Everest Re (EG) 10-K 1 Mar 21 2020 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Feb. 01, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Transition Report	false
Entity File Number	1-15731
Entity Registrant Name	EVEREST RE GROUP, LTD.
Entity Incorporation State Country Code	D0
Entity Tax Identification Number	98-0365432
Entity Address Address Line 1	Seon Place – 4th Floor
Entity Address Address Line 2	141 Front Street
Entity Address Address Line 3	PO Box HM 845
Entity Address City Or Town	Hamilton
Entity Address Postal Zip Code	HM 19
Entity Address Country	BM
City Area Code	441
Local Phone Number	295-0006
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Icfr Auditor Attestation Flag	true
Entity Public Float			$ 8,242,153
Security 12b Title	Common Shares, $0.01 par value
Trading Symbol	RE
Security Exchange Name	NYSE
Entity Common Stock Shares Outstanding		39,991,662
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Certain information required by Items 10, 11, 12, 13 and 14 of Form 10-K is incorporated by reference into Part III hereof from the registrant’s proxy statement for the 2021 Annual General Meeting of Shareholders, which will be filed with the Securities and Exchange Commission within 120 days of the close of the registrant’s fiscal year ended December 31, 2020.
Amendment Flag	false
Entity Central Index Key	0001095073
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
ASSETS:
Fixed maturities - available for sale, at market value (amortized cost: 2020, $119,225,067; 2019, 16,473,491 , credit allowances: 2020, $(1,745); 2019, $0 )	$ 20,040,173	$ 16,824,944
Fixed maturities - available for sale, at fair value		5,826
Equity securities, at fair value	1,472,236	931,457
Short-term investments (cost: 2020, $1,135,088; 2019, $414,639)	1,134,950	414,706
Other invested assets (cost: 2020, $2,012,581; 2019, $1,763,531)	2,012,581	1,763,531
Cash	801,651	808,036
Total investments and cash	25,461,591	20,748,500
Accrued investment income	141,304	116,804
Premiums receivable	2,680,562	2,259,088
Reinsurance receivables	1,994,555	1,763,471
Funds held by reinsureds	716,655	489,901
Deferred acquisition costs	622,053	581,863
Prepaid reinsurance premiums	412,015	445,716
Income taxes	17,253	305,711
Other assets	742,369	612,997
TOTAL ASSETS	32,788,357	27,324,051
LIABILITIES:
Reserve for losses and loss adjustment expenses	16,398,997	13,611,313
Future policy benefit reserve	37,723	42,592
Unearned premium reserve	3,501,359	3,056,735
Funds held under reinsurance treaties	15,807	10,668
Other net payable to reinsurers	294,347	291,660
Losses in course of payment	127,971	51,950
Long term notes due 5/1/2067	223,674	236,758
Borrowings from FHLB	310,000
Accrued interest on debt and borrowings	10,460	2,878
Unsettled securities payable	206,693	30,650
Other liabilities	558,432	458,848
Total liabilities	23,062,181	18,191,126
Commitments and contingencies (Note 15)
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; (2020) 69,620 and (2019) 69,464 outstanding before treasury shares	696	694
Additional paid-in capital	2,245,301	2,219,660
Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of $80,451 at 2020 and $30,996 at 2019	534,899	28,152
Treasury shares, at cost; 29,636 shares (2020) and 28,665 shares (2019)	(3,622,172)	(3,422,152)
Retained earnings	10,567,452	10,306,571
Total shareholders' equity	9,726,176	9,132,925
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	32,788,357	27,324,051
Senior Notes [Member] | 4.868% Senior notes due 6/1/2044 [Member]
LIABILITIES:
Senior notes	397,194	397,074
Senior Notes [Member] | Senior Notes 3.5% [Member]
LIABILITIES:
Senior notes	$ 979,524

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fixed maturities - available for sale, at market value, amortized cost	$ 19,225,067	$ 16,473,491
Fixed maturities - available for sale, at market value, allowance for credit loss	(1,745)
Short-term investments, at cost	1,135,088	414,639
Other invested assets, at cost	$ 2,012,581	$ 1,763,531
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 Stock, Shares Authorized	200,000,000	200,000,000
Common shares, outstanding	69,620,000	69,464,000
Accumulated other comprehensive income (loss), net deferred income tax expense (benefit)	$ 80,451	$ 30,996
Treasury shares	29,636,000	28,665,000
Senior Notes [Member] | 4.868% Senior notes due 6/1/2044 [Member]
Debt instrument, maturity date	Jun. 1, 2044
Senior Notes [Member] | 3.5% Senior notes due 10/15/2050 [Member]
Debt instrument, maturity date	Oct. 15, 2050
Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt instrument, maturity date	May 1, 2067

Consolidated Statements Of Oper

Consolidated Statements Of Operations And Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUES:
Premiums earned	$ 8,681,513	$ 7,403,686	$ 6,931,699
Net Investment Income	642,465	647,139	581,183
Net realized capital gains (losses):
Credit allowances on fixed maturity securities	(1,745)
Other-than-temporary impairments on fixed maturity securities		(20,899)	(8,110)
Other net realized capital gains (losses)	269,394	205,903	(119,026)
Total net realized capital gains (losses)	267,649	185,004	(127,136)
Other income (expense)	6,487	(4,660)	(24,251)
Total revenues	9,598,114	8,231,169	7,361,495
CLAIMS AND EXPENSES:
Incurred losses and loss adjustment expenses	6,550,837	4,922,898	5,651,403
Commission, brokerage, taxes and fees	1,873,250	1,703,726	1,519,030
Other underwriting expenses	511,237	440,899	371,541
Corporate expenses	41,118	32,966	30,672
Interest, fees and bond issue cost amortization expense	36,323	31,693	31,031
Total claims and expenses	9,012,765	7,132,182	7,603,677
INCOME (LOSS) BEFORE TAXES	585,349	1,098,987	(242,182)
Income tax expense (benefit)	71,198	89,526	(331,223)
NET INCOME (LOSS)	514,151	1,009,461	89,041
Other comprehensive income (loss), net of tax:
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period	423,210	496,430	(255,656)
Reclassification adjustment for realized losses (gains) included in net income (loss)	(3,476)	(12,613)	27,496
Total URA(D) on securities arising during the period	419,734	483,817	(228,160)
Foreign currency translation adjustments	86,327	14,030	(76,816)
Benefit plan actuarial net gain (loss) for the period	(5,615)	(12,591)	(510)
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)	6,300	5,453	5,021
Total benefit plan net gain (loss) for the period	685	(7,138)	4,511
Total other comprehensive income (loss), net of tax	506,746	490,709	(300,465)
COMPREHENSIVE INCOME (LOSS)	$ 1,020,897	$ 1,500,170	$ (211,424)
EARNINGS PER COMMON SHARE:
Basic	$ 12.81	$ 24.77	$ 2.18
Diluted	$ 12.78	$ 24.70	$ 2.17

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock Outstanding [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss), Net of Deferred Income Taxes [Member]	Accumulated Other Comprehensive Income (Loss), Net of Deferred Income Taxes [Member]Cumulative Effect Period Of Adoption Adjustment [Member]	Retained Earnings [Member]	Retained Earnings [Member]Cumulative Effect Period Of Adoption Adjustment [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2017			$ 691	$ 2,165,768	$ (160,891)		$ 9,657,412		$ (3,322,244)
Balance (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2017
Balance (Accounting Standards Update 2016-01 [Member]) at Dec. 31, 2017						$ (1,201)		1,201
Balance, shares at Dec. 31, 2017		40,835,272
Issued during the period, net, shares		158,055
Treasury shares acquired, shares		(342,179)
Issued during the period, net			1
Share-based compensation plans				23,009
Net increase (decrease) during the period	$ (300,465)				(300,465)
Net income (loss)	89,041						89,041
Dividends declared ($6.20 per share 2020,$5.75 per share 2019 and $5.30 per share in 2018)	(216,221)						(216,221)
Purchase of treasury shares									(75,304)
Balance at Dec. 31, 2018	7,860,797		692	2,188,777	(462,557)		9,531,433		(3,397,548)
Balance (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2018
Balance (Accounting Standards Update 2016-01 [Member]) at Dec. 31, 2018
Balance, shares at Dec. 31, 2018		40,651,148
Issued during the period, net, shares		262,448
Treasury shares acquired, shares		(114,633)
Issued during the period, net			2
Share-based compensation plans				30,883
Net increase (decrease) during the period	490,709				490,709
Net income (loss)	1,009,461						1,009,461
Dividends declared ($6.20 per share 2020,$5.75 per share 2019 and $5.30 per share in 2018)	(234,322)						(234,322)
Purchase of treasury shares									(24,604)
Balance at Dec. 31, 2019	$ 9,132,925		694	2,219,660	28,152		10,306,571		(3,422,152)
Balance (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2019								(4,214)
Balance (Accounting Standards Update 2016-01 [Member]) at Dec. 31, 2019
Balance, shares at Dec. 31, 2019	69,464,000	40,798,963
Issued during the period, net, shares		155,410
Treasury shares acquired, shares		(970,892)
Issued during the period, net			2
Share-based compensation plans				25,641
Net increase (decrease) during the period	$ 506,746				506,746
Net income (loss)	514,151						514,151
Dividends declared ($6.20 per share 2020,$5.75 per share 2019 and $5.30 per share in 2018)	(249,056)						(249,056)
Purchase of treasury shares									(200,020)
Balance at Dec. 31, 2020	$ 9,726,176		$ 696	$ 2,245,301	$ 534,899		$ 10,567,452		$ (3,622,172)
Balance, shares at Dec. 31, 2020	69,620,000	39,983,481

Consolidated Statements Of Ch_2

Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Dividends declared	$ 6.20	$ 5.75	$ 5.30

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 514,151	$ 1,009,461	$ 89,041
Adjustments to reconcile net income to net cash provided by operating activities:
Decrease (increase) in premiums receivable	(387,123)	(62,018)	(382,987)
Decrease (increase) in funds held by reinsureds, net	(219,321)	(56,722)	(153,627)
Decrease (increase) in reinsurance receivables	(150,753)	67,444	(511,592)
Decrease (increase) in income taxes	239,883	237,479	(265,065)
Decrease (increase) in prepaid reinsurance premiums	55,334	(95,207)	(65,925)
Increase (decrease) in reserve for losses and loss adjustment expenses	2,627,813	402,380	1,377,711
Increase (decrease) in future policy benefit reserve	(4,869)	(4,186)	(4,236)
Increase (decrease) in unearned premiums	404,049	521,709	542,023
Increase (decrease) in other net payable to reinsurers	(24,163)	66,477	12,276
Increase (decrease) in losses in course of payment	74,759	(33,557)	123,209
Change in equity adjustments in limited partnerships	(103,772)	(108,332)	(102,052)
Distribution of limited partnership income	122,326	81,300	84,623
Change in other assets and liabilities, net	(95,968)	(54,176)	(322,107)
Non-cash compensation expense	39,209	34,018	32,369
Amortization of bond premium (accrual of bond discount)	49,673	30,936	29,272
Net realized capital (gains) losses	(267,649)	(185,004)	127,136
Net cash provided by (used in) operating activities	2,873,579	1,852,002	610,069
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from fixed maturities matured/called - available for sale, at market value	2,586,405	2,302,299	1,973,652
Proceeds from fixed maturities sold - available for sale, at market value	1,945,867	3,280,237	3,148,428
Proceeds from fixed maturities sold - available for sale, at fair value	4,907	2,917	1,751
Proceeds from equity securities sold, at fair value	376,347	283,965	1,199,409
Distributions from other invested assets	309,912	284,558	3,102,018
Cost of fixed maturities acquired - available for sale, at market value	(7,189,301)	(6,613,917)	(5,909,504)
Cost of fixed maturities acquired - available for sale, at fair value		(4,243)	(4,381)
Cost of equity securities acquired, at fair value	(637,082)	(329,417)	(921,937)
Cost of other invested assets acquired	(557,473)	(425,438)	(3,370,455)
Net change in short-term investments	(717,527)	(167,290)	455,350
Net change in unsettled securities transactions	194,574	(26,163)	46,048
Net cash provided by (used in) investing activities	(3,683,371)	(1,412,492)	(279,621)
CASH FLOWS FROM FINANCING ACTIVITIES:
Common shares issued during the period for share-based compensation, net of expense	(13,566)	(3,134)	(8,157)
Purchase of treasury shares	(200,020)	(24,604)	(75,304)
Dividends paid to shareholders	(249,097)	(234,322)	(216,221)
Proceeds from issuance of senior notes	979,417
Cost of debt repurchase	(10,647)
FHLB advances (repayments)	310,000
Cost of shares withheld on settlements of share-based compensation awards	(15,908)	(13,627)	(16,912)
Net cash provided by (used in) financing activities	800,220	(275,687)	(316,594)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	3,187	(11,882)	7,174
Net increase (decrease) in cash	(6,385)	151,941	21,028
Cash, beginning of period	808,036	656,095	635,067
Cash, end of period	801,651	808,036	656,095
SUPPLEMENTAL CASH FLOW INFORMATION:
Income taxes paid (recovered)	(169,748)	(148,585)	(65,064)
Interest paid	28,415	31,689	30,447
NON-CASH TRANSACTIONS:
Fixed maturities - available for sale, at market value			143,656
Short-term investments			243,864
Other invested assets			$ (387,520)

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Summary Of Significant Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A. Business and Basis of Presentation. 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. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The statements include all of the following domestic and foreign direct and indirect subsidiaries of Group: Everest International Reinsurance, Ltd. (“Everest International”), Mt. Logan Insurance Managers, Ltd., Mt. Logan Management, Ltd., Everest International Holdings (Bermuda), Ltd. (“International Holdings”), Everest Corporate Member Limited, Everest Service Company (UK), Ltd., Everest Preferred International Holdings, Ltd. (“Preferred International”), Everest Reinsurance (Bermuda), Ltd. (“Bermuda Re”), Everest Re Advisors, Ltd., Everest Advisors (UK), Ltd., Everest Underwriting Group (Ireland), Limited (“Holdings Ireland”), Everest Global Services, Inc. (“Global Services”), Everest Insurance Company of Canada (“Everest Canada”), Premiere Insurance Underwriting Services (“Premiere”), Everest Dublin Insurance Holdings Limited (Ireland) (“Everest Dublin Holdings”), Everest Insurance (Ireland), designated activity company (“Ireland Insurance”), Everest Reinsurance Company (Ireland), designated activity company (“Ireland Re”), Everest Reinsurance Holdings, Inc. (“Holdings”), Salus Systems, LLC (“Salus”), Everest International Assurance, Ltd. (Bermuda) (“Everest Assurance”), Specialty Insurance Group, Inc. (“Specialty”), Specialty Insurance Group - Leisure and Entertainment Risk Purchasing Group LLC (“Specialty RPG”), Mt. McKinley Managers, L.L.C., Everest Specialty Underwriters Services, LLC, Everest Reinsurance Company (“Everest Re”), Everest National Insurance Company (“Everest National”), Everest Reinsurance Company Ltda. (Brazil), Mt. Whitney Securities, Inc., Everest Indemnity Insurance Company (“Everest Indemnity”), Everest Denali Insurance Company (“Everest Denali”), Everest Premier Insurance Company (“Everest Premier”) and Everest Security Insurance Company (“Everest Security”). All amounts are reported in U.S. dollars. 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 have control and 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 intercompany accounts and transactions have been eliminated. Certain reclassifications and format changes have been made to prior years’ amounts to conform to the 2020 presentation. B. Investments. Fixed maturity investments available for sale, at market value, reflect unrealized appreciation and depreciation, as a result of temporary changes in market value during the period, in shareholders’ equity, net of income taxes in “accumulated other comprehensive income (loss)” in the consolidated balance sheets, since cash flows from these investments will be primarily used to settle its reserve for losses and loss adjustment expense liabilities. The Company anticipates holding these investments for an extended period as the cash flow from interest and maturities will fund the projected payout of these liabilities. The Company reviews all of its fixed maturity, available for sale securities whose fair value has fallen below their amortized cost at the time of review. The Company then assesses whether the decline in value is due to non-credit related or credit related factors. In making its assessment, the Company evaluates the current market and interest rate environment as well as specific issuer information. Generally, a change in a security’s value caused by a change in the market, interest rate or foreign exchange environment does not constitute a credit impairment, but rather a non-credit related decline in market value. Non-credit related declines in market value are recorded as unrealized losses in accumulated other comprehensive income (loss). If the Company intends to sell the security or is more likely than not to sell the security, the Company records the entire fair value adjustment in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). If the Company determines that the decline is credit related and the Company does not have the intent to sell the security; and it is more likely than not that the Company will not have to sell the security before recovery of its cost basis, the Company establishes a credit allowance equal to the estimated credit loss and is recorded in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). The amount of the allowance for a given security will generally be the difference between a discounted cash flow model and the Company’s carrying value. The fair value adjustment that is non-credit related is recorded as a component of other comprehensive income (loss), net of tax, and is included in accumulated other comprehensive income (loss) in the Company’s consolidated balance sheets. The Company will adjust the credit allowance account for future changes in credit loss estimates for a security and record this adjustment through net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). For equity securities, at fair value, the Company reflects changes in value as net realized capital gains and losses since these securities may be sold in the near term depending on financial market conditions. Interest income on all fixed maturities and dividend income on all equity securities are included as part of net investment income in the consolidated statements of operations and comprehensive income (loss). Short-term investments are stated at cost, which approximates market value. Realized gains or losses on sales of investments are determined on the basis of identified cost. For some non-publicly traded securities, market prices are determined through the use of pricing models that evaluate securities relative to the U.S. Treasury yield curve, taking into account the issue type, credit quality, and cash flow characteristics of each security. For other non-publicly traded securities, investment managers’ valuation committees will estimate fair value and in many instances, these fair values are supported with opinions from qualified independent third parties. All fair value estimates from investment managers are reviewed by the Company for reasonableness. For publicly traded securities, market value is based on quoted market prices or valuation models that use observable market inputs. When a sector of the financial markets is inactive or illiquid, the Company may use its own assumptions about future cash flows and risk-adjusted discount rates to determine fair value. Retrospective adjustments are employed to recalculate the values of asset-backed securities. 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 to effect the calculation of projected and prepayments for pass-through security types. Other invested assets include limited partnerships, rabbi trusts and prior to July 1, 2018, a private placement liquidity sweep facility. Cash contributions to and cash distributions from the sweep facility were reported gross in cash flows from investing activities in the consolidated statements of cash flows. Limited partnerships are accounted for under the equity method of accounting, which can be recorded on a monthly or quarterly lag. C. Allowance for Receivable Balances. Effective January 1, 2020, the Company adopted the Current Expected Credit Losses (CECL) methodology for estimating allowances for credit losses. The Company evaluates the recoverability of its premiums and reinsurance receivable balances and establishes an allowance for estimated uncollectible amounts. Prior to the adoption of CECL, an allowance for doubtful accounts was estimated on the basis of periodic evaluations of balances due from third parties, considering historical collection experience, solvency and current economic conditions. Premiums receivable, excluding receivables for losses within a deductible and retrospectively-rated policy premiums, are primarily comprised of premiums due from policyholders/ cedants. Balances are considered past due when amounts that have been billed are not collected within contractually stipulated time periods. For these balances, the allowance is estimated based on recent historical credit loss and collection experience, adjusted for current economic conditions and reasonable and supportable forecasts, when appropriate. In response to significant economic stress experienced as a result of the COVID-19 pandemic, during 2020, the Company increased the expected loss factors used to estimate the allowance based on collection experience during past moderate and severe recessions as well as experience during periods when we provided policyholders additional time to make premiums payments. A portion of the Company's Commercial Lines business is written with large deductibles or under retrospectively-rated plans. Under some commercial insurance contracts with a large deductible, the Company is obligated to pay the claimant the full amount of the claim and the Company is subsequently reimbursed by the policyholder for the deductible amount. As such, the Company is subject to credit risk until reimbursement is made. Retrospectively-rated policies are policies whereby the ultimate premium is adjusted based on actual losses incurred. Although the premium adjustment feature of a retrospectively-rated policy substantially reduces insurance risk for the Company, it presents credit risk to the Company. The Company’s results of operations could be adversely affected if a significant portion of such policyholders failed to reimburse the Company for the deductible amount or the amount of additional premium owed under retrospectively-rated policies. The Company manages these credit risks through credit analysis, collateral requirements, and oversight. The allowance for receivables for loss within a deductible and retrospectively-rated policy premiums is estimated as the amount of the receivable exposed to loss multiplied by estimated factors for probability of default. The probability of default is assigned based on each policyholder's credit rating, or a rating is estimated if no external rating is available. Credit ratings are reviewed and updated at least annually. The exposure amount is estimated net of collateral and other offsets, considering the nature of the collateral, potential future changes in collateral values, and historical loss information for the type of collateral obtained. The probability of default factors are historical corporate defaults for receivables with similar durations estimated through multiple economic cycles. Credit ratings are forward-looking and consider a variety of economic outcomes. The Company's evaluation of the required allowance for receivables for loss within a deductible and retrospectively-rated policy premiums considers the current economic environment as well as the probability-weighted macroeconomic scenarios. In response to significant economic stress experienced as a result of the COVID-19 pandemic, the Company increased the weight of both a moderate and severe recession scenario in our estimate of the allowance for loss within a deductible and retrospectively-rated policy premiums. The ultimate impact to the Company’s financial statements from the COVID-19 pandemic could vary significantly from our estimates depending on the duration and severity of the pandemic, the duration and severity of the economic downturn and the degree to which federal, state and local government actions to mitigate the economic impact of COVID-19 are effective. The Company records total credit loss expenses related to premiums receivable in other underwriting expenses and records credit loss expenses related to deductibles through losses incurred The allowance for uncollectible reinsurance reflects management’s best estimate of reinsurance cessions that may be uncollectible in the future due to reinsurers’ unwillingness or inability to pay. The allowance for uncollectible reinsurance comprises an allowance and an allowance for disputed balances. Based on this analysis, the Company may adjust the allowance for uncollectible reinsurance or charge off reinsurer balances that are determined to be uncollectible. The allowance is estimated as the amount of reinsurance receivable exposed to loss multiplied by estimated factors for the probability of default. The reinsurance receivable exposed is the amount of reinsurance receivable net of collateral and other offsets, considering the nature of the collateral, potential future changes in collateral values, and historical loss information for the type of collateral obtained. The probability of default factors are historical insurer and reinsurer defaults for liabilities with similar durations to the reinsured liabilities as estimated through multiple economic cycles. Credit ratings are forward-looking and consider a variety of economic outcomes. The Company's evaluation of the required allowance for reinsurance receivable considers the current economic environment as well as macroeconomic scenarios. The Company expects the impact of the COVID-19 pandemic to reinsurers to be somewhat mitigated by their regulated capital and liquidity positions. The ultimate impact to the Company's financial statements could vary significantly from our estimates depending on the duration and severity of the pandemic, the duration and severity of the economic downturn and the degree to which federal, state and local government actions to mitigate the economic impact of COVID-19 are effective. The Company records credit loss expenses related to reinsurance receivable in losses and loss adjustment expenses. Write-offs of reinsurance receivable and any related allowance are recorded in the period in which the balance is deemed uncollectible. Allowances are presented in the table below for the periods indicated. Years Ended December 31, (Dollars in thousands) 2020 2019 Reinsurance receivables and premium receivables $ 41,357 $ 25,605 D. Deferred Acquisition Costs. Acquisition costs, consisting principally of commissions and brokerage expenses and certain premium taxes and fees incurred at the time a contract or policy is issued and that vary with and are directly related to the Company’s reinsurance and insurance business, are deferred and amortized over the period in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value by line of business based on the related unearned premiums, anticipated claims and claim expenses and anticipated investment income. Deferred acquisition costs amortized to income are presented in the table below for the periods indicated. Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Deferred acquisition costs $ 1,873,250 $ 1,703,726 $ 1,519,030 E. Reserve for Losses and Loss Adjustment Expenses. The reserve for losses and loss adjustment expenses (“LAE”) is based on individual case estimates and reports received from ceding companies. A provision is included for losses and LAE incurred but not reported (“IBNR”) based on past experience. A provision is also included for certain potential liabilities relating to asbestos and environmental (“A&E”) exposures, for which liabilities cannot be estimated using traditional reserving techniques. See also Note 3. The reserves are reviewed periodically and any changes in estimates are reflected in earnings in the period the adjustment is made. The Company’s loss and LAE reserves represent management’s best estimate of the ultimate liability. Loss and LAE reserves are presented gross of reinsurance receivables and incurred losses and LAE are presented net of reinsurance. Accruals for commissions are established for reinsurance contracts that provide for the stated commission percentage to increase or decrease based on the loss experience of the contract. Changes in estimates for such arrangements are recorded as commission expense. Commission accruals for contracts with adjustable features are estimated based on expected loss and LAE. F. Future Policy Benefit Reserve. Liabilities for future policy benefits on annuity policies are carried at their accumulated values. Reserves for policy benefits include mortality claims in the process of settlement and IBNR claims. Actual experience in a particular period may fluctuate from expected results. G. Premium Revenues. Written premiums are earned ratably over the periods of the related insurance and reinsurance contracts. Unearned premium reserves are established relative to the unexpired contract period. For reinsurance contracts, such reserves are established based upon reports received from ceding companies or estimated using pro rata methods based on statistical data. Reinstatement premiums represent additional premium received on reinsurance coverages, most prevalently catastrophe related, when limits have been depleted under the original reinsurance contract and additional coverage is granted. Written and earned premiums and the related costs, which have not yet been reported to the Company, are estimated and accrued. Premiums are net of ceded reinsurance. H. Prepaid Reinsurance Premiums. Prepaid reinsurance premiums represent unearned premium reserves ceded to other reinsurers. Prepaid reinsurance premiums for any foreign reinsurers comprising more than 10% of the outstanding balance at December 31, 2020 were secured either through collateralized trust arrangements, rights of offset or letters of credit, thereby limiting the credit risk to the Company. I. Income Taxes. Holdings and its wholly owned subsidiaries file a consolidated U.S. federal income tax return. Foreign subsidiaries and branches of subsidiaries file local tax returns as required. Group and subsidiaries not included in Holdings’ consolidated tax return file separate company U.S. federal income tax returns as required. Deferred income taxes have been recorded to recognize the tax effect of temporary differences between the financial reporting and income tax bases of assets and liabilities, which arise because of differences between GAAP and income tax accounting rules. As an accounting policy, the Company has adopted the aggregate portfolio approach for releasing disproportionate income tax effects from AOCI. J. Foreign Currency. As a global entity, the Company transacts business in numerous currencies through business units located around the world. The base transactional currency for each business unit is determined by the local currency used for most economic activity in that area. Movements in exchange rates related to assets and liabilities at the business units between the original currency and the base currency are recorded through the consolidated statements of operations and comprehensive income (loss) in other income (expense), except for currency movements related to available for sale investments, which are excluded from net income (loss) and accumulated in shareholders’ equity, net of deferred taxes. The business units’ base currency financial statements are translated to U.S. dollars using the exchange rates at the end of period for the balance sheets and the average exchange rates in effect for the reporting period for the income statements. Gains and losses resulting from translating the foreign currency financial statements, net of deferred income taxes, are excluded from net income loss and accumulated in shareholders’ equity. K. 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. Years Ended December 31, (Dollars in thousands, except per share amounts) 2020 2019 2018 Net income (loss) per share: Numerator Net income (loss) $ 514,151 $ 1,009,461 $ 89,041 Less: dividends declared-common shares and nonvested common shares ( 249,056) ( 234,322) ( 216,221) Undistributed earnings 265,094 775,139 ( 127,180) Percentage allocated to common shareholders (1) 98.7 % 98.9 % 99.0 % 261,770 766,386 ( 125,848) Add: dividends declared-common shareholders 246,054 231,796 214,088 Numerator for basic and diluted earnings per common share $ 507,824 $ 998,182 $ 88,239 Denominator Denominator for basic earnings per weighted-average common shares 39,656 40,291 40,388 Effect of dilutive securities: Options 77 129 198 Denominator for diluted earnings per adjusted weighted-average common shares 39,734 40,420 40,586 Per common share net income (loss) Basic $ 12.81 $ 24.77 $ 2.18 Diluted $ 12.78 $ 24.70 $ 2.17 (1) Basic weighted-average common shares outstanding 39,656 40,291 40,388 Basic weighted-average common shares outstanding and nonvested common shares expected to vest 40,160 40,751 40,816 Percentage allocated to common shareholders 98.7 % 98.9 % 99.0 % (Some amounts may not reconcile due to rounding.) M. Deposit Assets and Liabilities. In the normal course of its operations, the Company may enter into contracts that do not meet risk transfer provisions. Such contracts are accounted for using the deposit accounting method and are included in other liabilities in the Company’s consolidated balance sheets. For such contracts, the Company originally records deposit liabilities for an amount equivalent to the assets received. Actuarial studies are used to estimate the final liabilities under such contracts with any change reflected in the consolidated statements of operations and comprehensive income (loss). N. Share-Based Compensation. Share-based compensation stock option, restricted share and performance share unit awards are fair valued at the grant date and expensed over the vesting period of the award. The tax benefit on the recorded expense is deferred until the time the award is exercised or vests (becomes unrestricted). See Note 16. O. Application of Recently Issued Accounting Guidance. Accounting for Income Taxes. In December 2019, The Financial Accounting Standards Board (“FASB”) issued ASU 2019-12, which provides simplification of existing guidance for income taxes, including the removal of certain exceptions related to recognition of deferred tax liabilities on foreign subsidiaries. The guidance is effective for annual reporting periods beginning after December 15, 2020 and interim periods within that annual reporting period. The Company is currently evaluating the impact of the adoption of ASU 2019-12 on its financial statements. Accounting for Cloud Computing Arrangement. In August 2018, FASB issued ASU 2018-15, which outlines accounting for implementation costs of a cloud computing arrangement that is a service contract. This guidance requires that implementation costs of a cloud computing arrangement that is a service contract must be capitalized and expensed in accordance with the existing provisions provided in Subtopic 350-40 regarding development of internal use software. In addition, any capitalized implementation costs should be amortized over the term of the hosting arrangement. The guidance is effective for annual reporting periods beginning after December 15, 2019 and interim periods within that annual reporting period. The Company adopted the guidance as of January 1, 2020. The adoption of ASU 2018-15 did not have a material impact on the Company’s financial statements. Accounting for Long Duration Contracts. In August 2018, FASB issued ASU 2018-12, which discusses changes to the recognition, measurement and presentation of long duration contracts. The main provisions of this guidance address the following: 1) In determining liability for future policy benefits, companies must review cash flow assumptions at least annually and the discount rate assumption at each reporting period date 2) Amortization of deferred acquisition costs has been simplified to be in constant level proportion to either premiums, gross profits or gross margins 3) Disaggregated roll forwards of beginning and ending liabilities for future policy benefits are required. The guidance was originally effective for annual reporting periods beginning after December 15, 2020 and interim periods within that annual reporting period. However, FASB issued ASU 2019-09 in November 2019 and then ASU 2020-11 in November 2021, which ultimately defers the effective date of ASU 2018-12 until annual reporting periods beginning after December 15, 2022. The Company is currently evaluating the impact of the adoption of ASU 2018-12 on its financial statements. Accounting for Impact on Income Taxes due to Tax Reform. In December 2017, the SEC issued Staff Accounting Bulletin (“SAB”) 118 which provides guidance on the application of FASB Accounting Standards Codification (“ASC”) Topic 740, Income Taxes, due to the enactment of TCJA. SAB 118 became effective upon release. The Company has adopted the provisions of SAB 118 with respect to measuring the tax effects for the modifications to the determination of tax basis loss reserves. In 2018, the Company recorded adjustments to the amount of tax expense it recorded in 2017 with respect to the TCJA as estimated amounts were finalized, which did not have a material impact on the Company’s financial statements. Amortization of Bond Premium. In March 2017, FASB issued ASU 2017-08 which outlines guidance on the amortization period for premium on callable debt securities. The new guidance requires that the premium on callable debt securities be amortized through the earliest call date rather than through the maturity date of the callable security. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018. The Company adopted the guidance effective January 1, 2019. The adoption of ASU 2017-08 did not have a material impact on the Company’s financial statements. Valuation of Financial Instruments. In June 2016, FASB issued ASU 2016-13 (and has subsequently issued related guidance and amendments in ASU 2019-11 and ASU 2019-10 in November 2019) which outline guidance on the valuation of and accounting for assets measured at amortized cost and available for sale debt securities. The new guidance requires the carrying value of assets measured at amortized cost, including reinsurance and premiums receivables to be presented as the net amount expected to be collected on the financial asset (amortized cost less an allowance for credit losses valuation account). The allowance reflects expected credit losses of the financial asset which considers available information using a combination both historical information, current market conditions and reasonable and supportable forecasts. For available-for-sale debt securities, the guidance modified the previous other than temporary impairment model, now requiring an allowance for estimated credit related losses rather than a permanent impairment, which will be limited to the amount by which fair value is below amortized cost. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. The Company adopted the guidance effective January 1, 2020, on a modified retrospective basis. The adoption resulted in a cumulative reduction of $ 4,214 thousand in retained earnings, net of tax, which is disclosed separately within the Consolidated Statements of Shareholders’ Equity. Leases . In February 2016, FASB issued ASU 2016-02 (and subsequently issued ASU 2018-11 in July, 2018) which outline new guidance on the accounting for leases. The new guidance requires the recognition of lease assets and lease liabilities on the balance sheets for most leases that were previously deemed operating leases and required only lease expense presentation in the statements of operations. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018. The Company adopted ASU 2016-02 effective January 1, 2019 and elected to utilize a cumulative-effect adjustment to the opening balance of retained earnings for the year of adoption. Accordingly, the Company’s reporting for the comparative periods prior to adoption continue to be presented in the financial statements in accordance with previous lease accounting guidance. The Company also elected to apply the package of practical expedients applicable to the Company in the updated guidance for transition for leases in effect at adoption. The Company did not elect the hindsight practical expedient to determine the lease term of existing leases (e.g. The Company did not re-assess lease renewals, termination options nor purchase options in determining lease terms). The adoption of the updated guidance resulted in the Company recognizing a right-of-use asset of $ 69,869 thousand as part of other assets and a lease liability of $ 77,270 thousand as part of other liabilities in the consolidated balance sheet at the time of adoption, as well as de-recognizing the liability for deferred rent that was required under the previous guidance. The cumulative effect adjustment to the opening balance of retained earnings was zero Recognition and Measurement of Financial Instruments. In January 2016, the FASB issued ASU 2016-01 which outlines revised guidance on the accounting for equity investments. The new guidance states that all equity investments in unconsolidated entities will be measured at fair value, with the change in value being recorded through the income statement rather than being recorded within other comprehensive income. The updated 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 2016-01 resulted in a cumulative change adjustment of $ 1,201 thousand between AOCI and retained earnings, which is disclosed separately within the consolidated statement of changes in shareholders’ equity. 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	12 Months Ended
	Dec. 31, 2020
Investments [Abstract]
Investments	2. INVESTMENTS Effective January 1, 2020, the Company adopted ASU 2016-13 which modified the previous other than temporary impairment model for available for sale fixed maturity securities. The guidance requires the Company to record allowances for credit losses for securities that are deemed to have valuation deterioration due to credit related factors. The initial table below presents the amortized cost, allowance for credit losses, gross unrealized appreciation/(depreciation) and market value of fixed maturity securities as of December 31, 2020 in accordance with ASU 2016-13 guidance. The second table presents the amortized cost, gross unrealized appreciation/(depreciation), market value and other-than-temporary impairments (“OTTI”) in AOCI as of December 31, 2019, in accordance with previously applicable guidance. At December 31, 2020 Amortized Allowance for Unrealized Unrealized Market (Dollars in thousands) Cost Credit Losses Appreciation Depreciation Value Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,325,156 $ - $ 49,084 $ ( 7,134) $ 1,367,106 Obligations of U.S. states and political subdivisions 543,895 - 34,654 ( 1,254) 577,295 Corporate securities 6,824,800 ( 1,220) 380,677 ( 55,231) 7,149,026 Asset-backed securities 2,540,809 - 30,691 ( 5,698) 2,565,802 Mortgage-backed securities Commercial 915,923 - 75,275 ( 895) 990,303 Agency residential 2,206,139 - 64,663 ( 3,063) 2,267,739 Non-agency residential 5,187 - 9 ( 2) 5,194 Foreign government securities 1,565,260 ( 22) 102,587 ( 22,450) 1,645,375 Foreign corporate securities 3,297,898 ( 503) 204,023 ( 29,085) 3,472,333 Total fixed maturity securities $ 19,225,067 $ ( 1,745) $ 941,663 $ ( 124,812) $ 20,040,173 At December 31, 2019 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 $ 1,489,660 $ 28,357 $ ( 2,214) $ 1,515,803 $ - Obligations of U.S. states and political subdivisions 507,353 29,651 ( 89) 536,915 - Corporate securities 6,227,661 185,052 ( 37,767) 6,374,946 469 Asset-backed securities 892,373 6,818 ( 1,858) 897,333 - Mortgage-backed securities Commercial 814,570 31,236 ( 1,249) 844,557 - Agency residential 2,173,099 36,361 ( 10,879) 2,198,581 - Non-agency residential 5,723 - ( 20) 5,703 - Foreign government securities 1,492,315 47,148 ( 33,513) 1,505,950 71 Foreign corporate securities 2,870,737 107,999 ( 33,580) 2,945,156 447 Total fixed maturity securities $ 16,473,491 $ 472,622 $ ( 121,169) $ 16,824,944 $ 987 (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. 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 December 31, 2020 At December 31, 2019 Amortized Market Amortized Market (Dollars in thousands) Cost Value Cost Value Fixed maturity securities – available for sale: Due in one year or less $ 1,365,793 $ 1,374,674 $ 1,456,960 $ 1,457,919 Due after one year through five years 6,529,189 6,774,785 6,757,107 6,869,359 Due after five years through ten years 4,414,211 4,751,903 3,471,370 3,609,816 Due after ten years 1,247,816 1,309,773 902,289 941,676 Asset-backed securities 2,540,809 2,565,802 892,373 897,333 Mortgage-backed securities: Commercial 915,923 990,303 814,570 844,557 Agency residential 2,206,139 2,267,739 2,173,099 2,198,581 Non-agency residential 5,187 5,194 5,723 5,703 Total fixed maturity securities $ 19,225,067 $ 20,040,173 $ 16,473,491 $ 16,824,944 The changes in net unrealized appreciation (depreciation) for the Company’s investments are derived from the following sources for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 Increase (decrease) during the period between the market value and cost of investments carried at market value, and deferred taxes thereon: Fixed maturity securities $ 465,192 $ 534,410 Fixed maturity securities, other-than-temporary impairment - ( 1,559) Change in unrealized appreciation (depreciation), pre-tax 465,192 532,851 Deferred tax benefit (expense) ( 45,458) ( 49,149) Deferred tax benefit (expense), other-than-temporary impairment - 115 Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders’ equity $ 419,734 $ 483,817 The Company reviews all of its fixed maturity, available for sale securities whose fair value has fallen below their amortized cost at the time of review. The Company then assesses whether the decline in value is due to non-credit related or credit related factors. In making its assessment, the Company evaluates the current market and interest rate environment as well as specific issuer information. Generally, a change in a security’s value caused by a change in the market, interest rate or foreign exchange environment does not constitute a credit impairment, but rather a non-credit related decline in market value. Non-credit related declines in market value are recorded as unrealized losses in accumulated other comprehensive income (loss). If the Company intends to sell the security or is more likely than not to sell the security, the Company records the entire fair value adjustment in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). If the Company determines that the decline is credit related and the Company does not have the intent to sell the security; and it is more likely than not that the Company will not have to sell the security before recovery of its cost basis, the Company establishes a credit allowance equal to the estimated credit loss and is recorded in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). The amount of the allowance for a given security will generally be the difference between a discounted cash flow model and the Company’s carrying value. The fair value adjustment that is non-credit related is recorded as a component of other comprehensive income (loss), net of tax, and is included in accumulated other comprehensive income (loss) in the Company’s consolidated balance sheets. The Company will adjust the credit allowance account for future changes in credit loss estimates for a security and record this adjustment through net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). The Company does not create an allowance for uncollectible interest. If interest is not received when due, the interest receivable is immediately reversed and no additional interest is accrued. If future interest is received that has not been accrued, it is recorded as income at that time. Prior to the adoption of ASU 2016-13 effective January 1, 2020, estimated credit losses were recorded as adjustments to the carrying value of the security and any subsequent improvement in market value were recorded through other comprehensive income. 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. 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 December 31, 2020 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 $ 135,190 $ ( 7,134) $ - $ - $ 135,190 $ ( 7,134) Obligations of U.S. states and political subdivisions 19,524 ( 999) 4,059 ( 255) 23,583 ( 1,254) Corporate securities 669,755 ( 26,159) 247,962 ( 29,072) 917,717 ( 55,231) Asset-backed securities 235,566 ( 4,768) 85,595 ( 930) 321,161 ( 5,698) Mortgage-backed securities Commercial 53,511 ( 578) 6,592 ( 317) 60,103 ( 895) Agency residential 434,447 ( 2,016) 50,353 ( 1,047) 484,800 ( 3,063) Non-agency residential 185 ( 2) - - 185 ( 2) Foreign government securities 114,755 ( 8,813) 150,812 ( 13,637) 265,567 ( 22,450) Foreign corporate securities 354,548 ( 17,489) 115,595 ( 11,596) 470,143 ( 29,085) Total fixed maturity securities $ 2,017,481 $ ( 67,958) $ 660,968 $ ( 56,854) $ 2,678,449 $ ( 124,812) Duration of Unrealized Loss at December 31, 2020 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 $ 96,144 $ ( 4,942) $ 112,419 $ ( 12,071) $ 208,563 $ ( 17,013) Due in one year through five years 653,816 ( 32,469) 283,866 ( 21,319) 937,682 ( 53,788) Due in five years through ten years 422,517 ( 19,392) 49,749 ( 2,034) 472,266 ( 21,426) Due after ten years 121,295 ( 3,791) 72,394 ( 19,136) 193,689 ( 22,927) Asset-backed securities 235,566 ( 4,768) 85,595 ( 930) 321,161 ( 5,698) Mortgage-backed securities 488,143 ( 2,596) 56,945 ( 1,364) 545,088 ( 3,960) Total fixed maturity securities $ 2,017,481 $ ( 67,958) $ 660,968 $ ( 56,854) $ 2,678,449 $ ( 124,812) The aggregate market value and gross unrealized losses related to investments in an unrealized loss position at December 31, 2020 were $ 2,678,449 thousand and $ 124,812 thousand, respectively. The market value of securities for the single issuer (the United States government) whose securities comprised the largest unrealized loss position at December 31, 2020, did not exceed 0.7% of the overall market value of the Company’s fixed maturity securities. The market value of the securities for the issuer with the second largest unrealized loss comprised less than 0.1% of the Company’s fixed maturity securities. In addition, as indicated on the above table, there was no significant concentration of unrealized losses in any one market sector. The $ 67,958 thousand of unrealized losses related to fixed maturity securities that have been in an unrealized loss position for less than one year were generally comprised of domestic and foreign corporate securities, foreign government securities and agency residential asset-backed securities. Of these unrealized losses, $ 63,424 thousand were related to securities that were rated investment grade by at least one nationally recognized statistical rating agency. The $ 56,854 thousand of unrealized losses related to fixed maturity securities in an unrealized loss position for more than one year related primarily to domestic and foreign corporate securities, foreign government securities and agency residential mortgage-backed securities. Of these unrealized losses, $ 33,533 thousand were related to securities that were rated investment grade by at least one nationally recognized statistical rating agency. There was no gross unrealized depreciation for mortgage-backed securities related to sub-prime and alt-A loans. In all instances, there were no projected cash flow shortfalls to recover the full book value of the investments and the related interest obligations. The mortgage-backed securities still have excess credit coverage and are current on interest and principal payments. 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, 2019 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 $ 85,527 $ ( 1,005) $ 249,371 $ ( 1,209) $ 334,898 $ ( 2,214) Obligations of U.S. states and political subdivisions 4,600 ( 38) 5,522 ( 51) 10,122 ( 89) Corporate securities 547,120 ( 9,877) 395,369 ( 27,890) 942,489 ( 37,767) Asset-backed securities 176,222 ( 1,027) 94,190 ( 831) 270,412 ( 1,858) Mortgage-backed securities Commercial 83,127 ( 689) 23,063 ( 560) 106,190 ( 1,249) Agency residential 344,267 ( 1,834) 488,680 ( 9,045) 832,947 ( 10,879) Non-agency residential 332 - 3,976 ( 20) 4,308 ( 20) Foreign government securities 210,766 ( 4,770) 283,648 ( 28,743) 494,414 ( 33,513) Foreign corporate securities 278,403 ( 7,553) 365,808 ( 26,027) 644,211 ( 33,580) Total fixed maturity securities $ 1,730,364 $ ( 26,793) $ 1,909,627 $ ( 94,376) $ 3,639,991 $ ( 121,169) Duration of Unrealized Loss at December 31, 2019 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 $ 67,879 $ ( 1,237) $ 416,583 $ ( 23,004) $ 484,462 $ ( 24,241) Due in one year through five years 464,753 ( 7,960) 689,195 ( 38,138) 1,153,948 ( 46,098) Due in five years through ten years 495,741 ( 12,388) 103,612 ( 11,100) 599,353 ( 23,488) Due after ten years 98,043 ( 1,658) 90,328 ( 11,678) 188,371 ( 13,336) Asset-backed securities 176,222 ( 1,027) 94,190 ( 831) 270,412 ( 1,858) Mortgage-backed securities 427,726 ( 2,523) 515,719 ( 9,625) 943,445 ( 12,148) Total fixed maturity securities $ 1,730,364 $ ( 26,793) $ 1,909,627 $ ( 94,376) $ 3,639,991 $ ( 121,169) The aggregate market value and gross unrealized losses related to investments in an unrealized loss position at December 31, 2019 were $ 3,639,991 thousand and $ 121,169 thousand, respectively. The market value of securities for the single issuer whose securities comprised the largest unrealized loss position at December 31, 2019, did not exceed 0.8% of the overall market value of the Company’s fixed maturity securities. In addition, as indicated on the above table, there was no significant concentration of unrealized losses in any one market sector. The $ 26,793 thousand of unrealized losses related to fixed maturity securities that have been in an unrealized loss position for less than one year were generally comprised of domestic and foreign corporate securities and foreign government securities. Of these unrealized losses, $ 23,104 thousand were related to securities that were rated investment grade by at least one nationally recognized statistical rating agency. The $ 94,376 thousand of unrealized losses related to fixed maturity securities in an unrealized loss position for more than one year related primarily to foreign and domestic corporate securities, foreign government securities and agency residential mortgage-backed securities. Of these unrealized losses, $ 73,144 thousand were related to securities that were rated investment grade by at least one nationally recognized statistical rating agency. There was no gross unrealized depreciation for mortgage-backed securities related to sub-prime and alt-A loans. In all instances, there were no projected cash flow shortfalls to recover the full book value of the investments and the related 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: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Fixed maturities $ 542,363 $ 520,291 $ 465,793 Equity securities 18,776 19,505 25,327 Short-term investments and cash 5,012 17,619 14,395 Other invested assets Limited partnerships 112,853 105,815 93,327 Other 1,699 14,117 16,960 Gross investment income before adjustments 680,703 677,347 615,802 Funds held interest income (expense) 12,754 13,271 6,300 Future policy benefit reserve income (expense) ( 1,237) ( 1,380) ( 1,419) Gross investment income 692,220 689,238 620,683 Investment expenses ( 49,755) ( 42,099) ( 39,500) Net investment income $ 642,465 $ 647,139 $ 581,183 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 $ 1,594,446 thousand in limited partnerships and private placement loans at December 31, 2020. These commitments will be funded when called in accordance with the partnership and loan agreements, which have investment periods that expire, unless extended, through 2026 Beginning in 2016, the Company participated in a private placement liquidity sweep facility (“the facility”). The primary purpose of the facility is to enhance the Company’s return on its short-term investments and cash positions. The facility invests in high quality, short-duration securities and permits daily liquidity. Through the second quarter of 2018, the Company’s participation in the facility was classified within other invested assets on the Company’s Balance Sheets. Starting in the third quarter of 2018, the Company consolidated its participation in the facility. As a result of the consolidation of the underlying investments of the facility, effective July 1, 2018, the Company reclassified $ 143,656 thousand from other invested assets to fixed maturity securities, available for sale, at market value and reclassified $ 243,864 thousand from other invested assets to short-term investments. As of December 31, 2020, the market value of investments in the facility consolidated within the Company’s balance sheets was $ 627,958 thousand. The components of net realized capital gains (losses) are presented in the table below for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Fixed maturity securities, market value: Allowance for credit losses $ ( 1,745) $ - $ - Other-than-temporary impairments - ( 20,899) ( 8,110) Gains (losses) from sales ( 2,214) 28,025 ( 21,719) Fixed maturity securities, fair value: Gains (losses) from sales ( 2,863) 355 ( 1,799) Gains (losses) from fair value adjustments 1,944 1,808 1,506 Equity securities, fair value: Gains (losses) from sales ( 8,963) 4,148 ( 29,941) Gains (losses) from fair value adjustments 278,461 165,200 ( 68,832) Other invested assets 1,705 6,003 1,815 Short-term investments gain (loss) 1,324 364 ( 56) Total net realized capital gains (losses) $ 267,649 $ 185,004 $ ( 127,136) Roll Forward of Allowance for Credit Losses Twelve Months Ended December 31, 2020 Foreign Foreign Corporate Government Corporate Securities Securities Securities Total (Dollars in thousands) Beginning Balance $ - $ - $ - $ - Credit losses on securities where credit losses were not previously recorded ( 27,666) ( 518) ( 4,700) ( 32,884) Increases in allowance on previously impaired securities ( 6,136) ( 28) ( 481) ( 6,645) Decreases in allowance on previously impaired securities 4,333 309 883 5,525 Reduction in allowance due to disposals 28,249 215 3,795 32,259 Balance as of December 31, 2020 $ ( 1,220) $ ( 22) $ ( 503) $ ( 1,745) The Company recorded as net realized capital gains (losses) in the consolidated statements of operations and comprehensive income (loss) fair value re-measurements, allowances for credit losses per ASU 2016-13 and write-downs in the value of securities deemed to be impaired on an other-than-temporary basis in prior years 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: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Proceeds from sales of fixed maturity securities $ 1,950,774 $ 3,283,154 $ 3,150,179 Gross gains from sales 79,609 63,721 33,996 Gross losses from sales ( 84,686) ( 35,341) ( 57,514) Proceeds from sales of equity securities $ 376,347 $ 283,965 $ 1,199,409 Gross gains from sales 37,415 14,274 31,718 Gross losses from sales ( 46,378) ( 10,126) ( 61,659) Securities with a carrying value amount of $ 1,617,928 thousand at December 31, 2020 were on deposit with various state or governmental insurance departments in compliance with insurance laws.

