fixed maturity securities Due in one year or less $ 247,927 $ (962 ) $ 206,113 $ (7,643 ) $ 454,040 $ (8,605 ) Due in one year through five years 2,930,977 (42,480 ) 1,200,414 (52,143 ) 4,131,391 (94,623 ) Due in five years through ten years 612,702 (20,154 ) 292,245 (12,680 ) 904,947 (32,834 ) Due after ten years 88,792 (1,945 ) 45,693 (941 ) 134,485 (2,886 ) Asset-backed securities 301,316 (1,467 ) 72,780 (515 ) 374,096 (1,982 ) Mortgage-backed securities 712,762 (5,408 ) 1,407,888 (32,843 ) 2,120,650 (38,251 ) Total fixed maturity securities $ 4,894,476 $ (72,416 ) $ 3,225,133 $ (106,765 ) $ 8,119,609 $ (179,181 )
Summary Of Components Of Net Investment Income	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Fixed maturities $ 108,682 $ 103,245 Equity securities 6,827 8,745 Short-term investments and cash 1,732 630 Other invested assets Limited partnerships 23,381 10,998 Other 4,325 2,272 Gross investment income before adjustments 144,947 125,890 Funds held interest income (expense) 3,630 3,148 Future policy benefit reserve income (expense) (209 ) (319 ) Gross investment income 148,368 128,719 Investment expenses (10,074 ) (6,430 ) Net investment income $ 138,294 $ 122,289
Summary Of Components Of Net Realized Capital Gains (Losses)	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Fixed maturity securities, market value: Other-than-temporary impairments $ (70 ) $ (1,229 ) Gains (losses) from sales 10,392 11,373 Fixed maturity securities, fair value: Gains (losses) from sales (14 ) - Equity securities, market value: Gains (losses) from sales - (3,436 ) Equity securities, fair value: Gains (losses) from sales 40 4,516 Gains (losses) from fair value adjustments (35,253 ) 41,507 Other invested assets 3 1 Short-term investments gain (loss) 1 (4 ) Total net realized capital gains (losses) $ (24,901 ) $ 52,728
Summary Of Gross Gains (Losses) From Sales Of Fixed Maturity And Equity Securities	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Proceeds from sales of fixed maturity securities $ 364,288 $ 428,491 Gross gains from sales 13,002 15,473 Gross losses from sales (2,624 ) (4,100 ) Proceeds from sales of equity securities $ 199,875 $ 159,117 Gross gains from sales 6,687 8,208 Gross losses from sales (6,647 ) (7,128 )

Reserve For Losses, LAE And F27

Reserve For Losses, LAE And Future Policy Benefit Reserve (Tables)	3 Months Ended
	Mar. 31, 2018
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Summary Of Activity In The Reserve For Losses And LAE	Three Months Ended Twelve Months Ended March 31, December 31, (Dollars in thousands) 2018 2017 Gross reserves at beginning of period $ 11,884,321 $ 10,312,313 Less reinsurance recoverables (1,212,649 ) (990,862 ) Net reserves at beginning of period 10,671,672 9,321,451 Incurred related to: Current year 957,177 4,815,967 Prior years 100,000 (293,386 ) Total incurred losses and LAE 1,057,177 4,522,581 Paid related to: Current year 140,761 1,280,605 Prior years 1,055,225 2,062,634 Total paid losses and LAE 1,195,986 3,343,239 Foreign exchange/translation adjustment 25,512 170,879 Net reserves at end of period 10,558,375 10,671,672 Plus reinsurance recoverables 1,234,971 1,212,649 Gross reserves at end of period $ 11,793,346 $ 11,884,321

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2018
Derivatives [Abstract]
Summary Of The Fair Value Of The Equity Index Put Options	(Dollars in thousands) Derivatives not designated as Location of fair value At At hedging instruments in balance sheets March 31, 2018 December 31, 2017 Equity index put option contracts Equity index put option liability $ 12,205 $ 12,477 Total $ 12,205 $ 12,477 The change in fair value of the equity index put option contracts can be found in the Company's statement of operations and comprehensive income (loss) as follows: (Dollars in thousands) For the Three Months Ended Derivatives not designated as Location of gain (loss) in statements of March 31, hedging instruments operations and comprehensive income (loss) 2018 2017 Equity index put option contracts Net derivative gain (loss) $ 273 $ 2,630 Total $ 273 $ 2,630

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value [Abstract]
Fair Value Measurement Levels For All Assets And Liabilities	Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) March 31, 2018 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,497,413 $ - $ 1,497,413 $ - Obligations of U.S. States and political subdivisions 536,547 - 536,547 - Corporate securities 5,777,747 - 5,557,192 220,555 Asset-backed securities 506,430 - 506,430 - Mortgage-backed securities Commercial 227,299 - 227,299 - Agency residential 2,222,995 - 2,222,995 - Non-agency residential 476 - 476 - Foreign government securities 1,274,322 - 1,274,322 - Foreign corporate securities 2,801,352 - 2,789,984 11,368 Total fixed maturities, market value 14,844,581 - 14,612,658 231,923 Fixed maturities, fair value 1,821 - - 1,821 Equity securities, fair value 1,169,531 1,123,632 45,899 - Liabilities: Equity index put option contracts $ 12,205 $ - $ - $ 12,205 Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2017 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,536,692 $ - $ 1,536,692 $ - Obligations of U.S. States and political subdivisions 585,469 - 585,469 - Corporate securities 5,699,005 - 5,488,819 210,186 Asset-backed securities 531,360 - 531,360 - Mortgage-backed securities Commercial 234,041 - 234,041 - Agency residential 2,210,902 - 2,210,902 - Non-agency residential 494 - 494 - Foreign government securities 1,314,027 - 1,314,027 - Foreign corporate securities 2,644,844 - 2,637,892 6,952 Total fixed maturities, market value 14,756,834 - 14,539,696 217,138 Equity securities, market value 129,530 113,506 16,024 - Equity securities, fair value 963,572 941,739 21,833 - Liabilities: Equity index put option contracts $ 12,477 $ - $ - $ 12,477
Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type	Total Fixed Maturities, Market Value Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Corporate Foreign Corporate Foreign (Dollars in thousands) Securities Corporate Total Securities Corporate Total Beginning balance fixed maturities at market value $ 210,186 $ 6,952 $ 217,138 $ 65,197 $ 2,538 $ 67,735 Total gains or (losses) (realized/unrealized) Included in earnings 722 94 816 214 (24 ) 190 Included in other comprehensive income (loss) 235 - 235 (29 ) - (29 ) Purchases, issuances and settlements 9,412 4,322 13,734 18,940 288 19,228 Transfers in and/or (out) of Level 3 - - - - - - Ending balance $ 220,555 $ 11,368 $ 231,923 $ 84,322 $ 2,802 $ 87,124 The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ - $ - $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.) Total Fixed Maturities, Fair Value Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Foreign Foreign (Dollars in thousands) Corporate Total Corporate Total Beginning balance fixed maturities at fair value $ - $ - $ - $ - Total gains or (losses) (realized/unrealized) Included in earnings (14 ) (14 ) - - Included in other comprehensive income (loss) - - - - Purchases, issuances and settlements 1,835 1,835 - - Transfers in and/or (out) of Level 3 - - - - Ending balance $ 1,821 $ 1,821 $ - $ - The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.)
Fair Value Measurements Using Significant Unobservable Inputs For Equity Index Put Option Contracts	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Liabilities: Balance, beginning of period $ 12,477 $ 22,059 Total (gains) or losses (realized/unrealized) Included in earnings (273 ) (2,630 ) Included in other comprehensive income (loss) - - Purchases, issuances and settlements - - Transfers in and/or (out) of Level 3 - - Balance, end of period $ 12,205 $ 19,429 The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to liabilities still held at the reporting date $ - $ - (Some amounts may not reconcile due to rounding.)