Reserve For Losses, LAE And Fut

Reserve For Losses, LAE And Future Policy Benefit Reserve	12 Months Ended
	Dec. 31, 2020
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Reserve For Losses LAE And Future Policy Benefit Reserve	3. RESERVE FOR LOSSES, LAE AND FUTURE POLICY BENEFIT RESERVE Reserves for losses and LAE. Activity in the reserve for losses and LAE is summarized for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross reserves beginning of period $ 13,611,313 $ 13,119,090 11,884,321 Less reinsurance recoverables ( 1,640,712) ( 1,619,641) ( 1,212,649) Net reserves beginning of period 11,970,601 11,499,449 10,671,672 Incurred related to: Current year 6,149,410 4,986,456 5,264,327 Prior years 401,427 ( 63,558) 387,076 Total incurred losses and LAE 6,550,837 4,922,898 5,651,403 Paid related to: Current year 2,046,260 2,042,246 1,700,765 Prior years 2,080,816 2,460,825 3,011,175 Total paid losses and LAE 4,127,076 4,503,071 4,711,940 Foreign exchange/translation adjustment 160,944 51,325 ( 111,686) Net reserves end of period 14,555,306 11,970,601 11,499,449 Plus reinsurance recoverables 1,843,691 1,640,712 1,619,641 Gross reserves end of period $ 16,398,997 $ 13,611,313 13,119,090 (Some amounts may not reconcile due to rounding.) Current year incurred losses were $ 6,149,410 thousand, $ 4,986,456 thousand and $ 5,264,327 thousand at December 31, 2020, 2019 and 2018, respectively. The increase in current year incurred losses from 2019 to 2020 was primarily due to an increase of $ 772,399 thousand in current year attritional losses primarily due to higher premiums earned, $ 511,056 thousand of losses related to COVID-19 in 2020, partially offset by a $ 120,500 thousand decline in current year catastrophe losses. The decrease in current year incurred losses in 2019 compared to 2018 was primarily due to $ 693,458 thousand of lower catastrophe losses in 2019 compared to 2018, partially offset by $ 415,585 thousand of additional attritional losses attributable to higher premiums earned in 2019 compared to 2018. Incurred prior years losses increased by $ 401,427 thousand in 2020, decreased by $ 63,558 thousand in 2019 and increased by $ 387,076 thousand in 2018. The increase for 2020 primarily related to higher ultimate loss estimates for long-tail casualty business in the reinsurance segment for accident years 2015 to 2018, notably general liability, professional lines, and auto liability. The reserve charge also includes actions on non-CAT property lines, primarily for the 2017 to 2019 accident years and driven by a few large losses to aggregate programs. The decrease for 2019 primarily related to reserve reductions associated short-tail lines of business and worker’s compensation. The increase for 2018 was mainly due to $ 561,197 thousand of adverse development on prior years catastrophe losses, primarily related to Hurricanes Harvey, Irma and Maria, as well as the 2017 California wildfires. The increase in loss estimates for Hurricanes Harvey, Irma and Maria was mostly driven by re-opened claims, loss inflation from higher than expected loss adjustment expenses and in particular, their impact on aggregate covers. This reserve increase was partially offset by $ 174,121 thousand of favorable development on prior years attritional losses which mainly related to U.S. and international property and casualty reinsurance business, as well as favorable development in the Insurance segment which largely related to workers’ compensation business. The following is information about incurred and paid claims development as of December 31, 2020, net of reinsurance, as well as cumulative claim frequency and the total of incurred but not reported liabilities (IBNR) plus expected development on reported claims included within the net incurred claims amounts. Each of the Company’s financial reporting segments has been disaggregated into casualty and property business. The casualty and property segregation results in groups that have homogeneous loss development characteristics and are large enough to represent credible trends. Generally, casualty claims take longer to be reported and settled, resulting in longer payout patterns and increased volatility. Property claims on the other hand, tend to be reported and settled quicker and therefore tend to exhibit less volatility. The property business is more exposed to catastrophe losses, which can result in year over year fluctuations in incurred claims depending on the frequency and severity of catastrophes claims in any one accident year. The information about incurred and paid claims development for the years ended December 31, 2012 to December 31, 2019 is presented as supplementary information. These tables present nine years of incurred and paid claims development as it is impracticable to retrospectively create the tables for ten years. For the reinsurance groups, for the years prior to 2012, the total of IBNR plus expected development on reported claims was not prepared on an accident year basis. The Company calculated these IBNR amounts in the aggregate for each business unit in total as of prior year end points in time. While business written in the United States would have been allocated to accident year for regulatory reporting purposes, business written outside of the United States would not have been similarly allocated. Attempting to allocate the non-U.S. business IBNR reserves to accident year currently for older year end valuations would require making assumptions and estimates which may not be in line with assumptions that would have been made at the time. A similar situation applies to insurance where the accumulation of the business lines reported in the regulatory filings are not consistent with the breakout of the tables presented below. As a result of not being able to present the information prior to 2012, prospectively an additional year will be added to the tables each reporting year until a ten year table is presented. The Cumulative Number of Reported Claims is shown only for Insurance Casualty as it is impracticable to provide the information for the remaining groups. The reinsurance groups each include pro rata contracts for which ceding companies provide only summary information via a bordereau. This summary information does not include the number of reported claims underlying the paid and reported losses. Therefore, it is not possible to provide this information. The Insurance Property group includes Accident & Health insurance business. This business is written via a master contract and individual claim counts are not provided. This business represents a significant enough portion of the business in the Insurance Property group so that including the number of reported claims for the remaining business would distort any analytics performed on the group. The Cumulative Number of Reported Claims shown for the Insurance Casualty is determined by claim and line of business. For example, a claim event with three claimants in the same line of business is a single claim. However, a claim event with a single claimant that spans two lines of business contributes two claims. The following tables present the ultimate loss and ALAE and the paid loss and ALAE, net of reinsurance for casualty and property, as well as the average annual percentage payout of incurred claims by age, net of reinsurance for each of our disclosed lines of business. Reinsurance – Casualty Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 917,560 $ 811,282 $ 712,407 $ 698,212 $ 682,333 $ 684,537 $ 689,068 $ 663,308 $ 641,893 43,700 N/A 2013 730,202 821,395 809,631 800,451 770,745 741,873 721,961 721,902 56,597 N/A 2014 780,730 820,870 828,341 805,087 763,611 740,786 753,967 72,825 N/A 2015 805,551 845,303 840,659 837,802 821,513 858,157 113,144 N/A 2016 818,293 895,558 892,576 887,698 963,300 195,650 N/A 2017 903,896 863,306 870,174 951,461 319,560 N/A 2018 1,356,788 1,354,279 1,431,276 639,205 N/A 2019 1,740,245 1,810,434 1,118,428 N/A 2020 1,963,469 1,497,536 N/A $ 10,095,859 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 42,576 99,763 182,550 278,492 358,953 429,165 509,020 543,688 555,736 2013 50,506 125,739 217,243 317,744 392,503 500,316 552,824 579,350 2014 58,833 124,433 216,441 307,587 434,450 511,143 557,209 2015 58,406 165,005 273,896 421,223 511,414 581,942 2016 94,154 196,746 333,163 441,325 558,379 2017 83,286 192,547 327,625 475,472 2018 159,215 299,369 465,181 2019 219,229 354,292 2020 194,704 $ 4,322,265 All outstanding liabilities prior to 2012, net of reinsurance 940,597 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 6,714,191 (Some amounts may not reconcile due to rounding.) Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Casualty 9.5 % 9.7 % 12.9 % 14.1 % 12.4 % 10.9 % 8.4 % 4.5 % 1.9 % Reinsurance – Property Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 1,625,024 1,311,752 1,188,304 1,187,096 1,181,200 1,174,224 1,162,252 1,181,653 1,184,476 7,419 N/A 2013 1,326,814 969,175 857,241 801,457 795,978 791,400 798,652 797,047 1,722 N/A 2014 1,388,249 1,230,656 1,080,269 987,401 987,230 988,193 980,449 3,325 N/A 2015 1,420,523 1,090,474 1,014,531 988,469 991,202 983,478 2,384 N/A 2016 1,730,936 1,557,262 1,593,116 1,587,145 1,564,702 20,676 N/A 2017 2,825,218 3,447,971 3,558,713 3,687,487 28,865 N/A 2018 2,684,311 2,559,953 2,561,852 121,379 N/A 2019 2,165,898 2,192,239 434,700 N/A 2020 2,487,352 1,341,994 N/A 16,439,082 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 417,397 723,394 896,372 1,016,689 1,051,968 1,086,813 1,098,004 1,120,273 1,126,302 2013 394,228 567,616 670,369 728,570 749,345 759,925 768,490 770,215 2014 388,263 678,897 812,441 889,561 921,183 931,451 937,437 2015 390,284 633,428 792,018 876,356 905,281 926,388 2016 480,453 986,043 1,269,622 1,394,284 1,447,824 2017 835,042 2,207,048 2,775,818 3,161,267 2018 576,573 1,579,781 1,969,117 2019 770,686 1,250,409 2020 616,160 12,205,119 All outstanding liabilities prior to 2012, net of reinsurance 105,209 Liabilities for claims and claim adjustment expenses, net of reinsurance 4,339,172 (Some amounts may not reconcile due to rounding.) Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Property 29.6 % 31.3 % 15.4 % 9.2 % 3.1 % 1.9 % 0.9 % 1.2 % 0.5 % Insurance – Casualty Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 349,724 351,529 347,068 348,262 353,395 344,008 346,983 351,444 353,945 11,283 15,780 2013 393,710 393,539 392,976 393,148 351,399 344,498 350,947 349,985 20,093 21,385 2014 431,323 457,296 454,827 460,888 397,334 398,153 399,048 38,361 25,221 2015 519,917 528,517 536,155 542,687 469,132 472,125 80,007 26,996 2016 554,253 552,192 581,273 617,051 554,621 138,312 31,673 2017 614,949 605,062 628,149 660,114 180,513 35,020 2018 708,808 715,008 754,053 275,213 34,884 2019 852,767 856,466 444,603 37,597 2020 990,982 649,288 26,068 5,391,340 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 33,194 101,301 157,924 213,488 246,455 272,114 294,444 306,937 311,865 2013 33,314 117,046 176,326 224,633 260,223 285,873 303,786 310,928 2014 41,194 124,937 201,689 256,886 297,762 326,011 339,487 2015 44,317 134,761 218,990 292,115 353,445 382,748 2016 54,740 164,384 269,163 343,020 402,693 2017 53,922 172,476 281,500 381,442 2018 63,614 208,531 319,858 2019 72,399 235,087 2020 63,878 2,747,987 All outstanding liabilities prior to 2012, net of reinsurance 224,752 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 2,868,104 (Some amounts may not reconcile due to rounding.) Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Casualty 8.5 % 19.6 % 17.0 % 14.6 % 10.8 % 6.9 % 4.9 % 2.8 % 1.4 % Insurance – Property Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 106,364 89,039 81,774 82,476 82,045 81,828 82,006 82,553 82,614 1 N/A 2013 112,083 98,206 91,336 92,224 92,313 92,473 92,328 91,895 29 N/A 2014 131,754 123,745 119,991 119,525 119,346 119,483 119,139 57 N/A 2015 173,062 153,031 144,084 146,934 144,923 146,630 286 N/A 2016 291,370 275,812 280,872 292,986 295,364 308 N/A 2017 498,359 502,935 496,583 499,724 6,358 N/A 2018 409,527 403,294 398,616 5,436 N/A 2019 349,177 352,038 14,100 N/A 2020 623,267 255,707 N/A 2,609,287 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 56,506 81,798 80,496 81,777 81,918 81,708 81,847 82,483 82,613 2013 68,712 93,181 91,921 92,191 91,800 91,840 91,857 91,866 2014 81,853 116,090 118,278 118,271 118,606 118,726 118,801 2015 102,241 141,396 142,563 145,371 146,870 146,958 2016 162,916 250,073 272,583 290,476 293,457 2017 179,432 425,607 460,412 483,178 2018 245,944 359,452 379,937 2019 227,639 317,960 2020 293,269 2,208,038 All outstanding liabilities prior to 2012, net of reinsurance 39 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 401,287 (Some amounts may not reconcile due to rounding.) Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Property 54.4 % 33.2 % 4.8 % 3.6 % 2.8 % - % 0.6 % 0.4 % 0.2 % Reconciliation of the Disclosure of Incurred and Paid Claims Development to the Liability for Unpaid Claims and Claim Adjustment Expenses The reconciliation of the net incurred and paid claims development tables to the liability for claims and claim adjustment expenses in the consolidated statement of financial position is as follows. December 31, 2020 (Dollars in thousands) Net outstanding liabilities Reinsurance Casualty $ 6,714,191 Reinsurance Property 4,339,172 Insurance Casualty 2,868,104 Insurance Property 401,287 Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance 14,322,754 Reinsurance recoverable on unpaid claims Reinsurance Casualty 399,865 Reinsurance Property 456,062 Insurance Casualty 818,701 Insurance Property 169,062 Total reinsurance recoverable on unpaid claims 1,843,691 Insurance lines other than short-duration - Unallocated claims adjustment expenses 194,111 Other 38,441 232,552 Total gross liability for unpaid claims and claim adjustment expense $ 16,398,997 (Some amounts may not reconcile due to rounding.) Reserving Methodology The Company maintains reserves equal to our estimated ultimate liability for losses and loss adjustment expense (LAE) for reported and unreported claims for our insurance and reinsurance businesses. Because reserves are based on estimates of ultimate losses and LAE by underwriting or accident year, the Company uses a variety of statistical and actuarial techniques to monitor reserve adequacy over time, evaluate new information as it becomes known, and adjust reserves whenever an adjustment appears warranted. The Company considers many factors when setting reserves including: (1) exposure base and projected ultimate premium; (2) expected loss ratios by product and class of business, which are developed collaboratively by underwriters and actuaries; (3) actuarial methodologies and assumptions which analyze loss reporting and payment experience, reports from ceding companies and historical trends, such as reserving patterns, loss payments, and product mix; (4) current legal interpretations of coverage and liability; and (5) economic conditions. Insurance and reinsurance loss and LAE reserves represent the Company’s best estimate of its ultimate liability. Actual loss and LAE ultimately paid may deviate, perhaps substantially, from such reserves. Net income (gain or loss) will be impacted in a period in which the change in estimated ultimate loss and LAE is recorded. The detailed data required to evaluate ultimate losses for the Company’s insurance business is accumulated from its underwriting and claim systems. Reserving for reinsurance requires evaluation of loss information received from ceding companies. Ceding companies report losses in many forms depending on the type of contract and the agreed or contractual reporting requirements. Generally, pro rata contracts require the submission of a monthly/quarterly account, which includes premium and loss activity for the period with corresponding reserves as established by the ceding company. This information is recorded into the Company’s records. For certain pro rata contracts, the Company may require a detailed loss report for claims that exceed a certain dollar threshold or relate to a particular type of loss. Excess of loss and facultative contracts generally require individual loss reporting with precautionary notices provided when a loss reaches a significant percentage of the attachment point of the contract or when certain causes of loss or types of injury occur. Experienced claims staff handles individual loss reports and supporting claim information. Based on evaluation of a claim, the Company may establish additional case reserves in addition to the case reserves reported by the ceding company. To ensure ceding companies are submitting required and accurate data, Everest’s Underwriting, Claim, Reinsurance Accounting, and Internal Audit Departments perform various reviews of ceding companies, particularly larger ceding companies, including on-site audits. The Company segments both reinsurance and insurance reserves into exposure groupings for actuarial analysis. The Company assigns business to exposure groupings so that the underlying exposures have reasonably homogeneous loss development characteristics and are large enough to facilitate credible estimation of ultimate losses. The Company periodically reviews its exposure groupings and may change groupings over time as business changes. The Company currently uses approximately 200 exposure groupings to develop reserve estimates. One of the key selection characteristics for the exposure groupings is the historical duration of the claims settlement process. Business in which claims are reported and settled relatively quickly are commonly referred to as short tail lines, principally property lines. On the other hand, casualty claims tend to take longer to be reported and settled and casualty lines are generally referred to as long tail lines. Estimates of ultimate losses for shorter tail lines, with the exception of loss estimates for large catastrophic events, generally exhibit less volatility than those for the longer tail lines. The Company uses a variety of actuarial methodologies, such as the expected loss ratio method, chain ladder methods, and Bornhuetter-Ferguson methods, supplemented by judgment where appropriate, to estimate ultimate loss and LAE for each exposure group. Expected Loss Ratio Method: The expected loss ratio method uses earned premium times an expected loss ratio to calculate ultimate losses for a given underwriting or accident year. This method relies entirely on expectation to project ultimate losses with no consideration given to actual losses. As such, it may be appropriate for an immature underwriting or accident year where few, if any, losses have been reported or paid, but less appropriate for a more mature year. Chain Ladder Method: Chain ladder methods use a standard loss development triangle to project ultimate losses. Age-to-age development factors are selected for each development period and combined to calculate age-to-ultimate development factors which are then applied to paid or reported losses to project ultimate losses. This method relies entirely on actual paid or reported losses to project ultimate losses. No other factors such as changes in pricing or other expectations are taken into account. It is most appropriate for groups with homogeneous, stable experience where past development patterns are expected to continue in the future. It is least appropriate for groups which have changed significantly over time or which are more volatile. Bornhuetter-Ferguson Method: The Bornhuetter-Ferguson method is a combination of the expected loss ratio method and the chain ladder method. Ultimate losses are projected based partly on actual paid or reported losses and partly on expectation. Incurred but not reported (IBNR) reserves are calculated using earned premium, an a priori loss ratio, and selected age-to-age development factors and added to actual reported (paid) losses to determine ultimate losses. It is more responsive to actual reported or paid development than the expected loss ratio method but less responsive than the chain ladder method. The reliability of the method depends on the accuracy of the selected a priori loss ratio. Although the Company uses similar actuarial methods for both short tail and long tail lines, the faster reporting of experience for the short tail lines allows the Company to have greater confidence in its estimates of ultimate losses for short tail lines at an earlier stage than for long tail lines. As a result, the Company utilizes, as well, exposure-based methods to estimate its ultimate losses for longer tail lines, especially for immature underwriting or accident years. For both short and long tail lines, the Company supplements these general approaches with analytically based judgments. Key actuarial assumptions contain no explicit provisions for reserve uncertainty nor does the Company supplement the actuarially determined reserves for uncertainty. Carried reserves at each reporting date are the Company’s best estimate of ultimate unpaid losses and LAE at that date. The Company completes detailed reserve studies for each exposure group annually for both reinsurance and insurance operations. The completed annual reserve studies are “rolled-forward” for each accounting period until the subsequent reserve study is completed. Analyzing the roll-forward process involves comparing actual reported losses to expected losses based on the most recent reserve study. The Company analyzes significant variances between actual and expected losses and post adjustments to its reserves as warranted. Certain reserves, including losses from widespread catastrophic events and COVID-19 related losses, cannot be estimated using traditional actuarial methods. These types of events are reserved for separately using a variety of statistical and actuarial techniques. We estimate losses for these types of events based on information derived from catastrophe models, quantitative and qualitative exposure analyses, reports and communications from ceding companies and development patterns for historically similar events, where available. The Company continues to receive claims under expired insurance and reinsurance contracts asserting injuries and/or damages relating to or resulting from environmental pollution and hazardous substances, including asbestos. Environmental claims typically assert liability for (a) the mitigation or remediation of environmental contamination or (b) bodily injury or property damage caused by the release of hazardous substances into the land, air or water. Asbestos claims typically assert liability for bodily injury from exposure to asbestos or for property damage resulting from asbestos or products containing asbestos. The Company’s reserves include an estimate of the Company’s ultimate liability for A&E claims. The Company’s A&E liabilities emanate from Mt. McKinley’s direct insurance business and Everest Re’s assumed reinsurance business. All of the contracts of insurance and reinsurance, under which the Company has received claims during the past three years, expired more than 20 years ago. There are significant uncertainties surrounding the Company’s reserves for its A&E losses. A&E exposures represent a separate exposure group for monitoring and evaluating reserve adequacy. The following table summarizes incurred losses with respect to A&E reserves on both a gross and net of reinsurance basis for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 2018 Gross basis: Beginning of period reserves $ 257,921 $ 347,495 $ 448,994 Incurred losses 1,540 2,070 ( 2,473) Paid losses ( 40,120) ( 91,644) ( 99,026) End of period reserves $ 219,341 $ 257,921 $ 347,495 Net basis: Beginning of period reserves $ 228,701 $ 261,456 $ 318,081 Incurred losses ( 772) - - Paid losses ( 29,674) ( 32,756) ( 56,624) End of period reserves $ 198,255 $ 228,701 $ 261,456 In 2015, the Company sold Mt. McKinley, a Delaware domiciled insurance company and wholly-owned subsidiary of the Company to Clearwater Insurance Company, a Delaware domiciled insurance company. Concurrently with the closing, the Company entered into a retrocession treaty with an affiliate of Clearwater Insurance Company. Per the retrocession treaty, the Company retroceded 100% of the liabilities associated with certain Mt. McKinley policies, which related entirely to A&E business and had been reinsured by Bermuda Re. As consideration for entering into the retrocession treaty, Everest Re Bermuda transferred cash of $ 140,279 thousand, an amount equal to the net loss reserves as of the closing date. The maximum liability retroceded under the retrocession treaty will be $ 440,279 thousand, equal to the retrocession payment plus $ 300,000 thousand. The Company will retain liability for any amounts exceeding the maximum liability retroceded under the retrocession treaty. On December 20, 2019, the retrocession treaty was amended and included a partial commutation. As a result of this amendment and partial commutation, gross A&E reserves and correspondingly reinsurance receivable were reduced by $ 43,362 thousand. In addition, the maximum liability permitted to be retroceded increased to $, 450298 thousand. Reinsurance Receivables. Reinsurance receivables for both paid and recoverable on unpaid losses totaled $ 1,994,555 thousand and $ 1,763,471 thousand at December 31, 2020 and December 31, 2019, respectively. At December 31, 2020, $ 699,734 thousand, or 35.1%, was receivable from Mt. Logan Re collateralized segregated accounts and $ 211,594 thousand, or 10.6% was receivable from Munich Reinsurance America, Inc. (“Munich Re”). No other retrocessionaire accounted for more than 5% of our receivables. Future Policy Benefit Reserve. Activity in the reserve for future policy benefits is summarized for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 2018 Balance at beginning of year $ 42,592 $ 46,778 $ 51,014 Liabilities assumed 35 53 110 Adjustments to reserves ( 1,113) 350 806 Benefits paid in the current year ( 3,791) ( 4,589) ( 5,151) Balance at end of year $ 37,723 $ 42,592 $ 46,778 (Some amounts may not reconcile due to rounding.)

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2020
Fair Value [Abstract]
Fair Value	4. 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 managing publicly traded securities 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. 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. At December 31, 2020, $ 1,330,224 thousand of fixed maturities, market value were fair valued using unobservable inputs. The majority of these fixed maturities were valued by investment managers’ valuation committees and many of these fair values were substantiated by valuations from independent third parties. The Company has procedures in place to evaluate these independent third party valuations. At December 31, 2019, $ 772,979 thousand of fixed maturities, market value and $ 5,826 thousand of fixed maturities, fair value were fair valued using unobservable inputs. The Company internally manages a public equity portfolio which had a fair value at December 31, 2020 and 2019, respectively, of $ 784,746 thousand and $ 170,888 thousand, respectively, and all prices were obtained from publicly published sources. 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. In addition to the valuations from investment managers, some of 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 may 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 Level 1 and Level 2 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 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, 2020 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,367,106 $ - $ 1,367,106 $ - Obligations of U.S. States and political subdivisions 577,295 - 577,295 - Corporate securities 7,149,026 - 6,447,534 701,492 Asset-backed securities 2,565,802 - 1,942,769 623,033 Mortgage-backed securities Commercial 990,303 - 990,303 - Agency residential 2,267,739 - 2,267,739 - Non-agency residential 5,194 - 5,194 - Foreign government securities 1,645,375 - 1,645,375 - Foreign corporate securities 3,472,333 - 3,466,634 5,699 Total fixed maturities, market value 20,040,173 - 18,709,949 1,330,224 Equity securities, fair value 1,472,236 1,368,704 103,532 - There were no transfers between Level 1 and Level 2 for the twelve months ended December 31, 2020. 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, 2019 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,515,803 $ - $ 1,515,803 $ - Obligations of U.S. States and political subdivisions 536,915 - 536,915 - Corporate securities 6,374,946 - 5,757,358 617,588 Asset-backed securities 897,333 - 743,692 153,641 Mortgage-backed securities Commercial 844,557 - 844,557 - Agency residential 2,198,581 - 2,198,581 - Non-agency residential 5,703 - 5,703 - Foreign government securities 1,505,950 - 1,505,950 - Foreign corporate securities 2,945,156 - 2,943,406 1,750 Total fixed maturities, market value 16,824,944 - 16,051,965 772,979 Fixed maturities, fair value 5,826 - - 5,826 Equity securities, fair value 931,457 864,584 66,873 - In addition, $ 224,698 thousand and $ 209,578 thousand of investments within other invested assets on the consolidated balance sheets as of December 31, 2020 and 2019, respectively, are not included within the fair value hierarchy tables as the assets are measured at NAV as a practical expedient to determine fair value. 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 December 31, 2020 December 31, 2019 Corporate Asset-Backed Foreign Corporate Asset-Backed Foreign (Dollars in thousands) Securities Securities Corporate Total Securities Securities Corporate Total Beginning balance fixed maturities at market value $ 617,588 $ 153,641 $ 1,750 $ 772,979 $ 428,215 $ - $ 7,744 $ 435,959 Total gains or (losses) (realized/unrealized) Included in earnings 1,216 681 ( 125) 1,772 4,937 - ( 12) 4,925 Included in other comprehensive income (loss) ( 1,115) 11,678 147 10,710 ( 20) 3,632 ( 110) 3,502 Purchases, issuances and settlements 84,840 457,033 3,814 545,687 179,761 150,009 ( 5,872) 323,898 Transfers in and/or (out) of Level 3 ( 1,037) - 113 ( 924) 4,695 - - 4,695 Ending balance $ 701,492 $ 623,033 $ 5,699 $ 1,330,224 $ 617,588 $ 153,641 $ 1,750 $ 772,979 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 $ ( 539) $ - $ - $ ( 539) $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.) Total Fixed Maturities, Fair Value December 31, 2020 December 31, 2019 Foreign Foreign (Dollars in thousands) Corporate Total Corporate Total Beginning balance fixed maturities at market value $ 5,826 $ 5,826 $ 2,337 $ 2,337 Total gains or (losses) (realized/unrealized) Included in earnings ( 919) ( 919) 2,163 2,163 Included in other comprehensive income (loss) - - - - Purchases, issuances and settlements ( 4,907) ( 4,907) 1,326 1,326 Transfers in and/or (out) of Level 3 - - - - Ending balance $ - $ - $ 5,826 $ 5,826 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 $ - $ - $ 1,795 $ 1,795 (Some amounts may not reconcile due to rounding.) The net transfers to/(from) Level 3, fair value measurements using significant unobservable inputs for fixed maturities, market value were $( 924) thousand and $ 4,695 thousand as of December 31, 2020 and 2019, respectively. The transfers during 2020 were previously priced by investment managers and were subsequently priced using a recognized pricing service as of December 31, 2020. The transfers during 2019 were related to securities that were previously priced using a recognized pricing service and were subsequently priced by investment managers as of December 31, 2019. Years Ended December 31, (Dollars in thousands) 2020 2019 Common Stock Balance, beginning of period $ - $ - Total (gains) or losses (realized/unrealized) Included in earnings - - Included in other comprehensive income (loss) - - Purchases, issuances and settlements 9,877 - Transfers in and/or (out) of Level 3 ( 9,877) - Balance, end of period $ - $ - 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.) The net transfers to/(from) Level 3, fair value measurements using significant unobservable inputs for equity securities, fair value were ($ 9,877) thousand for 2020. The transfer of ($ 9,877) thousand was related to preferred stock in a private entity purchased during the second quarter of 2020 which was priced at cost originally and was subsequently priced based upon the book value of the underlying private entity as of December 31, 2020.

Credit Facilities

Credit Facilities	12 Months Ended
	Dec. 31, 2020
Credit Facilities [Abstract]
Credit Facilities	5. CREDIT FACILITIES The Company has two active credit facilities for a total commitment of up to $ 1,000,000 thousand and an additional credit facility for a total commitment of up to £ 52,175 thousand, providing for the issuance of letters of credit and/or unsecured revolving credit lines. The following table presents the interest and fees incurred in connection with the two credit facilities for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Credit facility interest and fees incurred - Wells Fargo Bank $ 664 $ 420 $ 420 Loan interest and fees incurred - Federal Home Loan Bank 151 - - Total interest and fees incurred $ 815 $ 420 $ 420 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 thousand senior credit facility with a syndicate of lenders, which amended and restated in its entirety the June 22, 2012, four year, $ 800,000 thousand senior credit facility. Both the May 26, 2016 and June 22, 2012 senior credit facilities, which have similar terms, are referred to as the “Group Credit Facility”. Wells Fargo Corporation (“Wells Fargo Bank”) is the administrative agent for the Group Credit Facility, which consists of two tranches. Tranche one provides up to $ 200,000 thousand of unsecured revolving credit for liquidity and general corporate purposes, and for the issuance of unsecured standby letters of credit. The interest on the revolving loans shall, at the Company’s option, be either (1) the Base Rate (as defined below) or (2) an adjusted London Interbank Offered Rate (“LIBOR”) plus a margin. The Base Rate is the higher of (a) the prime commercial lending rate established by Wells Fargo Bank, (b) the Federal Funds Rate plus 0.5% per annum or (c) the one month LIBOR Rate plus 1.0% per annum. The amount of margin and the fees payable for the Group Credit Facility depends on Group’s senior unsecured debt rating. Tranche two exclusively provides up to $ 600,000 thousand for the issuance of standby letters of credit on a collateralized basis. The Group Credit Facility requires Group to maintain a debt to capital ratio of not greater than 0.35 to 1 and to maintain a minimum net worth. Minimum net worth is an amount equal to the sum of $ 5,370,979 thousand plus 25% of consolidated net income for each of Group’s fiscal quarters, for which statements are available ending on or after March 31, 2016 and for which consolidated net income is positive, plus 25% of any increase in consolidated net worth during such period attributable to the issuance of ordinary and preferred shares, which at December 31, 2020, was $ 6,391,043 thousand. As of December 31, 2020, the Company was in compliance with all Group Credit Facility covenants. On March 25, 2020, Group borrowed $ 50,000 thousand under Tranche one of the credit facility as an unsecured revolving credit loan. The loan was fully paid off on June 26, 2020. There were no revolving credit borrowings from the facility during the year ended 2019. The following table summarizes the outstanding letters of credit for the periods indicated: (Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Wells Fargo Bank Group Credit Facility Tranche One $ 200,000 $ 164,242 12/31/2021 $ 200,000 $ 33,737 12/31/2020 Tranche Two 600,000 589,690 12/31/2021 600,000 2,381 07/29/2020 Tranche Two - 1,649 09/30/2020 Tranche Two - 573,353 12/31/2020 Tranche Two - 12,364 01/04/2021 Total Wells Fargo Bank Group Credit Facility $ 800,000 $ 753,932 $ 800,000 $ 623,484 Bermuda Re Letter of Credit Facility Effective December 31, 2020, 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 $ 200,000 thousand of secured letters of credit to collateralize reinsurance obligations as a non-admitted reinsurer. The interest on drawn letters of credit shall be (A) 0.35% per annum of the principal amount of issued standard letters of credit (expiry of 15 months or less) and (B) 0.45% per annum of the principal amount of issued extended tenor letters of credit (expiry maximum of up to 60 months). The commitment fee on undrawn credit shall be 0.15% per annum. The following table summarizes the outstanding letters of credit for the periods indicated: (Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Citibank Bilateral Letter of Credit Agreement $ 200,000 $ 4,425 02/28/2021 $ 200,000 $ 4,425 02/29/2020 3,672 11/24/2021 512 09/03/2020 448 12/16/2021 3,672 11/24/2020 115 12/20/2021 177 12/16/2020 136,383 12/31/2021 125 12/20/2020 39,619 12/30/2024 101,404 12/31/2020 821 08/15/2022 559 08/15/2021 - 37,096 12/30/2023 Total Citibank Bilateral Agreement $ 200,000 $ 185,483 $ 200,000 $ 147,970 Everest International Credit Facility Effective May 12, 2020, Everest International amended its credit facility with Lloyds Bank plc (“Everest International Credit Facility”). The current amendment of the Everest International Credit Facility provides up to £ 52,175 thousand for the issuance of standby letters of credit on a collateralized basis. The Company pays a commitment fee of 0.1% per annum on the average daily amount of the remainder of (1) the aggregate amount available under the facility and (2) the aggregate amount of drawings outstanding under the facility. The Company pays a credit commission fee of 0.35% per annum on drawings outstanding under the facility. The Everest International Credit Facility requires Group to maintain a debt to capital ratio of not greater than 0.35 to 1 and to maintain a minimum net worth. Minimum net worth is an amount equal to the sum of $ 6,393,047 thousand ( 70% of consolidated net worth as of December 31, 2019), plus 25% of consolidated net income for each of Group’s fiscal quarters, for which statements are available ending on or after January 1, 2020 and for which net income is positive, plus 25% of any increase in consolidated net worth of Group during such period attributable to the issuance of ordinary and preferred shares, which at December 31, 2020, was $ 6,527,996 thousand. As of December 31, 2020, the Company was in compliance with all Everest International Credit Facility requirements. The following table summarizes the outstanding letters of credit for the periods indicated: (Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Lloyd's Bank plc £ 52,175 £ 52,175 12/31/2024 £ 47,000 £ 47,000 12/31/2023 - - - - Total Lloyd's Bank Credit Facility £ 52,175 £ 52,175 £ 47,000 £ 47,000 Federal Home Loan Bank Membership Effective August 15, 2019, Everest Reinsurance Company (“Everest Re”) became a member of the Federal Home Loan Bank of New York (“FHLBNY”), which allows Everest Re to borrow up to 10% of its statutory admitted assets. As of December 31, 2020, Everest Re had admitted assets of approximately $ 16,840,721 thousand which provides borrowing capacity of up to approximately $ 1,684,072 thousand. During 2020, Everest Re borrowed $ 400,000 thousand under its FHLBNY capacity. The borrowings have interest payable at an interest rate of 0.35%. As of December 31, 2020, $ 310,000 of these borrowings remain outstanding, with maturities in November December 2021 4.5% of borrowed funds be used to acquire additional membership stock.

Senior Notes

Senior Notes	12 Months Ended
	Dec. 31, 2020
Senior Notes [Abstract]
Senior Notes	6. 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. December 31, 2020 December 31, 2019 Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Date Due Principal Amounts Sheet Amount Market Value Sheet Amount Market Value 4.868 0% Senior notes 6/5/2014 6/1/2044 400,000 $ 397,194 $ 528,000 $ 397,074 $ 452,848 3.5% Senior notes 10/7/2020 10/15/2050 1,000,000 979,524 1,138,100 - - On June 5, 2014, Holdings issued $ 400,000 thousand of 30 year senior notes with an interest coupon rate of 4.868%, which will mature on June 1, 2044. Interest will be paid semi-annually on June 1 and December 1 of each year. On October 7, 2020, Holdings issued $ 1,000,000 thousand of 30 year senior notes with an interest coupon rate of 3.50%, which will mature on October 15, 2050. Interest will be paid semi-annually on April 15 and October 15 of each year. Interest expense incurred in connection with these senior notes is as follows for the periods indicated: Years Ended December 31, (Dollars In thousands 2020 2019 2018 Interest expense incurred 4.868% senior notes $ 19,472 $ 19,472 $ 19,472 Interest expense incurred 3.5% senior notes 8,115 - -

Long Term Subordinated Notes

Long Term Subordinated Notes	12 Months Ended
	Dec. 31, 2020
Long Term Subordinated Notes [Abstract]
Long Term Subordinated Notes	7. 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 December 31, 2020 December 31, 2019 Original Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Principal Amount Scheduled Final Sheet Amount Market Value Sheet Amount Market Value Long term subordinated notes 4/26/2007 $ 400,000 5/15/2037 5/1/2067 $ 223,674 $ 206,447 $ 236,758 $ 233,191 During the fixed rate interest period from May 3, 2007 through May 14, 2017, interest was at the annual rate of 6.6%, payable semi-annually in arrears on November 15 and May 15 of each year, commencing on November 15, 2007. During the floating rate interest period from May 15, 2017 through maturity, interest will be based on the 3 month LIBOR plus 238.5 basis points, reset quarterly, payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year, subject to Holdings’ right to defer interest on one or more occasions for up to ten 2.6%. Holdings may redeem the long term subordinated notes on or after May 15, 2017, in whole or in part at 100% of the principal amount plus accrued and unpaid interest; however, redemption on or after the scheduled maturity date and prior to May 1, 2047 is subject to a replacement capital covenant. This covenant is for the benefit of certain senior note holders and it mandates that Holdings receive proceeds from the sale of another subordinated debt issue, of at least similar size, before it may redeem the subordinated notes. Effective upon the maturity of the Company’s 5.40% senior notes on October 15, 2014, the Company’s 4.868% senior notes, due on June 1, 2044, have become the Company’s long term indebtedness that ranks senior to the long term subordinated notes. The Company repurchased and retired $ 13,183 thousand of its outstanding long term subordinated notes for the year ended December 31, 2020. The Company realized a gain of $ 2,536 thousand from the repurchase of the long term subordinated notes for the year ended 2020. 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 thousand. Interest expense incurred in connection with these long term subordinated notes is as follows for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Interest expense incurred $ 7,645 $ 11,587 $ 10,926

Collateralized Reinsurance And

Collateralized Reinsurance And Trust Agreements	12 Months Ended
	Dec. 31, 2020
Collateralized Reinsurance And Trust Agreements [Abstract]
Collateralized Reinsurance And Trust Agreements	8. 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 December 31, 2020, the total amount on deposit in trust accounts was $ 1,234,720 thousand. 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% of the voting common shares are owned by Group. Separate segregated accounts for Mt. Logan Re began being established effective July 1, 2013 and non-voting, redeemable preferred shares have been issued to capitalize the segregated accounts. Each segregated account invests predominantly in a diversified set of catastrophe exposures, diversified by risk/peril and across different geographic regions globally. 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. Years Ended December 31, Mt. Logan Re Segregated Accounts 2020 2019 2018 (Dollars in thousands) Ceded written premiums 303,178 291,979 260,612 Ceded earned premiums 306,184 294,762 262,518 Ceded losses and LAE 241,347 187,192 319,046 Assumed written premiums 18,831 17,005 11,032 Assumed earned premiums 18,831 17,005 11,032 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 $ 806,564 thousand and $ 993,036 thousand at December 31, 2020 and 2019, respectively. Of this amount, Group had investments recorded at $ 67,645 thousand and $ 46,390 thousand at December 31, 2020 and 2019, respectively, in the segregated accounts. Effective April 1, 2018, the Company entered into a retroactive reinsurance transaction with one of the Mt. Logan Re segregated accounts to retrocede $ 269,198 thousand of casualty reserves held by Bermuda Re related to accident years 2002 through 2015. As consideration for entering the agreement, the Company transferred cash of $ 252,000 thousand to the Mt. Logan Re segregated account. The maximum liability to be retroceded under the agreement will be $ 319,000 thousand. The Company will retain liability for any amounts exceeding the maximum liability. On April 24, 2014, the Company entered into two collateralized reinsurance agreements with Kilimanjaro Re Limited (“Kilimanjaro”), a Bermuda based special purpose reinsurer, to provide the Company with catastrophe reinsurance coverage. These agreements are multi-year reinsurance contracts which cover specified named storm and earthquake events. The first agreement provides up to $ 250,000 thousand of reinsurance coverage from named storms in specified states of the Southeastern United States. The second agreement provides up to $ 200,000 thousand of reinsurance coverage from named storms in specified states of the Southeast, Mid-Atlantic and Northeast regions of the United States and Puerto Rico as well as reinsurance coverage from earthquakes in specified states of the Southeast, Mid-Atlantic, Northeast and West regions of the United States, Puerto Rico and British Columbia. These reinsurance agreements expired in April, 2018 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 thousand of reinsurance coverage from earthquakes in the United States, Puerto Rico and Canada. These reinsurance agreements expired in November, 2019 On December 1, 2015 the Company entered into two collateralized reinsurance agreements with Kilimanjaro to provide the Company with catastrophe reinsurance coverage. These agreements are multi-year reinsurance contracts which cover named storm and earthquake events. The first agreement provides up to $ 300,000 thousand of reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico and Canada. The second agreement provides up to $ 325,000 thousand of reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico and Canada. On April 13, 2017 the Company entered into six collateralized reinsurance agreements with Kilimanjaro to provide the Company with annual aggregate catastrophe reinsurance coverage. The initial three agreements are four year reinsurance contracts which cover named storm and earthquake events. These agreements provide up to $ 225,000 thousand, $ 400,000 thousand and $ 325,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico and Canada. The subsequent three agreements are five year reinsurance contracts which cover named storm and earthquake events. These agreements provide up to $ 50,000 thousand, $ 75,000 thousand and $ 175,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico and Canada. On April 30, 2018 the Company entered into four collateralized reinsurance agreements with Kilimanjaro to provide the Company with catastrophe reinsurance coverage. These agreements are multi-year reinsurance contracts which cover named storm and earthquake events. The first two agreements are four year reinsurance contracts which provide up to $ 62,500 thousand and $ 200,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico, the U.S. Virgin Islands and Canada. The remaining two agreements are five year reinsurance contracts which provide up to $ 62,500 thousand and $ 200,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico, the U.S. Virgin Islands and Canada. On December 12, 2019, the Company entered into four collateralized reinsurance agreements with Kilimanjaro to provide the Company with catastrophe reinsurance coverage. These agreements are multi-year reinsurance contracts which cover named storm and earthquake events. The first two agreements are four year reinsurance contracts which provide up to $ 150,000 thousand and $ 275,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United States, Puerto Rico, the U.S. Virgin Islands and Canada. The remaining two agreements are five year reinsurance contracts which provide up to $ 150,000 thousand and $ 275,000 thousand, respectively, of annual aggregate reinsurance coverage from named storms and earthquakes in the United State, Puerto Rico, the U.S. Virgin Islands and Canada. 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. Currently, none of the published insured loss estimates for catastrophe events during the applicable covered periods of the various agreements have exceeded the single event retentions or aggregate retentions under the terms of the agreements that would result 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 thousand of notes (“Series 2014-1 Notes”). The $ 450,000 thousand of Series 2014-1 Notes were fully redeemed on April 30, 2018 and are no longer outstanding. On November 18, 2014, Kilimanjaro issued $ 500,000 thousand of notes (“Series 2014-2 Notes”). The $ 500,000 thousand of Series 2014-2 Notes were fully redeemed in November 2019 and are no longer outstanding. On December 1, 2015, Kilimanjaro issued $ 625,000 thousand of notes (“Series 2015-1 Notes”). On April 13, 2017, Kilimanjaro issued $ 950,000 thousand of notes (“Series 2017-1 Notes”) and $ 300,000 thousand of notes (“Series 2017-2 Notes”). On April 30, 2018, Kilimanjaro issued $ 262,500 thousand of notes (“Series 2018-1 Notes”) and $ 262,500 thousand of notes (“Series 2018-2 Notes”). On December 12, 2019, Kilimanjaro issued $ 425,000 thousand of notes (“Series 2019-1 Notes”) and $ 425,000 thousand of notes (“Series 2019-2 Notes”).The proceeds from the issuance of the Notes listed above are held in reinsurance trust throughout the duration of the applicable reinsurance agreements and invested solely in US government money market funds with a rating of at least “AAAm” by Standard & Poor’s.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	9. LEASES Effective January 1, 2019, the Company adopted ASU 2016-02 and ASU 2018-11 which outline new guidance on the accounting for leases. The Company enters into lease agreements for real estate that is primarily used for office space in the ordinary course of business. These leases are accounted for as operating leases, whereby lease expense is recognized on a straight-line basis over the term of the lease. Most leases include an option to extend or renew the lease term. The exercise of the renewal is at the Company’s discretion. The operating lease liability includes lease payments related to options to extend or renew the lease term if the Company is reasonably certain of exercise those options. The Company, in determining the present value of lease payments utilizes either the rate implicit in the lease if that rate is readily determinable or the Company’s incremental secured borrowing rate commensurate with terms of the underlying lease. Supplemental information related to operating leases is as follows for the periods indicated: Year Ended December 31, (Dollars in thousands) 2020 2019 Lease expense incurred: Operating lease cost $ 32,508 $ 24,524 At December 31, (Dollars in thousands) 2020 2019 Operating lease right of use assets $ 149,125 $ 161,435 Operating lease liabilities 165,292 169,909 Year Ended December 31, (Dollars in thousands) 2020 2019 Operating cash flows from operating leases $ ( 20,594) $ ( 20,041) At December 31, 2020 2019 Weighted average remaining operating lease term 12.3 years 12.6 years Weighted average discount rate on operating leases 4.10 % 3.91 % Maturities of the existing lease liabilities are expected to occur as follows: (Dollars in thousands) 2021 $ 18,536 2022 20,971 2023 20,198 2024 19,947 2025 16,956 Thereafter 124,258 Undiscounted lease payments 220,866 Less: present value adjustment 55,574 Total operating lease liability $ 165,292 On July 2, 2019, the Company entered into a lease agreement to relocate its U.S. corporate offices from Liberty Corner, New Jersey to Warren, New Jersey. The new lease, which covers approximately 315,000 square feet of office space, became effective in October, 2019 and runs through 2036 . The initial base rent payment of the lease will be approximately $ 650 thousand per month or $ 7,800 thousand per year. The Company relocated the existing operations and employees of the Liberty Corner, New Jersey facility to the new corporate complex as of December, 2020.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Taxes [Abstract]
Income Taxes	10. INCOME TAXES Under Bermuda law, no income or capital gains taxes are imposed on Group and its Bermuda Subsidiaries. The Minister of Finance of Bermuda has assured Group and its Bermuda subsidiaries that, pursuant to The Exempted Undertakings Tax Protection Amendment Act of 2011, they will be exempt until 2035 from imposition of any such taxes. All of the income of Group's non-Bermuda subsidiaries is subject to the applicable federal, foreign, state and local taxes on corporations. Additionally, the income of the foreign branches of the Company's insurance operating companies, in particular the UK branch of Bermuda Re, is subject to various rates of income tax. Group's U.S. subsidiaries conduct business in and are subject to taxation in the U.S. Should the U.S. subsidiaries distribute current or accumulated earnings and profits in the form of dividends or otherwise, the Company would be subject to an accrual of 5% U.S. withholding tax. Currently, however, no withholding tax has been accrued with respect to such un-remitted earnings as management has no intention of remitting them. The cumulative amount that would be subject to withholding tax, if distributed, is not practicable to compute. The provision for income taxes in the consolidated statement of operations and comprehensive income (loss) has been determined in accordance with the individual income of each entity and the respective applicable tax laws. The provision reflects the permanent differences between financial and taxable income relevant to each entity. The Coronavirus Aid, Relief, and Economic Security (“CARES”) Act, enacted on March 27, 2020, provided that U.S. companies could carryback for five years net operating losses incurred in 2018, 2019 and/or 2020. This beneficial tax provision in the CARES Act enabled the Company to carryback its significant 2018 net operating losses to prior tax years with higher effective tax rates of 35% versus 21% in 2018 and later years. As a result, the Company was able to record a net income tax benefit from the five-year carryback of $ 32.5 million and obtain federal income tax cash refunds of $ 182.5 million including interest in 2020. The significant components of the provision are as follows for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Current tax expense (benefit): U.S. $ ( 107,757) $ ( 5,044) $ ( 38,625) Non-U.S. 2,948 14,420 6,497 Total current tax expense (benefit) ( 104,809) 9,376 ( 32,128) Deferred tax expense (benefit): U.S. 178,523 80,247 ( 298,998) Non-U.S. ( 2,516) ( 97) ( 97) Total deferred tax expense (benefit) 176,007 80,150 ( 299,095) Total income tax expense (benefit) $ 71,198 $ 89,526 $ ( 331,223) (Some amounts may not reconcile due to rounding.) The weighted average expected tax provision has been calculated using the pre-tax income (loss) in each jurisdiction multiplied by that jurisdiction's applicable statutory tax rate. Reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate for the periods indicated is provided below: Years Ended December 31, 2020 2019 2018 (Dollars in thousands) U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Underwriting gain (loss) $ 24,041 $ ( 277,852) $ 38,964 $ 297,199 $ ( 1,407,020) $ 796,745 Net investment income 339,721 302,744 325,179 321,960 283,569 297,614 Net realized capital gains (losses) 234,970 32,679 155,609 29,394 ( 90,033) ( 37,103) Net derivative gain (loss) - 1,541 - 6,374 - 520 Corporate expenses ( 15,985) ( 25,133) ( 13,063) ( 19,903) ( 11,035) ( 19,637) Interest, fee and bond issue cost amortization expense ( 35,659) ( 664) ( 34,931) 3,239 ( 30,611) ( 420) Other income (expense) ( 14,656) 19,602 ( 1,976) ( 9,057) ( 5,894) ( 18,877) Pre-tax income (loss) $ 532,432 $ 52,917 $ 469,782 $ 629,206 $ ( 1,261,024) $ 1,018,842 Expected tax provision at the applicable statutory rate(s) 111,846 ( 10,356) 98,766 17,205 ( 264,912) 9,647 Increase (decrease) in taxes resulting from: Tax exempt income ( 3,598) - ( 3,680) - ( 3,824) - Dividend received deduction ( 1,100) - ( 998) - ( 1,520) - Proration 1,049 - 1,050 - 1,150 - Affiliated preferred stock dividends 6,517 - 6,517 - 6,517 - Creditable foreign premium tax ( 11,513) - ( 9,852) - ( 13,475) - Tax audit settlement - - ( 1,576) - ( 2,094) - U.S. rate differential on carryback of net operation losses to PY - - - - ( 43,734) - U.S. rate differential on deferred tax 2017 return to provision - - - - ( 28,411) - Share based compensation tax benefits formerly in APIC ( 2,605) ( 388) ( 2,984) ( 373) ( 3,333) ( 120) Impact of CARES Act ( 32,500) - - - - - Valuation allowance 277 15,144 138 3,772 73 2,257 Change in uncertain tax positions - - ( 8,434) - 8,434 - Other 2,393 ( 3,968) ( 3,744) ( 6,281) 7,506 ( 5,384) Total income tax provision $ 70,766 $ 432 $ 75,203 $ 14,323 $ ( 337,623) $ 6,400 (Some amounts may not reconcile due to rounding.) Reconciliation of the beginning and ending unrecognized tax benefits, for the periods indicated, is as follows: (Dollars in thousands) 2020 2019 2018 Balance at January 1 $ - $ 8,434 $ - Additions based on tax positions related to the current year - - 8,434 Additions for tax positions of prior years - - - Reductions for tax positions of prior years - ( 8,434) - Settlements with taxing authorities - - - Lapses of applicable statutes of limitations - - - Balance at December 31 $ - $ - $ 8,434 At December 31, 2020, the Company’s unrecognized tax benefits, excluding interest and penalties, that would impact the effective tax rate was $ 0 Interest and penalties related to unrecognized tax benefits are recognized in income tax expense. At December 31, 2020, the Company accrued $ 0 thousand for the payment of interest (net of the federal benefit) and penalties. At December 31, 2019 and 2018, there were no accrued liabilities, respectively, for the payment of interest and penalties. The Company’s 2014 and subsequent U.S. tax years are open to audit by the IRS. In 2018, the IRS opened an audit of the 2014 tax year. To date, the Company has received only one notice of proposed adjustment for an immaterial amount of tax. The Company proposed affirmative beneficial income tax return adjustments to the IRS at the start of the audit. Subsequent to the Company’s CARES Act net operating loss carryback, the Company expects a tax refund of $ 16,287 thousand of recaptured foreign tax credits related to the affirmative adjustments. In 2019, the IRS opened an audit of the 2015 through 2017 tax years. To date, the Company has not received any Information Document Requests (“IDRs”) or notices of proposed adjustment. The Company had filed amended tax returns requesting refunds for 2015 and 2016 for $ 1,519 thousand and $ 4,685 thousand, respectively. During 2020, the IRS added 2018 to the audit and indicated that, subsequent to the CARES Act, it would audit tax years 2014 – 2018 all together and conclude its audits simultaneously. To date, the Company has not received any IDRs or notices of proposed adjustment for the 2018 tax year. Deferred Income taxes reflect the tax effect of the temporary differences between the value of assets and liabilities for financial statement purposes and such values are measured by the U.S. tax laws and regulations. The principal items making up the net deferred income tax assets/(liabilities) are as follows for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 Deferred tax assets: Loss reserves $ 96,840 $ 66,025 Unearned premium reserves 85,028 75,130 Foreign tax credits 46,109 186,706 Net operating loss carryforward 33,504 31,698 Lease liability 31,989 33,042 Net unrealized losses on benefit plans 19,636 19,818 Equity compensation 7,367 7,817 Other tax credits 4,591 2,294 Uncollectible reinsurance reserves 3,142 3,142 Investment impairments 1,121 3,961 Unrealized foreign currency losses 603 7,964 Other assets 7,285 4,520 Total deferred tax assets 337,215 442,117 Deferred tax liabilities: Net unrealized investment gains 90,268 39,413 Deferred acquisition costs 79,994 81,931 Net fair value income 75,692 25,936 Right of use asset 28,822 31,510 Partnership investments 26,119 15,039 Benefit plan asset 1,765 2,333 Other liabilities 6,710 4,937 Total deferred tax liabilities 309,370 201,099 Net deferred tax assets 27,845 241,018 Less: Valuation allowance ( 28,805) ( 12,997) Total net deferred tax assets/(liabilities) $ ( 960) $ 228,021 (Some amounts may not reconcile due to rounding.) At December 31, 2020 and 2019, the Company had $ 28,805 thousand and $ 12,997 thousand of Valuation Allowance (“VA”), respectively. The majority of the VA relates to the Company’s UK operations and were due primarily to net operating losses incurred in 2020 as a result of COVID 19. The VA is a result of our conclusion under US GAAP accounting principles, that the UK, Swiss, Irish, Canadian and U.S. jurisdictions could not demonstrate that it was more likely than not that the related deferred tax assets will be realized. This was primarily due to factors such as cumulative losses in recent years and the inability to demonstrate profits within the specific jurisdictions related to recent changes in market conditions. Tax effected UK NOLs of $ 26,428 thousand do not expire. Tax effected Swiss NOLs of $ 2,317 thousand expire in 2028 2,300 thousand do not expire. Tax effected Canadian NOLs of $ 1,774 thousand begin to expire in 2035 684 thousand begin to expire in 2037 Due to the passage of the CARES Act in 2020, which allowed for a five-year carryback of NOLs, as of December 31, 2020 the Company no longer has a Consolidated U.S. NOL carryforward Without the Consolidated U.S. NOL carryforward, the Company was able to utilize a significant amount of U.S. Foreign Tax Credits (“FTCs”) in both 2019 and 2020. As a result, its FTC carryforwards were significantly reduced at December 31, 2020 to only $ 46,109 thousand. The remaining FTC carryforwards expire between 2025 and 2030. During 2018, the Company completed its accounting for the TCJA in accordance with SEC Staff Accounting Bulletin 118, including interpretation of the additional guidance issued by the IRS and U.S. Department of the Treasury, and recognized an income tax benefit of $ 28,411 thousand primarily related to the 2017 tax return to tax provision true-up recorded in 2018. Effective January 1, 2017, the Company adopted ASU 2016-09 which provided new guidance on the treatment of the tax effects of share-based compensation transactions. ASU 2016-09 required that the income tax effects of restricted stock vestings and stock option exercises resulting from the change in value of share based compensation awards between the grant date and settlement (vesting/exercise) date be recorded as part of income tax expense (benefit) within the consolidated statements of operations and comprehensive income (loss). Per the new guidance, the Company recorded excess tax benefits of $ 2,993 thousand, $ 3,357 thousand and $ 3,453 thousand related to restricted stock vestings and stock option exercises as part of income tax expense (benefit) within the consolidated statements of operations and comprehensive income (loss) in 2020, 2019 and 2018, respectively. In years prior to 2017, the Company recorded tax benefits related to restricted stock vestings and stock option exercises as part of additional paid-in capital in the shareholders' equity section of the consolidated balance sheets. The adoption of ASU 2016-09 did not impact the accounting treatment of tax benefits related to dividends on restricted stock. The tax benefits related to the payment of dividends on restricted stock have been recorded as part of additional paid-in capital in the shareholders' equity section of the consolidated balance sheets in all years. The tax benefits related to the payment of dividends on restricted stock were $ 583 thousand, $ 484 thousand and $ 403 thousand in 2020, 2019 and 2018, respectively. For the year ended December 31, 2020, we consider our earnings within each jurisdiction to be indefinitely reinvested. Should the subsidiaries distribute current or accumulated earnings and profits in the form of dividends or otherwise, the Company would be subject to withholding taxes. The cumulative amount that would be subject to withholding tax, if distributed, is not practicable to compute.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2020
Reinsurance [Abstract]
Reinsurance	11. REINSURANCE The Company utilizes reinsurance agreements to reduce its exposure to large claims and catastrophic loss occurrences. These agreements provide for recovery from reinsurers of a portion of losses and LAE under certain circumstances without relieving the Company of its underlying obligations to the policyholders. Losses and LAE incurred and premiums earned are reported after deduction for reinsurance. In the event that one or more of the reinsurers were unable to meet their obligations under these reinsurance agreements, the Company would not realize the full value of the reinsurance recoverable balances. The Company's procedures include carefully selecting its reinsurers, structuring agreements to provide collateral funds where necessary, and regularly monitoring the financial condition and ratings of its reinsurers. Reinsurance receivables include balances due from reinsurance companies and are presented net of an allowance for uncollectible reinsurance. Reinsurance receivables include an estimate of the amount of gross losses and loss adjustment expense reserves that may be ceded under the terms of the reinsurance agreements, including incurred but not reported unpaid losses. The Company’s estimate of losses and loss adjustment expense reserves ceded to reinsurers is based on assumptions that are consistent with those used in establishing the gross reserves for amounts the Company owes to its claimants. The Company estimates its ceded reinsurance receivable based on the terms of any applicable facultative and treaty reinsurance, including an estimate of how incurred but not reported losses will ultimately be ceded under reinsurance agreements. Accordingly, the Company’s estimate of reinsurance receivables is subject to similar risks and uncertainties as the estimate of the gross reserve for unpaid losses and loss adjustment expenses. The Company may hold partial collateral, including letters of credit and funds held, under these agreements. See also Note 1C, Note 3 and Note 8. Balances are considered past due when amounts that have been billed are not collected within contractually stipulated time periods, generally 30, 60 or 90 days. To manage reinsurer credit risk, a reinsurance security review committee evaluates the credit standing, financial performance, management and operational quality of each potential reinsurer. In placing reinsurance, the Company considers the nature of the risk reinsured, including the expected liability payout duration, and establishes limits tiered by reinsurer credit rating. Where its contracts permit, the Company secures future claim obligations with various forms of collateral or other credit enhancement, including irrevocable letters of credit, secured trusts, funds held accounts and group wide offsets. The Company periodically evaluates the recoverability of its reinsurance receivable assets and establishes an allowance for uncollectible reinsurance. The allowance for uncollectible reinsurance reflects management’s best estimate of reinsurance cessions that may be uncollectible in the future due to reinsurers’ unwillingness or inability to pay. The allowance for uncollectible reinsurance comprises an allowance and an allowance for disputed balances. Based on this analysis, the Company may adjust the allowance for uncollectible reinsurance or charge off reinsurer balances that are determined to be uncollectible. Due to the inherent uncertainties as to collection and the length of time before reinsurance receivable become due, it is possible that future adjustments to the Company’s reinsurance receivable, net of the allowance, could be required, which could have a material adverse effect on the Company’s consolidated results of operations or cash flows in a particular quarter or annual period. The allowance is estimated as the amount of reinsurance receivable exposed to loss multiplied by estimated factors for the probability of default. The probability of default is assigned based on each reinsurer's credit rating, or a rating is estimated if no external rating is available. Credit ratings are reviewed and updated at least annually. The probability of default factors are historical insurer and reinsurer defaults for liabilities with similar durations to the reinsured liabilities as estimated through multiple economic cycles. Credit ratings are forward-looking and consider a variety of economic outcomes. The Company's evaluation of the required allowance for reinsurance receivable considers the current economic environment as well as macroeconomic scenarios. Insurance companies, including reinsurers, are regulated and hold risk-based capital to mitigate the risk of loss due to economic factors and other risks. Non-U.S. reinsurers are either subject to a capital regime substantively equivalent to domestic insurers or we hold collateral to support collection of reinsurance receivable. As a result, there is limited history of losses from insurer defaults. The Company expects the impact of the COVID-19 pandemic to reinsurers to be somewhat mitigated by their regulated capital and liquidity positions. The ultimate impact to the Company's financial statements could vary significantly from our estimates depending on the duration and severity of the pandemic, the duration and severity of the economic downturn and the degree to which federal, state and local government actions to mitigate the economic impact of COVID-19 are effective. The Company records credit loss expenses related to reinsurance receivable in losses and loss adjustment expenses. Write-offs of reinsurance receivable and any related allowance are recorded in the period in which the balance is deemed uncollectible. The allowance for reinsurance receivables is $ 17,178 thousand and $ 14,190 thousand as of December 31, 2020 and 2019, respectively. Premiums written and earned and incurred losses and LAE are comprised of the following for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Written premiums: Direct $ 3,217,999 $ 2,783,036 $ 2,240,951 Assumed 7,264,362 6,350,328 6,234,203 Ceded ( 1,365,378) ( 1,308,940) ( 1,060,726) Net written premiums $ 9,116,983 $ 7,824,424 $ 7,414,428 Premiums earned: Direct $ 3,028,095 $ 2,551,662 $ 2,129,320 Assumed 7,054,680 6,059,222 5,807,332 Ceded ( 1,401,262) ( 1,207,198) ( 1,004,953) Net premiums earned $ 8,681,513 $ 7,403,686 $ 6,931,699 Incurred losses and LAE: Direct $ 2,141,065 $ 1,618,686 $ 1,372,589 Assumed 5,163,946 3,923,298 5,046,947 Ceded ( 754,174) ( 619,086) ( 768,133) Net incurred losses and LAE $ 6,550,837 $ 4,922,898 $ 5,651,403

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2020
Other Comprehensive Income (Loss) [Abstract]
Other Comprehensive Income (Loss)	12. OTHER COMPREHENSIVE INCOME (LOSS) The following table presents the components of comprehensive income (loss) in the consolidated statements of operations for the periods indicated: Years Ended December 31, 2020 2020 2019 2018 (Dollars in thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized appreciation (depreciation) ("URA(D)") on securities - non-credit related $ 462,939 $ ( 39,729) $ 423,210 $ 547,539 $ ( 49,665) $ 497,874 $ ( 275,511) $ 21,061 $ ( 254,450) URA(D) on securities - OTTI - - - ( 1,559) 115 ( 1,444) ( 1,071) ( 135) ( 1,206) Reclassification of net realized losses (gains) included in net income (loss) 2,253 ( 5,729) ( 3,476) ( 13,129) 516 ( 12,613) 28,014 ( 518) 27,496 Foreign currency translation adjustments 90,142 ( 3,815) 86,327 18,585 ( 4,555) 14,030 ( 86,520) 9,704 ( 76,816) Benefit plan actuarial net gain (loss) ( 7,107) 1,492 ( 5,615) ( 15,938) 3,347 ( 12,591) ( 646) 136 ( 510) Reclassification of benefit plan liability amortization included in net income (loss) 7,974 ( 1,674) 6,300 6,902 ( 1,449) 5,453 6,356 ( 1,335) 5,021 Total other comprehensive income (loss) $ 556,201 $ ( 49,455) $ 506,746 $ 542,400 $ ( 51,691) $ 490,709 $ ( 329,378) $ 28,913 $ ( 300,465) The following table presents details of the amounts reclassified from AOCI for the periods indicated: Years Ended December 31, Affected line item within the statements of AOCI component 2020 2019 operations and comprehensive income (loss) (Dollars in thousands) URA(D) on securities $ 2,253 $ ( 13,129) Other net realized capital gains (losses) ( 5,729) 516 Income tax expense (benefit) $ ( 3,476) $ ( 12,613) Net income (loss) Benefit plan net gain (loss) $ 7,974 $ 6,902 Other underwriting expenses ( 1,674) ( 1,449) Income tax expense (benefit) $ 6,300 $ 5,453 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: Years Ended December 31, (Dollars in thousands) 2020 2019 Beginning balance of URA (D) on securities $ 304,425 $ ( 179,392) Current period change in URA (D) of investments - non-credit related 419,734 485,261 Current period change in URA (D) of investments - non-credit OTTI - ( 1,444) Ending balance of URA (D) on securities 724,159 304,425 Beginning balance of foreign currency translation adjustments ( 201,717) ( 215,747) Current period change in foreign currency translation adjustments 86,327 14,030 Ending balance of foreign currency translation adjustments ( 115,390) ( 201,717) Beginning balance of benefit plan net gain (loss) ( 74,556) ( 67,418) Current period change in benefit plan net gain (loss) 685 ( 7,138) Ending balance of benefit plan net gain (loss) ( 73,870) ( 74,556) Ending balance of accumulated other comprehensive income (loss) $ 534,899 $ 28,152 (Some amounts may not reconcile due to rounding.)