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Common Share [Abstract]
Schedule Of Net Income (Loss) Per Common Share	Three Months Ended March 31, (Dollars in thousands, except per share amounts) 2018 2017 Net income (loss) per share: Numerator Net income (loss) $ 210,318 $ 291,643 Less: dividends declared-common shares and nonvested common shares (53,240 ) (51,281 ) Undistributed earnings 157,078 240,362 Percentage allocated to common shareholders (1) 98.9 % 98.9 % 155,410 237,754 Add: dividends declared-common shareholders 52,697 50,753 Numerator for basic and diluted earnings per common share $ 208,107 $ 288,507 Denominator Denominator for basic earnings per weighted-average common shares 40,469 40,529 Effect of dilutive securities: Options 220 267 Denominator for diluted earnings per adjusted weighted-average common shares 40,689 40,796 Per common share net income (loss) Basic $ 5.14 $ 7.12 Diluted $ 5.11 $ 7.07 (1) Basic weighted-average common shares outstanding 40,469 40,529 Basic weighted-average common shares outstanding and nonvested common shares expected to vest 40,903 40,973 Percentage allocated to common shareholders 98.9 % 98.9 % (Some amounts may not reconcile due to rounding.)

Commitments And Contingencies (

Commitments And Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies [Abstract]
Summary Of Estimated Cost To Replace Annuities For Contingent Liability	At March 31, At December 31, (Dollars in thousands) 2018 2017 The Prudential $ 144,516 $ 144,618 Unaffiliated life insurance company 32,718 34,444

Other Comprehensive Income (L32

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Other Comprehensive Income (Loss) [Abstract]
Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations	Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 (Dollars in thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized appreciation (depreciation) ("URA(D)") on securities - temporary $ (209,160 ) $ 18,746 $ (190,414 ) $ 31,206 $ (8,382 ) $ 22,824 URA(D) on securities - OTTI (189 ) (21 ) (210 ) (4,501 ) 1,225 (3,276 ) Reclassification of net realized losses (gains) included in net income (loss) (10,325 ) 1,553 (8,772 ) (6,708 ) 4,509 (2,199 ) Foreign currency translation adjustments 17,345 354 17,699 13,813 (1,920 ) 11,893 Reclassification of benefit plan liability amortization included in net income (loss) 2,298 (483 ) 1,815 3,083 (1,079 ) 2,004 Total other comprehensive income (loss) $ (200,031 ) $ 20,149 $ (179,882 ) $ 36,893 $ (5,647 ) $ 31,246
Reclassification From Accumulated Other Comprehensive Income	Three Months Ended March 31, Affected line item within the statements of AOCI component 2018 2017 operations and comprehensive income (loss) (Dollars in thousands) URA(D) on securities $ (10,325 ) $ (6,708 ) Other net realized capital gains (losses) 1,553 4,509 Income tax expense (benefit) $ (8,772 ) $ (2,199 ) Net income (loss) Benefit plan net gain (loss) $ 2,298 $ 3,083 Other underwriting expenses (483 ) (1,079 ) Income tax expense (benefit) $ 1,815 $ 2,004 Net income (loss)
Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax, In The Consolidated Balance Sheets	Three Months Ended Twelve Months Ended March 31, December 31, (Dollars in thousands) 2018 2017 Beginning balance of URA (D) on securities $ 49,969 $ 115,558 Current period change in URA (D) of investments - temporary (199,186 ) (67,268 ) Current period change in URA (D) of investments - non-credit OTTI (210 ) (4,030 ) Reclass due to early adoption of ASU 2018-02 - 5,709 Cumulative change due to ASU 2016-01 (1,201 ) - Ending balance of URA (D) on securities (150,628 ) 49,969 Beginning balance of foreign currency translation adjustments (138,931 ) (266,818 ) Current period change in foreign currency translation adjustments 17,699 121,917 Reclass due to early adoption of ASU 2018-02 - 5,970 Ending balance of foreign currency translation adjustments (121,232 ) (138,931 ) Beginning balance of benefit plan net gain (loss) (71,929 ) (65,504 ) Current period change in benefit plan net gain (loss) 1,815 6,504 Reclass due to early adoption of ASU 2018-02 - (12,929 ) Ending balance of benefit plan net gain (loss) (70,114 ) (71,929 ) Ending balance of accumulated other comprehensive income (loss) $ (341,974 ) $ (160,891 ) (Some amounts may not reconcile due to rounding.)

Credit Facilities (Tables)

Credit Facilities (Tables)	3 Months Ended
	Mar. 31, 2018
Line of Credit Facility [Line Items]
Summary Of Costs Incurred Connection With Credit Facilities	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Credit facility interest and fees incurred $ 105 $ 104
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And/Or Borrowings	(Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Wells Fargo Bank Group Credit Facility Tranche One $ 200,000 $ - $ 200,000 $ - Tranche Two 600,000 564,638 12/31/2018 600,000 538,214 12/31/2018 Total Wells Fargo Bank Group Credit Facility $ 800,000 $ 564,638 $ 800,000 $ 538,214
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And/Or Borrowings	(Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Citibank Bilateral Letter of Credit Agreement $ 250,000 $ 3,672 11/24/2018 $ 250,000 $ 3,297 2/28/2018 108,875 12/31/2018 3,672 11/24/2018 3,297 2/28/2019 73,626 12/31/2018 346 8/30/2019 344 8/30/2019 3,599 12/31/2019 93,855 12/30/2021 95,667 3/30/2022 - Total Citibank Bilateral Agreement $ 250,000 $ 215,456 $ 250,000 $ 174,794
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And/Or Borrowings	(Dollars in thousands) At March 31, 2018 At December 31, 2017 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Lloyd's Bank plc £ 145,000 £ - £ 145,000 £ - - - - - Total Lloyd's Bank Credit Facility £ 145,000 £ - £ 145,000 £ -

Collateralized Reinsurance An34

Collateralized Reinsurance And Trust Agreements (Tables)	3 Months Ended
	Mar. 31, 2018
Collateralized Reinsurance And Trust Agreements [Abstract]
Premiums And Losses Ceded By The Company To Affiliate	Three Months Ended March 31, Mt. Logan Re Segregated Accounts 2018 2017 (Dollars in thousands) Ceded written premiums 81,036 54,218 Ceded earned premiums 61,409 40,597 Ceded losses and LAE 21,069 19,585 Assumed written premiums 3,043 2,732 Assumed earned premiums 3,043 2,732 Assumed losses and LAE - -

Senior Notes (Tables)

Senior Notes (Tables)	3 Months Ended
	Mar. 31, 2018
Senior Notes [Abstract]
Schedule Of Outstanding Senior Notes	March 31, 2018 December 31, 2017 Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Date Due Principal Amounts Sheet Amount Market Value Sheet Amount Market Value 4.868 06/05/2014 06/01/2044 400,000 $ 396,864 $ 399,080 $ 396,834 $ 420,340
Schedule Of Interest Expense Incurred In Connection With Senior Notes	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Interest expense incurred $ 4,868 $ 4,868

Long Term Subordinated Notes (T

Long Term Subordinated Notes (Tables)	3 Months Ended
	Mar. 31, 2018
Long Term Subordinated Notes [Abstract]
Schedule Of Outstanding Fixed To Floating Rate Long Term Subordinated Notes	Maturity Date March 31, 2018 December 31, 2017 Original Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Principal Amount Scheduled Final Sheet Amount Market Value Sheet Amount Market Value 6.6 04/26/2007 $ 400,000 05/15/2037 05/01/2067 $ 236,585 $ 238,421 $ 236,561 $ 233,072
Schedule Of Interest Expense Incurred In Connection With Long Term Subordinated Notes	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Interest expense incurred $ 2,391 $ 3,937

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule Of Underwriting Results For Operating Segments	Three Months Ended U.S. Reinsurance March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 644,222 $ 578,958 Net written premiums 545,831 517,369 Premiums earned $ 563,385 $ 481,524 Incurred losses and LAE 545,193 262,066 Commission and brokerage 127,320 102,358 Other underwriting expenses 16,886 14,251 Underwriting gain (loss) $ (126,014 ) $ 102,849 Three Months Ended International March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 366,724 $ 266,417 Net written premiums 345,155 245,662 Premiums earned $ 343,604 $ 271,581 Incurred losses and LAE 127,024 159,501 Commission and brokerage 82,177 66,150 Other underwriting expenses 10,576 9,480 Underwriting gain (loss) $ 123,827 $ 36,450 Three Months Ended Bermuda March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 415,686 $ 321,122 Net written premiums 394,968 305,032 Premiums earned $ 319,134 $ 235,106 Incurred losses and LAE 129,513 128,432 Commission and brokerage 81,487 58,423 Other underwriting expenses 10,133 9,480 Underwriting gain (loss) $ 98,001 $ 38,771 Three Months Ended Insurance March 31, (Dollars in thousands) 2018 2017 Gross written premiums $ 504,975 $ 434,447 Net written premiums 386,252 345,751 Premiums earned $ 393,304 $ 323,886 Incurred losses and LAE 255,447 220,789 Commission and brokerage 66,655 55,338 Other underwriting expenses 58,689 42,676 Underwriting gain (loss) $ 12,513 $ 5,083
Schedule Of Underwriting Results For Operating Segments To Income (Loss) Before Taxes	Three Months Ended March 31, (Dollars in thousands) 2018 2017 Underwriting gain (loss) $ 108,327 $ 183,153 Net investment income 138,294 122,289 Net realized capital gains (losses) (24,901 ) 52,728 Net derivative gain (loss) 273 2,630 Corporate expenses (8,996 ) (8,457 ) Interest, fee and bond issue cost amortization expense (7,418 ) (8,964 ) Other income (expense) 12,064 (4,966 ) Income (loss) before taxes $ 217,643 $ 338,413
Schedule Of Gross Written Premiums Derived From Largest Non-U.S. Market	Three Months Ended March 31, (Dollars in thousands) 2018 2017 United Kingdom gross written premium $ 258,259 $ 170,820

Retirement Benefits (Tables)

Retirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2018
Retirement Benefits [Abstract]
Summary Of Pension Expense	Pension Benefits Three Months Ended March 31, (Dollars in thousands) 2018 2017 Service cost $ 2,977 $ 3,299 Interest cost 2,585 2,276 Expected return on plan assets (3,670 ) (3,155 ) Amortization of net (income) loss 2,237 3,040 Net periodic benefit cost $ 4,128 $ 5,460 Other Benefits Three Months Ended March 31, (Dollars in thousands) 2018 2017 Service cost $ 446 $ 440 Interest cost 307 249 Amortization of prior service cost (33 ) (33 ) Amortization of net (income) loss 94 76 Net periodic benefit cost $ 814 $ 732 (Some amounts may not reconcile due to rounding.)

Basis Of Presentation (Details)

Basis Of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Item Effected [Line Items]
Cumulative change due to adoption of Accounting Standards Update 2016-01	$ (1,201)
Tax Cut and Jobs Act [Member]
Item Effected [Line Items]
U.S. tax rate	21.00%	35.00%
Reclass due to early adoption of Accounting Standards Update 2018-02	$ 1,250

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold that triggers a review of available for sale debt securities for declines in market value	80.00%
Aggregate market value of investments in unrealized loss position	$ 10,682,756		$ 8,233,115
Gross unrealized losses on investments in unrealized loss position	324,138		182,553
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation	165,100		72,416
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation	159,038		110,137
Gross unrealized depreciation	0		0
Additional contractual commitments	777,058
Other invested assets	$ 1,527,701		1,631,850
Sales Revenue, Net [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold of unrealized losses not exceeded by any one single issuer	5.00%	5.00%
Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Limited partnership financial reporting lag time, months	1 month
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Limited partnership financial reporting lag time, months	3 months
Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation	$ 155,350		103,739
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation	153,293		68,107
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate market value of investments in unrealized loss position	10,682,756		8,119,609
Gross unrealized losses on investments in unrealized loss position	324,138		179,181
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation	165,100		72,416
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation	$ 159,038		$ 106,765
Fixed Maturity Securities [Member] | Sales Revenue, Net [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold of unrealized losses not exceeded by any one single issuer	1.10%		1.10%
Fixed Maturity Securities [Member] | Sales Revenue, Net [Member] | US Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold of unrealized losses not exceeded by any one single issuer	9.60%		8.90%
Private Placement Liquidity Sweep [Member]
Schedule of Available-for-sale Securities [Line Items]
Other invested assets	$ 220,241		$ 447,915

Investments (Summary Of Unreali

Investments (Summary Of Unrealized Appreciation (Depreciation) Of Available For Sale, Fixed Maturity And Equity Security Investments) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 14,997,018	$ 14,689,598
Unrealized Appreciation		171,701	246,417
Unrealized Depreciation		(324,138)	(179,181)
Market Value		14,844,581	14,756,834
OTTI in AOCI	[1]	3,427	3,616
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,516,251	1,540,952
Unrealized Appreciation		7,019	9,816
Unrealized Depreciation		(25,857)	(14,076)
Market Value		1,497,413	1,536,692
OTTI in AOCI	[1]
Obligations Of U.S. States And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		523,611	563,790
Unrealized Appreciation		14,630	22,123
Unrealized Depreciation		(1,694)	(444)
Market Value		536,547	585,469
OTTI in AOCI	[1]	165
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		5,834,818	5,658,456
Unrealized Appreciation		50,974	81,724
Unrealized Depreciation		(108,045)	(41,175)
Market Value		5,777,747	5,699,005
OTTI in AOCI	[1]	2,481	2,488
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		511,328	532,473
Unrealized Appreciation		409	869
Unrealized Depreciation		(5,307)	(1,982)
Market Value		506,430	531,360
OTTI in AOCI	[1]
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		232,693	235,794
Unrealized Appreciation		2	616
Unrealized Depreciation		(5,396)	(2,369)
Market Value		227,299	234,041
OTTI in AOCI	[1]
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,272,215	2,236,361
Unrealized Appreciation		8,860	10,379
Unrealized Depreciation		(58,080)	(35,838)
Market Value		2,222,995	2,210,902
OTTI in AOCI	[1]
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		478	497
Unrealized Appreciation		42	41
Unrealized Depreciation		(44)	(44)
Market Value		476	494
OTTI in AOCI	[1]
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,283,177	1,305,070
Unrealized Appreciation		35,703	43,804
Unrealized Depreciation		(44,558)	(34,847)
Market Value		1,274,322	1,314,027
OTTI in AOCI	[1]	163	178
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,822,447	2,616,205
Unrealized Appreciation		54,062	77,045
Unrealized Depreciation		(75,157)	(48,406)
Market Value		2,801,352	2,644,844
OTTI in AOCI	[1]	618	950
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost			130,287
Unrealized Appreciation			2,615
Unrealized Depreciation			(3,372)
Market Value			129,530
OTTI in AOCI	[1]
[1]	Represents the amount of OTTI recognized in AOCI. Amount includes unrealized gains and losses on impaired securities relating to changes in the value of such securities subsequent to the impairment measurement date