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2020
Employee Benefit Plans [Abstract]
Employee Benefit Plans	13. EMPLOYEE BENEFIT PLANS Defined Benefit Pension Plans. The Company maintains both qualified and non-qualified defined benefit pension plans for its U.S. employees employed prior to April 1, 2010. Generally, the Company computes the benefits based on average earnings over a period prescribed by the plans and credited length of service. The Company’s non-qualified defined benefit pension plan provided compensating pension benefits for participants whose benefits have been curtailed under the qualified plan due to Internal Revenue Code limitations. Effective January 1, 2018, participants of the Company’s non-qualified defined benefit pension plan may no longer accrue additional service benefits. Although not required to make contributions under IRS regulations, the following table summarizes the Company’s contributions to the defined benefit pension plans for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Company contributions $ 6,825 $ 4,750 $ 77,743 The following table summarizes the Company’s pension expense for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Pension expense $ 8,429 $ 10,042 $ 9,728 The following table summarizes the status of these defined benefit plans for U.S. employees for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 Change in projected benefit obligation: Benefit obligation at beginning of year $ 355,356 $ 300,244 Service cost 9,522 8,255 Interest cost 10,112 11,712 Actuarial (gain)/loss 43,595 46,206 Curtailment - - Benefits paid ( 14,115) ( 11,062) Projected benefit obligation at end of year 404,471 355,356 Change in plan assets: Fair value of plan assets at beginning of year 301,467 260,531 Actual return on plan assets 60,286 47,247 Actual contributions during the year 6,825 4,750 Administrative expenses paid - - Benefits paid ( 14,115) ( 11,062) Fair value of plan assets at end of year 354,464 301,467 Funded status at end of year $ ( 50,007) $ ( 53,889) (Some amounts may not reconcile due to rounding.) Amounts recognized in the consolidated balance sheets for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Other assets (due beyond one year) $ - $ - Other liabilities (due within one year) ( 2,197) ( 7,362) Other liabilities (due beyond one year) ( 47,810) ( 46,527) Net amount recognized in the consolidated balance sheets $ ( 50,007) $ ( 53,889) (Some amounts may not reconcile due to rounding.) Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive income (loss) for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Accumulated income (loss) $ ( 91,979) $ ( 97,466) Accumulated other comprehensive income (loss) $ ( 91,979) $ ( 97,466) (Some amounts may not reconcile due to rounding.) Other changes in other comprehensive income (loss) for the periods indicated are as follows: Years Ended December 31, (Dollars in thousands) 2020 2019 Other comprehensive income (loss) at December 31, prior year $ ( 97,466) $ ( 88,580) Net gain (loss) arising during period ( 4,090) ( 16,927) Recognition of amortizations in net periodic benefit cost: Actuarial loss 9,576 8,042 Curtailment loss recognized - - Other comprehensive income (loss) at December 31, current year $ ( 91,979) $ ( 97,466) (Some amounts may not reconcile due to rounding.) Net periodic benefit cost for U.S. employees included the following components for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Service cost $ 9,522 $ 8,255 $ 9,801 Interest cost 10,112 11,712 10,290 Expected return on assets ( 20,781) ( 17,968) ( 17,202) Amortization of actuarial loss from earlier periods 8,551 7,635 6,839 Settlement 1,025 408 - Net periodic benefit cost $ 8,429 $ 10,042 $ 9,728 Other changes recognized in other comprehensive income (loss): Other comprehensive income (loss) attributable to change from prior year ( 5,486) 8,885 Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 2,943 $ 18,927 (Some amounts may not reconcile due to rounding.) The estimated transition obligation, actuarial loss and prior service cost that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year are $ 0 thousand, $ 7,709 thousand and $ 0 thousand, respectively. The weighted average discount rates used to determine net periodic benefit cost for 2020, 2019 and 2018 were 3.28%, 4.27% and 3.62%, respectively. The rate of compensation increase used to determine the net periodic benefit cost for 2020, 2019 and 2018 was 4.00%. The expected long-term rate of return on plan assets was 7.00% for 2020, 2019 and 2018 based on expected portfolio returns and allocations. The weighted average discount rates used to determine the actuarial present value of the projected benefit obligation for years end 2020, 2019 and 2018 were 2.55%, 3.28% and 4.27%, respectively. The following table summarizes the accumulated benefit obligation for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Qualified Plan $ 336,027 $ 288,328 Non-qualified Plan 16,258 21,642 Total $ 352,285 $ 309,970 (Some amounts may not reconcile due to rounding.) The following table displays the plans with projected benefit obligations in excess of plan assets for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Qualified Plan Projected benefit obligation $ 388,213 $ 333,715 Fair value of plan assets 354,464 301,467 Non-qualified Plan Projected benefit obligation $ 16,258 $ 21,642 Fair value of plan assets - - The following table displays the plans with accumulated benefit obligations in excess of plan assets for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Qualified Plan Accumulated benefit obligation $ - $ - Fair value of plan assets - - Non-qualified Plan Accumulated benefit obligation $ 16,258 $ 21,642 Fair value of plan assets - - The following table displays the expected benefit payments in the periods indicated: (Dollars in thousands) 2021 $ 11,757 2022 12,220 2023 13,064 2024 14,100 2025 15,190 Next 5 years 90,808 Plan assets consist of shares in investment trusts with 72%, 27%, 1% and 0% of the underlying assets consisting of equity securities, fixed maturities, limited partnerships and multi-strategy equity funds and cash, respectively. The Company manages the qualified plan investments for U.S. employees. The assets in the plan consist of debt and equity mutual funds. Due to the long term nature of the plan, the target asset allocation has historically been 70% equities and 30% bonds. The following tables present the fair value measurement levels for the qualified plan assets at fair value for 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, 2020 (Level 1) (Level 2) (Level 3) Assets: Short-term investments, which approximates fair value (a) $ 1,204 $ 1,204 $ - $ - Mutual funds, fair value Fixed income (b) 93,609 93,609 - - Equities (c) 255,054 255,054 - - Total $ 349,867 $ 349,867 $ - $ - (Some amounts may not reconcile due to rounding.) (a) This category includes high quality, short-term money market instruments, which are issued and payable in U.S. dollars. (b) This category includes fixed income funds, which invest in investment grade securities of corporations, governments and government agencies with approximately 70% in U.S. securities and 30% in international securities. (c) This category includes funds, which invest in small, mid and multi-cap equity securities including common stocks, securities convertible into common stock and securities with common stock characteristics, such as rights and warrants, with approximately 50% in U.S. equities and 50% in international equities. There were no transfers between Level 1 and Level 2 for the twelve months ended December 31, 2020. Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2019 (Level 1) (Level 2) (Level 3) Assets: Short-term investments, which approximates fair value (a) $ 1,749 $ 1,749 $ - $ - Mutual funds, fair value Fixed income (b) 90,483 90,483 - - Equities (c) 188,884 188,884 - - Total $ 281,116 $ 281,116 $ - $ - (Some amounts may not reconcile due to rounding.) (a) This category includes high quality, short-term money market instruments, which are issued and payable in U.S. dollars. (b) This category includes fixed income funds, which invest in investment grade securities of corporations, governments and government agencies with approximately 70% in U.S. securities and 30% in international securities. (c) This category includes funds, which invest in small, mid and multi-cap equity securities including common stocks, securities convertible into common stock and securities with common stock characteristics, such as rights and warrants, with approximately 50% in U.S. equities and 50% in international equities. In addition, $ 4,596 thousand and $ 20,351 thousand of investments which were recorded as part of the qualified plan assets at December 31, 2020 and 2019, respectively, are not included within the fair value hierarchy tables as the assets are valued using the NAV practical expedient guidance within ASU 2015-07. The Company contributed $ 0 thousand to the qualified pension benefit plan for the years ended December 31, 2020 and 2019. Defined Contribution Plans. The Company also maintains both qualified and non-qualified defined contribution plans (“Savings Plan” and “Non-Qualified Savings Plan”, respectively) covering U.S. employees. Under the plans, the Company contributes up to a maximum 3% of the participants’ compensation based on the contribution percentage of the employee. The Non-Qualified Savings Plan provides compensating savings plan benefits for participants whose benefits have been curtailed under the Savings Plan due to Internal Revenue Code limitations. In addition, effective for new hires (and rehires) on or after April 1, 2010, the Company will contribute between 3% and 8% of an employee’s earnings for each payroll period based on the employee’s age. These contributions will be 100% vested after three years. The following table presents the Company’s incurred expenses related to these plans for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Incurred expenses $ 14,386 $ 10,794 $ 9,301 In addition, the Company maintains several defined contribution pension plans covering non-U.S. employees. Each non-U.S. office (Brazil, Canada, London, Belgium, Singapore, Ireland, Zurich and Bermuda) maintains a separate plan for the non-U.S. employees working in that location. The Company contributes various amounts based on salary, age and/or years of service. In the current year, the contributions as a percentage of salary for the branch offices ranged from 5.1% to 64.8%. The contributions are generally used to purchase pension benefits from local insurance providers. The following table presents the Company’s incurred expenses related to these plans for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Incurred expenses $ 3,039 $ 2,216 $ 2,057 Post-Retirement Plan. The Company sponsors a Retiree Health Plan for employees employed prior to April 1, 2010. This plan provides healthcare benefits for eligible retired employees (and their eligible dependents), who have elected coverage. The Company anticipates that most covered employees will become eligible for these benefits if they retire while working for the Company. The cost of these benefits is shared with the retiree. The Company accrues the post-retirement benefit expense during the period of the employee’s service. A medical cost trend rate of 6.75% in 2020 was assumed to decrease gradually to 4.75% in 2030 and then remain at that level. The following table presents the post-retirement benefit expenses for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Post-retirement benefit expenses $ 1,334 $ 1,231 $ 1,829 The following table summarizes the status of this plan for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Change in projected benefit obligation: Benefit obligation at beginning of year $ 29,376 $ 28,483 Service cost 1,066 983 Interest cost 845 980 Amendments - - Actuarial (gain)/loss 4,042 ( 582) Benefits paid ( 232) ( 488) Benefit obligation at end of year 35,098 29,376 Change in plan assets: Fair value of plan assets at beginning of year - - Employer contributions 232 488 Benefits paid ( 232) ( 488) Fair value of plan assets at end of year - - Funded status at end of year $ ( 35,098) $ ( 29,376) Amounts recognized in the consolidated balance sheets for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Other liabilities (due within one year) $ ( 613) $ ( 611) Other liabilities (due beyond one year) ( 34,484) ( 28,764) Net amount recognized in the consolidated balance sheets $ ( 35,098) $ ( 29,376) (Some amounts may not reconcile due to rounding.) Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive income (loss) for the periods indicated: At December 31, (Dollars in thousands) 2020 2019 Accumulated income (loss) $ ( 3,854) $ 188 Accumulated prior service credit (cost) 2,327 2,904 Accumulated other comprehensive income (loss) $ ( 1,527) $ 3,092 Other changes in other comprehensive income (loss) for the periods indicated are as follows: Years Ended December 31, (Dollars in thousands) 2020 2019 Other comprehensive income (loss) at December 31, prior year $ 3,092 $ 3,242 Net gain (loss) arising during period ( 4,042) 582 Prior Service credit (cost) arising during period - - Recognition of amortizations in net periodic benefit cost: Actuarial loss (gain) - ( 155) Prior service cost ( 577) ( 577) Other comprehensive income (loss) at December 31, current year $ ( 1,527) $ 3,092 Net periodic benefit cost included the following components for the periods indicated: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Service cost $ 1,066 $ 983 $ 1,312 Interest cost 845 980 999 Prior service credit recognition ( 577) ( 577) ( 577) Net gain recognition - ( 155) 94 Net periodic cost $ 1,334 $ 1,231 $ 1,829 Other changes recognized in other comprehensive income (loss): Other comprehensive gain (loss) attributable to change from prior year 4,619 150 Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 5,953 $ 1,381 (Some amounts may not reconcile due to rounding.) The estimated transition obligation, actuarial gain and prior service credit that will be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost over the next fiscal year are $ 0 thousand, $ 46 thousand and $ 577 thousand, respectively. The weighted average discount rates used to determine net periodic benefit cost for 2020, 2019 and 2018 were 3.28%, 4.27% and 3.62%, respectively. The weighted average discount rates used to determine the actuarial present value of the projected benefit obligation at year end 2020, 2019 and 2018 were 2.55%, 3.28% and 4.27%, respectively. The following table displays the expected benefit payments in the years indicated: (Dollars in thousands) 2021 $ 613 2022 715 2023 806 2024 851 2025 989 Next 5 years 6,955

Dividend Restrictions And Statu

Dividend Restrictions And Statutory Financial Information	12 Months Ended
	Dec. 31, 2020
Dividend Restrictions And Statutory Financial Information [Abstract]
Dividend Restrictions And Statutory Financial Information	14. DIVIDEND RESTRICTIONS AND STATUTORY FINANCIAL INFORMATION Group and its operating subsidiaries are subject to various regulatory restrictions, including the amount of dividends that may be paid and the level of capital that the operating entities must maintain. These regulatory restrictions are based upon statutory capital as opposed to GAAP basis equity or net assets. Group and one of its primary operating subsidiaries, Bermuda Re, are regulated by Bermuda law and its other primary operating subsidiary, Everest Re, is regulated by Delaware law. Bermuda Re is subject to the Bermuda Solvency Capital Requirement (“BSCR”) administered by the Bermuda Monetary Authority (“BMA”) and Everest Re is subject to the Risk-Based Capital Model (“RBC”) developed by the National Association of Insurance Commissioners (“NAIC”). These models represent the aggregate regulatory restrictions on net assets and statutory capital and surplus. Dividend Restrictions. Under Bermuda law, Group is prohibited from declaring or paying a dividend if such payment would reduce the realizable value of its assets to an amount less than the aggregate value of its liabilities and its issued share capital and share premium (additional paid-in capital) accounts. Group’s ability to pay dividends and its operating expenses is dependent upon dividends from its subsidiaries. Under Bermuda law, Bermuda Re is prohibited from declaring or making payment of a dividend if it fails to meet its minimum solvency margin or minimum liquidity ratio. As a long term insurer, Bermuda Re is also unable to declare or pay a dividend to anyone who is not a policyholder unless, after payment of the dividend, the value of the assets in their long term business fund, as certified by their approved actuary, exceeds their liabilities for long term business by at least the $ 250 thousand minimum solvency margin. Prior approval of the BMA is required if Bermuda Re’s dividend payments would exceed 25% of their prior year-end total statutory capital and surplus. Bermuda Re prepares its statutory financial statements in conformity with the accounting principles set forth in Bermuda in The Insurance Act 1978, amendments thereto and related regulations. The statutory capital and surplus of Bermuda Re was $ 2,944,455 thousand and $ 3,197,418 thousand at December 31, 2020 and 2019, respectively. The statutory net income of Bermuda Re was $ 222,765 thousand, $ 503,610 thousand and $ 873,111 thousand for the years ended December 31, 2020, 2019 and 2018, respectively. Delaware law provides that an insurance company which is a member of an insurance holding company system and is domiciled in the state shall not pay dividends without giving prior notice to the Insurance Commissioner of Delaware and may not pay dividends without the approval of the Insurance Commissioner if the value of the proposed dividend, together with all other dividends and distributions made in the preceding twelve months, exceeds the greater of (1) 10% of statutory surplus or (2) net income, not including realized capital gains, each as reported in the prior year’s statutory annual statement. In addition, no dividend may be paid in excess of unassigned earned surplus. At December 31, 2020, Everest Re has $ 592,082 thousand available for payment of dividends in 2021 without the need for prior regulatory approval. Everest Re prepares its statutory financial statements in accordance with accounting practices prescribed or permitted by the NAIC and the Delaware Insurance Department. Prescribed statutory accounting practices are set forth in the NAIC Accounting Practices and Procedures Manual. The capital and statutory surplus of Everest Re was $ 5,276,003 thousand and $ 3,739,140 thousand at December 31, 2020 and 2019, respectively. The statutory net income of Everest Re was $ 595,077 thousand and $ 363,034 thousand for the years ended December 31, 2020 and 2019, respectively, and statutory net loss of Everest Re was $ 1,317,991 thousand for the year ended December 31, 2018. There are certain regulatory and contractual restrictions on the ability of Holdings’ operating subsidiaries to transfer funds to Holdings in the form of cash dividends, loans or advances. The insurance laws of the State of Delaware, where Holdings’ direct insurance subsidiaries are domiciled, require regulatory approval before those subsidiaries can pay dividends or make loans or advances to Holdings that exceed certain statutory thresholds. Capital Restrictions. In Bermuda, Bermuda Re is subject to the BSCR administered by the BMA. No regulatory action is taken if an insurer’s capital and surplus is equal to or in excess of their enhanced capital requirement determined by the BSCR model. In addition, the BMA has established a target capital level for each insurer, which is 120% of the enhanced capital requirement. In the United States, Everest Re is subject to the RBC developed by the NAIC which determines an authorized control level risk-based capital. As long as the total adjusted capital is 200% or more of the authorized control level capital, no action is required by the Company. The regulatory targeted capital and the actual statutory capital for Bermuda Re and Everest Re were as follows: Bermuda Re (1) Everest Re (1) At December 31, At December 31, (Dollars in thousands) 2020 (1) 2019 2020 2019 Regulatory targeted capital $ - $ 2,061,065 $ 2,489,772 $ 2,001,226 Actual capital $ 2,944,455 $ 3,197,418 $ 5,276,003 $ 3,739,140 (a) Regulatory targeted capital represents the target capital level from the applicable year's BSCR calculation. (b) Regulatory targeted capital represents 200% of the RBC authorized control level calculation for the applicable year. (c) The 2020 BSCR calculation is not yet due to be completed; however, the Company anticipates that Bermuda Re's December 31, 2020 actual capital will exceed the targeted capital level.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies [Abstract]
Commitments And Contingencies	15. 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 had one equity index put option contract at December 31, 2020, based on the Standard & Poor’s 500 (“S&P 500”) index. Based on historical index volatilities and trends and the December 31, 2020 S&P 500 index value, the Company estimates the probability that the equity index put option contract of the S&P 500 index falling below the strike price on the exercise date to be less than 0.2%. The theoretical maximum payout under this equity index put option contract would occur if on the exercise date the S&P 500 index value was zero. At December 31, 2020, the present value of the theoretical maximum payout using a 3% discount factor was $ 147,894 thousand. Conversely, if the contract had expired on December 31, 2020, with the S&P index at 3,756.07, there would have been no settlement amount. The Company has entered into separate annuity agreements with The Prudential Insurance 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 December 31, (Dollars in thousands) 2020 2019 The Prudential $ 140,773 $ 141,703 Unaffiliated life insurance company 35,128 35,082

Share-Based Compensation Plans

Share-Based Compensation Plans	12 Months Ended
	Dec. 31, 2020
Share-Based Compensation Plans [Abstract]
Share-Based Compensation Plans	16. SHARE-BASED COMPENSATION PLANS The Company has a 2020 Stock Incentive Plan (“2020 Employee Plan”), a 2010 Stock Incentive Plan (“2010 Employee Plan”), a 2009 Non-Employee Director Stock Option and Restricted Stock Plan (“2009 Director Plan”) and a 2003 Non-Employee Director Equity Compensation Plan (“2003 Director Plan”). The 2020 Employee Plan was established in June 2020. Under the 2020 Employee Plan, 1,400,000 common shares have been authorized to be granted as non-qualified share options, share appreciation rights, restricted share awards or performance share unit awards to officers and key employees of the Company. At December 31, 2020, there were 1,366,900 remaining shares available to be granted under the 2020 Employee Plan. The 2020 Employee Plan replaced a 2010 Employee Plan, which replaced a 2002 Employee Plan, which replaced a 1995 Employee Plan; therefore, no further awards will be granted under the 2002 Employee Plan or the 1995 Employee Plan. Through December 31, 2020, only non-qualified share options, restricted share awards and performance share unit awards had been granted under the employee plans. Under the 2009 Director Plan, 37,439 common shares have been authorized to be granted as share options or restricted share awards to non-employee directors of the Company. At December 31, 2020, there were 34,957 remaining shares available to be granted under the 2009 Director Plan. The 2009 Director Plan replaced a 1995 Director Plan, which expired. Under the 2003 Director Plan, 500,000 common shares have been authorized to be granted as share options or share awards to non-employee directors of the Company. At December 31, 2020 there were 316,702 remaining shares available to be granted under the 2003 Director Plan. Options and restricted shares granted under the 2020 Employee Plan, 2010 Employee Plan and the 2002 Employee Plan vest at the earliest of 20% per year over five years or in accordance with any applicable employment agreement. Options and restricted shares granted under the 2003 Director Plan generally vest at 33% per year over three years, unless an alternate vesting period is authorized by the Board. Options and restricted shares granted under the 2009 Director Plan will vest as provided in the award agreement. All options are exercisable at fair market value of the stock at the date of grant and expire ten years after the date of grant. Performance Share Unit awards granted under the 2020 Employee Plan and the 2010 Employee Plan will vest 100% after three years. The Performance Share Unit awards represent the right to receive between and 0 1.75 shares of stock for each unit awarded depending upon performance in relation to certain metrics. The performance share unit valuation will be based partly on growth in book value per share over the three year vesting period, compared to designated peer companies. The remaining portion of the performance share valuation will be based upon operating return on equity for each of the separate operating years within the vesting period. For share options, restricted shares and performance share units granted under the 2020 Employee Plan, the 2010 Employee Plan, the 2002 Employee Plan, the 2009 Director Plan and the 2003 Director Plan, share-based compensation expense recognized in the consolidated statements of operations and comprehensive income (loss) was $ 39,209 thousand, $ 34,018 thousand and $ 32,369 thousand for the years ended December 31, 2020, 2019 and 2018, respectively. The corresponding income tax benefit recorded in the consolidated statements of operations and comprehensive income (loss) for share-based compensation was $ 7,107 thousand, $ 8,384 thousand and $ 7,401 thousand for the years ended December 31, 2020, 2019 and 2018, respectively. For the year ended December 31, 2020, a total of 200,929 restricted shares were granted on February 26, 2020, September 11, 2020, and November 18, 2020, with a fair value of $ 277.145, $ 207.505 and $ 238.0975 per share, respectively. Additionally, 16,120 performance share units were awarded on February 26, 2020, with a fair value of $ 277.145 per unit. No share options were granted during the year ended December 31, 2020. For share options granted during previous years, the fair value per option was calculated on the date of the grant using the Black-Scholes option valuation model. The Company recognizes, as an increase to additional paid-in capital, a realized income tax benefit from dividends, charged to retained earnings and paid to employees on equity classified non-vested equity shares. In addition, the amount recognized in additional paid-in capital for the realized income tax benefit from dividends on those awards is included in the pool of excess tax benefits available to absorb tax deficiencies on share-based payment awards. For the years ended December 31, 2020, 2019 and 2018, the Company recognized $ 583 thousand, $ 484 thousand and $ 403 thousand, respectively, of additional paid-in capital due to tax benefits from dividends on restricted shares. A summary of the option activity under the Company’s shareholder approved plans as of December 31, 2020, 2019 and 2018, and changes during the year then ended is presented in the following tables: Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2020 170,704 $ 87.18 Granted - - Exercised 53,833 85.69 Forfeited/Cancelled/Expired – - Outstanding at December 31, 2020 116,871 87.87 0.7 $ 17,089 . Exercisable at December 31, 2020 116,871 87.87 0.7 $ 17,089 Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2019 279,164 $ 83.84 Granted - - Exercised 108,460 78.58 Forfeited/Cancelled/Expired - - Outstanding at December 31, 2019 170,704 87.18 1.4 $ 32,376 . Exercisable at December 31, 2019 170,704 87.18 1.4 $ 32,376 Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2018 360,364 $ 84.10 Granted - - Exercised 81,200 84.99 Forfeited/Cancelled/Expired - - Outstanding at December 31, 2018 279,164 83.84 1.9 $ 37,386 Exercisable at December 31, 2018 279,164 83.84 1.9 $ 37,386 There were no share options granted in 2020, 2019 and 2018. The aggregate intrinsic value (market price less exercise price) of options exercised during the years ended December 31, 2020, 2019 and 2018 was $ 9,982 thousand, $ 16,297 thousand and $ 11,737 thousand, respectively. The cash received from the exercised share options for the year ended December 31, 2020 was $ 4,613 thousand. The tax benefit realized from the options exercised for the year ended December 31, 2020 was $ 1,904 thousand. The following table summarizes information about share options outstanding for the period indicated: At December 31, 2020 Options Outstanding Options Exercisable Weighted- Average Weighted- Weighted- Number Remaining Average Number Average Range of Outstanding Contractual Exercise Exercisable Exercise Exercise Prices at 12/31/20 Life Price at 12/31/20 Price $86.62 - $88.31 44,000 0.2 $ 86.62 44,000 $ 86.62 $88.32 - $90.48 66,917 1.1 88.32 66,917 88.32 $90.49 - $110.13 5,954 0.5 91.99 5,954 91.99 116,871 0.7 87.87 116,871 87.87 The following table summarizes the status of the Company’s non-vested shares and changes for the periods indicated: Years Ended December 31, 2020 2019 2018 Weighted- Weighted- Weighted- Average Average Average Grant Date Grant Date Grant Date Restricted (non-vested) Shares Shares Fair Value Shares Fair Value Shares Fair Value Outstanding at January 1, 495,137 $ 228.02 414,407 $ 217.15 421,261 $ 194.01 Granted 200,929 269.86 232,601 232.36 173,065 240.59 Vested 175,413 220.88 138,322 203.41 141,982 178.31 Forfeited 37,226 246.20 13,549 221.35 37,937 212.48 Outstanding at December 31, 483,427 246.60 495,137 228.02 414,407 217.15 As of December 31, 2020, there was $ 88,233 thousand of total unrecognized compensation cost related to non-vested share-based compensation expense. That cost is expected to be recognized over a weighted-average period of 3.4 years. The total fair value of shares vested during the years ended December 31, 2020, 2019 and 2018, was $ 38,745 thousand, $ 28,135 thousand and $ 25,317 thousand, respectively. The tax benefit realized from the shares vested for the year ended December 31, 2020 was $ 8,519 thousand. In addition to the 2020 Employee Plan, the 2010 Employee Plan, the 2009 Director Plan and the 2003 Director Plan, Group issued 593 common shares in 2020, 459 common shares in 2019 and 480 common shares in 2018 to the Company’s non-employee directors as compensation for their service as directors. These issuances had aggregate values of approximately $ 125 thousand, $ 107 thousand and $ 113 thousand, respectively. Since its 1995 initial public offering, the Company has issued to certain key employees of the Company 2,718,140 restricted common shares, of which 369,164 restricted shares have been cancelled. The Company has issued to non-employee directors of the Company 175,829 restricted common shares, of which no restricted shares have been cancelled. The Company acquired 66,289, 71,437 and 65,974 common shares at a cost of $ 17,889 thousand, $ 14,181 thousand and $ 14,202 thousand in 2020, 2019 and 2018, respectively, from employees who chose to pay required withholding taxes and/or the exercise cost on option exercises or restricted share vestings by withholding shares. The following table summarized the status of the Company’s non-vested performance share unit awards and changes for the period indicated: Years Ended December 31, 2020 2019 2018 Weighted- Weighted- Weighted- Average Average Average Grant Date Grant Date Grant Date Performance Share Unit Awards Shares Fair Value Shares Fair Value Shares Fair Value Outstanding at January 1, 34,850 $ - 32,382 $ - 33,454 $ - Granted 16,120 277.15 16,855 223.45 13,325 242.39 Increase/(Decrease) on vesting units due to performance ( 2,227) - ( 3,455) - ( 267) - Vested 6,157 277.15 10,922 223.45 12,435 242.39 Forfeited 3,695 - - - 1,695 - Outstanding at December 31, 38,891 - 34,850 - 32,382 - The Company acquired 2,587, 5,008 and 5,214 common shares at a cost of $ 717 thousand, $ 1,119 thousand and $ 1,264 thousand in 2020, 2019 and 2018, respectively, from employees who chose to pay required withholding taxes on performance shares units settlements by withholding shares.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	17. SEGMENT REPORTING The Reinsurance operation writes worldwide property and casualty reinsurance and specialty lines of business, on both a treaty and facultative basis, through reinsurance brokers, as well as directly with ceding companies. Business is written in the U.S., Bermuda, and Ireland offices, as well as, through branches in Canada, Singapore and the United Kingdom. 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 through its offices in the U.S., Canada, Ireland and a branch located in Zurich. 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. 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: Reinsurance Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross written premiums $ 7,281,716 $ 6,355,889 $ 6,224,601 Net written premiums 6,767,579 5,732,272 5,706,453 Premiums earned $ 6,466,106 $ 5,491,296 $ 5,293,071 Incurred losses and LAE 4,933,411 3,675,178 4,585,602 Commission and brokerage 1,552,371 1,400,247 1,251,581 Other underwriting expenses 175,734 160,834 142,874 Underwriting gain (loss) $ ( 195,410) $ 255,037 $ ( 686,986) Insurance Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross written premiums $ 3,200,645 $ 2,777,475 $ 2,250,552 Net written premiums 2,349,404 2,092,152 1,707,975 Premiums earned $ 2,215,407 $ 1,912,390 $ 1,638,628 Incurred losses and LAE 1,617,426 1,247,720 1,065,801 Commission and brokerage 320,879 303,479 267,449 Other underwriting expenses 335,503 280,065 228,667 Underwriting gain (loss) $ ( 58,401) $ 81,126 $ 76,711 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: Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Underwriting gain (loss) $ ( 253,811) $ 336,163 $ ( 610,275) Net investment income 642,465 647,139 581,183 Net realized capital gains (losses) 267,649 185,004 ( 127,136) Corporate expenses ( 41,118) ( 32,966) ( 30,672) Interest, fee and bond issue cost amortization expense ( 36,323) ( 31,693) ( 31,031) Other income (expense) 6,487 ( 4,660) ( 24,251) Income (loss) before taxes $ 585,349 $ 1,098,987 $ ( 242,182) 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: Year Ended December 31, (Dollars in thousands) 2020 2019 2018 United Kingdom gross written premium $ 1,116,363 $ 964,358 $ 914,612 Approximately 20.1%, 23.1% and 19.7% of the Company’s gross written premiums in 2020, 2019 and 2018, respectively, were sourced through the Company’s largest intermediary.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	18. SUBSEQUENT EVENTS The Company has evaluated known recognized and non-recognized subsequent events. In February 2021, a severe winter storm impacted Texas and other southern states. Due to the recentness of this event, the Company is unable to estimate the amount of losses at this time. However, the Company anticipates that the losses from this event will adversely impact first quarter 2021 financial statements.

Unaudited Quarterly Financial D

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2020
Unaudited Quarterly Financial Data [Abstract]
Unaudited Quarterly Financial Data	19. UNAUDITED QUARTERLY FINANCIAL DATA Summarized quarterly financial data for the periods indicated: 2020 (Dollars in thousands, except per share amounts) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Operating data: Gross written premiums $ 2,570,871 $ 2,369,338 $ 2,791,604 $ 2,750,548 Net written premiums 2,201,479 2,017,478 2,448,680 2,449,346 Premiums earned 2,036,814 2,042,405 2,205,811 2,396,483 Net investment income 147,800 38,083 234,233 222,349 Net realized capital gains (losses) ( 210,588) 184,648 110,203 183,386 Total claims and underwriting expenses 2,008,222 1,991,462 2,320,417 2,615,223 Net income (loss) 16,612 190,880 243,057 63,601 Earnings per common share attributable to Everest Re Group: Basic $ 0.41 $ 4.78 $ 6.08 $ 1.59 Diluted $ 0.41 $ 4.77 $ 6.07 $ 1.59 2019 (Dollars in thousands, except per share amounts) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Operating data: Gross written premiums $ 2,127,108 $ 2,166,655 $ 2,403,274 $ 2,436,327 Net written premiums 1,851,698 1,783,983 2,068,557 2,120,186 Premiums earned 1,732,697 1,817,299 1,905,619 1,948,071 Net investment income 140,976 179,028 181,058 146,077 Net realized capital gains (losses) 92,232 30,272 ( 12,943) 75,443 Total claims and underwriting expenses 1,537,009 1,620,413 1,933,158 1,976,943 Net income (loss) 354,551 332,868 104,398 217,644 Earnings per common share attributable to Everest Re Group: Basic $ 8.70 $ 8.17 $ 2.56 $ 5.34 Diluted $ 8.67 $ 8.15 $ 2.56 $ 5.32

Schedule I - Summary Of Investm

Schedule I - Summary Of Investments - Other Than Investments In Related Parties	12 Months Ended
	Dec. 31, 2020
Schedule I - Summary Of Investments - Other Than Investments In Related Parties [Abstract]
Schedule I - Summary Of Investments - Other Than Investments In Related Parties	SCHEDULE I — SUMMARY OF INVESTMENTS — OTHER THAN INVESTMENTS IN RELATED PARTIES December 31, 2020 Column A Column B Column C Column D Amount Shown in Market Balance (Dollars in thousands) Cost Value Sheet Fixed maturities-available for sale Bonds: U.S. government and government agencies $ 1,325,156 $ 1,367,106 $ 1,367,106 State, municipalities and political subdivisions 543,895 577,295 577,295 Foreign government securities 1,565,260 1,645,375 1,645,375 Foreign corporate securities 3,297,898 3,472,333 3,472,333 Public utilities 305,922 329,977 329,977 All other corporate bonds 9,051,540 9,377,901 9,377,901 Mortgage - backed securities: Commercial 915,923 990,303 990,303 Agency residential 2,206,139 2,267,739 2,267,739 Non-agency residential 5,187 5,194 5,194 Redeemable preferred stock 8,147 6,950 6,950 Total fixed maturities-available for sale 19,225,067 20,040,173 20,040,173 Fixed maturities - available for sale at fair value (1) — — — Equity securities - at fair value (1) 1,113,298 1,472,236 1,472,236 Short-term investments 1,135,088 1,134,950 1,134,950 Other invested assets 2,012,581 2,012,581 2,012,581 Cash 801,651 801,651 801,651 Total investments and cash $ 24,287,685 $ 25,461,591 $ 25,461,591 (1) Original cost does not reflect fair value adjustments, which have been realized through the statements of operations and comprehensive income (loss).

Schedule II - Condensed Financi

Schedule II - Condensed Financial Information Of The Registrant	12 Months Ended
	Dec. 31, 2020
Schedule II - Condensed Financial Information Of The Registrant [Abstract]
Schedule II - Condensed Financial Information Of The Registrant	SCHEDULE II — CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT CONDENSED BALANCE SHEETS December 31, (Dollars and share amounts in thousands, except par value per share) 2020 2019 ASSETS: Fixed maturities - available for sale, at market value $ 3 $ 201,666 (amortized cost: 2020, $ 3; 2019, $ 201,581) Other invested assets (cost: 2020, $ 282,762; 2019, $ 41,700) 282,762 41,700 Cash 884 3,471 Investment in subsidiaries, at equity in the underlying net assets 9,660,713 9,134,038 Accrued investment income - 652 Receivable from subsidiaries 18,424 9,361 Other assets 64,692 44,646 TOTAL ASSETS $ 10,027,478 $ 9,435,534 LIABILITIES: Long term note payable, affiliated due 12/1/2028 $ 300,000 $ 300,000 Due to subsidiaries 1,933 1,491 Other liabilities ( 631) 1,118 Total liabilities 301,302 302,609 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 (2020) 69,620and (2019) 69,464 issued outstanding before treasury shares 696 694 Additional paid-in capital 2,245,301 2,219,660 Accumulated other comprehensive income (loss), net of deferred income tax expense (benefit) of $ 80,451 at 2020 and $ 30,996 at 2019 534,899 28,152 Treasury shares, at cost; 29,636 shares (2020) and 28,665 shares (2019) ( 3,622,172) ( 3,422,152) Retained earnings 10,567,452 10,306,571 Total shareholders' equity 9,726,176 9,132,925 TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY $ 10,027,478 $ 9,435,534 See notes to consolidated financial statements. SCHEDULE II — CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT CONDENSED STATEMENTS OF OPERATIONS Years Ended December 31, 2020 2019 2018 (Dollars in thousands) REVENUES: Net investment income $ 1,121 $ 3,484 $ 3,790 Net realized capital gains (losses) 28 ( 66) ( 57) Other income (expense) 5,833 458 ( 5,299) Net income (loss) of subsidiaries 535,866 1,026,233 112,859 Total revenues 542,848 1,030,109 111,293 EXPENSES: Interest expense - affiliated 5,155 2,087 4,085 Other expenses 23,542 18,561 18,167 Total expenses 28,697 20,648 22,252 INCOME (LOSS) BEFORE TAXES 514,151 1,009,461 89,041 NET INCOME (LOSS) $ 514,151 $ 1,009,461 $ 89,041 Other comprehensive income (loss), net of tax: Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period 423,210 496,430 ( 255,656) Reclassification adjustment for realized losses (gains) included in net income (loss) ( 3,476) ( 12,613) 27,496 Total URA(D) on securities arising during the period 419,734 483,817 ( 228,160) Foreign currency translation adjustments 86,327 14,030 ( 76,816) Benefit plan actuarial net gain (loss) for the period ( 5,615) ( 12,591) ( 510) Reclassification adjustment for amortization of net (gain) loss included in net income (loss) 6,300 5,453 5,021 Total benefit plan net gain (loss) for the period 685 ( 7,138) 4,511 Total other comprehensive income (loss), net of tax 506,746 490,709 ( 300,465) COMPREHENSIVE INCOME (LOSS) $ 1,020,897 $ 1,500,170 $ ( 211,424) See notes to consolidated financial statements. SCHEDULE II — CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT CONDENSED STATEMENTS OF CASH FLOWS Years Ended December 31, (Dollars in thousands) 2020 2019 2018 CASH FLOWS FROM OPERATING ACTIVITIES: Net income (loss) $ 514,151 $ 1,009,461 $ 89,041 Adjustments to reconcile net income to net cash provided by operating activities: Equity in retained (earnings) deficit of subsidiaries ( 535,866) ( 1,026,233) ( 112,859) Dividends received from Bermuda Re 650,000 600,000 750,000 Dividends received from Everest International - - 200,000 Dividends received from Mt. Logan Re - - - - Change in other assets and liabilities, net ( 21,145) 564 4,824 Increase (decrease) in due to/from affiliates ( 8,621) ( 2,209) 683 Amortization of bond premium (accrual of bond discount) ( 14) ( 9) ( 577) Realized capital losses (gains) ( 28) 66 57 Non-cash compensation expense 2,588 2,796 2,740 Net cash provided by (used in) operating activities 601,065 584,436 933,909 CASH FLOWS FROM INVESTING ACTIVITIES: Additional investment in subsidiaries ( 138,320) ( 478,125) ( 542,965) Proceeds from fixed maturities matured/called - available for sale, at market value 1,356 63 93 Proceeds from fixed maturities sold - available for sale, at market value 200,264 74,841 24,856 Distribution from other invested assets 559,767 644,918 1,026,297 Cost of fixed maturities acquired - available for sale, at market value - ( 200,267) - Cost of other invested assets acquired ( 800,828) ( 686,528) ( 923,828) Net change in short-term investments - - - Net cash provided by (used in) investing activities ( 177,761) ( 645,098) ( 415,547) CASH FLOWS FROM FINANCING ACTIVITIES: Common shares issued during the period, net 23,185 22,861 20,086 Purchase of treasury shares ( 200,020) ( 24,604) ( 75,304) Dividends paid to shareholders ( 249,056) ( 234,322) ( 216,221) Proceeds from issuance (cost of repayment) of long term note - affiliated - 300,000 ( 250,000) Net cash provided by (used in) financing activities ( 425,891) 63,935 ( 521,439) EFFECT OF EXCHANGE RATE CHANGES ON CASH - - - Net increase (decrease) in cash ( 2,587) 3,273 ( 3,077) Cash, beginning of period 3,471 198 3,275 Cash, end of period $ 884 $ 3,471 $ 198 See notes to consolidated financial statements. SCHEDULE II – CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT NOTES to conDENSED financial information 1.) The accompanying condensed financial information should be read in conjunction with the consolidated financial statements and related Notes of Everest Re Group, Ltd. and its Subsidiaries. 2.) Everest Re Group, Ltd. entered into a $ 300,000 thousand long term note agreement with Everest Reinsurance Company, an affiliated company, as of December 17, 2019. The note will pay interest annually at a rate of 1.69 % and is scheduled to mature in December, 2028 3.) Everest Re Group, Ltd. has invested funds in the segregated accounts of Mt. Logan Re, Ltd. (“Mt. Logan Re”), an affiliated entity. On the Condensed Balance Sheets, investments in Mt. Logan Re valued at $ 67,645 thousand and $ 46,390 thousand as of December 31, 2020 and 2019, respectively, have been recorded within Other Assets. On the Condensed Statements of Operations, income of $ 6,255 thousand, income of $ 765 thousand and expense of $ 4,695 thousand for the years ended December 31, 2020, 2019 and 2018, respectively, have been recorded in other income (expense).