Investments (Summary Of Amortiz

Investments (Summary Of Amortized Cost And Market Value Of Fixed Maturity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	$ 14,997,018	$ 14,689,598
Fixed maturity securities - available for sale, Market Value	14,844,581	14,756,834
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Due in one year or less, Amortized Cost	1,593,546	1,041,885
Fixed maturity securities - available for sale, Due after one year through five years, Amortized Cost	7,197,033	7,545,731
Fixed maturity securities - available for sale, Due after five years through ten years, Amortized Cost	2,314,395	2,214,473
Fixed maturity securities - available for sale, Due after ten years, Amortized Cost	875,330	882,384
Fixed maturity securities - available for sale, Due in one year or less, Market Value	1,592,697	1,050,094
Fixed maturity securities - available for sale, Due after one year through five years, Market Value	7,097,641	7,554,248
Fixed maturity securities - available for sale, Due after five years through ten years, Market Value	2,283,642	2,231,456
Fixed maturity securities - available for sale, Due after ten years, Market Value	913,401	944,239
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	511,328	532,473
Fixed maturity securities - available for sale, Market Value	506,430	531,360
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	232,693	235,794
Fixed maturity securities - available for sale, Market Value	227,299	234,041
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	2,272,215	2,236,361
Fixed maturity securities - available for sale, Market Value	2,222,995	2,210,902
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	478	497
Fixed maturity securities - available for sale, Market Value	$ 476	$ 494

Investments (Summary Of Changes

Investments (Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	$ (219,674)	$ 19,997
Deferred tax benefit (expense)	20,299	(3,873)
Deferred tax benefit (expense), other-than-temporary impairment	(21)	1,225
Total URA(D) on securities arising during the period	(199,396)	17,349
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	(219,485)	18,055
Fixed Maturity Securities, Other-Than-Temporary Impairment [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	(189)	(4,501)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax		5,999
Other Invested Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax		$ 444

Investments (Summary Of Aggrega

Investments (Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Security Type) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	$ 7,503,844	$ 4,894,476
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(165,100)	(72,416)
Fixed maturity securities, Greater than 12 months, Market Value	3,178,912	3,338,639
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(159,038)	(110,137)
Fixed maturity securities, Total, Market Value	10,682,756	8,233,115
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(324,138)	(182,553)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	7,503,844	4,894,476
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(165,100)	(72,416)
Fixed maturity securities, Greater than 12 months, Market Value	3,178,912	3,225,133
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(159,038)	(106,765)
Fixed maturity securities, Total, Market Value	10,682,756	8,119,609
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(324,138)	(179,181)
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	1,193,463	1,077,051
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(17,432)	(8,380)
Fixed maturity securities, Greater than 12 months, Market Value	225,194	224,189
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(8,425)	(5,696)
Fixed maturity securities, Total, Market Value	1,418,657	1,301,240
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(25,857)	(14,076)
Obligations Of U.S. States And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	48,613	4,400
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(383)	(27)
Fixed maturity securities, Greater than 12 months, Market Value	36,392	37,886
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(1,311)	(417)
Fixed maturity securities, Total, Market Value	85,005	42,286
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(1,694)	(444)
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	3,466,924	1,779,292
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(77,213)	(24,942)
Fixed maturity securities, Greater than 12 months, Market Value	674,674	700,098
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(30,832)	(16,233)
Fixed maturity securities, Total, Market Value	4,141,598	2,479,390
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(108,045)	(41,175)
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	337,232	301,316
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(4,400)	(1,467)
Fixed maturity securities, Greater than 12 months, Market Value	74,603	72,780
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(907)	(515)
Fixed maturity securities, Total, Market Value	411,835	374,096
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(5,307)	(1,982)
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	164,758	101,821
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(2,555)	(572)
Fixed maturity securities, Greater than 12 months, Market Value	62,303	64,272
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(2,841)	(1,797)
Fixed maturity securities, Total, Market Value	227,061	166,093
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(5,396)	(2,369)
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	683,971	610,941
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(12,440)	(4,836)
Fixed maturity securities, Greater than 12 months, Market Value	1,285,758	1,343,547
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(45,640)	(31,002)
Fixed maturity securities, Total, Market Value	1,969,729	1,954,488
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(58,080)	(35,838)
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation
Fixed maturity securities, Greater than 12 months, Market Value	13	69
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(44)	(44)
Fixed maturity securities, Total, Market Value	13	69
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(44)	(44)
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	300,778	327,790
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(12,541)	(12,811)
Fixed maturity securities, Greater than 12 months, Market Value	351,734	331,432
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(32,017)	(22,036)
Fixed maturity securities, Total, Market Value	652,512	659,222
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(44,558)	(34,847)
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value	1,308,105	691,865
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(38,136)	(19,381)
Fixed maturity securities, Greater than 12 months, Market Value	468,241	450,860
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(37,021)	(29,025)
Fixed maturity securities, Total, Market Value	1,776,346	1,142,725
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	$ (75,157)	(48,406)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Less than 12 months, Market Value
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation
Fixed maturity securities, Greater than 12 months, Market Value		113,506
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation		(3,372)
Fixed maturity securities, Total, Market Value		113,506
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total		$ (3,372)

Investments (Summary Of Aggre45

Investments (Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	$ 7,503,844	$ 4,894,476
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(165,100)	(72,416)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	3,178,912	3,338,639
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(159,038)	(110,137)
Fixed maturity securities, Total, Market Value	10,682,756	8,233,115
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(324,138)	(182,553)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	7,503,844	4,894,476
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(165,100)	(72,416)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	3,178,912	3,225,133
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(159,038)	(106,765)
Fixed maturity securities, Total, Market Value	10,682,756	8,119,609
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(324,138)	(179,181)
Due In One Year Or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	952,178	247,927
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(3,382)	(962)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	197,004	206,113
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(9,958)	(7,643)
Fixed maturity securities, Total, Market Value	1,149,182	454,040
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(13,340)	(8,605)
Due In One Year Through Five Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	4,143,873	2,930,977
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(95,121)	(42,480)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	1,208,285	1,200,414
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(74,158)	(52,143)
Fixed maturity securities, Total, Market Value	5,352,158	4,131,391
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(169,279)	(94,623)
Due In Five Years Through Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	1,021,638	612,702
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(40,701)	(20,154)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	309,198	292,245
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(23,485)	(12,680)
Fixed maturity securities, Total, Market Value	1,330,836	904,947
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(64,186)	(32,834)
Due After Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	200,194	88,792
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(6,501)	(1,945)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	41,748	45,693
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(2,005)	(941)
Fixed maturity securities, Total, Market Value	241,942	134,485
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(8,506)	(2,886)
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	337,232	301,316
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(4,400)	(1,467)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	74,603	72,780
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(907)	(515)
Fixed maturity securities, Total, Market Value	411,835	374,096
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(5,307)	(1,982)
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	848,729	712,762
Fixed maturity securities, Duration of Unrealized loss, less than 12 months, Gross Unrealized Depreciation	(14,995)	(5,408)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	1,348,074	1,407,888
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(48,525)	(32,843)
Fixed maturity securities, Total, Market Value	2,196,803	2,120,650
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	$ (63,520)	$ (38,251)

Investments (Summary Of Compone

Investments (Summary Of Components Of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ 144,947	$ 125,890
Funds held interest income (expense)	3,630	3,148
Future policy benefit reserve income (expense)	(209)	(319)
Gross investment income	148,368	128,719
Investment expenses	(10,074)	(6,430)
Net investment income	138,294	122,289
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	108,682	103,245
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	6,827	8,745
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	1,732	630
Limited Partnerships [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	23,381	10,998
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ 4,325	$ 2,272