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2020
Schedule III - Supplementary Insurance Information [Abstract]
Schedule III - Supplementary Insurance Information	SCHEDULE III — SUPPLEMENTARY INSURANCE INFORMATION Column A Column B Column C Column D Column E Column F Column G Column H Column I Column J Reserve Incurred Geographic Area for Losses Loss and Amortization Deferred and Loss Unearned Net Loss of Deferred Other Net Acquisition Adjustment Premium Premiums Investment Adjustment Acquisition Operating Written (Dollars in thousands) Costs Expenses Reserves Earned Income Expenses Costs Expenses Premium As of and the Year Ended December 31, 2020 Domestic $ 341,836 $ 9,501,573 $ 2,206,378 $ 5,123,460 $ 341,797 $ 3,920,837 $ 1,063,266 $ 409,912 $ 5,313,490 International 85,678 2,781,210 430,227 1,752,244 37,208 1,074,727 399,908 45,757 1,854,813 Bermuda 194,539 4,116,214 864,754 1,805,809 263,460 1,555,273 410,076 55,568 1,948,680 Total $ 622,053 $ 16,398,997 $ 3,501,359 $ 8,681,513 $ 642,465 $ 6,550,837 $ 1,873,250 $ 511,237 $ 9,116,983 As of and the Year Ended December 31, 2019 Domestic $ 358,108 $ 7,823,095 $ 2,014,712 $ 4,383,837 $ 320,923 $ 2,761,871 $ 1,007,282 $ 348,861 $ 4,605,731 International 66,183 2,655,458 344,222 1,475,669 37,297 1,193,816 342,400 41,690 1,551,753 Bermuda 157,572 3,132,760 697,801 1,544,180 288,919 967,211 354,044 50,348 1,666,940 Total $ 581,863 $ 13,611,313 $ 3,056,735 $ 7,403,686 $ 647,139 $ 4,922,898 $ 1,703,726 $ 440,899 $ 7,824,424 As of and the Year Ended December 31, 2018 Domestic $ 334,818 $ 8,154,003 $ 1,695,208 $ 4,167,619 $ 287,002 $ 3,849,982 $ 835,823 $ 288,933 $ 4,350,157 International 54,253 2,209,202 261,611 1,439,882 34,965 992,704 364,010 39,042 1,458,745 Bermuda 122,502 2,755,885 560,793 1,324,198 259,216 808,717 319,197 43,566 1,605,526 Total $ 511,573 $ 13,119,090 $ 2,517,612 $ 6,931,699 $ 581,183 $ 5,651,403 $ 1,519,030 $ 371,541 $ 7,414,428 (Some amounts may not reconcile due to rounding.)

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2020
Schedule IV - Reinsurance [Abstract]
Schedule IV - Reinsurance	SCHEDULE IV — REINSURANCE Column A Column B Column C Column D Column E Column F Ceded to Assumed Gross Other from Other Net Assumed (Dollars in thousands) Amount Companies Companies Amount to Net December 31, 2020 Total property and liability insurance premiums earned $ 3,028,095 $ 1,401,262 $ 7,054,680 $ 8,681,513 $ 81.3% December 31, 2019 Total property and liability insurance premiums earned $ 2,556,386 $ 1,207,198 $ 6,054,498 $ 7,403,686 $ 81.8% December 31, 2018 Total property and liability insurance premiums earned $ 2,129,320 $ 1,004,953 $ 5,807,332 $ 6,931,699 $ 83.8%

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2020
Summary Of Significant Accounting Policies [Abstract]
Business And Basis Of Presentation	A. Business and Basis of Presentation. 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. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The statements include all of the following domestic and foreign direct and indirect subsidiaries of Group: Everest International Reinsurance, Ltd. (“Everest International”), Mt. Logan Insurance Managers, Ltd., Mt. Logan Management, Ltd., Everest International Holdings (Bermuda), Ltd. (“International Holdings”), Everest Corporate Member Limited, Everest Service Company (UK), Ltd., Everest Preferred International Holdings, Ltd. (“Preferred International”), Everest Reinsurance (Bermuda), Ltd. (“Bermuda Re”), Everest Re Advisors, Ltd., Everest Advisors (UK), Ltd., Everest Underwriting Group (Ireland), Limited (“Holdings Ireland”), Everest Global Services, Inc. (“Global Services”), Everest Insurance Company of Canada (“Everest Canada”), Premiere Insurance Underwriting Services (“Premiere”), Everest Dublin Insurance Holdings Limited (Ireland) (“Everest Dublin Holdings”), Everest Insurance (Ireland), designated activity company (“Ireland Insurance”), Everest Reinsurance Company (Ireland), designated activity company (“Ireland Re”), Everest Reinsurance Holdings, Inc. (“Holdings”), Salus Systems, LLC (“Salus”), Everest International Assurance, Ltd. (Bermuda) (“Everest Assurance”), Specialty Insurance Group, Inc. (“Specialty”), Specialty Insurance Group - Leisure and Entertainment Risk Purchasing Group LLC (“Specialty RPG”), Mt. McKinley Managers, L.L.C., Everest Specialty Underwriters Services, LLC, Everest Reinsurance Company (“Everest Re”), Everest National Insurance Company (“Everest National”), Everest Reinsurance Company Ltda. (Brazil), Mt. Whitney Securities, Inc., Everest Indemnity Insurance Company (“Everest Indemnity”), Everest Denali Insurance Company (“Everest Denali”), Everest Premier Insurance Company (“Everest Premier”) and Everest Security Insurance Company (“Everest Security”). All amounts are reported in U.S. dollars. 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 have control and 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 intercompany accounts and transactions have been eliminated. Certain reclassifications and format changes have been made to prior years’ amounts to conform to the 2020 presentation.
Investments	B. Investments. Fixed maturity investments available for sale, at market value, reflect unrealized appreciation and depreciation, as a result of temporary changes in market value during the period, in shareholders’ equity, net of income taxes in “accumulated other comprehensive income (loss)” in the consolidated balance sheets, since cash flows from these investments will be primarily used to settle its reserve for losses and loss adjustment expense liabilities. The Company anticipates holding these investments for an extended period as the cash flow from interest and maturities will fund the projected payout of these liabilities. The Company reviews all of its fixed maturity, available for sale securities whose fair value has fallen below their amortized cost at the time of review. The Company then assesses whether the decline in value is due to non-credit related or credit related factors. In making its assessment, the Company evaluates the current market and interest rate environment as well as specific issuer information. Generally, a change in a security’s value caused by a change in the market, interest rate or foreign exchange environment does not constitute a credit impairment, but rather a non-credit related decline in market value. Non-credit related declines in market value are recorded as unrealized losses in accumulated other comprehensive income (loss). If the Company intends to sell the security or is more likely than not to sell the security, the Company records the entire fair value adjustment in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). If the Company determines that the decline is credit related and the Company does not have the intent to sell the security; and it is more likely than not that the Company will not have to sell the security before recovery of its cost basis, the Company establishes a credit allowance equal to the estimated credit loss and is recorded in net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). The amount of the allowance for a given security will generally be the difference between a discounted cash flow model and the Company’s carrying value. The fair value adjustment that is non-credit related is recorded as a component of other comprehensive income (loss), net of tax, and is included in accumulated other comprehensive income (loss) in the Company’s consolidated balance sheets. The Company will adjust the credit allowance account for future changes in credit loss estimates for a security and record this adjustment through net realized capital gains (losses) in the Company’s consolidated statements of operations and comprehensive income (loss). For equity securities, at fair value, the Company reflects changes in value as net realized capital gains and losses since these securities may be sold in the near term depending on financial market conditions. Interest income on all fixed maturities and dividend income on all equity securities are included as part of net investment income in the consolidated statements of operations and comprehensive income (loss). Short-term investments are stated at cost, which approximates market value. Realized gains or losses on sales of investments are determined on the basis of identified cost. For some non-publicly traded securities, market prices are determined through the use of pricing models that evaluate securities relative to the U.S. Treasury yield curve, taking into account the issue type, credit quality, and cash flow characteristics of each security. For other non-publicly traded securities, investment managers’ valuation committees will estimate fair value and in many instances, these fair values are supported with opinions from qualified independent third parties. All fair value estimates from investment managers are reviewed by the Company for reasonableness. For publicly traded securities, market value is based on quoted market prices or valuation models that use observable market inputs. When a sector of the financial markets is inactive or illiquid, the Company may use its own assumptions about future cash flows and risk-adjusted discount rates to determine fair value. Retrospective adjustments are employed to recalculate the values of asset-backed securities. 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 to effect the calculation of projected and prepayments for pass-through security types. Other invested assets include limited partnerships, rabbi trusts and prior to July 1, 2018, a private placement liquidity sweep facility. Cash contributions to and cash distributions from the sweep facility were reported gross in cash flows from investing activities in the consolidated statements of cash flows. Limited partnerships are accounted for under the equity method of accounting, which can be recorded on a monthly or quarterly lag.
Allowance for Receivable Balances	C. Allowance for Receivable Balances. Effective January 1, 2020, the Company adopted the Current Expected Credit Losses (CECL) methodology for estimating allowances for credit losses. The Company evaluates the recoverability of its premiums and reinsurance receivable balances and establishes an allowance for estimated uncollectible amounts. Prior to the adoption of CECL, an allowance for doubtful accounts was estimated on the basis of periodic evaluations of balances due from third parties, considering historical collection experience, solvency and current economic conditions. Premiums receivable, excluding receivables for losses within a deductible and retrospectively-rated policy premiums, are primarily comprised of premiums due from policyholders/ cedants. Balances are considered past due when amounts that have been billed are not collected within contractually stipulated time periods. For these balances, the allowance is estimated based on recent historical credit loss and collection experience, adjusted for current economic conditions and reasonable and supportable forecasts, when appropriate. In response to significant economic stress experienced as a result of the COVID-19 pandemic, during 2020, the Company increased the expected loss factors used to estimate the allowance based on collection experience during past moderate and severe recessions as well as experience during periods when we provided policyholders additional time to make premiums payments. A portion of the Company's Commercial Lines business is written with large deductibles or under retrospectively-rated plans. Under some commercial insurance contracts with a large deductible, the Company is obligated to pay the claimant the full amount of the claim and the Company is subsequently reimbursed by the policyholder for the deductible amount. As such, the Company is subject to credit risk until reimbursement is made. Retrospectively-rated policies are policies whereby the ultimate premium is adjusted based on actual losses incurred. Although the premium adjustment feature of a retrospectively-rated policy substantially reduces insurance risk for the Company, it presents credit risk to the Company. The Company’s results of operations could be adversely affected if a significant portion of such policyholders failed to reimburse the Company for the deductible amount or the amount of additional premium owed under retrospectively-rated policies. The Company manages these credit risks through credit analysis, collateral requirements, and oversight. The allowance for receivables for loss within a deductible and retrospectively-rated policy premiums is estimated as the amount of the receivable exposed to loss multiplied by estimated factors for probability of default. The probability of default is assigned based on each policyholder's credit rating, or a rating is estimated if no external rating is available. Credit ratings are reviewed and updated at least annually. The exposure amount is estimated net of collateral and other offsets, considering the nature of the collateral, potential future changes in collateral values, and historical loss information for the type of collateral obtained. The probability of default factors are historical corporate defaults for receivables with similar durations estimated through multiple economic cycles. Credit ratings are forward-looking and consider a variety of economic outcomes. The Company's evaluation of the required allowance for receivables for loss within a deductible and retrospectively-rated policy premiums considers the current economic environment as well as the probability-weighted macroeconomic scenarios. In response to significant economic stress experienced as a result of the COVID-19 pandemic, the Company increased the weight of both a moderate and severe recession scenario in our estimate of the allowance for loss within a deductible and retrospectively-rated policy premiums. The ultimate impact to the Company’s financial statements from the COVID-19 pandemic could vary significantly from our estimates depending on the duration and severity of the pandemic, the duration and severity of the economic downturn and the degree to which federal, state and local government actions to mitigate the economic impact of COVID-19 are effective. The Company records total credit loss expenses related to premiums receivable in other underwriting expenses and records credit loss expenses related to deductibles through losses incurred The allowance for uncollectible reinsurance reflects management’s best estimate of reinsurance cessions that may be uncollectible in the future due to reinsurers’ unwillingness or inability to pay. The allowance for uncollectible reinsurance comprises an allowance and an allowance for disputed balances. Based on this analysis, the Company may adjust the allowance for uncollectible reinsurance or charge off reinsurer balances that are determined to be uncollectible. The allowance is estimated as the amount of reinsurance receivable exposed to loss multiplied by estimated factors for the probability of default. The reinsurance receivable exposed is the amount of reinsurance receivable net of collateral and other offsets, considering the nature of the collateral, potential future changes in collateral values, and historical loss information for the type of collateral obtained. The probability of default factors are historical insurer and reinsurer defaults for liabilities with similar durations to the reinsured liabilities as estimated through multiple economic cycles. Credit ratings are forward-looking and consider a variety of economic outcomes. The Company's evaluation of the required allowance for reinsurance receivable considers the current economic environment as well as macroeconomic scenarios. The Company expects the impact of the COVID-19 pandemic to reinsurers to be somewhat mitigated by their regulated capital and liquidity positions. The ultimate impact to the Company's financial statements could vary significantly from our estimates depending on the duration and severity of the pandemic, the duration and severity of the economic downturn and the degree to which federal, state and local government actions to mitigate the economic impact of COVID-19 are effective. The Company records credit loss expenses related to reinsurance receivable in losses and loss adjustment expenses. Write-offs of reinsurance receivable and any related allowance are recorded in the period in which the balance is deemed uncollectible. Allowances are presented in the table below for the periods indicated. Years Ended December 31, (Dollars in thousands) 2020 2019 Reinsurance receivables and premium receivables $ 41,357 $ 25,605
Deferred Acquisition Costs	D. Deferred Acquisition Costs. Acquisition costs, consisting principally of commissions and brokerage expenses and certain premium taxes and fees incurred at the time a contract or policy is issued and that vary with and are directly related to the Company’s reinsurance and insurance business, are deferred and amortized over the period in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value by line of business based on the related unearned premiums, anticipated claims and claim expenses and anticipated investment income. Deferred acquisition costs amortized to income are presented in the table below for the periods indicated. Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Deferred acquisition costs $ 1,873,250 $ 1,703,726 $ 1,519,030
Reserve For Losses And Loss Adjustment Expenses	E. Reserve for Losses and Loss Adjustment Expenses. The reserve for losses and loss adjustment expenses (“LAE”) is based on individual case estimates and reports received from ceding companies. A provision is included for losses and LAE incurred but not reported (“IBNR”) based on past experience. A provision is also included for certain potential liabilities relating to asbestos and environmental (“A&E”) exposures, for which liabilities cannot be estimated using traditional reserving techniques. See also Note 3. The reserves are reviewed periodically and any changes in estimates are reflected in earnings in the period the adjustment is made. The Company’s loss and LAE reserves represent management’s best estimate of the ultimate liability. Loss and LAE reserves are presented gross of reinsurance receivables and incurred losses and LAE are presented net of reinsurance. Accruals for commissions are established for reinsurance contracts that provide for the stated commission percentage to increase or decrease based on the loss experience of the contract. Changes in estimates for such arrangements are recorded as commission expense. Commission accruals for contracts with adjustable features are estimated based on expected loss and LAE.
Future Policy Benefit Reserve	F. Future Policy Benefit Reserve. Liabilities for future policy benefits on annuity policies are carried at their accumulated values. Reserves for policy benefits include mortality claims in the process of settlement and IBNR claims. Actual experience in a particular period may fluctuate from expected results.
Premium Revenues	G. Premium Revenues. Written premiums are earned ratably over the periods of the related insurance and reinsurance contracts. Unearned premium reserves are established relative to the unexpired contract period. For reinsurance contracts, such reserves are established based upon reports received from ceding companies or estimated using pro rata methods based on statistical data. Reinstatement premiums represent additional premium received on reinsurance coverages, most prevalently catastrophe related, when limits have been depleted under the original reinsurance contract and additional coverage is granted. Written and earned premiums and the related costs, which have not yet been reported to the Company, are estimated and accrued. Premiums are net of ceded reinsurance.
Prepaid Reinsurance Premiums	H. Prepaid Reinsurance Premiums. Prepaid reinsurance premiums represent unearned premium reserves ceded to other reinsurers. Prepaid reinsurance premiums for any foreign reinsurers comprising more than 10% of the outstanding balance at December 31, 2020 were secured either through collateralized trust arrangements, rights of offset or letters of credit, thereby limiting the credit risk to the Company.
Income Taxes	I. Income Taxes. Holdings and its wholly owned subsidiaries file a consolidated U.S. federal income tax return. Foreign subsidiaries and branches of subsidiaries file local tax returns as required. Group and subsidiaries not included in Holdings’ consolidated tax return file separate company U.S. federal income tax returns as required. Deferred income taxes have been recorded to recognize the tax effect of temporary differences between the financial reporting and income tax bases of assets and liabilities, which arise because of differences between GAAP and income tax accounting rules. As an accounting policy, the Company has adopted the aggregate portfolio approach for releasing disproportionate income tax effects from AOCI.
Foreign Currency	J. Foreign Currency. As a global entity, the Company transacts business in numerous currencies through business units located around the world. The base transactional currency for each business unit is determined by the local currency used for most economic activity in that area. Movements in exchange rates related to assets and liabilities at the business units between the original currency and the base currency are recorded through the consolidated statements of operations and comprehensive income (loss) in other income (expense), except for currency movements related to available for sale investments, which are excluded from net income (loss) and accumulated in shareholders’ equity, net of deferred taxes. The business units’ base currency financial statements are translated to U.S. dollars using the exchange rates at the end of period for the balance sheets and the average exchange rates in effect for the reporting period for the income statements. Gains and losses resulting from translating the foreign currency financial statements, net of deferred income taxes, are excluded from net income loss and accumulated in shareholders’ equity.
Earnings Per Common Share	K. 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. Years Ended December 31, (Dollars in thousands, except per share amounts) 2020 2019 2018 Net income (loss) per share: Numerator Net income (loss) $ 514,151 $ 1,009,461 $ 89,041 Less: dividends declared-common shares and nonvested common shares ( 249,056) ( 234,322) ( 216,221) Undistributed earnings 265,094 775,139 ( 127,180) Percentage allocated to common shareholders (1) 98.7 % 98.9 % 99.0 % 261,770 766,386 ( 125,848) Add: dividends declared-common shareholders 246,054 231,796 214,088 Numerator for basic and diluted earnings per common share $ 507,824 $ 998,182 $ 88,239 Denominator Denominator for basic earnings per weighted-average common shares 39,656 40,291 40,388 Effect of dilutive securities: Options 77 129 198 Denominator for diluted earnings per adjusted weighted-average common shares 39,734 40,420 40,586 Per common share net income (loss) Basic $ 12.81 $ 24.77 $ 2.18 Diluted $ 12.78 $ 24.70 $ 2.17 (1) Basic weighted-average common shares outstanding 39,656 40,291 40,388 Basic weighted-average common shares outstanding and nonvested common shares expected to vest 40,160 40,751 40,816 Percentage allocated to common shareholders 98.7 % 98.9 % 99.0 % (Some amounts may not reconcile due to rounding.) There were no anti-diluted options outstanding for the years ended December 31, 2020, 2019 and 2018. All outstanding options expire on or between February 24, 2021 and September 19, 2022.
Segmentation	L. Segmentation. With recent changes in executive management and organizational structure, the Company manages its reinsurance and insurance operations as autonomous units and key strategic decisions are based on the aggregate operating results and projections for these segments of business. Accordingly, effective January 1, 2020, the Company revised it reporting segments to Reinsurance Operations and Insurance Operations. This replaces the previous reported segments of U.S. Reinsurance, International (reinsurance), Bermuda (reinsurance) and Insurance. The prior year presented segment information has been reformatted to reflect this change. See also Note 17.
Deposit Assets And Liabilities	M. Deposit Assets and Liabilities. In the normal course of its operations, the Company may enter into contracts that do not meet risk transfer provisions. Such contracts are accounted for using the deposit accounting method and are included in other liabilities in the Company’s consolidated balance sheets. For such contracts, the Company originally records deposit liabilities for an amount equivalent to the assets received. Actuarial studies are used to estimate the final liabilities under such contracts with any change reflected in the consolidated statements of operations and comprehensive income (loss).
Share-Based Compensation	N. Share-Based Compensation. Share-based compensation stock option, restricted share and performance share unit awards are fair valued at the grant date and expensed over the vesting period of the award. The tax benefit on the recorded expense is deferred until the time the award is exercised or vests (becomes unrestricted). See Note 16.
Application Of Recently Issued Accounting Guidance	O. Application of Recently Issued Accounting Guidance. Accounting for Income Taxes. In December 2019, The Financial Accounting Standards Board (“FASB”) issued ASU 2019-12, which provides simplification of existing guidance for income taxes, including the removal of certain exceptions related to recognition of deferred tax liabilities on foreign subsidiaries. The guidance is effective for annual reporting periods beginning after December 15, 2020 and interim periods within that annual reporting period. The Company is currently evaluating the impact of the adoption of ASU 2019-12 on its financial statements. Accounting for Cloud Computing Arrangement. In August 2018, FASB issued ASU 2018-15, which outlines accounting for implementation costs of a cloud computing arrangement that is a service contract. This guidance requires that implementation costs of a cloud computing arrangement that is a service contract must be capitalized and expensed in accordance with the existing provisions provided in Subtopic 350-40 regarding development of internal use software. In addition, any capitalized implementation costs should be amortized over the term of the hosting arrangement. The guidance is effective for annual reporting periods beginning after December 15, 2019 and interim periods within that annual reporting period. The Company adopted the guidance as of January 1, 2020. The adoption of ASU 2018-15 did not have a material impact on the Company’s financial statements. Accounting for Long Duration Contracts. In August 2018, FASB issued ASU 2018-12, which discusses changes to the recognition, measurement and presentation of long duration contracts. The main provisions of this guidance address the following: 1) In determining liability for future policy benefits, companies must review cash flow assumptions at least annually and the discount rate assumption at each reporting period date 2) Amortization of deferred acquisition costs has been simplified to be in constant level proportion to either premiums, gross profits or gross margins 3) Disaggregated roll forwards of beginning and ending liabilities for future policy benefits are required. The guidance was originally effective for annual reporting periods beginning after December 15, 2020 and interim periods within that annual reporting period. However, FASB issued ASU 2019-09 in November 2019 and then ASU 2020-11 in November 2021, which ultimately defers the effective date of ASU 2018-12 until annual reporting periods beginning after December 15, 2022. The Company is currently evaluating the impact of the adoption of ASU 2018-12 on its financial statements. Accounting for Impact on Income Taxes due to Tax Reform. In December 2017, the SEC issued Staff Accounting Bulletin (“SAB”) 118 which provides guidance on the application of FASB Accounting Standards Codification (“ASC”) Topic 740, Income Taxes, due to the enactment of TCJA. SAB 118 became effective upon release. The Company has adopted the provisions of SAB 118 with respect to measuring the tax effects for the modifications to the determination of tax basis loss reserves. In 2018, the Company recorded adjustments to the amount of tax expense it recorded in 2017 with respect to the TCJA as estimated amounts were finalized, which did not have a material impact on the Company’s financial statements. Amortization of Bond Premium. In March 2017, FASB issued ASU 2017-08 which outlines guidance on the amortization period for premium on callable debt securities. The new guidance requires that the premium on callable debt securities be amortized through the earliest call date rather than through the maturity date of the callable security. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018. The Company adopted the guidance effective January 1, 2019. The adoption of ASU 2017-08 did not have a material impact on the Company’s financial statements. Valuation of Financial Instruments. In June 2016, FASB issued ASU 2016-13 (and has subsequently issued related guidance and amendments in ASU 2019-11 and ASU 2019-10 in November 2019) which outline guidance on the valuation of and accounting for assets measured at amortized cost and available for sale debt securities. The new guidance requires the carrying value of assets measured at amortized cost, including reinsurance and premiums receivables to be presented as the net amount expected to be collected on the financial asset (amortized cost less an allowance for credit losses valuation account). The allowance reflects expected credit losses of the financial asset which considers available information using a combination both historical information, current market conditions and reasonable and supportable forecasts. For available-for-sale debt securities, the guidance modified the previous other than temporary impairment model, now requiring an allowance for estimated credit related losses rather than a permanent impairment, which will be limited to the amount by which fair value is below amortized cost. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. The Company adopted the guidance effective January 1, 2020, on a modified retrospective basis. The adoption resulted in a cumulative reduction of $ 4,214 thousand in retained earnings, net of tax, which is disclosed separately within the Consolidated Statements of Shareholders’ Equity. Leases . In February 2016, FASB issued ASU 2016-02 (and subsequently issued ASU 2018-11 in July, 2018) which outline new guidance on the accounting for leases. The new guidance requires the recognition of lease assets and lease liabilities on the balance sheets for most leases that were previously deemed operating leases and required only lease expense presentation in the statements of operations. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018. The Company adopted ASU 2016-02 effective January 1, 2019 and elected to utilize a cumulative-effect adjustment to the opening balance of retained earnings for the year of adoption. Accordingly, the Company’s reporting for the comparative periods prior to adoption continue to be presented in the financial statements in accordance with previous lease accounting guidance. The Company also elected to apply the package of practical expedients applicable to the Company in the updated guidance for transition for leases in effect at adoption. The Company did not elect the hindsight practical expedient to determine the lease term of existing leases (e.g. The Company did not re-assess lease renewals, termination options nor purchase options in determining lease terms). The adoption of the updated guidance resulted in the Company recognizing a right-of-use asset of $ 69,869 thousand as part of other assets and a lease liability of $ 77,270 thousand as part of other liabilities in the consolidated balance sheet at the time of adoption, as well as de-recognizing the liability for deferred rent that was required under the previous guidance. The cumulative effect adjustment to the opening balance of retained earnings was zero Recognition and Measurement of Financial Instruments. In January 2016, the FASB issued ASU 2016-01 which outlines revised guidance on the accounting for equity investments. The new guidance states that all equity investments in unconsolidated entities will be measured at fair value, with the change in value being recorded through the income statement rather than being recorded within other comprehensive income. The updated 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 2016-01 resulted in a cumulative change adjustment of $ 1,201 thousand between AOCI and retained earnings, which is disclosed separately within the consolidated statement of changes in shareholders’ equity. 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.

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Summary Of Significant Accounting Policies [Abstract]
Schedule Of Uncollectible Reinsurance Recoverable And Premium Receivables	Years Ended December 31, (Dollars in thousands) 2020 2019 Reinsurance receivables and premium receivables $ 41,357 $ 25,605
Schedule Of Deferred Acquisition Costs Amortized To Income	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Deferred acquisition costs $ 1,873,250 $ 1,703,726 $ 1,519,030
Net Income (Loss) Per Common Share	Years Ended December 31, (Dollars in thousands, except per share amounts) 2020 2019 2018 Net income (loss) per share: Numerator Net income (loss) $ 514,151 $ 1,009,461 $ 89,041 Less: dividends declared-common shares and nonvested common shares ( 249,056) ( 234,322) ( 216,221) Undistributed earnings 265,094 775,139 ( 127,180) Percentage allocated to common shareholders (1) 98.7 % 98.9 % 99.0 % 261,770 766,386 ( 125,848) Add: dividends declared-common shareholders 246,054 231,796 214,088 Numerator for basic and diluted earnings per common share $ 507,824 $ 998,182 $ 88,239 Denominator Denominator for basic earnings per weighted-average common shares 39,656 40,291 40,388 Effect of dilutive securities: Options 77 129 198 Denominator for diluted earnings per adjusted weighted-average common shares 39,734 40,420 40,586 Per common share net income (loss) Basic $ 12.81 $ 24.77 $ 2.18 Diluted $ 12.78 $ 24.70 $ 2.17 (1) Basic weighted-average common shares outstanding 39,656 40,291 40,388 Basic weighted-average common shares outstanding and nonvested common shares expected to vest 40,160 40,751 40,816 Percentage allocated to common shareholders 98.7 % 98.9 % 99.0 % (Some amounts may not reconcile due to rounding.)

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2020
Investments [Abstract]
Summary Of Unrealized Appreciation (Depreciation) Of Available For Sale, Fixed Maturity And Equity Security Investments	At December 31, 2020 Amortized Allowance for Unrealized Unrealized Market (Dollars in thousands) Cost Credit Losses Appreciation Depreciation Value Fixed maturity securities U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,325,156 $ - $ 49,084 $ ( 7,134) $ 1,367,106 Obligations of U.S. states and political subdivisions 543,895 - 34,654 ( 1,254) 577,295 Corporate securities 6,824,800 ( 1,220) 380,677 ( 55,231) 7,149,026 Asset-backed securities 2,540,809 - 30,691 ( 5,698) 2,565,802 Mortgage-backed securities Commercial 915,923 - 75,275 ( 895) 990,303 Agency residential 2,206,139 - 64,663 ( 3,063) 2,267,739 Non-agency residential 5,187 - 9 ( 2) 5,194 Foreign government securities 1,565,260 ( 22) 102,587 ( 22,450) 1,645,375 Foreign corporate securities 3,297,898 ( 503) 204,023 ( 29,085) 3,472,333 Total fixed maturity securities $ 19,225,067 $ ( 1,745) $ 941,663 $ ( 124,812) $ 20,040,173 At December 31, 2019 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 $ 1,489,660 $ 28,357 $ ( 2,214) $ 1,515,803 $ - Obligations of U.S. states and political subdivisions 507,353 29,651 ( 89) 536,915 - Corporate securities 6,227,661 185,052 ( 37,767) 6,374,946 469 Asset-backed securities 892,373 6,818 ( 1,858) 897,333 - Mortgage-backed securities Commercial 814,570 31,236 ( 1,249) 844,557 - Agency residential 2,173,099 36,361 ( 10,879) 2,198,581 - Non-agency residential 5,723 - ( 20) 5,703 - Foreign government securities 1,492,315 47,148 ( 33,513) 1,505,950 71 Foreign corporate securities 2,870,737 107,999 ( 33,580) 2,945,156 447 Total fixed maturity securities $ 16,473,491 $ 472,622 $ ( 121,169) $ 16,824,944 $ 987 (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.
Summary Of Amortized Cost And Market Value Of Fixed Maturity Securities, By Contractual Maturity	At December 31, 2020 At December 31, 2019 Amortized Market Amortized Market (Dollars in thousands) Cost Value Cost Value Fixed maturity securities – available for sale: Due in one year or less $ 1,365,793 $ 1,374,674 $ 1,456,960 $ 1,457,919 Due after one year through five years 6,529,189 6,774,785 6,757,107 6,869,359 Due after five years through ten years 4,414,211 4,751,903 3,471,370 3,609,816 Due after ten years 1,247,816 1,309,773 902,289 941,676 Asset-backed securities 2,540,809 2,565,802 892,373 897,333 Mortgage-backed securities: Commercial 915,923 990,303 814,570 844,557 Agency residential 2,206,139 2,267,739 2,173,099 2,198,581 Non-agency residential 5,187 5,194 5,723 5,703 Total fixed maturity securities $ 19,225,067 $ 20,040,173 $ 16,473,491 $ 16,824,944
Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments	Years Ended December 31, (Dollars in thousands) 2020 2019 Increase (decrease) during the period between the market value and cost of investments carried at market value, and deferred taxes thereon: Fixed maturity securities $ 465,192 $ 534,410 Fixed maturity securities, other-than-temporary impairment - ( 1,559) Change in unrealized appreciation (depreciation), pre-tax 465,192 532,851 Deferred tax benefit (expense) ( 45,458) ( 49,149) Deferred tax benefit (expense), other-than-temporary impairment - 115 Change in unrealized appreciation (depreciation), net of deferred taxes, included in shareholders’ equity $ 419,734 $ 483,817
Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Security Type	Duration of Unrealized Loss at December 31, 2020 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 $ 135,190 $ ( 7,134) $ - $ - $ 135,190 $ ( 7,134) Obligations of U.S. states and political subdivisions 19,524 ( 999) 4,059 ( 255) 23,583 ( 1,254) Corporate securities 669,755 ( 26,159) 247,962 ( 29,072) 917,717 ( 55,231) Asset-backed securities 235,566 ( 4,768) 85,595 ( 930) 321,161 ( 5,698) Mortgage-backed securities Commercial 53,511 ( 578) 6,592 ( 317) 60,103 ( 895) Agency residential 434,447 ( 2,016) 50,353 ( 1,047) 484,800 ( 3,063) Non-agency residential 185 ( 2) - - 185 ( 2) Foreign government securities 114,755 ( 8,813) 150,812 ( 13,637) 265,567 ( 22,450) Foreign corporate securities 354,548 ( 17,489) 115,595 ( 11,596) 470,143 ( 29,085) Total fixed maturity securities $ 2,017,481 $ ( 67,958) $ 660,968 $ ( 56,854) $ 2,678,449 $ ( 124,812) Duration of Unrealized Loss at December 31, 2019 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 $ 85,527 $ ( 1,005) $ 249,371 $ ( 1,209) $ 334,898 $ ( 2,214) Obligations of U.S. states and political subdivisions 4,600 ( 38) 5,522 ( 51) 10,122 ( 89) Corporate securities 547,120 ( 9,877) 395,369 ( 27,890) 942,489 ( 37,767) Asset-backed securities 176,222 ( 1,027) 94,190 ( 831) 270,412 ( 1,858) Mortgage-backed securities Commercial 83,127 ( 689) 23,063 ( 560) 106,190 ( 1,249) Agency residential 344,267 ( 1,834) 488,680 ( 9,045) 832,947 ( 10,879) Non-agency residential 332 - 3,976 ( 20) 4,308 ( 20) Foreign government securities 210,766 ( 4,770) 283,648 ( 28,743) 494,414 ( 33,513) Foreign corporate securities 278,403 ( 7,553) 365,808 ( 26,027) 644,211 ( 33,580) Total fixed maturity securities $ 1,730,364 $ ( 26,793) $ 1,909,627 $ ( 94,376) $ 3,639,991 $ ( 121,169)
Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity	Duration of Unrealized Loss at December 31, 2020 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 $ 96,144 $ ( 4,942) $ 112,419 $ ( 12,071) $ 208,563 $ ( 17,013) Due in one year through five years 653,816 ( 32,469) 283,866 ( 21,319) 937,682 ( 53,788) Due in five years through ten years 422,517 ( 19,392) 49,749 ( 2,034) 472,266 ( 21,426) Due after ten years 121,295 ( 3,791) 72,394 ( 19,136) 193,689 ( 22,927) Asset-backed securities 235,566 ( 4,768) 85,595 ( 930) 321,161 ( 5,698) Mortgage-backed securities 488,143 ( 2,596) 56,945 ( 1,364) 545,088 ( 3,960) Total fixed maturity securities $ 2,017,481 $ ( 67,958) $ 660,968 $ ( 56,854) $ 2,678,449 $ ( 124,812) Duration of Unrealized Loss at December 31, 2019 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 $ 67,879 $ ( 1,237) $ 416,583 $ ( 23,004) $ 484,462 $ ( 24,241) Due in one year through five years 464,753 ( 7,960) 689,195 ( 38,138) 1,153,948 ( 46,098) Due in five years through ten years 495,741 ( 12,388) 103,612 ( 11,100) 599,353 ( 23,488) Due after ten years 98,043 ( 1,658) 90,328 ( 11,678) 188,371 ( 13,336) Asset-backed securities 176,222 ( 1,027) 94,190 ( 831) 270,412 ( 1,858) Mortgage-backed securities 427,726 ( 2,523) 515,719 ( 9,625) 943,445 ( 12,148) Total fixed maturity securities $ 1,730,364 $ ( 26,793) $ 1,909,627 $ ( 94,376) $ 3,639,991 $ ( 121,169)
Summary Of Components Of Net Investment Income	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Fixed maturities $ 542,363 $ 520,291 $ 465,793 Equity securities 18,776 19,505 25,327 Short-term investments and cash 5,012 17,619 14,395 Other invested assets Limited partnerships 112,853 105,815 93,327 Other 1,699 14,117 16,960 Gross investment income before adjustments 680,703 677,347 615,802 Funds held interest income (expense) 12,754 13,271 6,300 Future policy benefit reserve income (expense) ( 1,237) ( 1,380) ( 1,419) Gross investment income 692,220 689,238 620,683 Investment expenses ( 49,755) ( 42,099) ( 39,500) Net investment income $ 642,465 $ 647,139 $ 581,183
Summary Of Components Of Net Realized Capital Gains (Losses)	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Fixed maturity securities, market value: Allowance for credit losses $ ( 1,745) $ - $ - Other-than-temporary impairments - ( 20,899) ( 8,110) Gains (losses) from sales ( 2,214) 28,025 ( 21,719) Fixed maturity securities, fair value: Gains (losses) from sales ( 2,863) 355 ( 1,799) Gains (losses) from fair value adjustments 1,944 1,808 1,506 Equity securities, fair value: Gains (losses) from sales ( 8,963) 4,148 ( 29,941) Gains (losses) from fair value adjustments 278,461 165,200 ( 68,832) Other invested assets 1,705 6,003 1,815 Short-term investments gain (loss) 1,324 364 ( 56) Total net realized capital gains (losses) $ 267,649 $ 185,004 $ ( 127,136) Roll Forward of Allowance for Credit Losses Twelve Months Ended December 31, 2020 Foreign Foreign Corporate Government Corporate Securities Securities Securities Total (Dollars in thousands) Beginning Balance $ - $ - $ - $ - Credit losses on securities where credit losses were not previously recorded ( 27,666) ( 518) ( 4,700) ( 32,884) Increases in allowance on previously impaired securities ( 6,136) ( 28) ( 481) ( 6,645) Decreases in allowance on previously impaired securities 4,333 309 883 5,525 Reduction in allowance due to disposals 28,249 215 3,795 32,259 Balance as of December 31, 2020 $ ( 1,220) $ ( 22) $ ( 503) $ ( 1,745)
Summary Of Gross Gains (Losses) From Sales Of Fixed Maturity And Equity Securities	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Proceeds from sales of fixed maturity securities $ 1,950,774 $ 3,283,154 $ 3,150,179 Gross gains from sales 79,609 63,721 33,996 Gross losses from sales ( 84,686) ( 35,341) ( 57,514) Proceeds from sales of equity securities $ 376,347 $ 283,965 $ 1,199,409 Gross gains from sales 37,415 14,274 31,718 Gross losses from sales ( 46,378) ( 10,126) ( 61,659)