Investments (Summary Of Compo47

Investments (Summary Of Components Of Net Realized Capital Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments	$ (70)	$ (1,229)
Total net realized capital gains (losses)	(24,901)	52,728
Fixed Maturity Securities [Member] | Market Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments	(70)	(1,229)
Gains (losses) from sales	10,392	11,373
Fixed Maturity Securities [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	(14)
Equity Securities [Member] | Market Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales		(3,436)
Equity Securities [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	40	4,516
Gains (losses) from fair value adjustments	(35,253)	41,507
Other Invested Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	3	1
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales	$ 1	$ (4)

Investments (Summary Of Gross G

Investments (Summary Of Gross Gains (Losses) From Sales Of Fixed Maturity And Equity Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of fixed maturity securities	$ 364,288	$ 428,491
Gross gains from sales	13,002	15,473
Gross losses from sales	(2,624)	(4,100)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of fixed maturity securities	199,875	159,117
Gross gains from sales	6,687	8,208
Gross losses from sales	$ (6,647)	$ (7,128)

Reserve For Losses, LAE And F49

Reserve For Losses, LAE And Future Policy Benefit Reserve (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Increase (decrease) in insurance business	$ 100,000	$ (293,386)
Partially offset, related to development on A&E reserves		37,137
Property and Short-Tail Business [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Increase (decrease) in reinsurance business		238,378
Workers Compensation [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Increase (decrease) in insurance business		$ 55,007

Reserve For Losses, LAE And F50

Reserve For Losses, LAE And Future Policy Benefit Reserve (Summary Of Activity In The Reserve For Losses And LAE) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Gross reserves at beginning of period	$ 11,884,321	$ 10,312,313
Less Reinsurance recoverable	(1,234,971)	(1,212,649)	$ (990,862)
Net reserves at beginning of period	10,671,672	9,321,451
Incurred related to: Current year	957,177	4,815,967
Incurred related to: Prior years	100,000	(293,386)
Total incurred losses and LAE	1,057,177	4,522,581
Paid related to: Current year	140,761	1,280,605
Paid related to: Prior years	1,055,225	2,062,634
Total paid losses and LAE	1,195,986	3,343,239
Foreign exchange/translation adjustment	25,512	170,879
Net reserves at end of period	10,558,375	10,671,672
Plus reinsurance recoverable	1,234,971	1,212,649
Gross reserves at end of period	$ 11,793,346	$ 11,884,321

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018USD ($)itemsecurity	Dec. 31, 2017USD ($)	Dec. 31, 2005security	Dec. 31, 2001security
Derivative [Line Items]
Number of equity index put option contracts	7		7	7
Number of equity indices | item	2
Equity index put option liability	$ 12,205,000	$ 12,477,000
Equity Index Put Option Contracts [Member]
Derivative [Line Items]
Number of equity index put option contracts | item	1
Equity index put option liability	$ 0
Equity Index Put Option Contracts [Member] | Fair Value [Member]
Derivative [Line Items]
Equity index put option liability	$ 12,205,000	$ 12,477,000
Standard & Poor's 500 Index [Member]
Derivative [Line Items]
Number of equity index put option contracts | security	5
Theoretical maximum payout occurs based on index value	$ 0
Present value of theoretical maximum payouts	403,464,000
Settlement amount if contracts had expired	$ 0
Equity Index If Contracts Had Expired	2,640.87
Standard & Poor's 500 Index [Member] | Maximum [Member]
Derivative [Line Items]
Estimates the probability of equity index put option contract will falling below the strike price on the exercise date	2.00%
FTSE 100 Index [Member]
Derivative [Line Items]
Number of equity index put option contracts | security	1
Theoretical maximum payout occurs based on index value	$ 0
Discount factor	3.00%
Present value of theoretical maximum payouts	$ 42,531,000
Settlement amount if contracts had expired	$ 0
Equity Index If Contracts Had Expired | item	7,056.61
FTSE 100 Index [Member] | Maximum [Member]
Derivative [Line Items]
Estimates the probability of equity index put option contract will falling below the strike price on the exercise date	17.00%

Derivatives (Summary Of The Fai

Derivatives (Summary Of The Fair Value Of The Equity Index Put Options) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Option Indexed to Issuer's Equity [Line Items]
Equity index put option liability	$ 12,205		$ 12,477
Net derivative gain (loss)	273	$ 2,630
Equity Index Put Option Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Option Indexed to Issuer's Equity [Line Items]
Equity index put option liability	12,205		$ 12,477
Net derivative gain (loss)	$ 273	$ 2,630

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018USD ($)securityitem	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)security	Dec. 31, 2005security	Dec. 31, 2001security
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of public equity portfolio	$ 500,330,000		$ 386,241,000
Number of equity index put option contracts	7			7	7
Derivatives, Number Of Indices | item	2
Equity index put option liability	$ 12,205,000		12,477,000
other invested assets	362,264,000		382,283,000
Transfers between level 1 and 2	0
Transfers from level 3	0	$ 0
Accounting Standards Update 2015-07 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
other invested assets	$ 82,902,000		$ 79,505,000
Unavailability Of Prices [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of securities | security	75		66
Unavailability Of Prices [Member] | Private Placement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of securities | security	73		65
Available-for-sale Securities	$ 164,818,000		$ 165,173,000
Standard & Poor's 500 Index [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of equity index put option contracts | security	5
Theoretical maximum payout occurs based on index value	$ 0
Present value of theoretical maximum payouts	403,464,000
Settlement amount if contracts had expired	$ 0
FTSE 100 Index [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of equity index put option contracts | security	1
Theoretical maximum payout occurs based on index value	$ 0
Discount factor	3.00%
Present value of theoretical maximum payouts	$ 42,531,000
Settlement amount if contracts had expired	$ 0
Maximum [Member] | Standard & Poor's 500 Index [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimates the probability of equity index put option contract will falling below the strike price on the exercise date	2.00%
Maximum [Member] | FTSE 100 Index [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimates the probability of equity index put option contract will falling below the strike price on the exercise date	17.00%
Par Value [Member] | Unavailability Of Prices [Member] | Private Placement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of securities | security	2		1
Available-for-sale Securities	$ 68,927,000		$ 51,965,000
Equity Index Put Option Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of equity index put option contracts | item	1
Equity index put option liability	$ 0
Equity Index Put Option Contracts [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity index put option liability	$ 12,205,000		$ 12,477,000

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurement Levels For All Assets And Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	$ 14,844,581	$ 14,756,834
Fixed maturities, fair value	1,821
Equity securities, market value		129,530
Equity securities, fair value	1,169,531	963,572
Equity index put option contracts	12,205	12,477
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, fair value
Equity securities, market value		113,506
Equity securities, fair value	1,123,632	941,739
Equity index put option contracts
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, fair value
Equity securities, market value		16,024
Equity securities, fair value	45,899	21,833
Equity index put option contracts
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, fair value	1,821
Equity securities, market value
Equity securities, fair value
Equity index put option contracts	12,205	12,477
Fixed Maturity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	14,844,581	14,756,834
Fixed Maturity Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Fixed Maturity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	14,612,658	14,539,696
Fixed Maturity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	231,923	217,138
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	1,497,413	1,536,692
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	1,497,413	1,536,692
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Obligations Of U.S. States And Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	536,547	585,469
Obligations Of U.S. States And Political Subdivisions [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Obligations Of U.S. States And Political Subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	536,547	585,469
Obligations Of U.S. States And Political Subdivisions [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	5,777,747	5,699,005
Corporate Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	5,557,192	5,488,819
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	220,555	210,186
Asset-Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	506,430	531,360
Asset-Backed Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Asset-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	506,430	531,360
Asset-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Commercial Mortgage-Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	227,299	234,041
Commercial Mortgage-Backed Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Commercial Mortgage-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	227,299	234,041
Commercial Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Agency Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	2,222,995	2,210,902
Agency Residential [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Agency Residential [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	2,222,995	2,210,902
Agency Residential [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Non-Agency Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	476	494
Non-Agency Residential [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Non-Agency Residential [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	476	494
Non-Agency Residential [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Foreign Government Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	1,274,322	1,314,027
Foreign Government Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Foreign Government Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	1,274,322	1,314,027
Foreign Government Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Foreign Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	2,801,352	2,644,844
Foreign Corporate Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value
Foreign Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	2,789,984	2,637,892
Foreign Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, market value	$ 11,368	$ 6,952