Reserve For Losses, LAE And F_2

Reserve For Losses, LAE And Future Policy Benefit Reserve (Tables)	12 Months Ended
	Dec. 31, 2020
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Summary Of Activity In The Reserve For Losses And LAE	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross reserves beginning of period $ 13,611,313 $ 13,119,090 11,884,321 Less reinsurance recoverables ( 1,640,712) ( 1,619,641) ( 1,212,649) Net reserves beginning of period 11,970,601 11,499,449 10,671,672 Incurred related to: Current year 6,149,410 4,986,456 5,264,327 Prior years 401,427 ( 63,558) 387,076 Total incurred losses and LAE 6,550,837 4,922,898 5,651,403 Paid related to: Current year 2,046,260 2,042,246 1,700,765 Prior years 2,080,816 2,460,825 3,011,175 Total paid losses and LAE 4,127,076 4,503,071 4,711,940 Foreign exchange/translation adjustment 160,944 51,325 ( 111,686) Net reserves end of period 14,555,306 11,970,601 11,499,449 Plus reinsurance recoverables 1,843,691 1,640,712 1,619,641 Gross reserves end of period $ 16,398,997 $ 13,611,313 13,119,090 (Some amounts may not reconcile due to rounding.)
Ultimate Loss And ALAE And Paid Loss And ALAE, Net Of Reinsurance	Reinsurance – Casualty Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 917,560 $ 811,282 $ 712,407 $ 698,212 $ 682,333 $ 684,537 $ 689,068 $ 663,308 $ 641,893 43,700 N/A 2013 730,202 821,395 809,631 800,451 770,745 741,873 721,961 721,902 56,597 N/A 2014 780,730 820,870 828,341 805,087 763,611 740,786 753,967 72,825 N/A 2015 805,551 845,303 840,659 837,802 821,513 858,157 113,144 N/A 2016 818,293 895,558 892,576 887,698 963,300 195,650 N/A 2017 903,896 863,306 870,174 951,461 319,560 N/A 2018 1,356,788 1,354,279 1,431,276 639,205 N/A 2019 1,740,245 1,810,434 1,118,428 N/A 2020 1,963,469 1,497,536 N/A $ 10,095,859 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 42,576 99,763 182,550 278,492 358,953 429,165 509,020 543,688 555,736 2013 50,506 125,739 217,243 317,744 392,503 500,316 552,824 579,350 2014 58,833 124,433 216,441 307,587 434,450 511,143 557,209 2015 58,406 165,005 273,896 421,223 511,414 581,942 2016 94,154 196,746 333,163 441,325 558,379 2017 83,286 192,547 327,625 475,472 2018 159,215 299,369 465,181 2019 219,229 354,292 2020 194,704 $ 4,322,265 All outstanding liabilities prior to 2012, net of reinsurance 940,597 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 6,714,191 (Some amounts may not reconcile due to rounding.) Reinsurance – Property Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 1,625,024 1,311,752 1,188,304 1,187,096 1,181,200 1,174,224 1,162,252 1,181,653 1,184,476 7,419 N/A 2013 1,326,814 969,175 857,241 801,457 795,978 791,400 798,652 797,047 1,722 N/A 2014 1,388,249 1,230,656 1,080,269 987,401 987,230 988,193 980,449 3,325 N/A 2015 1,420,523 1,090,474 1,014,531 988,469 991,202 983,478 2,384 N/A 2016 1,730,936 1,557,262 1,593,116 1,587,145 1,564,702 20,676 N/A 2017 2,825,218 3,447,971 3,558,713 3,687,487 28,865 N/A 2018 2,684,311 2,559,953 2,561,852 121,379 N/A 2019 2,165,898 2,192,239 434,700 N/A 2020 2,487,352 1,341,994 N/A 16,439,082 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 417,397 723,394 896,372 1,016,689 1,051,968 1,086,813 1,098,004 1,120,273 1,126,302 2013 394,228 567,616 670,369 728,570 749,345 759,925 768,490 770,215 2014 388,263 678,897 812,441 889,561 921,183 931,451 937,437 2015 390,284 633,428 792,018 876,356 905,281 926,388 2016 480,453 986,043 1,269,622 1,394,284 1,447,824 2017 835,042 2,207,048 2,775,818 3,161,267 2018 576,573 1,579,781 1,969,117 2019 770,686 1,250,409 2020 616,160 12,205,119 All outstanding liabilities prior to 2012, net of reinsurance 105,209 Liabilities for claims and claim adjustment expenses, net of reinsurance 4,339,172 (Some amounts may not reconcile due to rounding.) Insurance – Casualty Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 349,724 351,529 347,068 348,262 353,395 344,008 346,983 351,444 353,945 11,283 15,780 2013 393,710 393,539 392,976 393,148 351,399 344,498 350,947 349,985 20,093 21,385 2014 431,323 457,296 454,827 460,888 397,334 398,153 399,048 38,361 25,221 2015 519,917 528,517 536,155 542,687 469,132 472,125 80,007 26,996 2016 554,253 552,192 581,273 617,051 554,621 138,312 31,673 2017 614,949 605,062 628,149 660,114 180,513 35,020 2018 708,808 715,008 754,053 275,213 34,884 2019 852,767 856,466 444,603 37,597 2020 990,982 649,288 26,068 5,391,340 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 33,194 101,301 157,924 213,488 246,455 272,114 294,444 306,937 311,865 2013 33,314 117,046 176,326 224,633 260,223 285,873 303,786 310,928 2014 41,194 124,937 201,689 256,886 297,762 326,011 339,487 2015 44,317 134,761 218,990 292,115 353,445 382,748 2016 54,740 164,384 269,163 343,020 402,693 2017 53,922 172,476 281,500 381,442 2018 63,614 208,531 319,858 2019 72,399 235,087 2020 63,878 2,747,987 All outstanding liabilities prior to 2012, net of reinsurance 224,752 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 2,868,104 (Some amounts may not reconcile due to rounding.) Insurance – Property Business At December 31, 2020 Total of IBNR Liabilities Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance Plus Expected Years Ended December 31, Development Cumulative 2012 2013 2014 2015 2016 2017 2018 2019 2020 on Reported Number of Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) Claims Reported Claims (Dollars in thousands) 2012 $ 106,364 89,039 81,774 82,476 82,045 81,828 82,006 82,553 82,614 1 N/A 2013 112,083 98,206 91,336 92,224 92,313 92,473 92,328 91,895 29 N/A 2014 131,754 123,745 119,991 119,525 119,346 119,483 119,139 57 N/A 2015 173,062 153,031 144,084 146,934 144,923 146,630 286 N/A 2016 291,370 275,812 280,872 292,986 295,364 308 N/A 2017 498,359 502,935 496,583 499,724 6,358 N/A 2018 409,527 403,294 398,616 5,436 N/A 2019 349,177 352,038 14,100 N/A 2020 623,267 255,707 N/A 2,609,287 (Some amounts may not reconcile due to rounding.) Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2019 2020 Accident Year (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (Dollars in thousands) 2012 $ 56,506 81,798 80,496 81,777 81,918 81,708 81,847 82,483 82,613 2013 68,712 93,181 91,921 92,191 91,800 91,840 91,857 91,866 2014 81,853 116,090 118,278 118,271 118,606 118,726 118,801 2015 102,241 141,396 142,563 145,371 146,870 146,958 2016 162,916 250,073 272,583 290,476 293,457 2017 179,432 425,607 460,412 483,178 2018 245,944 359,452 379,937 2019 227,639 317,960 2020 293,269 2,208,038 All outstanding liabilities prior to 2012, net of reinsurance 39 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 401,287 (Some amounts may not reconcile due to rounding.)
Average Annual Percentage Payout Incurred Claims By Age, Net Of Reinsurance	Reinsurance – Casualty Business Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Casualty 9.5 % 9.7 % 12.9 % 14.1 % 12.4 % 10.9 % 8.4 % 4.5 % 1.9 % Reinsurance – Property Business Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Property 29.6 % 31.3 % 15.4 % 9.2 % 3.1 % 1.9 % 0.9 % 1.2 % 0.5 % Insurance – Casualty Business Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Casualty 8.5 % 19.6 % 17.0 % 14.6 % 10.8 % 6.9 % 4.9 % 2.8 % 1.4 % Insurance – Property Business Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (unaudited) Years 1 2 3 4 5 6 7 8 9 Property 54.4 % 33.2 % 4.8 % 3.6 % 2.8 % - % 0.6 % 0.4 % 0.2 %
Reconciliation of the Net Incurred and Paid Claims Development	December 31, 2020 (Dollars in thousands) Net outstanding liabilities Reinsurance Casualty $ 6,714,191 Reinsurance Property 4,339,172 Insurance Casualty 2,868,104 Insurance Property 401,287 Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance 14,322,754 Reinsurance recoverable on unpaid claims Reinsurance Casualty 399,865 Reinsurance Property 456,062 Insurance Casualty 818,701 Insurance Property 169,062 Total reinsurance recoverable on unpaid claims 1,843,691 Insurance lines other than short-duration - Unallocated claims adjustment expenses 194,111 Other 38,441 232,552 Total gross liability for unpaid claims and claim adjustment expense $ 16,398,997 (Some amounts may not reconcile due to rounding.)
Summary Of Incurred Losses With Respect To A&E Reserve On Both Gross And Net Of Reinsurance Basis	At December 31, (Dollars in thousands) 2020 2019 2018 Gross basis: Beginning of period reserves $ 257,921 $ 347,495 $ 448,994 Incurred losses 1,540 2,070 ( 2,473) Paid losses ( 40,120) ( 91,644) ( 99,026) End of period reserves $ 219,341 $ 257,921 $ 347,495 Net basis: Beginning of period reserves $ 228,701 $ 261,456 $ 318,081 Incurred losses ( 772) - - Paid losses ( 29,674) ( 32,756) ( 56,624) End of period reserves $ 198,255 $ 228,701 $ 261,456
Summary Of Activity In The Reserve For Future Policy Benefits	At December 31, (Dollars in thousands) 2020 2019 2018 Balance at beginning of year $ 42,592 $ 46,778 $ 51,014 Liabilities assumed 35 53 110 Adjustments to reserves ( 1,113) 350 806 Benefits paid in the current year ( 3,791) ( 4,589) ( 5,151) Balance at end of year $ 37,723 $ 42,592 $ 46,778 (Some amounts may not reconcile due to rounding.)

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2020
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) December 31, 2020 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,367,106 $ - $ 1,367,106 $ - Obligations of U.S. States and political subdivisions 577,295 - 577,295 - Corporate securities 7,149,026 - 6,447,534 701,492 Asset-backed securities 2,565,802 - 1,942,769 623,033 Mortgage-backed securities Commercial 990,303 - 990,303 - Agency residential 2,267,739 - 2,267,739 - Non-agency residential 5,194 - 5,194 - Foreign government securities 1,645,375 - 1,645,375 - Foreign corporate securities 3,472,333 - 3,466,634 5,699 Total fixed maturities, market value 20,040,173 - 18,709,949 1,330,224 Equity securities, fair value 1,472,236 1,368,704 103,532 - Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2019 (Level 1) (Level 2) (Level 3) Assets: Fixed maturities, market value U.S. Treasury securities and obligations of U.S. government agencies and corporations $ 1,515,803 $ - $ 1,515,803 $ - Obligations of U.S. States and political subdivisions 536,915 - 536,915 - Corporate securities 6,374,946 - 5,757,358 617,588 Asset-backed securities 897,333 - 743,692 153,641 Mortgage-backed securities Commercial 844,557 - 844,557 - Agency residential 2,198,581 - 2,198,581 - Non-agency residential 5,703 - 5,703 - Foreign government securities 1,505,950 - 1,505,950 - Foreign corporate securities 2,945,156 - 2,943,406 1,750 Total fixed maturities, market value 16,824,944 - 16,051,965 772,979 Fixed maturities, fair value 5,826 - - 5,826 Equity securities, fair value 931,457 864,584 66,873 -
Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type	Total Fixed Maturities, Market Value December 31, 2020 December 31, 2019 Corporate Asset-Backed Foreign Corporate Asset-Backed Foreign (Dollars in thousands) Securities Securities Corporate Total Securities Securities Corporate Total Beginning balance fixed maturities at market value $ 617,588 $ 153,641 $ 1,750 $ 772,979 $ 428,215 $ - $ 7,744 $ 435,959 Total gains or (losses) (realized/unrealized) Included in earnings 1,216 681 ( 125) 1,772 4,937 - ( 12) 4,925 Included in other comprehensive income (loss) ( 1,115) 11,678 147 10,710 ( 20) 3,632 ( 110) 3,502 Purchases, issuances and settlements 84,840 457,033 3,814 545,687 179,761 150,009 ( 5,872) 323,898 Transfers in and/or (out) of Level 3 ( 1,037) - 113 ( 924) 4,695 - - 4,695 Ending balance $ 701,492 $ 623,033 $ 5,699 $ 1,330,224 $ 617,588 $ 153,641 $ 1,750 $ 772,979 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 $ ( 539) $ - $ - $ ( 539) $ - $ - $ - $ - (Some amounts may not reconcile due to rounding.) Total Fixed Maturities, Fair Value December 31, 2020 December 31, 2019 Foreign Foreign (Dollars in thousands) Corporate Total Corporate Total Beginning balance fixed maturities at market value $ 5,826 $ 5,826 $ 2,337 $ 2,337 Total gains or (losses) (realized/unrealized) Included in earnings ( 919) ( 919) 2,163 2,163 Included in other comprehensive income (loss) - - - - Purchases, issuances and settlements ( 4,907) ( 4,907) 1,326 1,326 Transfers in and/or (out) of Level 3 - - - - Ending balance $ - $ - $ 5,826 $ 5,826 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 $ - $ - $ 1,795 $ 1,795 (Some amounts may not reconcile due to rounding.)
Fair Value Measurements Using Significant Unobservable Inputs For Equity Index Put Option Contracts	Years Ended December 31, (Dollars in thousands) 2020 2019 Common Stock Balance, beginning of period $ - $ - Total (gains) or losses (realized/unrealized) Included in earnings - - Included in other comprehensive income (loss) - - Purchases, issuances and settlements 9,877 - Transfers in and/or (out) of Level 3 ( 9,877) - Balance, end of period $ - $ - 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.)

Credit Facilities (Tables)

Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2020
Line of Credit Facility [Line Items]
Summary Of Costs Incurred Connection With Credit Facilities	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Credit facility interest and fees incurred - Wells Fargo Bank $ 664 $ 420 $ 420 Loan interest and fees incurred - Federal Home Loan Bank 151 - - Total interest and fees incurred $ 815 $ 420 $ 420
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And Borrowings	(Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Wells Fargo Bank Group Credit Facility Tranche One $ 200,000 $ 164,242 12/31/2021 $ 200,000 $ 33,737 12/31/2020 Tranche Two 600,000 589,690 12/31/2021 600,000 2,381 07/29/2020 Tranche Two - 1,649 09/30/2020 Tranche Two - 573,353 12/31/2020 Tranche Two - 12,364 01/04/2021 Total Wells Fargo Bank Group Credit Facility $ 800,000 $ 753,932 $ 800,000 $ 623,484
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And Borrowings	(Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Citibank Bilateral Letter of Credit Agreement $ 200,000 $ 4,425 02/28/2021 $ 200,000 $ 4,425 02/29/2020 3,672 11/24/2021 512 09/03/2020 448 12/16/2021 3,672 11/24/2020 115 12/20/2021 177 12/16/2020 136,383 12/31/2021 125 12/20/2020 39,619 12/30/2024 101,404 12/31/2020 821 08/15/2022 559 08/15/2021 - 37,096 12/30/2023 Total Citibank Bilateral Agreement $ 200,000 $ 185,483 $ 200,000 $ 147,970
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Summary Of Outstanding Letters Of Credit And Borrowings	(Dollars in thousands) At December 31, 2020 At December 31, 2019 Bank Commitment In Use Date of Expiry Commitment In Use Date of Expiry Lloyd's Bank plc £ 52,175 £ 52,175 12/31/2024 £ 47,000 £ 47,000 12/31/2023 - - - - Total Lloyd's Bank Credit Facility £ 52,175 £ 52,175 £ 47,000 £ 47,000

Senior Notes (Tables)

Senior Notes (Tables)	12 Months Ended
	Dec. 31, 2020
Senior Notes [Abstract]
Schedule Of Outstanding Senior Notes	December 31, 2020 December 31, 2019 Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Date Due Principal Amounts Sheet Amount Market Value Sheet Amount Market Value 4.868 0% Senior notes 6/5/2014 6/1/2044 400,000 $ 397,194 $ 528,000 $ 397,074 $ 452,848 3.5% Senior notes 10/7/2020 10/15/2050 1,000,000 979,524 1,138,100 - -
Schedule Of Interest Expense Incurred In Connection With Senior Notes	Years Ended December 31, (Dollars In thousands 2020 2019 2018 Interest expense incurred 4.868% senior notes $ 19,472 $ 19,472 $ 19,472 Interest expense incurred 3.5% senior notes 8,115 - -

Long Term Subordinated Notes (T

Long Term Subordinated Notes (Tables)	12 Months Ended
	Dec. 31, 2020
Long Term Subordinated Notes [Abstract]
Schedule Of Outstanding Fixed To Floating Rate Long Term Subordinated Notes	Maturity Date December 31, 2020 December 31, 2019 Original Consolidated Balance Consolidated Balance (Dollars in thousands) Date Issued Principal Amount Scheduled Final Sheet Amount Market Value Sheet Amount Market Value Long term subordinated notes 4/26/2007 $ 400,000 5/15/2037 5/1/2067 $ 223,674 $ 206,447 $ 236,758 $ 233,191
Schedule Of Interest Expense Incurred In Connection With Long Term Subordinated Notes	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Interest expense incurred $ 7,645 $ 11,587 $ 10,926

Collateralized Reinsurance An_2

Collateralized Reinsurance And Trust Agreements (Tables)	12 Months Ended
	Dec. 31, 2020
Collateralized Reinsurance And Trust Agreements [Abstract]
Premiums And Losses Ceded By The Company To Affiliate	Years Ended December 31, Mt. Logan Re Segregated Accounts 2020 2019 2018 (Dollars in thousands) Ceded written premiums 303,178 291,979 260,612 Ceded earned premiums 306,184 294,762 262,518 Ceded losses and LAE 241,347 187,192 319,046 Assumed written premiums 18,831 17,005 11,032 Assumed earned premiums 18,831 17,005 11,032 Assumed losses and LAE - - -

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Supplemental Information Relating to Operating Leases	Year Ended December 31, (Dollars in thousands) 2020 2019 Lease expense incurred: Operating lease cost $ 32,508 $ 24,524 At December 31, (Dollars in thousands) 2020 2019 Operating lease right of use assets $ 149,125 $ 161,435 Operating lease liabilities 165,292 169,909 Year Ended December 31, (Dollars in thousands) 2020 2019 Operating cash flows from operating leases $ ( 20,594) $ ( 20,041) At December 31, 2020 2019 Weighted average remaining operating lease term 12.3 years 12.6 years Weighted average discount rate on operating leases 4.10 % 3.91 %
Maturities of Lease Liabilities	(Dollars in thousands) 2021 $ 18,536 2022 20,971 2023 20,198 2024 19,947 2025 16,956 Thereafter 124,258 Undiscounted lease payments 220,866 Less: present value adjustment 55,574 Total operating lease liability $ 165,292

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Taxes [Abstract]
Components Of The Provision	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Current tax expense (benefit): U.S. $ ( 107,757) $ ( 5,044) $ ( 38,625) Non-U.S. 2,948 14,420 6,497 Total current tax expense (benefit) ( 104,809) 9,376 ( 32,128) Deferred tax expense (benefit): U.S. 178,523 80,247 ( 298,998) Non-U.S. ( 2,516) ( 97) ( 97) Total deferred tax expense (benefit) 176,007 80,150 ( 299,095) Total income tax expense (benefit) $ 71,198 $ 89,526 $ ( 331,223) (Some amounts may not reconcile due to rounding.)
Reconciliation Of The Difference Between The Provision For Income Taxes And The Expected Tax Provision At The Weighted Average Tax Rate	Years Ended December 31, 2020 2019 2018 (Dollars in thousands) U.S. Non-U.S. U.S. Non-U.S. U.S. Non-U.S. Underwriting gain (loss) $ 24,041 $ ( 277,852) $ 38,964 $ 297,199 $ ( 1,407,020) $ 796,745 Net investment income 339,721 302,744 325,179 321,960 283,569 297,614 Net realized capital gains (losses) 234,970 32,679 155,609 29,394 ( 90,033) ( 37,103) Net derivative gain (loss) - 1,541 - 6,374 - 520 Corporate expenses ( 15,985) ( 25,133) ( 13,063) ( 19,903) ( 11,035) ( 19,637) Interest, fee and bond issue cost amortization expense ( 35,659) ( 664) ( 34,931) 3,239 ( 30,611) ( 420) Other income (expense) ( 14,656) 19,602 ( 1,976) ( 9,057) ( 5,894) ( 18,877) Pre-tax income (loss) $ 532,432 $ 52,917 $ 469,782 $ 629,206 $ ( 1,261,024) $ 1,018,842 Expected tax provision at the applicable statutory rate(s) 111,846 ( 10,356) 98,766 17,205 ( 264,912) 9,647 Increase (decrease) in taxes resulting from: Tax exempt income ( 3,598) - ( 3,680) - ( 3,824) - Dividend received deduction ( 1,100) - ( 998) - ( 1,520) - Proration 1,049 - 1,050 - 1,150 - Affiliated preferred stock dividends 6,517 - 6,517 - 6,517 - Creditable foreign premium tax ( 11,513) - ( 9,852) - ( 13,475) - Tax audit settlement - - ( 1,576) - ( 2,094) - U.S. rate differential on carryback of net operation losses to PY - - - - ( 43,734) - U.S. rate differential on deferred tax 2017 return to provision - - - - ( 28,411) - Share based compensation tax benefits formerly in APIC ( 2,605) ( 388) ( 2,984) ( 373) ( 3,333) ( 120) Impact of CARES Act ( 32,500) - - - - - Valuation allowance 277 15,144 138 3,772 73 2,257 Change in uncertain tax positions - - ( 8,434) - 8,434 - Other 2,393 ( 3,968) ( 3,744) ( 6,281) 7,506 ( 5,384) Total income tax provision $ 70,766 $ 432 $ 75,203 $ 14,323 $ ( 337,623) $ 6,400 (Some amounts may not reconcile due to rounding.)
Reconciliation Of The Beginning And Ending Amount Of Unrecognized Tax Benefits	(Dollars in thousands) 2020 2019 2018 Balance at January 1 $ - $ 8,434 $ - Additions based on tax positions related to the current year - - 8,434 Additions for tax positions of prior years - - - Reductions for tax positions of prior years - ( 8,434) - Settlements with taxing authorities - - - Lapses of applicable statutes of limitations - - - Balance at December 31 $ - $ - $ 8,434
Net Deferred Income Tax Assets	Years Ended December 31, (Dollars in thousands) 2020 2019 Deferred tax assets: Loss reserves $ 96,840 $ 66,025 Unearned premium reserves 85,028 75,130 Foreign tax credits 46,109 186,706 Net operating loss carryforward 33,504 31,698 Lease liability 31,989 33,042 Net unrealized losses on benefit plans 19,636 19,818 Equity compensation 7,367 7,817 Other tax credits 4,591 2,294 Uncollectible reinsurance reserves 3,142 3,142 Investment impairments 1,121 3,961 Unrealized foreign currency losses 603 7,964 Other assets 7,285 4,520 Total deferred tax assets 337,215 442,117 Deferred tax liabilities: Net unrealized investment gains 90,268 39,413 Deferred acquisition costs 79,994 81,931 Net fair value income 75,692 25,936 Right of use asset 28,822 31,510 Partnership investments 26,119 15,039 Benefit plan asset 1,765 2,333 Other liabilities 6,710 4,937 Total deferred tax liabilities 309,370 201,099 Net deferred tax assets 27,845 241,018 Less: Valuation allowance ( 28,805) ( 12,997) Total net deferred tax assets/(liabilities) $ ( 960) $ 228,021 (Some amounts may not reconcile due to rounding.)

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2020
Reinsurance [Abstract]
Premiums Written And Earned And Incurred Losses And LAE	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Written premiums: Direct $ 3,217,999 $ 2,783,036 $ 2,240,951 Assumed 7,264,362 6,350,328 6,234,203 Ceded ( 1,365,378) ( 1,308,940) ( 1,060,726) Net written premiums $ 9,116,983 $ 7,824,424 $ 7,414,428 Premiums earned: Direct $ 3,028,095 $ 2,551,662 $ 2,129,320 Assumed 7,054,680 6,059,222 5,807,332 Ceded ( 1,401,262) ( 1,207,198) ( 1,004,953) Net premiums earned $ 8,681,513 $ 7,403,686 $ 6,931,699 Incurred losses and LAE: Direct $ 2,141,065 $ 1,618,686 $ 1,372,589 Assumed 5,163,946 3,923,298 5,046,947 Ceded ( 754,174) ( 619,086) ( 768,133) Net incurred losses and LAE $ 6,550,837 $ 4,922,898 $ 5,651,403

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2020
Other Comprehensive Income (Loss) [Abstract]
Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations	Years Ended December 31, 2020 2020 2019 2018 (Dollars in thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized appreciation (depreciation) ("URA(D)") on securities - non-credit related $ 462,939 $ ( 39,729) $ 423,210 $ 547,539 $ ( 49,665) $ 497,874 $ ( 275,511) $ 21,061 $ ( 254,450) URA(D) on securities - OTTI - - - ( 1,559) 115 ( 1,444) ( 1,071) ( 135) ( 1,206) Reclassification of net realized losses (gains) included in net income (loss) 2,253 ( 5,729) ( 3,476) ( 13,129) 516 ( 12,613) 28,014 ( 518) 27,496 Foreign currency translation adjustments 90,142 ( 3,815) 86,327 18,585 ( 4,555) 14,030 ( 86,520) 9,704 ( 76,816) Benefit plan actuarial net gain (loss) ( 7,107) 1,492 ( 5,615) ( 15,938) 3,347 ( 12,591) ( 646) 136 ( 510) Reclassification of benefit plan liability amortization included in net income (loss) 7,974 ( 1,674) 6,300 6,902 ( 1,449) 5,453 6,356 ( 1,335) 5,021 Total other comprehensive income (loss) $ 556,201 $ ( 49,455) $ 506,746 $ 542,400 $ ( 51,691) $ 490,709 $ ( 329,378) $ 28,913 $ ( 300,465)
Reclassification From Accumulated Other Comprehensive Income	Years Ended December 31, Affected line item within the statements of AOCI component 2020 2019 operations and comprehensive income (loss) (Dollars in thousands) URA(D) on securities $ 2,253 $ ( 13,129) Other net realized capital gains (losses) ( 5,729) 516 Income tax expense (benefit) $ ( 3,476) $ ( 12,613) Net income (loss) Benefit plan net gain (loss) $ 7,974 $ 6,902 Other underwriting expenses ( 1,674) ( 1,449) Income tax expense (benefit) $ 6,300 $ 5,453 Net income (loss)
Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax, In The Consolidated Balance Sheets	Years Ended December 31, (Dollars in thousands) 2020 2019 Beginning balance of URA (D) on securities $ 304,425 $ ( 179,392) Current period change in URA (D) of investments - non-credit related 419,734 485,261 Current period change in URA (D) of investments - non-credit OTTI - ( 1,444) Ending balance of URA (D) on securities 724,159 304,425 Beginning balance of foreign currency translation adjustments ( 201,717) ( 215,747) Current period change in foreign currency translation adjustments 86,327 14,030 Ending balance of foreign currency translation adjustments ( 115,390) ( 201,717) Beginning balance of benefit plan net gain (loss) ( 74,556) ( 67,418) Current period change in benefit plan net gain (loss) 685 ( 7,138) Ending balance of benefit plan net gain (loss) ( 73,870) ( 74,556) Ending balance of accumulated other comprehensive income (loss) $ 534,899 $ 28,152 (Some amounts may not reconcile due to rounding.)

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Summary Of Contributions To Defined Benefit Pension Plans	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Company contributions $ 6,825 $ 4,750 $ 77,743
Summary Of Accumulated Benefit Obligation	At December 31, (Dollars in thousands) 2020 2019 Qualified Plan $ 336,027 $ 288,328 Non-qualified Plan 16,258 21,642 Total $ 352,285 $ 309,970 (Some amounts may not reconcile due to rounding.)
Projected Benefit Obligations In Excess Of Plan Assets	At December 31, (Dollars in thousands) 2020 2019 Qualified Plan Projected benefit obligation $ 388,213 $ 333,715 Fair value of plan assets 354,464 301,467 Non-qualified Plan Projected benefit obligation $ 16,258 $ 21,642 Fair value of plan assets - -
Accumulated Benefit Obligations In Excess Of Plan Assets	At December 31, (Dollars in thousands) 2020 2019 Qualified Plan Accumulated benefit obligation $ - $ - Fair value of plan assets - - Non-qualified Plan Accumulated benefit obligation $ 16,258 $ 21,642 Fair value of plan assets - -
Incurred Expenses Related To Defined Contribution Plans For U.S. Employees	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Incurred expenses $ 14,386 $ 10,794 $ 9,301
Incurred Expenses Related To Defined Contribution Plans For Non-U.S. Employees	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Incurred expenses $ 3,039 $ 2,216 $ 2,057
Defined Benefit Pension Plan [Member]
Summary Of Pension Expenses	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Pension expense $ 8,429 $ 10,042 $ 9,728
Summary Of Status Of Plan	Years Ended December 31, (Dollars in thousands) 2020 2019 Change in projected benefit obligation: Benefit obligation at beginning of year $ 355,356 $ 300,244 Service cost 9,522 8,255 Interest cost 10,112 11,712 Actuarial (gain)/loss 43,595 46,206 Curtailment - - Benefits paid ( 14,115) ( 11,062) Projected benefit obligation at end of year 404,471 355,356 Change in plan assets: Fair value of plan assets at beginning of year 301,467 260,531 Actual return on plan assets 60,286 47,247 Actual contributions during the year 6,825 4,750 Administrative expenses paid - - Benefits paid ( 14,115) ( 11,062) Fair value of plan assets at end of year 354,464 301,467 Funded status at end of year $ ( 50,007) $ ( 53,889) (Some amounts may not reconcile due to rounding.)
Amounts Recognized In The Consolidated Balance Sheets	At December 31, (Dollars in thousands) 2020 2019 Other assets (due beyond one year) $ - $ - Other liabilities (due within one year) ( 2,197) ( 7,362) Other liabilities (due beyond one year) ( 47,810) ( 46,527) Net amount recognized in the consolidated balance sheets $ ( 50,007) $ ( 53,889) (Some amounts may not reconcile due to rounding.)
Amounts Not Yet Reflected In Net Periodic Benefit Cost And Included In Accumulated Other Comprehensive Income (Loss)	At December 31, (Dollars in thousands) 2020 2019 Accumulated income (loss) $ ( 91,979) $ ( 97,466) Accumulated other comprehensive income (loss) $ ( 91,979) $ ( 97,466) (Some amounts may not reconcile due to rounding.)
Other Changes In Other Comprehensive Income (Loss)	Years Ended December 31, (Dollars in thousands) 2020 2019 Other comprehensive income (loss) at December 31, prior year $ ( 97,466) $ ( 88,580) Net gain (loss) arising during period ( 4,090) ( 16,927) Recognition of amortizations in net periodic benefit cost: Actuarial loss 9,576 8,042 Curtailment loss recognized - - Other comprehensive income (loss) at December 31, current year $ ( 91,979) $ ( 97,466) (Some amounts may not reconcile due to rounding.)
Net Periodic Benefit Cost For U.S. Employees	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Service cost $ 9,522 $ 8,255 $ 9,801 Interest cost 10,112 11,712 10,290 Expected return on assets ( 20,781) ( 17,968) ( 17,202) Amortization of actuarial loss from earlier periods 8,551 7,635 6,839 Settlement 1,025 408 - Net periodic benefit cost $ 8,429 $ 10,042 $ 9,728 Other changes recognized in other comprehensive income (loss): Other comprehensive income (loss) attributable to change from prior year ( 5,486) 8,885 Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 2,943 $ 18,927 (Some amounts may not reconcile due to rounding.)
Expected Benefit Payments	(Dollars in thousands) 2021 $ 11,757 2022 12,220 2023 13,064 2024 14,100 2025 15,190 Next 5 years 90,808
Fair Value Measurement Levels For Qualified Plan Assets	Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2020 (Level 1) (Level 2) (Level 3) Assets: Short-term investments, which approximates fair value (a) $ 1,204 $ 1,204 $ - $ - Mutual funds, fair value Fixed income (b) 93,609 93,609 - - Equities (c) 255,054 255,054 - - Total $ 349,867 $ 349,867 $ - $ - (Some amounts may not reconcile due to rounding.) (a) This category includes high quality, short-term money market instruments, which are issued and payable in U.S. dollars. (b) This category includes fixed income funds, which invest in investment grade securities of corporations, governments and government agencies with approximately 70% in U.S. securities and 30% in international securities. (c) This category includes funds, which invest in small, mid and multi-cap equity securities including common stocks, securities convertible into common stock and securities with common stock characteristics, such as rights and warrants, with approximately 50% in U.S. equities and 50% in international equities. Fair Value Measurement Using: Quoted Prices in Active Significant Markets for Other Significant Identical Observable Unobservable Assets Inputs Inputs (Dollars in thousands) December 31, 2019 (Level 1) (Level 2) (Level 3) Assets: Short-term investments, which approximates fair value (a) $ 1,749 $ 1,749 $ - $ - Mutual funds, fair value Fixed income (b) 90,483 90,483 - - Equities (c) 188,884 188,884 - - Total $ 281,116 $ 281,116 $ - $ - (Some amounts may not reconcile due to rounding.) (a) This category includes high quality, short-term money market instruments, which are issued and payable in U.S. dollars. (b) This category includes fixed income funds, which invest in investment grade securities of corporations, governments and government agencies with approximately 70% in U.S. securities and 30% in international securities. (c) This category includes funds, which invest in small, mid and multi-cap equity securities including common stocks, securities convertible into common stock and securities with common stock characteristics, such as rights and warrants, with approximately 50% in U.S. equities and 50% in international equities.
Post-Retirement Plan [Member]
Summary Of Status Of Plan	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Post-retirement benefit expenses $ 1,334 $ 1,231 $ 1,829
Amounts Recognized In The Consolidated Balance Sheets	At December 31, (Dollars in thousands) 2020 2019 Other liabilities (due within one year) $ ( 613) $ ( 611) Other liabilities (due beyond one year) ( 34,484) ( 28,764) Net amount recognized in the consolidated balance sheets $ ( 35,098) $ ( 29,376) (Some amounts may not reconcile due to rounding.)
Amounts Not Yet Reflected In Net Periodic Benefit Cost And Included In Accumulated Other Comprehensive Income (Loss)	At December 31, (Dollars in thousands) 2020 2019 Accumulated income (loss) $ ( 3,854) $ 188 Accumulated prior service credit (cost) 2,327 2,904 Accumulated other comprehensive income (loss) $ ( 1,527) $ 3,092
Other Changes In Other Comprehensive Income (Loss)	Years Ended December 31, (Dollars in thousands) 2020 2019 Other comprehensive income (loss) at December 31, prior year $ 3,092 $ 3,242 Net gain (loss) arising during period ( 4,042) 582 Prior Service credit (cost) arising during period - - Recognition of amortizations in net periodic benefit cost: Actuarial loss (gain) - ( 155) Prior service cost ( 577) ( 577) Other comprehensive income (loss) at December 31, current year $ ( 1,527) $ 3,092
Net Periodic Benefit Cost For U.S. Employees	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Service cost $ 1,066 $ 983 $ 1,312 Interest cost 845 980 999 Prior service credit recognition ( 577) ( 577) ( 577) Net gain recognition - ( 155) 94 Net periodic cost $ 1,334 $ 1,231 $ 1,829 Other changes recognized in other comprehensive income (loss): Other comprehensive gain (loss) attributable to change from prior year 4,619 150 Total recognized in net periodic benefit cost and other comprehensive income (loss) $ 5,953 $ 1,381 (Some amounts may not reconcile due to rounding.)
Expected Benefit Payments	(Dollars in thousands) 2021 $ 613 2022 715 2023 806 2024 851 2025 989 Next 5 years 6,955
Post-Retirement Benefit Expenses	At December 31, (Dollars in thousands) 2020 2019 Change in projected benefit obligation: Benefit obligation at beginning of year $ 29,376 $ 28,483 Service cost 1,066 983 Interest cost 845 980 Amendments - - Actuarial (gain)/loss 4,042 ( 582) Benefits paid ( 232) ( 488) Benefit obligation at end of year 35,098 29,376 Change in plan assets: Fair value of plan assets at beginning of year - - Employer contributions 232 488 Benefits paid ( 232) ( 488) Fair value of plan assets at end of year - - Funded status at end of year $ ( 35,098) $ ( 29,376)

Dividend Restrictions And Sta_2

Dividend Restrictions And Statutory Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Dividend Restrictions And Statutory Financial Information [Abstract]
Regulatory Targeted Capital And The Actual Statutory Capital	Bermuda Re (1) Everest Re (1) At December 31, At December 31, (Dollars in thousands) 2020 (1) 2019 2020 2019 Regulatory targeted capital $ - $ 2,061,065 $ 2,489,772 $ 2,001,226 Actual capital $ 2,944,455 $ 3,197,418 $ 5,276,003 $ 3,739,140 (a) Regulatory targeted capital represents the target capital level from the applicable year's BSCR calculation. (b) Regulatory targeted capital represents 200% of the RBC authorized control level calculation for the applicable year. (c) The 2020 BSCR calculation is not yet due to be completed; however, the Company anticipates that Bermuda Re's December 31, 2020 actual capital will exceed the targeted capital level.