Fair Value (Activity Under Leve

Fair Value (Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers in and/or (out) of Level 3	$ 0	$ 0
Market Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	217,138	67,735
Total gains or (losses) (realized/unrealized) Included in earnings	816	190
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	235	(29)
Purchases, issuances and settlements	13,734	19,228
Transfers in and/or (out) of Level 3
Ending balance	231,923	87,124
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Market Value [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	210,186	65,197
Total gains or (losses) (realized/unrealized) Included in earnings	722	214
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	235	(29)
Purchases, issuances and settlements	9,412	18,940
Transfers in and/or (out) of Level 3
Ending balance	220,555	84,322
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Market Value [Member] | Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	6,952	2,538
Total gains or (losses) (realized/unrealized) Included in earnings	94	(24)
Purchases, issuances and settlements	4,322	288
Transfers in and/or (out) of Level 3
Ending balance	11,368	2,802
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or (losses) (realized/unrealized) Included in earnings	(14)
Purchases, issuances and settlements	1,835
Ending balance	1,821
Fair Value [Member] | Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or (losses) (realized/unrealized) Included in earnings	(14)
Purchases, issuances and settlements	1,835
Ending balance	$ 1,821

Earnings Per Common Share (Narr

Earnings Per Common Share (Narrative) (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation Of Earnings Per Share [Line Items]
Anti-dilutive options	0	0
Minimum [Member]
Antidilutive Securities Excluded from Computation Of Earnings Per Share [Line Items]
Options expiration date	February 18, 2019
Maximum [Member]
Antidilutive Securities Excluded from Computation Of Earnings Per Share [Line Items]
Options expiration date	September 19, 2022

Earnings Per Common Share (Sche

Earnings Per Common Share (Schedule Of Net Income (Loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Common Share [Abstract]
Net income (loss)	$ 210,318	$ 291,643
Less: dividends declared-common shares and nonvested common shares	(53,240)	(51,281)
Undistributed earnings	$ 157,078	$ 240,362
Percentage allocated to common shareholders	98.90%	98.90%
Net income (loss) available to common stockholders, total	$ 155,410	$ 237,754
Add: dividends declared-common shareholders	52,697	50,753
Numerator for basic and diluted earnings per common share	$ 208,107	$ 288,507
Denominator for basic earnings per weighted-average common shares	40,469	40,529
Effect of dilutive securities: Options	220	267
Denominator for diluted earnings per adjusted weighted-average common shares	40,689	40,796
Basic	$ 5.14	$ 7.12
Diluted	$ 5.11	$ 7.07
Basic weighted-average common shares outstanding	40,469	40,529
Basic weighted-average common shares outstanding and nonvested common shares expected to vest	40,903	40,973

Commitments And Contingencies58

Commitments And Contingencies (Summary Of Estimated Cost To Replace Annuities For Contingent Liability) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
The Prudential [Member]
Loss Contingencies [Line Items]
Estimated cost to replace annuities	$ 144,516	$ 144,618
Unaffiliated Life Insurance Company [Member]
Loss Contingencies [Line Items]
Estimated cost to replace annuities	$ 32,718	$ 34,444

Other Comprehensive Income (L59

Other Comprehensive Income (Loss) (Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Before Tax	$ (200,031)	$ 36,893
Total, Tax Effect	20,149	(5,647)
Total, Net of Tax	(179,882)	31,246
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(209,160)	31,206
Tax Effect	18,746	(8,382)
Net of Tax	(190,414)	22,824
Reclassification, Before Tax	(10,325)	(6,708)
Reclassification, Tax Effect	1,553	4,509
Reclassification, Net of Tax	(8,772)	(2,199)
Total, Net of Tax	(199,186)		$ (67,268)
URA(D) On Securities OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(189)	(4,501)
Tax Effect	(21)	1,225
Net of Tax	(210)	(3,276)
Total, Net of Tax	(210)		(4,030)
Foreign Currency Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	17,345	13,813
Tax Effect	354	(1,920)
Net of Tax	17,699	11,893
Total, Net of Tax	17,699		121,917
Benefit Plan Net Gain (Loss)[Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification, Before Tax	2,298	3,083
Reclassification, Tax Effect	(483)	(1,079)
Reclassification, Net of Tax	1,815	$ 2,004
Total, Net of Tax	$ 1,815		$ 6,504

Other Comprehensive Income (L60

Other Comprehensive Income (Loss) (Reclassification From Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)	$ (24,831)	$ 53,957
Income tax expense (benefit)	7,325	46,770
Net income (loss)	210,318	291,643
URA(D) On Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other underwriting expenses	(10,325)	(6,708)
Income tax expense (benefit)	1,553	4,509
Net income (loss)	(8,772)	(2,199)
URA(D) On Securities [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)	(10,325)	(6,708)
Income tax expense (benefit)	1,553	4,509
Net income (loss)	(8,772)	(2,199)
Benefit Plan Net Gain (Loss)[Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other underwriting expenses	2,298	3,083
Income tax expense (benefit)	(483)	(1,079)
Net income (loss)	$ 1,815	$ 2,004

Other Comprehensive Income (L61

Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax, In The Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 8,369,232
Current period change	(179,882)	$ 31,246
Cumulative change due to ASU 2016-01	(1,201)
Balance, end of period	8,344,180	8,347,876	$ 8,369,232
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	49,969	115,558	115,558
Current period change	(199,186)		(67,268)
Balance, end of period	(150,628)		49,969
URA(D) On Securities [Member] | Reclass due to early adoption of ASU 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Current period change			5,709
URA(D) On Securities OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Current period change	(210)		(4,030)
Foreign Currency Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(138,931)	(266,818)	(266,818)
Current period change	17,699		121,917
Balance, end of period	(121,232)		(138,931)
Foreign Currency Adjustment [Member] | Reclass due to early adoption of ASU 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Current period change			5,970
Benefit Plan Net Gain (Loss)[Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(71,929)	(65,504)	(65,504)
Current period change	1,815		6,504
Balance, end of period	(70,114)		(71,929)
Benefit Plan Net Gain (Loss)[Member] | Reclass due to early adoption of ASU 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Current period change			(12,929)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(160,891)	(216,764)	(216,764)
Current period change	(179,882)	31,246
Cumulative change due to ASU 2016-01	(1,201)
Balance, end of period	$ (341,974)	$ (185,518)	$ (160,891)