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies [Abstract]
Summary Of Estimated Cost To Replace Annuities For Contingent Liability	At December 31, (Dollars in thousands) 2020 2019 The Prudential $ 140,773 $ 141,703 Unaffiliated life insurance company 35,128 35,082

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Share-Based Compensation Plans [Abstract]
Company's Shareholder Approved Plans	Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2020 170,704 $ 87.18 Granted - - Exercised 53,833 85.69 Forfeited/Cancelled/Expired – - Outstanding at December 31, 2020 116,871 87.87 0.7 $ 17,089 . Exercisable at December 31, 2020 116,871 87.87 0.7 $ 17,089 Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2019 279,164 $ 83.84 Granted - - Exercised 108,460 78.58 Forfeited/Cancelled/Expired - - Outstanding at December 31, 2019 170,704 87.18 1.4 $ 32,376 . Exercisable at December 31, 2019 170,704 87.18 1.4 $ 32,376 Weighted- Weighted- Average Average Remaining Aggregate (Aggregate Intrinsic Value in thousands) Exercise Contractual Intrinsic Options Shares Price/Share Term Value Outstanding at January 1, 2018 360,364 $ 84.10 Granted - - Exercised 81,200 84.99 Forfeited/Cancelled/Expired - - Outstanding at December 31, 2018 279,164 83.84 1.9 $ 37,386 Exercisable at December 31, 2018 279,164 83.84 1.9 $ 37,386
Share Options Outstanding And Exercisable	At December 31, 2020 Options Outstanding Options Exercisable Weighted- Average Weighted- Weighted- Number Remaining Average Number Average Range of Outstanding Contractual Exercise Exercisable Exercise Exercise Prices at 12/31/20 Life Price at 12/31/20 Price $86.62 - $88.31 44,000 0.2 $ 86.62 44,000 $ 86.62 $88.32 - $90.48 66,917 1.1 88.32 66,917 88.32 $90.49 - $110.13 5,954 0.5 91.99 5,954 91.99 116,871 0.7 87.87 116,871 87.87
Summary Of Company's Non-Vested Shares And Changes	Years Ended December 31, 2020 2019 2018 Weighted- Weighted- Weighted- Average Average Average Grant Date Grant Date Grant Date Restricted (non-vested) Shares Shares Fair Value Shares Fair Value Shares Fair Value Outstanding at January 1, 495,137 $ 228.02 414,407 $ 217.15 421,261 $ 194.01 Granted 200,929 269.86 232,601 232.36 173,065 240.59 Vested 175,413 220.88 138,322 203.41 141,982 178.31 Forfeited 37,226 246.20 13,549 221.35 37,937 212.48 Outstanding at December 31, 483,427 246.60 495,137 228.02 414,407 217.15
Company's Non-Vested Performance Share Unit Awards	Years Ended December 31, 2020 2019 2018 Weighted- Weighted- Weighted- Average Average Average Grant Date Grant Date Grant Date Performance Share Unit Awards Shares Fair Value Shares Fair Value Shares Fair Value Outstanding at January 1, 34,850 $ - 32,382 $ - 33,454 $ - Granted 16,120 277.15 16,855 223.45 13,325 242.39 Increase/(Decrease) on vesting units due to performance ( 2,227) - ( 3,455) - ( 267) - Vested 6,157 277.15 10,922 223.45 12,435 242.39 Forfeited 3,695 - - - 1,695 - Outstanding at December 31, 38,891 - 34,850 - 32,382 -

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Schedule Of Underwriting Results For Operating Segments	Reinsurance Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross written premiums $ 7,281,716 $ 6,355,889 $ 6,224,601 Net written premiums 6,767,579 5,732,272 5,706,453 Premiums earned $ 6,466,106 $ 5,491,296 $ 5,293,071 Incurred losses and LAE 4,933,411 3,675,178 4,585,602 Commission and brokerage 1,552,371 1,400,247 1,251,581 Other underwriting expenses 175,734 160,834 142,874 Underwriting gain (loss) $ ( 195,410) $ 255,037 $ ( 686,986) Insurance Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Gross written premiums $ 3,200,645 $ 2,777,475 $ 2,250,552 Net written premiums 2,349,404 2,092,152 1,707,975 Premiums earned $ 2,215,407 $ 1,912,390 $ 1,638,628 Incurred losses and LAE 1,617,426 1,247,720 1,065,801 Commission and brokerage 320,879 303,479 267,449 Other underwriting expenses 335,503 280,065 228,667 Underwriting gain (loss) $ ( 58,401) $ 81,126 $ 76,711
Schedule Of Underwriting Results For Operating Segments To Income (Loss) Before Taxes	Years Ended December 31, (Dollars in thousands) 2020 2019 2018 Underwriting gain (loss) $ ( 253,811) $ 336,163 $ ( 610,275) Net investment income 642,465 647,139 581,183 Net realized capital gains (losses) 267,649 185,004 ( 127,136) Corporate expenses ( 41,118) ( 32,966) ( 30,672) Interest, fee and bond issue cost amortization expense ( 36,323) ( 31,693) ( 31,031) Other income (expense) 6,487 ( 4,660) ( 24,251) Income (loss) before taxes $ 585,349 $ 1,098,987 $ ( 242,182)
Schedule Of Gross Written Premiums Derived From Largest Non-U.S. Market	Year Ended December 31, (Dollars in thousands) 2020 2019 2018 United Kingdom gross written premium $ 1,116,363 $ 964,358 $ 914,612

Unaudited Quarterly Financial_2

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2020
Unaudited Quarterly Financial Data [Abstract]
Summary Of Quarterly Financial Data	2020 (Dollars in thousands, except per share amounts) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Operating data: Gross written premiums $ 2,570,871 $ 2,369,338 $ 2,791,604 $ 2,750,548 Net written premiums 2,201,479 2,017,478 2,448,680 2,449,346 Premiums earned 2,036,814 2,042,405 2,205,811 2,396,483 Net investment income 147,800 38,083 234,233 222,349 Net realized capital gains (losses) ( 210,588) 184,648 110,203 183,386 Total claims and underwriting expenses 2,008,222 1,991,462 2,320,417 2,615,223 Net income (loss) 16,612 190,880 243,057 63,601 Earnings per common share attributable to Everest Re Group: Basic $ 0.41 $ 4.78 $ 6.08 $ 1.59 Diluted $ 0.41 $ 4.77 $ 6.07 $ 1.59 2019 (Dollars in thousands, except per share amounts) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Operating data: Gross written premiums $ 2,127,108 $ 2,166,655 $ 2,403,274 $ 2,436,327 Net written premiums 1,851,698 1,783,983 2,068,557 2,120,186 Premiums earned 1,732,697 1,817,299 1,905,619 1,948,071 Net investment income 140,976 179,028 181,058 146,077 Net realized capital gains (losses) 92,232 30,272 ( 12,943) 75,443 Total claims and underwriting expenses 1,537,009 1,620,413 1,933,158 1,976,943 Net income (loss) 354,551 332,868 104,398 217,644 Earnings per common share attributable to Everest Re Group: Basic $ 8.70 $ 8.17 $ 2.56 $ 5.34 Diluted $ 8.67 $ 8.15 $ 2.56 $ 5.32

Summary Of Significant Accoun_4

Summary Of Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Dec. 31, 2005Item	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Minimum percent of prepaid reinsurance premiums for any foreign reinsurers that were collateralized	10.00%
Derivatives, number of indices | Item				2
Anti-dilutive options | shares	0	0	0
Change in beginning balance due to adoption of ASU	$ 9,726,176	$ 9,132,925	$ 7,860,797
Operating lease right of use assets	$ 149,125	$ 161,435	$ 69,869
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets	Other assets
Operating lease liabilities	$ 165,292	$ 169,909	$ 77,270
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities	Other liabilities
Accumulated Other Comprehensive Income [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in beginning balance due to adoption of ASU	$ 534,899	$ 28,152	$ (462,557)		$ (160,891)
Accumulated Other Comprehensive Income [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-01 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in beginning balance due to adoption of ASU					(1,201)
Retained Earnings [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in beginning balance due to adoption of ASU	$ 10,567,452	10,306,571	9,531,433		9,657,412
Retained Earnings [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in beginning balance due to adoption of ASU		(4,214)
Retained Earnings [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | Accounting Standards Update 2016-01 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in beginning balance due to adoption of ASU					$ 1,201
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Options expiration date	Feb. 24, 2021
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Options expiration date	Sep. 19, 2022

Summary Of Significant Accoun_5

Summary Of Significant Accounting Policies (Schedule Of Uncollectible Reinsurance Recoverable And Premium Receivables) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Abstract]
Reinsurance receivables and premium receivables	$ 41,357	$ 25,605

Summary Of Significant Accoun_6

Summary Of Significant Accounting Policies (Schedule Of Deferred Acquisition Costs Amortized To Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Abstract]
Deferred acquisition costs	$ 1,873,250	$ 1,703,726	$ 1,519,030

Summary Of Significant Accoun_7

Summary Of Significant Accounting Policies (Net Income (Loss) Per Common Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Abstract]
Net income (loss)	$ 63,601	$ 243,057	$ 190,880	$ 16,612	$ 217,644	$ 104,398	$ 332,868	$ 354,551	$ 514,151	$ 1,009,461	$ 89,041
Less: dividends declared-common shares and nonvested common shares									(249,056)	(234,322)	(216,221)
Undistributed earnings									$ 265,094	$ 775,139	$ (127,180)
Percentage allocated to common shareholders									98.70%	98.90%	99.00%
Net income (loss) available to common stockholders, total									$ 261,770	$ 766,386	$ (125,848)
Add: dividends declared-common shareholders									246,054	231,796	214,088
Numerator for basic and diluted earnings per common share									$ 507,824	$ 998,182	$ 88,239
Denominator for basic earnings per weighted-average common shares									39,656	40,291	40,388
Effect of dilutive securities: Options									77	129	198
Denominator for diluted earnings per adjusted weighted-average common shares									39,734	40,420	40,586
Basic	$ 1.59	$ 6.08	$ 4.78	$ 0.41	$ 5.34	$ 2.56	$ 8.17	$ 8.70	$ 12.81	$ 24.77	$ 2.18
Diluted	$ 1.59	$ 6.07	$ 4.77	$ 0.41	$ 5.32	$ 2.56	$ 8.15	$ 8.67	$ 12.78	$ 24.70	$ 2.17
Basic weighted-average common shares outstanding									39,656	40,291	40,388
Basic weighted-average common shares outstanding and nonvested common shares expected to vest									40,160	40,751	40,816

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Additional contractual commitments		$ 1,594,446,000
Contractual commitments, investment period expiration date		Dec. 31, 2026
Reclassification of other invested assets to fixed maturity securities	$ 143,656,000
Reclassification of other invested assets to short-term investments	$ 243,864,000
Securities, carrying value		$ 1,617,928,000
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate market value of investments in unrealized loss position		2,678,449,000	$ 3,639,991,000
Gross unrealized losses on investments in unrealized loss position		124,812,000	121,169,000
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation		67,958,000	26,793,000
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation		56,854,000	94,376,000
Market value of investments		$ 20,040,173,000	$ 16,824,944,000
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		0.10%	0.80%
Fixed Maturity Securities [Member] | US Government 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		0.70%
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		$ 63,424,000	$ 23,104,000
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation		33,533,000	73,144,000
Sub-prime and Alt-A Loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized depreciation		0	$ 0
Private Placement Liquidity Sweep [Member]
Schedule of Available-for-sale Securities [Line Items]
Market value of investments		$ 627,958,000

Investments (Summary Of Unreali

Investments (Summary Of Unrealized Appreciation (Depreciation) Of Available For Sale, Fixed Maturity And Equity Security Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Allowance for credit losses	$ (1,745)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,225,067	16,473,491
Allowance for credit losses	(1,745)
Unrealized Appreciation	941,663	472,622
Unrealized Depreciation	(124,812)	(121,169)
Market Value	20,040,173	16,824,944
OTTI in AOCI		987
U.S. Treasury Securities And Obligations Of U.S. Government Agencies And Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,325,156	1,489,660
Allowance for credit losses
Unrealized Appreciation	49,084	28,357
Unrealized Depreciation	(7,134)	(2,214)
Market Value	1,367,106	1,515,803
OTTI in AOCI
Obligations Of U.S. States And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	543,895	507,353
Allowance for credit losses
Unrealized Appreciation	34,654	29,651
Unrealized Depreciation	(1,254)	(89)
Market Value	577,295	536,915
OTTI in AOCI
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,824,800	6,227,661
Allowance for credit losses	(1,220)
Unrealized Appreciation	380,677	185,052
Unrealized Depreciation	(55,231)	(37,767)
Market Value	7,149,026	6,374,946
OTTI in AOCI		469
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,540,809	892,373
Allowance for credit losses
Unrealized Appreciation	30,691	6,818
Unrealized Depreciation	(5,698)	(1,858)
Market Value	2,565,802	897,333
OTTI in AOCI
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	915,923	814,570
Allowance for credit losses
Unrealized Appreciation	75,275	31,236
Unrealized Depreciation	(895)	(1,249)
Market Value	990,303	844,557
OTTI in AOCI
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,206,139	2,173,099
Allowance for credit losses
Unrealized Appreciation	64,663	36,361
Unrealized Depreciation	(3,063)	(10,879)
Market Value	2,267,739	2,198,581
OTTI in AOCI
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,187	5,723
Allowance for credit losses
Unrealized Appreciation	9
Unrealized Depreciation	(2)	(20)
Market Value	5,194	5,703
OTTI in AOCI
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,565,260	1,492,315
Allowance for credit losses	(22)
Unrealized Appreciation	102,587	47,148
Unrealized Depreciation	(22,450)	(33,513)
Market Value	1,645,375	1,505,950
OTTI in AOCI		71
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,297,898	2,870,737
Allowance for credit losses	(503)
Unrealized Appreciation	204,023	107,999
Unrealized Depreciation	(29,085)	(33,580)
Market Value	$ 3,472,333	2,945,156
OTTI in AOCI		$ 447

Investments (Summary Of Amortiz

Investments (Summary Of Amortized Cost And Market Value Of Fixed Maturity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	$ 19,225,067	$ 16,473,491
Fixed maturity securities - available for sale, Market Value	20,040,173	16,824,944
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	1,365,793	1,456,960
Fixed maturity securities - available for sale, Due after one year through five years, Amortized Cost	6,529,189	6,757,107
Fixed maturity securities - available for sale, Due after five years through ten years, Amortized Cost	4,414,211	3,471,370
Fixed maturity securities - available for sale, Due after ten years, Amortized Cost	1,247,816	902,289
Fixed maturity securities - available for sale, Due in one year or less, Market Value	1,374,674	1,457,919
Fixed maturity securities - available for sale, Due after one year through five years, Market Value	6,774,785	6,869,359
Fixed maturity securities - available for sale, Due after five years through ten years, Market Value	4,751,903	3,609,816
Fixed maturity securities - available for sale, Due after ten years, Market Value	1,309,773	941,676
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	2,540,809	892,373
Fixed maturity securities - available for sale, Market Value	2,565,802	897,333
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	915,923	814,570
Fixed maturity securities - available for sale, Market Value	990,303	844,557
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	2,206,139	2,173,099
Fixed maturity securities - available for sale, Market Value	2,267,739	2,198,581
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities - available for sale, Amortized Cost	5,187	5,723
Fixed maturity securities - available for sale, Market Value	$ 5,194	$ 5,703

Investments (Summary Of Changes

Investments (Summary Of Changes In Net Unrealized Appreciation (Depreciation) For The Company's Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Deferred tax benefit (expense)	$ (176,007)	$ (80,150)	$ 299,095
Total URA(D) on securities arising during the period	419,734	483,817	$ (228,160)
Amortized Cost [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	465,192	532,851
Deferred tax benefit (expense)	(45,458)	(49,149)
Deferred tax benefit (expense), other-than-temporary impairment		115
Total URA(D) on securities arising during the period	419,734	483,817
Amortized Cost [Member] | Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax	465,192	534,410
Amortized Cost [Member] | Fixed Maturity Securities, Other-Than-Temporary Impairment [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in unrealized appreciation (depreciation), pre-tax		$ (1,559)

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	Dec. 31, 2020	Dec. 31, 2019
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	$ 2,017,481	$ 1,730,364
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(67,958)	(26,793)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	660,968	1,909,627
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(56,854)	(94,376)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	2,678,449	3,639,991
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(124,812)	(121,169)
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, Duration of Unrealized Loss, Less than 12 months, Market Value	135,190	85,527
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(7,134)	(1,005)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value		249,371
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation		(1,209)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	135,190	334,898
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(7,134)	(2,214)
Obligations Of U.S. States And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	19,524	4,600
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(999)	(38)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	4,059	5,522
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(255)	(51)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	23,583	10,122
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(1,254)	(89)
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	669,755	547,120
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(26,159)	(9,877)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	247,962	395,369
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(29,072)	(27,890)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	917,717	942,489
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(55,231)	(37,767)
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	235,566	176,222
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(4,768)	(1,027)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	85,595	94,190
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(930)	(831)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	321,161	270,412
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(5,698)	(1,858)
Commercial 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	53,511	83,127
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(578)	(689)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	6,592	23,063
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(317)	(560)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	60,103	106,190
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(895)	(1,249)
Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	434,447	344,267
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(2,016)	(1,834)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	50,353	488,680
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(1,047)	(9,045)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	484,800	832,947
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(3,063)	(10,879)
Non-Agency Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	185	332
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(2)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value		3,976
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation		(20)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	185	4,308
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(2)	(20)
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	114,755	210,766
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(8,813)	(4,770)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	150,812	283,648
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(13,637)	(28,743)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	265,567	494,414
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(22,450)	(33,513)
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	354,548	278,403
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(17,489)	(7,553)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	115,595	365,808
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(11,596)	(26,027)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	470,143	644,211
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	$ (29,085)	$ (33,580)

Investments (Summary Of Aggre_2

Investments (Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
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	$ 2,017,481	$ 1,730,364
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(67,958)	(26,793)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	660,968	1,909,627
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(56,854)	(94,376)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	2,678,449	3,639,991
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(124,812)	(121,169)
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	96,144	67,879
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(4,942)	(1,237)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	112,419	416,583
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(12,071)	(23,004)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	208,563	484,462
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(17,013)	(24,241)
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	653,816	464,753
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(32,469)	(7,960)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	283,866	689,195
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(21,319)	(38,138)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	937,682	1,153,948
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(53,788)	(46,098)
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	422,517	495,741
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(19,392)	(12,388)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	49,749	103,612
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(2,034)	(11,100)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	472,266	599,353
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(21,426)	(23,488)
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	121,295	98,043
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(3,791)	(1,658)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	72,394	90,328
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(19,136)	(11,678)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	193,689	188,371
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(22,927)	(13,336)
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	235,566	176,222
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(4,768)	(1,027)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	85,595	94,190
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(930)	(831)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	321,161	270,412
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	(5,698)	(1,858)
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	488,143	427,726
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(2,596)	(2,523)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	56,945	515,719
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(1,364)	(9,625)
Fixed maturity securities, Duration of Unrealized Loss, Total, Market Value	545,088	943,445
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation, Total	$ (3,960)	$ (12,148)

Investments (Summary Of Compone

Investments (Summary Of Components Of Net Investment Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ 680,703	$ 677,347	$ 615,802
Funds held interest income (expense)	12,754	13,271	6,300
Future policy benefit reserve income (expense)	(1,237)	(1,380)	(1,419)
Gross investment income	692,220	689,238	620,683
Investment expenses	(49,755)	(42,099)	(39,500)
Net investment income	642,465	647,139	581,183
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	542,363	520,291	465,793
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	18,776	19,505	25,327
Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	5,012	17,619	14,395
Limited Partnerships [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	112,853	105,815	93,327
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross investment income before adjustments	$ 1,699	$ 14,117	$ 16,960

Investments (Summary Of Compo_2

Investments (Summary Of Components Of Net Realized Capital Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments										$ (20,899)	$ (8,110)
Total net realized capital gains (losses)	$ 183,386	$ 110,203	$ 184,648	$ (210,588)	$ 75,443	$ (12,943)	$ 30,272	$ 92,232	267,649	185,004	(127,136)
Beginning Balance
Credit losses on securities where credit losses were not previously recorded									(32,884)
Increases in allowance on previously impaired securities									(6,645)
Decrease in allowance on previously impaired securities									5,525
Reduction in allowance due to disposals									32,259
Ending Balance	(1,745)								(1,745)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Ending Balance	(1,745)								(1,745)
Fixed Maturity Securities [Member] | Market Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Allowance for credit losses									(1,745)
Other-than-temporary impairments										(20,899)	(8,110)
Gains (losses) from sales									(2,214)	28,025	(21,719)
Fixed Maturity Securities [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									(2,863)	355	(1,799)
Gains (losses) from fair value adjustments									1,944	1,808	1,506
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance
Credit losses on securities where credit losses were not previously recorded									(27,666)
Increases in allowance on previously impaired securities									(6,136)
Decrease in allowance on previously impaired securities									4,333
Reduction in allowance due to disposals									28,249
Ending Balance	(1,220)								(1,220)
Equity Securities [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									(8,963)	4,148	(29,941)
Gains (losses) from fair value adjustments									278,461	165,200	(68,832)
Other Invested Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									1,705	6,003	1,815
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from sales									1,324	364	$ (56)
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance
Credit losses on securities where credit losses were not previously recorded									(518)
Increases in allowance on previously impaired securities									(28)
Decrease in allowance on previously impaired securities									309
Reduction in allowance due to disposals									215
Ending Balance	(22)								(22)
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance
Credit losses on securities where credit losses were not previously recorded									(4,700)
Increases in allowance on previously impaired securities									(481)
Decrease in allowance on previously impaired securities									883
Reduction in allowance due to disposals									3,795
Ending Balance	$ (503)								$ (503)

Investments (Summary Of Gross G

Investments (Summary Of Gross Gains (Losses) From Sales Of Fixed Maturity And Equity Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of securities	$ 1,950,774	$ 3,283,154	$ 3,150,179
Gross gains from sales	79,609	63,721	33,996
Gross losses from sales	(84,686)	(35,341)	(57,514)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of securities	376,347	283,965	1,199,409
Gross gains from sales	37,415	14,274	31,718
Gross losses from sales	$ (46,378)	$ (10,126)	$ (61,659)

Reserve For Losses, LAE And F_3

Reserve For Losses, LAE And Future Policy Benefit Reserve (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2015USD ($)
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Current year losses	$ 6,149,410	$ 4,986,456	$ 5,264,327
Increase (decrease) in insurance business	401,427	(63,558)	387,076
Reinsurance recoverable for paid and unpaid losses	$ 1,994,555	1,763,471
Partially offset, related to development on reserves			174,121
Contracts of insurance and reinsurance received claims during the past three years, in years	20 years
Business acquisition, cost of acquired entity and operations, cash paid				$ 140,279
Liabilities retroceded, percentage				100.00%
Maximum liability retroceded		450,298		$ 440,279
Decrease in amount of liabliities retroceded		43,362
Total amount of liabilities retroceded				$ 300,000
Number of exposure groupings | Item	200
Reinsurance Recoverable For Paid And Unpaid Claims And Claims Adjustments [Member] | Reinsurer Concentration Risk [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Concentration risk, percentage	5.00%
Catastrophe Losses [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Current year losses	$ (120,500)	(693,458)
Increase (decrease) in insurance business			$ 561,197
Covid-19 [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Current year losses	511,056
Higher Premiums Earned [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Current year losses	772,399	$ 415,585
Mt Logan Re [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Reinsurance recoverable for paid and unpaid losses	$ 699,734
Mt Logan Re [Member] | Reinsurance Recoverable For Paid And Unpaid Claims And Claims Adjustments [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Concentration risk, percentage	35.10%
Munich Reinsurance Company [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Reinsurance recoverable for paid and unpaid losses	$ 211,594
Munich Reinsurance Company [Member] | Reinsurance Recoverable For Paid And Unpaid Claims And Claims Adjustments [Member]
Reserve For Losses LAE And Future Policy Benefit Reserve [Line Items]
Concentration risk, percentage	10.60%

Reserve For Losses, LAE And F_4

Reserve For Losses, LAE And Future Policy Benefit Reserve (Summary Of Activity In The Reserve For Losses And LAE) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Gross reserves beginning of period	$ 13,611,313	$ 13,119,090	$ 11,884,321
Less reinsurance recoverables	(1,640,712)	(1,619,641)	(1,212,649)
Net reserves beginning of period	11,970,601	11,499,449	10,671,672
Incurred related to: Current year	6,149,410	4,986,456	5,264,327
Incurred related to: Prior years	401,427	(63,558)	387,076
Total incurred losses and LAE	6,550,837	4,922,898	5,651,403
Paid related to: Current year	2,046,260	2,042,246	1,700,765
Paid related to: Prior years	2,080,816	2,460,825	3,011,175
Total paid losses and LAE	4,127,076	4,503,071	4,711,940
Foreign exchange/translation adjustment	160,944	51,325	(111,686)
Net reserves end of period	14,555,306	11,970,601	11,499,449
Plus reinsurance recoverables	1,843,691	1,640,712	1,619,641
Gross reserves end of period	$ 16,398,997	$ 13,611,313	$ 13,119,090

Reserve For Losses, LAE And F_5

Reserve For Losses, LAE And Future Policy Benefit Reserve (Ultimate Loss and ALAE And Paid Loss And ALAE, Net Of Reinsurance) (Details) $ in Thousands	Dec. 31, 2020USD ($)Item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Claims Development [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	$ 14,322,754
Reinsurance [Member] | Casualty Business [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	10,095,859
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	4,322,265
All outstanding liabilities prior to 2012, net of reinsurance	940,597
Liabilities for claims and claim adjustment expenses, net of reinsurance	6,714,191
Reinsurance [Member] | Casualty Business [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	641,893	$ 663,308	$ 689,068	$ 684,537	$ 682,333	$ 698,212	$ 712,407	$ 811,282	$ 917,560
Total of IBNR Liabilities Plus Expected Development on Reported Claims	43,700
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	555,736	543,688	509,020	429,165	358,953	278,492	182,550	99,763	42,576
Reinsurance [Member] | Casualty Business [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	721,902	721,961	741,873	770,745	800,451	809,631	821,395	730,202
Total of IBNR Liabilities Plus Expected Development on Reported Claims	56,597
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	579,350	552,824	500,316	392,503	317,744	217,243	125,739	50,506
Reinsurance [Member] | Casualty Business [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	753,967	740,786	763,611	805,087	828,341	820,870	780,730
Total of IBNR Liabilities Plus Expected Development on Reported Claims	72,825
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	557,209	511,143	434,450	307,587	216,441	124,433	58,833
Reinsurance [Member] | Casualty Business [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	858,157	821,513	837,802	840,659	845,303	805,551
Total of IBNR Liabilities Plus Expected Development on Reported Claims	113,144
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	581,942	511,414	421,223	273,896	165,005	58,406
Reinsurance [Member] | Casualty Business [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	963,300	887,698	892,576	895,558	818,293
Total of IBNR Liabilities Plus Expected Development on Reported Claims	195,650
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	558,379	441,325	333,163	196,746	94,154
Reinsurance [Member] | Casualty Business [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	951,461	870,174	863,306	903,896
Total of IBNR Liabilities Plus Expected Development on Reported Claims	319,560
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	475,472	327,625	192,547	83,286
Reinsurance [Member] | Casualty Business [Member] | 2018 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	1,431,276	1,354,279	1,356,788
Total of IBNR Liabilities Plus Expected Development on Reported Claims	639,205
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	465,181	299,369	159,215
Reinsurance [Member] | Casualty Business [Member] | 2019 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	1,810,434	1,740,245
Total of IBNR Liabilities Plus Expected Development on Reported Claims	1,118,428
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	354,292	219,229
Reinsurance [Member] | Casualty Business [Member] | 2020 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	1,963,469
Total of IBNR Liabilities Plus Expected Development on Reported Claims	1,497,536
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	194,704
Reinsurance [Member] | Property Business [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	16,439,082
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	12,205,119
All outstanding liabilities prior to 2012, net of reinsurance	105,209
Liabilities for claims and claim adjustment expenses, net of reinsurance	4,339,172
Reinsurance [Member] | Property Business [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	1,184,476	1,181,653	1,162,252	1,174,224	1,181,200	1,187,096	1,188,304	1,311,752	1,625,024
Total of IBNR Liabilities Plus Expected Development on Reported Claims	7,419
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	1,126,302	1,120,273	1,098,004	1,086,813	1,051,968	1,016,689	896,372	723,394	417,397
Reinsurance [Member] | Property Business [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	797,047	798,652	791,400	795,978	801,457	857,241	969,175	1,326,814
Total of IBNR Liabilities Plus Expected Development on Reported Claims	1,722
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	770,215	768,490	759,925	749,345	728,570	670,369	567,616	394,228
Reinsurance [Member] | Property Business [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	980,449	988,193	987,230	987,401	1,080,269	1,230,656	1,388,249
Total of IBNR Liabilities Plus Expected Development on Reported Claims	3,325
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	937,437	931,451	921,183	889,561	812,441	678,897	388,263
Reinsurance [Member] | Property Business [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	983,478	991,202	988,469	1,014,531	1,090,474	1,420,523
Total of IBNR Liabilities Plus Expected Development on Reported Claims	2,384
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	926,388	905,281	876,356	792,018	633,428	390,284
Reinsurance [Member] | Property Business [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	1,564,702	1,587,145	1,593,116	1,557,262	1,730,936
Total of IBNR Liabilities Plus Expected Development on Reported Claims	20,676
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	1,447,824	1,394,284	1,269,622	986,043	480,453
Reinsurance [Member] | Property Business [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	3,687,487	3,558,713	3,447,971	2,825,218
Total of IBNR Liabilities Plus Expected Development on Reported Claims	28,865
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	3,161,267	2,775,818	2,207,048	835,042
Reinsurance [Member] | Property Business [Member] | 2018 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	2,561,852	2,559,953	2,684,311
Total of IBNR Liabilities Plus Expected Development on Reported Claims	121,379
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	1,969,117	1,579,781	576,573
Reinsurance [Member] | Property Business [Member] | 2019 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	2,192,239	2,165,898
Total of IBNR Liabilities Plus Expected Development on Reported Claims	434,700
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	1,250,409	770,686
Reinsurance [Member] | Property Business [Member] | 2020 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	2,487,352
Total of IBNR Liabilities Plus Expected Development on Reported Claims	1,341,994
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	616,160
Insurance [Member] | Casualty Business [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	5,391,340
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	2,747,987
All outstanding liabilities prior to 2012, net of reinsurance	224,752
Liabilities for claims and claim adjustment expenses, net of reinsurance	2,868,104
Insurance [Member] | Casualty Business [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	353,945	351,444	346,983	344,008	353,395	348,262	347,068	351,529	349,724
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 11,283
Cumulative Number of Reported Claims | Item	15,780
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 311,865	306,937	294,444	272,114	246,455	213,488	157,924	101,301	33,194
Insurance [Member] | Casualty Business [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	349,985	350,947	344,498	351,399	393,148	392,976	393,539	393,710
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 20,093
Cumulative Number of Reported Claims | Item	21,385
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 310,928	303,786	285,873	260,223	224,633	176,326	117,046	33,314
Insurance [Member] | Casualty Business [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	399,048	398,153	397,334	460,888	454,827	457,296	431,323
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 38,361
Cumulative Number of Reported Claims | Item	25,221
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 339,487	326,011	297,762	256,886	201,689	124,937	41,194
Insurance [Member] | Casualty Business [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	472,125	469,132	542,687	536,155	528,517	519,917
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 80,007
Cumulative Number of Reported Claims | Item	26,996
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 382,748	353,445	292,115	218,990	134,761	44,317
Insurance [Member] | Casualty Business [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	554,621	617,051	581,273	552,192	554,253
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 138,312
Cumulative Number of Reported Claims | Item	31,673
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 402,693	343,020	269,163	164,384	54,740
Insurance [Member] | Casualty Business [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	660,114	628,149	605,062	614,949
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 180,513
Cumulative Number of Reported Claims | Item	35,020
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 381,442	281,500	172,476	53,922
Insurance [Member] | Casualty Business [Member] | 2018 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	754,053	715,008	708,808
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 275,213
Cumulative Number of Reported Claims | Item	34,884
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 319,858	208,531	63,614
Insurance [Member] | Casualty Business [Member] | 2019 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	856,466	852,767
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 444,603
Cumulative Number of Reported Claims | Item	37,597
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 235,087	72,399
Insurance [Member] | Casualty Business [Member] | 2020 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	990,982
Total of IBNR Liabilities Plus Expected Development on Reported Claims	$ 649,288
Cumulative Number of Reported Claims | Item	26,068
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 63,878
Insurance [Member] | Property Business [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	2,609,287
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	2,208,038
All outstanding liabilities prior to 2012, net of reinsurance	39
Liabilities for claims and claim adjustment expenses, net of reinsurance	401,287
Insurance [Member] | Property Business [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	82,614	82,553	82,006	81,828	82,045	82,476	81,774	89,039	106,364
Total of IBNR Liabilities Plus Expected Development on Reported Claims	1
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	82,613	82,483	81,847	81,708	81,918	81,777	80,496	81,798	$ 56,506
Insurance [Member] | Property Business [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	91,895	92,328	92,473	92,313	92,224	91,336	98,206	112,083
Total of IBNR Liabilities Plus Expected Development on Reported Claims	29
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	91,866	91,857	91,840	91,800	92,191	91,921	93,181	$ 68,712
Insurance [Member] | Property Business [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	119,139	119,483	119,346	119,525	119,991	123,745	131,754
Total of IBNR Liabilities Plus Expected Development on Reported Claims	57
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	118,801	118,726	118,606	118,271	118,278	116,090	$ 81,853
Insurance [Member] | Property Business [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	146,630	144,923	146,934	144,084	153,031	173,062
Total of IBNR Liabilities Plus Expected Development on Reported Claims	286
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	146,958	146,870	145,371	142,563	141,396	$ 102,241
Insurance [Member] | Property Business [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	295,364	292,986	280,872	275,812	291,370
Total of IBNR Liabilities Plus Expected Development on Reported Claims	308
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	293,457	290,476	272,583	250,073	$ 162,916
Insurance [Member] | Property Business [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	499,724	496,583	502,935	498,359
Total of IBNR Liabilities Plus Expected Development on Reported Claims	6,358
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	483,178	460,412	425,607	$ 179,432
Insurance [Member] | Property Business [Member] | 2018 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	398,616	403,294	409,527
Total of IBNR Liabilities Plus Expected Development on Reported Claims	5,436
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	379,937	359,452	$ 245,944
Insurance [Member] | Property Business [Member] | 2019 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	352,038	349,177
Total of IBNR Liabilities Plus Expected Development on Reported Claims	14,100
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	317,960	$ 227,639
Insurance [Member] | Property Business [Member] | 2020 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of reinsurance	623,267
Total of IBNR Liabilities Plus Expected Development on Reported Claims	255,707
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 293,269

Reserve For Losses, LAE And F_6

Reserve For Losses, LAE And Future Policy Benefit Reserve (Average Annual Percentage Payout Incurred Claims By Age, Net Of Reinsurance) (Details)	Dec. 31, 2020
Reinsurance [Member] | Casualty Business [Member]
Shortduration Insurance Contracts Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year One	9.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Two	9.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Three	12.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Four	14.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Five	12.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Six	10.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Seven	8.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Eight	4.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Nine	1.90%
Reinsurance [Member] | Property Business [Member]
Shortduration Insurance Contracts Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year One	29.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Two	31.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Three	15.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Four	9.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Five	3.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Six	1.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Seven	0.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Eight	1.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Nine	0.50%
Insurance [Member] | Casualty Business [Member]
Shortduration Insurance Contracts Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year One	8.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Two	19.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Three	17.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Four	14.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Five	10.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Six	6.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Seven	4.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Eight	2.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Nine	1.40%
Insurance [Member] | Property Business [Member]
Shortduration Insurance Contracts Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year One	54.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Two	33.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Three	4.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Four	3.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Five	2.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Six	0.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Seven	0.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Eight	0.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year Nine	0.20%

Reserve For Losses, LAE And F_7

Reserve For Losses, LAE And Future Policy Benefit Reserve (Reconciliation of the Net Incurred and Paid Claims Development) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shortduration Insurance Contracts Reconciliation Of Claims Development To Liability [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	$ 14,322,754
Total reinsurance recoverable on unpaid claims	1,843,691
Unallocated claims adjustment expenses	194,111
Other	38,441
Total expenses	232,552
Total gross liability for unpaid claims and claim adjustment expense	16,398,997	$ 13,611,313	$ 13,119,090	$ 11,884,321
Reinsurance [Member] | Casualty Business [Member]
Shortduration Insurance Contracts Reconciliation Of Claims Development To Liability [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	6,714,191
Total reinsurance recoverable on unpaid claims	399,865
Reinsurance [Member] | Property Business [Member]
Shortduration Insurance Contracts Reconciliation Of Claims Development To Liability [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	4,339,172
Total reinsurance recoverable on unpaid claims	456,062
Insurance [Member] | Casualty Business [Member]
Shortduration Insurance Contracts Reconciliation Of Claims Development To Liability [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	2,868,104
Total reinsurance recoverable on unpaid claims	818,701
Insurance [Member] | Property Business [Member]
Shortduration Insurance Contracts Reconciliation Of Claims Development To Liability [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	401,287
Total reinsurance recoverable on unpaid claims	$ 169,062

Reserve For Losses, LAE And F_8

Reserve For Losses, LAE And Future Policy Benefit Reserve (Summary Of Incurred Losses With Respect To A&E Reserve On Both Gross And Net Of Reinsurance Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Gross basis: Beginning of period reserves	$ 257,921	$ 347,495	$ 448,994
Gross basis: Incurred losses	1,540	2,070	(2,473)
Gross basis: Paid losses	(40,120)	(91,644)	(99,026)
Gross basis: End of period reserves	219,341	257,921	347,495
Net basis: Beginning of period reserves	228,701	261,456	318,081
Net basis: Incurred losses	(772)
Net basis: Paid losses	(29,674)	(32,756)	(56,624)
Net basis: End of period reserves	$ 198,255	$ 228,701	$ 261,456

Reserve For Losses, LAE And F_9

Reserve For Losses, LAE And Future Policy Benefit Reserve (Summary Of Activity In The Reserve For Future Policy Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserve For Losses LAE And Future Policy Benefit Reserve [Abstract]
Balance at beginning of year	$ 42,592	$ 46,778	$ 51,014
Liabilities assumed	35	53	110
Adjustments to reserves	(1,113)	350	806
Benefits paid in the current year	(3,791)	(4,589)	(5,151)
Balance at end of year	$ 37,723	$ 42,592	$ 46,778

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2005Item
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of public equity portfolio	$ 784,746,000	$ 170,888,000
Number of equity index put option contracts | Item			7
Derivatives, number of indices | Item			2
Other invested assets	742,369,000	612,997,000
Transfers between level 1 and 2	0
Market Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers from level 3	(924,000)	4,695,000
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers from level 3
Fair Value [Member] | Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other invested assets	224,698,000	209,578,000
Fixed Maturities [Member] | Market Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities	1,330,224,000	772,979,000
Fixed Maturities [Member] | Market Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers from level 3	(924,000)	4,695,000
Fixed Maturities [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities		$ 5,826,000
Equity Securities [Member] | Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers from level 3	$ (9,877,000)

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurement Levels For All Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	$ 20,040,173	$ 16,824,944
Fixed maturities, fair value		5,826
Equity securities, fair value	1,472,236	931,457
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, fair value	1,368,704	864,584
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, fair value
Equity securities, fair value	103,532	66,873
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities, fair value		5,826
Equity securities, fair value
Fixed Maturity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	20,040,173	16,824,944
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 - available for sale, at 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 - available for sale, at market value	18,709,949	16,051,965
Fixed Maturity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	1,330,224	772,979
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 - available for sale, at market value	1,367,106	1,515,803
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 - available for sale, at 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 - available for sale, at market value	1,367,106	1,515,803
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 - available for sale, at market value
Obligations Of U.S. States And Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	577,295	536,915
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 - available for sale, at 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 - available for sale, at market value	577,295	536,915
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 - available for sale, at market value
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	7,149,026	6,374,946
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 - available for sale, at market value
Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	6,447,534	5,757,358
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	701,492	617,588
Asset-Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	2,565,802	897,333
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 - available for sale, at 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 - available for sale, at market value	1,942,769	743,692
Asset-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	623,033	153,641
Commercial Mortgage-Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	990,303	844,557
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 - available for sale, at 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 - available for sale, at market value	990,303	844,557
Commercial Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value
Agency Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	2,267,739	2,198,581
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 - available for sale, at market value
Agency Residential [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	2,267,739	2,198,581
Agency Residential [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value
Non-Agency Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	5,194	5,703
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 - available for sale, at 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 - available for sale, at market value	5,194	5,703
Non-Agency Residential [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value
Foreign Government Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	1,645,375	1,505,950
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 - available for sale, at 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 - available for sale, at market value	1,645,375	1,505,950
Foreign Government Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value
Foreign Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	3,472,333	2,945,156
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 - available for sale, at 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 - available for sale, at market value	3,466,634	2,943,406
Foreign Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturities - available for sale, at market value	$ 5,699	$ 1,750