Credit Facilities (Narrative) (

Credit Facilities (Narrative) (Details) £ in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018GBP (£)item	Dec. 31, 2017GBP (£)	Dec. 31, 2015	Mar. 31, 2018USD ($)item	Dec. 31, 2017USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, number of facilities | item	2
Line of credit facility, commitment				$ 1,050,000
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, number of tranches | item	2			2
Line of credit facility, term of credit facility	4 years
Line of credit facility, commitment				$ 800,000	$ 800,000
Line of credit facility, required minimum debt-to-capital ratio	0.35			0.35
Line of credit facility, required minimum net worth				$ 5,370,979
Percentage amount of consolidated net income required to be reserved to maintain compliance with facility covenants	25.00%
Percentage amount of increase in consolidated net worth from new issuance required to be reserved to maintain compliance with facility covenants	25.00%
Increase in reserves due to new issuance during the period required to maintain compliance with facility covenants				5,919,732
Wells Fargo Bank Group Credit Facility [Member] | Before Amended And Restated Agreement [Member]
Line of Credit Facility [Line Items]
Line of credit facility, term of credit facility	5 years
Line of credit facility, commitment				800,000
Wells Fargo Bank Group Credit Facility Tranche One [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment				200,000	200,000
Wells Fargo Bank Group Credit Facility Tranche One [Member] | Interest Rate Base Rate Option 1(b) [Member]
Line of Credit Facility [Line Items]
Line of credit facility, spread on variable rate basis	0.50%
Wells Fargo Bank Group Credit Facility Tranche One [Member] | Interest Rate Base Rate Option 1(c) [Member]
Line of Credit Facility [Line Items]
Line of credit facility, spread on variable rate basis	1.00%
Wells Fargo Bank Group Credit Facility Tranche Two [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date	Dec. 31, 2018	Dec. 31, 2018
Line of credit facility, commitment				600,000	600,000
Citibank Holdings Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, term of credit facility	3 years
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment				$ 250,000	$ 250,000
Per annum commitment fee on undrawn credit	0.15%
Citibank Bilateral Agreement [Member] | Interest Rate Base Rate Option 1(a) [Member]
Line of Credit Facility [Line Items]
Percentage of interest on the principal amount of letters of credit issued	0.35%
Maximum term allowed to execute issued letters of credit	15 months
Citibank Bilateral Agreement [Member] | Interest Rate Base Rate Option 1(b) [Member]
Line of Credit Facility [Line Items]
Percentage of interest on the principal amount of issued extended tenor letters of credit	0.45%
Maximum term allowed to execute issued letters of credit	60 months
Everest International Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, required minimum debt-to-capital ratio	0.35			0.35
Line of credit facility, required minimum net worth				$ 5,326,009
Consolidated net worth, percentage			70.00%
Percentage amount of consolidated net income required to be reserved to maintain compliance with facility covenants	25.00%
Percentage amount of increase in consolidated net worth from new issuance required to be reserved to maintain compliance with facility covenants	25.00%
Increase in reserves due to new issuance during the period required to maintain compliance with facility covenants				$ 5,919,732
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, initiation date	Nov. 9, 2016
Line of credit facility, term of credit facility	4 years
Line of credit facility, commitment | £	£ 145,000	£ 145,000
Percentage commitment fee per annum	0.10%
Per annum commitment fee on undrawn credit	0.35%

Credit Facilities (Summary Of C

Credit Facilities (Summary Of Costs Incurred Connection With Credit Facilities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Credit Facilities [Abstract]
Credit facility interest and fees incurred	$ 105	$ 104

Credit Facilities (Summary Of O

Credit Facilities (Summary Of Outstanding Letters Of Credit And/Or Borrowings) (Details) £ in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018GBP (£)	Dec. 31, 2017GBP (£)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Line of Credit Facility [Line Items]
Commitment			$ 1,050,000
Wells Fargo Bank Group Credit Facility Tranche One [Member]
Line of Credit Facility [Line Items]
Commitment			200,000	$ 200,000
In Use
Wells Fargo Bank Group Credit Facility Tranche Two [Member]
Line of Credit Facility [Line Items]
Commitment			600,000	600,000
In Use			564,638	538,214
Date of Expiry	Dec. 31, 2018	Dec. 31, 2018
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment			800,000	800,000
In Use			564,638	538,214
Citibank Bilateral Letter Of Credit Agreement One [Member]
Line of Credit Facility [Line Items]
Commitment			250,000	250,000
In Use			3,672	3,297
Date of Expiry	Nov. 24, 2018	Feb. 28, 2018
Citibank Bilateral Letter Of Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
In Use			108,875	3,672
Date of Expiry	Dec. 31, 2018	Nov. 24, 2018
Citibank Bilateral Letter Of Credit Agreement Three [Member]
Line of Credit Facility [Line Items]
In Use			3,297	73,626
Date of Expiry	Feb. 28, 2019	Dec. 31, 2018
Citibank Bilateral Letter Of Credit Agreement Four [Member]
Line of Credit Facility [Line Items]
In Use			346	344
Date of Expiry	Aug. 30, 2019	Aug. 30, 2019
Citibank Bilateral Letter Of Credit Agreement Five [Member]
Line of Credit Facility [Line Items]
In Use			3,599	93,855
Date of Expiry	Dec. 31, 2019	Dec. 30, 2021
Citibank Bilateral Letter Of Credit Agreement Six [Member]
Line of Credit Facility [Line Items]
In Use			95,667
Date of Expiry	Mar. 30, 2022
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Commitment			250,000	250,000
In Use			$ 215,456	$ 174,794
Lloyds Bank PLC [Member]
Line of Credit Facility [Line Items]
Commitment | £	£ 145,000	£ 145,000
Lloyd's Bank Issuance One [Member]
Line of Credit Facility [Line Items]
Commitment | £
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment | £	£ 145,000	£ 145,000

Collateralized Reinsurance An65

Collateralized Reinsurance And Trust Agreements (Narrative) (Details) $ in Thousands	Apr. 30, 2018USD ($)item	Apr. 13, 2017USD ($)item	Dec. 01, 2015USD ($)item	Nov. 18, 2014USD ($)	Apr. 24, 2014USD ($)item	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Effects of Reinsurance [Line Items]
Amount on deposit in trust accounts						$ 862,629
Preferred shares, par value: $0.01; 50,000 shares authorized; no shares issued or outstanding
Kilimanjaro Re Limited [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item		6	2		2
Kilimanjaro Re Limited [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item	4
Catastrophe reinsurance bonds funded amount	$ 525,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount				$ 500,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item	4
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 Through 3 [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item		3
Reinsurance Contracts		4 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 And 2 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item	2
Reinsurance Contracts	4 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 3 And 4 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item	2
Reinsurance Contracts	5 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 4 Through 6 [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item		3
Reinsurance Contracts		5 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		$ 225,000	$ 300,000		$ 250,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	$ 62,500
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		400,000	325,000		200,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	200,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 3 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		325,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 3 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	62,500
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 4 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		50,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 4 [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	200,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 5 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		75,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 6 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		175,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2014-1 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount					$ 450,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2014-1 Notes [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Catastrophe Reinsurance Bonds Redeemed Amount	450,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2014-2 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount				$ 500,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2015-1 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount			$ 625,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2017-1 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount		950,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2017-2 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount		$ 300,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2018-1 Notes [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount	262,500
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2018-2 Notes [Member] | Subsequent Event [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount	$ 262,500
Mt. Logan Re [Member]
Effects of Reinsurance [Line Items]
Percentage of voting common shares owned by Group						100.00%
Assumed net risk exposures						$ 1,077,895	837,202
Preferred shares, par value: $0.01; 50,000 shares authorized; no shares issued or outstanding						$ 51,564	$ 50,373

Collateralized Reinsurance An66

Collateralized Reinsurance And Trust Agreements (Premiums And Losses Ceded By The Company To Affiliate) (Details) - Mt. Logan Re Segregated Accounts [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Effects of Reinsurance [Line Items]
Ceded written premiums	$ 81,036	$ 54,218
Ceded earned premiums	61,409	40,597
Ceded losses and LAE	21,069	19,585
Assumed written premiums	3,043	2,732
Assumed earned premiums	3,043	2,732
Assumed losses and LAE

Senior Notes (Narrative) (Detai

Senior Notes (Narrative) (Details) - Senior Notes [Member] - 4.868% Senior notes due 6/1/2044 [Member] - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Date Issued	Jun. 5, 2014
Principal amounts	$ 400,000,000
Debt Instrument, Term	30 years
Debt instrument, stated interest rate	4.868%	4.868%
Maturity Date	Jun. 1, 2044

Senior Notes (Schedule Of Outst

Senior Notes (Schedule Of Outstanding Senior Notes) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Consolidated balance sheet amount	$ 396,864,000	$ 396,834,000
4.868% Senior notes due 6/1/2044 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.868%	4.868%
Date issued	Jun. 5, 2014
Date due	Jun. 1, 2044
Principal amounts	$ 400,000,000
Consolidated balance sheet amount	396,864,000	$ 396,834,000
Market value	$ 399,080,000	$ 420,340,000

Senior Notes (Schedule Of Inter

Senior Notes (Schedule Of Interest Expense Incurred In Connection With Senior Notes) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Senior Notes [Abstract]
Interest expense incurred	$ 4,868	$ 4,868

Long Term Subordinated Notes (N

Long Term Subordinated Notes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Redemption date	May 1, 2047
6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.60%	6.60%
Maturity Date	May 1, 2067
Reset quarterly interest rate	4.22%
Percentage of principal amount required for redemption	100.00%
Outstanding debt reduction	$ 161,441
Fixed Rate Interest Period [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.60%
Interest payment commencement date	Nov. 15, 2007
Interest basis, term of LIBOR rate	3 months
Interest basis, 3 month LIBOR plus number of basis points, reset quarterly	2.385%
Right to defer interest on one or more occasions for up to number of consecutive years	10 years
Fixed Rate Interest Period [Member] | 6.6 % Long Term Subordinated Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest payment date	May 3, 2007
Fixed Rate Interest Period [Member] | 6.6 % Long Term Subordinated Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest payment date	May 14, 2017
Floating Rate Interest Period [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Right to defer interest on one or more occasions for up to number of consecutive years	10 years
5.4% Senior notes due 10/15/2014 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.40%
Maturity Date	Oct. 15, 2014
4.868% Senior notes due 6/1/2044 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.868%	4.868%
Maturity Date	Jun. 1, 2044

Long Term Subordinated Notes (S

Long Term Subordinated Notes (Schedule Of Outstanding Fixed To Floating Rate Long Term Subordinated Notes) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Consolidated balance sheet amount	$ 236,585,000	$ 236,561,000
6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.60%	6.60%
Date Issued	Apr. 26, 2007
Original Principal Amount	$ 400,000,000
Maturity Date	May 1, 2067
Consolidated balance sheet amount	$ 236,585,000	$ 236,561,000
Market value	$ 238,421,000	$ 233,072,000
Scheduled [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Maturity Date	May 15, 2037
Final [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Maturity Date	May 1, 2067

Long Term Subordinated Notes 72

Long Term Subordinated Notes (Schedule Of Interest Expense Incurred In Connection With Long Term Subordinated Notes) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Long Term Subordinated Notes [Abstract]
Interest expense incurred	$ 2,391	$ 3,937

Segment Reporting (Schedule Of

Segment Reporting (Schedule Of Underwriting Results For Operating Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Premiums earned	$ 1,619,427	$ 1,312,097
Incurred losses and LAE	1,057,177	770,788
Commission and brokerage	357,639	282,269
Other underwriting expenses	96,284	75,887
U.S. Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums	644,222	578,958
Net written premiums	545,831	517,369
Premiums earned	563,385	481,524
Incurred losses and LAE	545,193	262,066
Commission and brokerage	127,320	102,358
Other underwriting expenses	16,886	14,251
Underwriting gain (loss)	(126,014)	102,849
International [Member]
Segment Reporting Information [Line Items]
Gross written premiums	366,724	266,417
Net written premiums	345,155	245,662
Premiums earned	343,604	271,581
Incurred losses and LAE	127,024	159,501
Commission and brokerage	82,177	66,150
Other underwriting expenses	10,576	9,480
Underwriting gain (loss)	123,827	36,450
Bermuda [Member]
Segment Reporting Information [Line Items]
Gross written premiums	415,686	321,122
Net written premiums	394,968	305,032
Premiums earned	319,134	235,106
Incurred losses and LAE	129,513	128,432
Commission and brokerage	81,487	58,423
Other underwriting expenses	10,133	9,480
Underwriting gain (loss)	98,001	38,771
Insurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums	504,975	434,447
Net written premiums	386,252	345,751
Premiums earned	393,304	323,886
Incurred losses and LAE	255,447	220,789
Commission and brokerage	66,655	55,338
Other underwriting expenses	58,689	42,676
Underwriting gain (loss)	$ 12,513	$ 5,083

Segment Reporting (Schedule O74

Segment Reporting (Schedule Of Underwriting Results For Operating Segments To Income (Loss) Before Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net investment income	$ 138,294	$ 122,289
Net realized capital gains (losses)	(24,901)	52,728
Net derivative gain (loss)	273	2,630
Corporate expenses	(8,996)	(8,457)
Interest, fee and bond issue cost amortization expense	(7,418)	(8,964)
Other income (expense)	12,064	(4,966)
INCOME (LOSS) BEFORE TAXES	217,643	338,413
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss)	108,327	183,153
Net investment income	138,294	122,289
Net realized capital gains (losses)	(24,901)	52,728
Net derivative gain (loss)	273	2,630
Corporate expenses	(8,996)	(8,457)
Interest, fee and bond issue cost amortization expense	(7,418)	(8,964)
Other income (expense)	12,064	(4,966)
INCOME (LOSS) BEFORE TAXES	$ 217,643	$ 338,413

Segment Reporting (Schedule O75

Segment Reporting (Schedule Of Gross Written Premiums Derived From Largest Non-U.S. Market) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
United Kingdom Gross Written Premium [Member]
Segment Reporting Information [Line Items]
Gross written premiums	$ 258,259	$ 170,820

Share-Based Compensation Plans

Share-Based Compensation Plans (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation awards, number of restricted shares granted | shares	160,645
Share-based compensation awards, grant date	Feb. 21, 2018
Share-based compensation awards, per option fair value | $ / shares	$ 242.390
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation awards, number of performance awards granted | shares	13,325
Share-based compensation awards, grant date	Feb. 21, 2018
Share-based compensation awards, per option fair value | $ / shares	$ 242.39

Retirement Benefits (Summary Of

Retirement Benefits (Summary Of Pension Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$ 0	$ 0
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,977	3,299
Interest cost	2,585	2,276
Expected return on plan assets	(3,670)	(3,155)
Amortization of net (income) loss	2,237	3,040
Net periodic benefit cost	4,128	5,460
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	446	440
Interest cost	307	249
Amortization of prior service cost	(33)	(33)
Amortization of net (income) loss	94	76
Net periodic benefit cost	$ 814	$ 732

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - Kilimanjaro Re Limited [Member] $ in Thousands	Apr. 30, 2018USD ($)item	Apr. 13, 2017item	Dec. 01, 2015item	Apr. 24, 2014item
Subsequent Event [Line Items]
Number of collateralized reinsurance agreements		6	2	2
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of collateralized reinsurance agreements	4
Catastrophe reinsurance bonds funded amount | $	$ 525,000