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	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Market Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	$ 772,979	$ 435,959
Total gains or (losses) (realized/unrealized) Included in earnings	1,772	4,925
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	10,710	3,502
Purchases, issuances and settlements	545,687	323,898
Transfers in and/or (out) of Level 3	(924)	4,695
Ending balance	1,330,224	772,979
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	(539)
Market Value [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	617,588	428,215
Total gains or (losses) (realized/unrealized) Included in earnings	1,216	4,937
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(1,115)	(20)
Purchases, issuances and settlements	84,840	179,761
Transfers in and/or (out) of Level 3	(1,037)	4,695
Ending balance	701,492	617,588
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	(539)
Market Value [Member] | Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	153,641
Total gains or (losses) (realized/unrealized) Included in earnings	681
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	11,678	3,632
Purchases, issuances and settlements	457,033	150,009
Transfers in and/or (out) of Level 3
Ending balance	623,033	153,641
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 fixed maturities	1,750	7,744
Total gains or (losses) (realized/unrealized) Included in earnings	(125)	(12)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	147	(110)
Purchases, issuances and settlements	3,814	(5,872)
Transfers in and/or (out) of Level 3	113
Ending balance	5,699	1,750
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]
Beginning balance fixed maturities	5,826	2,337
Total gains or (losses) (realized/unrealized) Included in earnings	(919)	2,163
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)
Purchases, issuances and settlements	(4,907)	1,326
Transfers in and/or (out) of Level 3
Ending balance		5,826
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		1,795
Fair Value [Member] | Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	5,826	2,337
Total gains or (losses) (realized/unrealized) Included in earnings	(919)	2,163
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)
Purchases, issuances and settlements	(4,907)	1,326
Transfers in and/or (out) of Level 3
Ending balance		5,826
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		$ 1,795

Fair Value (Fair Value Measur_2

Fair Value (Fair Value Measurements Using Significant Unobservable Inputs For Equity Index Put Option Contracts) (Details) - Common Stock [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period
Total (gains) or losses (realized/unrealized) Included in earnings
Total (gains) or losses (realized/unrealized) Included in other comprehensive income (loss)
Transfers in and/or (out) of Level 3	9,877
Purchases, issuances and settlements	(9,877)
Balance, end of period
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

Credit Facilities (Narrative) (

Credit Facilities (Narrative) (Details)	May 26, 2016USD ($)	Jun. 22, 2012USD ($)	Dec. 31, 2020GBP (£)ItemRate	Dec. 31, 2019GBP (£)Rate	Dec. 31, 2020USD ($)Rate	Mar. 25, 2020USD ($)	Dec. 31, 2019USD ($)Rate	Nov. 07, 2019GBP (£)
Line of Credit Facility [Line Items]
Line of credit facility, number of facilities | Item			2
Line of credit facility, commitment			£ 52,175,000		$ 1,000,000,000
Borrowings from FHLB					310,000,000
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, term of credit facility	5 years	4 years
Line of credit facility, commitment	$ 800,000,000	$ 800,000,000			$ 800,000,000		800,000,000
Line of credit facility, required debt-to-capital ratio | Rate			35.00%		35.00%
Line of credit facility, required minimum net worth					$ 5,370,979,000
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					6,391,043,000
Revolving credit borrowings					753,932,000		623,484,000
Wells Fargo Bank Group Credit Facility Tranche One [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment					200,000,000
Revolving credit borrowings						$ 50,000,000	0
Wells Fargo Bank Group Credit Facility Tranche One [Member] | Federal Funds [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] | London Interbank Offered Rate (LIBOR) [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, commitment					600,000,000
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Line of credit facility, term of credit facility			15 months
Line of credit facility, commitment					200,000,000		200,000,000
Percentage of interest on the principal amount of letters of credit issued			0.35%
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
Per annum commitment fee on undrawn credit			0.15%
Revolving credit borrowings					185,483,000		$ 147,970,000
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment | £			£ 52,175,000	£ 47,000,000				£ 52,175,000
Line of credit facility, required debt-to-capital ratio | Rate				35.00%			35.00%
Line of credit facility, required minimum net worth							$ 6,393,047,000
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					$ 6,527,996,000
Percentage commitment fee per annum			0.10%
Per annum commitment fee on undrawn credit			0.35%
Revolving credit borrowings | £			£ 52,175,000	£ 47,000,000
Federal Home Loan Bank Of New York [Member]
Line of Credit Facility [Line Items]
Maximum percentage of admitted assets allowed for borrowing base			10.00%		10.00%
Admitted assets for FHLB					$ 16,840,721,000
Maximum amount available under FHLB					1,684,072,000
Borrowings from FHLB					400,000,000
Revolving credit borrowings					$ 310,000,000
FHLB advance interest rate			0.35%		0.35%
Amount of borrowed funds required to be used to acquire additional membership stock, percentage			4.50%
Federal Home Loan Bank Of New York [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
FHLB advance maturity			Nov. 30, 2021
Federal Home Loan Bank Of New York [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
FHLB advance maturity			Dec. 31, 2021

Credit Facilities (Summary Of C

Credit Facilities (Summary Of Costs Incurred Connection With Credit Facilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Credit facility interest and fees incurred	$ 815	$ 420	$ 420
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility interest and fees incurred	664	420	420
Federal Home Loan Bank Of New York [Member]
Line of Credit Facility [Line Items]
Credit facility interest and fees incurred	$ 151

Credit Facilities (Summary Of O

Credit Facilities (Summary Of Outstanding Letters Of Credit And Borrowings) (Details)	12 Months Ended
	Dec. 31, 2020GBP (£)	Dec. 31, 2019GBP (£)	Dec. 31, 2020USD ($)	Mar. 25, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 07, 2019GBP (£)	May 26, 2016USD ($)	Jun. 22, 2012USD ($)
Line of Credit Facility [Line Items]
Commitment	£ 52,175,000		$ 1,000,000,000
Wells Fargo Bank Group Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment			800,000,000		$ 800,000,000		$ 800,000,000	$ 800,000,000
In Use			753,932,000		623,484,000
Wells Fargo Bank Group Credit Facility Tranche One [Member]
Line of Credit Facility [Line Items]
Commitment			200,000,000
In Use				$ 50,000,000	0
Wells Fargo Bank Group Credit Facility Tranche One [Member] | Debt Instrument Redemption Period One [Member]
Line of Credit Facility [Line Items]
Commitment			200,000,000		200,000,000
In Use			164,242,000		33,737,000
Date of Expiry	Dec. 31, 2021	Dec. 31, 2020
Wells Fargo Bank Group Credit Facility Tranche Two [Member]
Line of Credit Facility [Line Items]
Commitment			600,000,000
Wells Fargo Bank Group Credit Facility Tranche Two [Member] | Debt Instrument Redemption Period One [Member]
Line of Credit Facility [Line Items]
Commitment			600,000,000		600,000,000
In Use			589,690,000		2,381,000
Date of Expiry	Dec. 31, 2021	Jul. 29, 2020
Wells Fargo Bank Group Credit Facility Tranche Two [Member] | Debt Instrument Redemption Period Two [Member]
Line of Credit Facility [Line Items]
In Use					1,649,000
Date of Expiry		Sep. 30, 2020
Wells Fargo Bank Group Credit Facility Tranche Two [Member] | Debt Instrument Redemption Period Three [Member]
Line of Credit Facility [Line Items]
In Use					573,353,000
Date of Expiry		Dec. 31, 2020
Wells Fargo Bank Group Credit Facility Tranche Two [Member] | Debt Instrument Redemption Period Four [Member]
Line of Credit Facility [Line Items]
In Use					12,364,000
Date of Expiry		Jan. 4, 2021
Citibank Bilateral Agreement [Member]
Line of Credit Facility [Line Items]
Commitment			200,000,000		200,000,000
In Use			185,483,000		147,970,000
Citibank Bilateral Letter Of Credit Agreement One [Member]
Line of Credit Facility [Line Items]
Commitment			200,000,000		200,000,000
In Use			4,425,000		4,425,000
Date of Expiry	Feb. 28, 2021	Feb. 29, 2020
Citibank Bilateral Letter Of Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
In Use			3,672,000		512,000
Date of Expiry	Nov. 24, 2021	Sep. 3, 2020
Citibank Bilateral Letter Of Credit Agreement Three [Member]
Line of Credit Facility [Line Items]
In Use			448,000		3,672,000
Date of Expiry	Dec. 16, 2021	Nov. 24, 2020
Citibank Bilateral Letter Of Credit Agreement Four [Member]
Line of Credit Facility [Line Items]
In Use			115,000		177,000
Date of Expiry	Dec. 20, 2021	Dec. 16, 2020
Citibank Bilateral Letter Of Credit Agreement Five [Member]
Line of Credit Facility [Line Items]
In Use			136,383,000		125,000
Date of Expiry	Dec. 31, 2021	Dec. 20, 2020
Citibank Bilateral Letter Of Credit Agreement Six [Member]
Line of Credit Facility [Line Items]
In Use			39,619,000		101,404,000
Date of Expiry	Dec. 30, 2024	Dec. 31, 2020
Citibank Bilateral Letter Of Credit Agreement Seven [Member]
Line of Credit Facility [Line Items]
In Use			821,000		559,000
Date of Expiry	Aug. 15, 2022	Aug. 15, 2021
Citibank Bilateral Letter Of Credit Agreement Eight [Member]
Line of Credit Facility [Line Items]
In Use					$ 37,096,000
Date of Expiry		Dec. 30, 2023
Lloyds Bank plc Credit Facility [Member]
Line of Credit Facility [Line Items]
Commitment | £	£ 52,175,000	£ 47,000,000				£ 52,175,000
In Use | £	52,175,000	47,000,000
Lloyd's Bank Issuance One [Member]
Line of Credit Facility [Line Items]
Commitment | £
In Use | £
Lloyd S Bank Plc [Member]
Line of Credit Facility [Line Items]
Commitment | £	52,175,000	47,000,000
In Use | £	£ 52,175,000	£ 47,000,000
Date of Expiry	Dec. 31, 2024	Dec. 31, 2023

Senior Notes (Narrative) (Detai

Senior Notes (Narrative) (Details) - Senior Notes [Member]	12 Months Ended
	Dec. 31, 2020USD ($)
4.868% Senior notes due 6/1/2044 [Member]
Debt Instrument [Line Items]
Date issued	Jun. 5, 2014
Debt instrument face amount	$ 400,000,000
Debt instrument, term	30 years
Debt instrument, stated interest rate	4.868%
Debt instrument, maturity date	Jun. 1, 2044
3.5% Senior notes due 10/15/2050 [Member]
Debt Instrument [Line Items]
Date issued	Oct. 7, 2020
Debt instrument face amount	$ 1,000,000,000
Debt instrument, term	30 years
Debt instrument, stated interest rate	3.50%
Debt instrument, maturity date	Oct. 15, 2050

Senior Notes (Schedule Of Outst

Senior Notes (Schedule Of Outstanding Senior Notes) (Details) - Senior Notes [Member] - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
4.868% Senior notes due 6/1/2044 [Member]
Debt Instrument [Line Items]
Date issued	Jun. 5, 2014
Date due	Jun. 1, 2044
Principal Amounts	$ 400,000,000
Consolidated Balance Sheet Amount	397,194,000	$ 397,074,000
Market Value	$ 528,000,000	452,848,000
3.5% Senior notes due 10/15/2050 [Member]
Debt Instrument [Line Items]
Date issued	Oct. 7, 2020
Date due	Oct. 15, 2050
Principal Amounts	$ 1,000,000,000
Consolidated Balance Sheet Amount	979,524,000
Market Value	$ 1,138,100,000

Senior Notes (Schedule Of Inter

Senior Notes (Schedule Of Interest Expense Incurred In Connection With Senior Notes) (Details) - Senior Notes [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
4.868% Senior notes due 6/1/2044 [Member]
Debt Instrument [Line Items]
Interest expense incurred	$ 19,472	$ 19,472	$ 19,472
3.5% Senior notes due 10/15/2050 [Member]
Debt Instrument [Line Items]
Interest expense incurred	$ 8,115

Long Term Subordinated Notes (N

Long Term Subordinated Notes (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Item	Feb. 15, 2021
Subordinated Debt [Member]
Debt Instrument [Line Items]
Outstanding debt reduction	$ 161,441
Subordinated Debt [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
Basis spread on variable rate	2.385%
Right to defer interest, number of occasions | Item	1
Right to defer interest on one or more occasions for up to number of consecutive years	10 years
Redemption date	May 1, 2047
Percentage of principal amount required for redemption	100.00%
Debt instrument, maturity date	May 1, 2067
Outstanding debt reduction	$ 13,183
Gain on repurchase and retirement of debt	$ 2,536
Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Reset quarterly interest rate		2.60%
Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest payment date	May 3, 2007
Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest payment date	May 14, 2017
Senior Notes [Member] | 5.4% Senior notes due 10/15/2014 [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.40%
Debt instrument, maturity date	Oct. 15, 2014
Senior Notes [Member] | 4.868% Senior notes due 6/1/2044 [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.868%
Debt instrument, 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 ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Consolidated balance sheet amount	$ 223,674,000	$ 236,758,000
Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Date Issued	Apr. 26, 2007
Principal Amounts	$ 400,000,000
Maturity Date	May 1, 2067
Consolidated balance sheet amount	$ 223,674,000	236,758,000
Market Value	$ 206,447,000	$ 233,191,000
Scheduled [Member] | Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Maturity Date	May 15, 2037
Final [Member] | Subordinated Debt [Member] | 6.6 % Long Term Subordinated Notes [Member]
Debt Instrument [Line Items]
Maturity Date	May 1, 2067

Long Term Subordinated Notes _2

Long Term Subordinated Notes (Schedule Of Interest Expense Incurred In Connection With Long Term Subordinated Notes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Long Term Subordinated Notes [Abstract]
Interest expense incurred	$ 7,645	$ 11,587	$ 10,926

Collateralized Reinsurance An_3

Collateralized Reinsurance And Trust Agreements (Narrative) (Details) $ in Thousands	Dec. 12, 2019USD ($)Item	Apr. 30, 2018USD ($)Item	Apr. 01, 2018USD ($)	Apr. 13, 2017USD ($)Item	Dec. 01, 2015USD ($)Item	Nov. 18, 2014USD ($)	Apr. 24, 2014USD ($)Item	Nov. 30, 2019USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Effects of Reinsurance [Line Items]
Amount on deposit in trust accounts									$ 1,234,720
Preferred shares
Reinsurance coverage amount									$ 1,365,378	1,308,940	$ 1,060,726
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | Item	4	4		6	2		2
Reinsurance coverage amount						$ 500,000
Reinsurance agreements expiration date						Nov. 30, 2019	Apr. 30, 2018
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 And 2 [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | Item	2	2
Reinsurance contract term	4 years	4 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 Through 3 [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | Item				3
Reinsurance contract term				4 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 3 And 4 [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | Item	2	2
Reinsurance contract term	5 years	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 contract term				5 years
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	$ 150,000	$ 62,500		$ 225,000	$ 300,000		$ 250,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	275,000	200,000		400,000	325,000		200,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 3 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	150,000	62,500		325,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 4 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	275,000	200,000		50,000
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
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
Catastrophe Reinsurance Bonds Redeemed 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 2017-2 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount				300,000
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 2018-1 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount		262,500
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2018-2 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount		$ 262,500
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2019-1 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount	425,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Series 2019-2 Notes [Member]
Effects of Reinsurance [Line Items]
Catastrophe reinsurance bonds funded amount	$ 425,000
Mt Logan Re [Member]
Effects of Reinsurance [Line Items]
Percentage of voting common shares owned by Group									100.00%
Assumed net risk exposures									$ 806,564	993,036
Net risk exposure investments									$ 67,645	$ 46,390
Retrocede amount			$ 269,198
Cash transferred			252,000
Mt Logan Re [Member] | Minimum [Member]
Effects of Reinsurance [Line Items]
Accident year									2002
Mt Logan Re [Member] | Maximum [Member]
Effects of Reinsurance [Line Items]
Accident year									2015
Liability retroceded			$ 319,000

Collateralized Reinsurance An_4

Collateralized Reinsurance And Trust Agreements (Premiums And Losses Ceded By The Company To Affiliate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effects of Reinsurance [Line Items]
Ceded written premiums	$ 1,365,378	$ 1,308,940	$ 1,060,726
Assumed written premiums	7,264,362	6,350,328	6,234,203
Mt. Logan Re Segregated Accounts [Member]
Effects of Reinsurance [Line Items]
Ceded written premiums	303,178	291,979	260,612
Ceded earned premiums	306,184	294,762	262,518
Ceded losses and LAE	241,347	187,192	319,046
Assumed written premiums	18,831	17,005	11,032
Assumed earned premiums	18,831	17,005	11,032
Assumed losses and LAE

Leases (Narrative) (Details)

Leases (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)	Jul. 02, 2019ft²
Lease [Line Items]
Area of property | ft²		315,000
Annual lease expense	$ 7,800
Monthly lease expense	$ 650
Lease expiration	2036

Leases (Supplemental Informatio

Leases (Supplemental Information Relating to Operating Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Lease expense incurred: Operating lease cost	$ 32,508	$ 24,524
Operating lease right of use assets	$ 149,125	$ 161,435	$ 69,869
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets	Other assets
Operating lease liabilities	$ 165,292	$ 169,909	$ 77,270
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities	Other liabilities
Operating cash flows from operating leases	$ (20,594)	$ (20,041)
Weighted average remaining operating lease term	12 years 3 months 18 days	12 years 7 months 6 days
Weighted average discount rate on operating leases	4.10%	3.91%

Leases (Maturities of Lease Lia

Leases (Maturities of Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
2021	$ 18,536
2022	20,971
2023	20,198
2024	19,947
2025	16,956
Thereafter	124,258
Undiscounted lease payments	220,866
Less: present value adjustment	55,574
Total operating lease liability	$ 165,292	$ 169,909	$ 77,270

Leases (Maturities of Lease L_2

Leases (Maturities of Lease Liabilities) (Details) (Alternative Calculation) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Undiscounted lease payments	$ 220,866
Less: present value adjustment	55,574
Total operating lease liability	$ 165,292	$ 169,909	$ 77,270

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Accrual withholding taxes, percent	5.00%
Income tax rate	21.00%	21.00%	21.00%	35.00%
Income tax expense (benefit)	$ 71,198,000	$ 89,526,000	$ (331,223,000)
Net refund	16,287,000
Unrecognized tax benefits that would impact the effective tax rate
Accrued interest and penalties, net of Federal benefit	0
Accrued interest and penalties		0
Deferred tax assets, valuation allowance	28,805,000	12,997,000
Foreign tax credits	46,109,000	186,706,000
Expense (benefit) from TCJA			(28,411,000)
ASU 2016-09 [Member]
Income Tax Contingency [Line Items]
Tax benefits related to restricted stock vestings and stock options exercises	2,993,000	3,357,000	3,453,000
Tax benefits related to payment of dividends on restricted stock	583,000	484,000	403,000
CARES Act [Member]
Income Tax Contingency [Line Items]
Income tax expense (benefit)	32,500,000
Net refund	182,500,000
Subsequent to CARES Act [Member]
Income Tax Contingency [Line Items]
Foreign tax credits	46,109,000
Her Majestys Revenue And Customs H M R C [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	26,428,000
Swiss Federal Tax Administration F T A [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 2,317,000
Net operating loss carryforwards, expiration	Dec. 31, 2028
Canada Revenue Agency [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 1,774,000
Net operating loss carryforwards, expiration	Dec. 31, 2035
Revenue Commissioners Ireland [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 2,300,000
Internal Revenue Service I R S [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 684,000
Net operating loss carryforwards, expiration	Dec. 31, 2037
Internal Revenue Service I R S [Member] | Subsequent to CARES Act [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 0
Foreign Country [Member]
Income Tax Contingency [Line Items]
Income tax expense (benefit)	432,000	$ 14,323,000	$ 6,400,000
Tax Year 2015 [Member]
Income Tax Contingency [Line Items]
Net refund	1,519,000
Tax Year 2016 [Member]
Income Tax Contingency [Line Items]
Net refund	$ 4,685,000

Income Taxes (Components Of The

Income Taxes (Components Of The Provision) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
U.S.	$ (107,757)	$ (5,044)	$ (38,625)
Non-U.S.	2,948	14,420	6,497
Total current tax expense (benefit)	(104,809)	9,376	(32,128)
U.S.	178,523	80,247	(298,998)
Non-U.S.	(2,516)	(97)	(97)
Total deferred tax expense (benefit)	176,007	80,150	(299,095)
Total income tax provision	$ 71,198	$ 89,526	$ (331,223)

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of The Difference Between The Provision For Income Taxes And The Expected Tax Provision At The Weighted Average Tax Rate) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Underwriting gain (loss)									$ (253,811)	$ 336,163	$ (610,275)
Net investment income	$ 222,349	$ 234,233	$ 38,083	$ 147,800	$ 146,077	$ 181,058	$ 179,028	$ 140,976	642,465	647,139	581,183
Net realized capital gains (losses)	$ 183,386	$ 110,203	$ 184,648	$ (210,588)	$ 75,443	$ (12,943)	$ 30,272	$ 92,232	267,649	185,004	(127,136)
Corporate expenses									(41,118)	(32,966)	(30,672)
Interest, fee and bond issue cost amortization expense									(36,323)	(31,693)	(31,031)
Other income (expense)									6,487	(4,660)	(24,251)
INCOME (LOSS) BEFORE TAXES									585,349	1,098,987	(242,182)
Total income tax provision									71,198	89,526	(331,223)
Domestic [Member]
Income Taxes [Line Items]
Underwriting gain (loss)									24,041	38,964	(1,407,020)
Net investment income									339,721	325,179	283,569
Net realized capital gains (losses)									234,970	155,609	(90,033)
Net derivative gain (loss)
Corporate expenses									(15,985)	(13,063)	(11,035)
Interest, fee and bond issue cost amortization expense									(35,659)	(34,931)	(30,611)
Other income (expense)									(14,656)	(1,976)	(5,894)
INCOME (LOSS) BEFORE TAXES									532,432	469,782	(1,261,024)
Expected tax provision at the applicable statutory rate(s)									111,846	98,766	(264,912)
Increase (decrease) in taxes resulting from: Tax exempt income									(3,598)	(3,680)	(3,824)
Increase (decrease) in taxes resulting from: Dividend received deduction									(1,100)	(998)	(1,520)
Increase (decrease) in taxes resulting from: Proration									1,049	1,050	1,150
Increase (decrease) in taxes resulting from: Affiliated preferred stock dividends									6,517	6,517	6,517
Increase (decrease) in taxes resulting from: Creditable foreign premium tax									(11,513)	(9,852)	(13,475)
Increase (decrease) in taxes resulting from: Tax audit settlement										(1,576)	(2,094)
Increase (decrease) in taxes resulting from: U.S. rate differential on carryback of net operation losses to PY											(43,734)
Increase (decrease) in taxes resulting from: U.S. rate differential on deferred tax 2017 return to provision											(28,411)
Increase (decrease) in taxes resulting from: Share based compensation tax benefits formerly in APIC									(2,605)	(2,984)	(3,333)
Increase (decrease) in taxes resulting from: Impact of CARES Act									(32,500)
Increase (decrease) in tax resulting from: Change in uncertain tax positions									277	138	73
Increase (decrease) in taxes resulting from: Valuation allowance										(8,434)	8,434
Increase (decrease) in taxes resulting from: Other									2,393	(3,744)	7,506
Total income tax provision									70,766	75,203	(337,623)
Non-U.S. [Member]
Income Taxes [Line Items]
Underwriting gain (loss)									(277,852)	297,199	796,745
Net investment income									302,744	321,960	297,614
Net realized capital gains (losses)									32,679	29,394	(37,103)
Net derivative gain (loss)									1,541	6,374	520
Corporate expenses									(25,133)	(19,903)	(19,637)
Interest, fee and bond issue cost amortization expense									(664)	3,239	(420)
Other income (expense)									19,602	(9,057)	(18,877)
INCOME (LOSS) BEFORE TAXES									52,917	629,206	1,018,842
Expected tax provision at the applicable statutory rate(s)									(10,356)	17,205	9,647
Increase (decrease) in taxes resulting from: Tax exempt income
Increase (decrease) in taxes resulting from: Dividend received deduction
Increase (decrease) in taxes resulting from: Proration
Increase (decrease) in taxes resulting from: Affiliated preferred stock dividends
Increase (decrease) in taxes resulting from: Creditable foreign premium tax
Increase (decrease) in taxes resulting from: Tax audit settlement
Increase (decrease) in taxes resulting from: U.S. rate differential on carryback of net operation losses to PY
Increase (decrease) in taxes resulting from: U.S. rate differential on deferred tax 2017 return to provision
Increase (decrease) in taxes resulting from: Share based compensation tax benefits formerly in APIC									(388)	(373)	(120)
Increase (decrease) in taxes resulting from: Impact of CARES Act
Increase (decrease) in tax resulting from: Change in uncertain tax positions									15,144	3,772	2,257
Increase (decrease) in taxes resulting from: Valuation allowance
Increase (decrease) in taxes resulting from: Other									(3,968)	(6,281)	(5,384)
Total income tax provision									$ 432	$ 14,323	$ 6,400

Income Taxes (Reconciliation _2

Income Taxes (Reconciliation Of The Beginning And Ending Amount Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Balance at January 1		$ 8,434
Additions based on tax positions related to the current year			8,434
Additions for tax positions of prior years
Reductions for tax positions of prior years		(8,434)
Settlements with taxing authorities
Lapses of applicable statutes of limitations
Balance at December 31			$ 8,434

Income Taxes (Net Deferred Inco

Income Taxes (Net Deferred Income Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Abstract]
Loss reserve	$ 96,840	$ 66,025
Unearned premium reserve	85,028	75,130
Foreign tax credits	46,109	186,706
Net operating loss carryforward	33,504	31,698
Lease liability	31,989	33,042
Net unrealized losses on benefit plans	19,636	19,818
Equity compensation	7,367	7,817
Other tax credits	4,591	2,294
Uncollectible reinsurance reserves	3,142	3,142
Investment impairments	1,121	3,961
Unrealized foreign currency losses	603	7,964
Other assets	7,285	4,520
Total deferred tax assets	337,215	442,117
Net unrealized investment gains	90,268	39,413
Deferred acquisition costs	79,994	81,931
Net fair value income	75,692	25,936
Right of use asset	28,822	31,510
Partnership investments	26,119	15,039
Benefit plan asset	1,765	2,333
Other liabilities	6,710	4,937
Total deferred tax liabilities	309,370	201,099
Net deferred tax assets	27,845	241,018
Less: Valuation allowance	(28,805)	(12,997)
Total net deferred tax assets		$ 228,021
Total net deferred tax assets	$ (960)

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Reinsurance [Abstract]
Allowance for reinsurance receivables	$ 17,178	$ 14,190

Reinsurance (Premiums Written A

Reinsurance (Premiums Written And Earned And Incurred Losses And LAE) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reinsurance [Abstract]
Written premiums: Direct									$ 3,217,999	$ 2,783,036	$ 2,240,951
Written premiums: Assumed									7,264,362	6,350,328	6,234,203
Written premiums: Ceded									(1,365,378)	(1,308,940)	(1,060,726)
Net written premiums	$ 2,449,346	$ 2,448,680	$ 2,017,478	$ 2,201,479	$ 2,120,186	$ 2,068,557	$ 1,783,983	$ 1,851,698	9,116,983	7,824,424	7,414,428
Premiums earned: Direct									3,028,095	2,551,662	2,129,320
Premiums earned: Assumed									7,054,680	6,059,222	5,807,332
Premiums earned: Ceded									(1,401,262)	(1,207,198)	(1,004,953)
Net premiums earned	$ 2,396,483	$ 2,205,811	$ 2,042,405	$ 2,036,814	$ 1,948,071	$ 1,905,619	$ 1,817,299	$ 1,732,697	8,681,513	7,403,686	6,931,699
Incurred losses and LAE: Direct									2,141,065	1,618,686	1,372,589
Incurred losses and LAE: Assumed									5,163,946	3,923,298	5,046,947
ncurred losses and LAE: Ceded									(754,174)	(619,086)	(768,133)
Net incurred losses and LAE									$ 6,550,837	$ 4,922,898	$ 5,651,403

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Before Tax	$ 556,201	$ 542,400	$ (329,378)
Total, Tax Effect	(49,455)	(51,691)	28,913
Total, Net of Tax	506,746	490,709	(300,465)
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	462,939	547,539	(275,511)
Tax Effect	(39,729)	(49,665)	(21,061)
Net of Tax	423,210	497,874	(254,450)
Reclassification, Before Tax	2,253	(13,129)	28,014
Reclassification, Tax Effect	(5,729)	516	(518)
Reclassification, Net of Tax	(3,476)	(12,613)	27,496
Total, Net of Tax	419,734	485,261
URA(D) On Securities OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax		(1,559)	(1,071)
Tax Effect		115	(135)
Net of Tax		(1,444)	(1,206)
Total, Net of Tax		(1,444)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	90,142	18,585	(86,520)
Tax Effect	(3,815)	(4,555)	9,704
Net of Tax	86,327	14,030	(76,816)
Total, Net of Tax	86,327	14,030
Benefit Plan Net Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(7,107)	(15,938)	(646)
Tax Effect	1,492	3,347	136
Net of Tax	(5,615)	(12,591)	(510)
Reclassification, Before Tax	7,974	6,902	6,356
Reclassification, Tax Effect	(1,674)	(1,449)	(1,335)
Reclassification, Net of Tax	6,300	5,453	$ 5,021
Total, Net of Tax	$ 685	$ (7,138)

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) (Reclassification From Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)									$ (71,198)	$ (89,526)	$ 331,223
NET INCOME (LOSS)	$ 63,601	$ 243,057	$ 190,880	$ 16,612	$ 217,644	$ 104,398	$ 332,868	$ 354,551	514,151	1,009,461	$ 89,041
URA(D) On Securities [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net realized capital gains (losses)									2,253	(13,129)
Income tax expense (benefit)									(5,729)	516
NET INCOME (LOSS)									(3,476)	(12,613)
Benefit Plan Net Gain (Loss) [Member] | Reclassification From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other underwriting expenses									7,974	6,902
Income tax expense (benefit)									(1,674)	(1,449)
NET INCOME (LOSS)									$ 6,300	$ 5,453

Other Comprehensive Income (L_5

Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax, In The Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 9,132,925	$ 7,860,797
Current period change	506,746	490,709	$ (300,465)
Balance	9,726,176	9,132,925	7,860,797
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	304,425	(179,392)
Current period change	419,734	485,261
Balance	724,159	304,425	(179,392)
URA(D) On Securities OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Current period change		(1,444)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(201,717)	(215,747)
Current period change	86,327	14,030
Balance	(115,390)	(201,717)	(215,747)
Benefit Plan Net Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(74,556)	(67,418)
Current period change	685	(7,138)
Balance	(73,870)	(74,556)	(67,418)
Accumulated Other Comprehensive Income (Loss), Net of Deferred Income Taxes [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	28,152	(462,557)	(160,891)
Current period change	506,746	490,709	(300,465)
Balance	$ 534,899	$ 28,152	$ (462,557)

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2030	Dec. 20, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan employer contribution percentage for branch offices, minimum	5.10%
Defined contribution plan employer contribution percentage for branch offices, maximum	64.80%
Company contributions	$ 6,825,000	$ 4,750,000	$ 77,743,000
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated transition obligation amortized from accumulated other comprehensive income into net public benefit cost over the next year	0
Estimated actuarial loss amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	(7,709,000)
Estimated prior service cost amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	0
Company contributions	6,825,000	4,750,000
Defined Benefit Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated transition obligation amortized from accumulated other comprehensive income into net public benefit cost over the next year	0
Estimated actuarial loss amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	46,000
Estimated prior service cost amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	$ (577,000)	$ (577,000)	$ (577,000)
Weighted average discount rate used to determine net periodic benefit cost	3.28%	4.27%	3.62%
Rate of compensation increase to determine the net periodic benefit cost	4.00%	4.00%	4.00%
Expected long-term rate of return on plan assets	7.00%	7.00%	7.00%
Weighted average discount rates used to determine actuarial present value of the projected benefit obligation	2.55%	3.28%	4.27%		3.28%
Defined contribution plans, employer contribution plans, employer contribution percentage, maximum	3.00%
Defined contribution plans, employer contribution percentage, for new hires, minimum	3.00%
Defined contribution plans, employer contribution percentage, for new hires, maximum	8.00%
Defined Contribution Plan Employer Contribution Percentage Vested After Three Years	100.00%
Healthcare inflation rate	6.75%
Defined Benefit Postretirement Health Coverage [Member] | Scenario Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Healthcare inflation rate				4.75%
Defined Benefit Postretirement Health Coverage [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets consist of shares in investment trusts, percentage	72.00%
Defined Benefit Postretirement Health Coverage [Member] | Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets consist of shares in investment trusts, percentage	27.00%
Defined Benefit Postretirement Health Coverage [Member] | Limited Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets consist of shares in investment trusts, percentage	1.00%
Defined Benefit Postretirement Health Coverage [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets consist of shares in investment trusts, percentage	0.00%
Defined Benefit Postretirement Health Coverage [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation percentage	70.00%
Defined Benefit Postretirement Health Coverage [Member] | Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation percentage	30.00%
Defined Benefit Postretirement Health Coverage [Member] | Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Private equity limited partnerships	$ 4,596,000	$ 20,351,000
Company contributions

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary Of Contributions To Defined Benefit Pension Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Company contributions	$ 6,825	$ 4,750	$ 77,743

Employee Benefit Plans (Summa_2

Employee Benefit Plans (Summary Of Pension Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension expense	$ 8,429	$ 10,042	$ 9,728

Employee Benefit Plans (Summa_3

Employee Benefit Plans (Summary Of Status Of Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Actual contributions during the year	$ 6,825	$ 4,750	$ 77,743
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	355,356	300,244
Service cost	9,522	8,255	9,801
Interest cost	10,112	11,712	10,290
Actuarial (gain)/loss	43,595	46,206
Benefits paid	(14,115)	(11,062)
Projected benefit obligation at end of year	404,471	355,356	300,244
Fair value of plan assets at beginning of year	301,467	260,531
Actual return on plan assets	60,286	47,247
Actual contributions during the year	6,825	4,750
Administrative expenses paid
Benefits paid	(14,115)	(11,062)
Fair value of plan assets at end of year	354,464	301,467	260,531
Funded status at end of year	(50,007)	(53,889)
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	29,376	28,483
Service cost	1,066	983	1,312
Interest cost	845	980	999
Amendments
Actuarial (gain)/loss	4,042	(582)
Benefits paid	(232)	(488)
Projected benefit obligation at end of year	35,098	29,376	28,483
Fair value of plan assets at beginning of year
Actual contributions by participant during the year	232	488
Benefits paid	(232)	(488)
Fair value of plan assets at end of year
Funded status at end of year	$ (35,098)	$ (29,376)

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Recognized In The Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets (due beyond one year)
Other liabilities (due within one year)	(2,197)	(7,362)
Other liabilities (due beyond one year)	(47,810)	(46,527)
Net amount recognized in the consolidated balance sheets	(50,007)	(53,889)
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other liabilities (due within one year)	(613)	(611)
Other liabilities (due beyond one year)	(34,484)	(28,764)
Net amount recognized in the consolidated balance sheets	$ (35,098)	$ (29,376)

Employee Benefit Plans (Amoun_2

Employee Benefit Plans (Amounts Not Yet Reflected In Net Periodic Benefit Cost And Included In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated income (loss)	$ (91,979)	$ (97,466)
Accumulated other comprehensive income (loss)	(91,979)	(97,466)	$ (88,580)
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated income (loss)	(3,854)	188
Accumulated prior service credit (cost)	2,327	2,904
Accumulated other comprehensive income (loss)	$ (1,527)	$ 3,092	$ 3,242

Employee Benefit Plans (Other C

Employee Benefit Plans (Other Changes In Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other comprehensive income (loss) at December 31, prior year	$ (97,466)	$ (88,580)
Net gain (loss) arising during period	4,090	16,927
Actuarial loss (gain)	9,576	8,042
Curtailment loss recognized
Other comprehensive income (loss) at December 31, current year	(91,979)	(97,466)
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other comprehensive income (loss) at December 31, prior year	3,092	3,242
Net gain (loss) arising during period	(4,042)	582
Prior Service credit (cost) arising during period
Actuarial loss (gain)		(155)
Prior service cost	(577)	(577)
Other comprehensive income (loss) at December 31, current year	$ (1,527)	$ 3,092

Employee Benefit Plans (Net Per

Employee Benefit Plans (Net Periodic Benefit Cost For U.S. Employees) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9,522,000	$ 8,255,000	$ 9,801,000
Interest cost	10,112,000	11,712,000	10,290,000
Prior service credit recognition	0
Expected return on assets	(20,781,000)	(17,968,000)	(17,202,000)
Amortization of actuarial loss from earlier periods	8,551,000	7,635,000	6,839,000
FAS 88 settlement charge	1,025,000	408,000
Net periodic benefit cost	8,429,000	10,042,000	9,728,000
Other comprehensive income (loss) attributable to change from prior year	(5,486,000)	8,885,000
Total recognized in net periodic benefit cost and other comprehensive income (loss)	2,943,000	18,927,000
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,066,000	983,000	1,312,000
Interest cost	845,000	980,000	999,000
Prior service credit recognition	(577,000)	(577,000)	(577,000)
Expected return on assets		(155,000)	94,000
Net periodic benefit cost	1,334,000	1,231,000	$ 1,829,000
Other comprehensive income (loss) attributable to change from prior year	4,619,000	150,000
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ 5,953,000	$ 1,381,000

Employee Benefit Plans (Summa_4

Employee Benefit Plans (Summary Of Accumulated Benefit Obligation) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 352,285	$ 309,970
Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	336,027	288,328
Non-Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 16,258	$ 21,642

Employee Benefit Plans (Project

Employee Benefit Plans (Projected Benefit Obligations In Excess Of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 388,213	$ 333,715
Fair value of plan assets	354,464	301,467
Non-Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	16,258	21,642
Fair value of plan assets

Employee Benefit Plans (Accumul

Employee Benefit Plans (Accumulated Benefit Obligations In Excess Of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation
Fair value of plan assets
Non-Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	16,258	21,642
Fair value of plan assets

Employee Benefit Plans (Expecte

Employee Benefit Plans (Expected Benefit Payments) (Details) $ in Thousands	Dec. 31, 2020USD ($)
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	$ 11,757
2022	12,220
2023	13,064
2024	14,100
2025	15,190
Next 5 years	90,808
Defined Benefit Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	613
2022	715
2023	806
2024	851
2025	989
Next 5 years	$ 6,955

Employee Benefit Plans (Fair Va

Employee Benefit Plans (Fair Value Measurement Levels For Qualified Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value	$ 1,204	$ 1,749
Total	349,867	281,116
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	93,609	90,483
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	255,054	188,884
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value	1,204	1,749
Total	349,867	281,116
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	93,609	90,483
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	255,054	188,884
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value
Total
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value
Significant Other Observable Inputs (Level 2) [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value
Total
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value
Significant Unobservable Inputs (Level 3) [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value

Employee Benefit Plans (Incurre

Employee Benefit Plans (Incurred Expenses Related To Defined Contribution Plans For U.S. Employees) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Incurred expenses	$ 14,386	$ 10,794	$ 9,301

Employee Benefit Plans (Incur_2

Employee Benefit Plans (Incurred Expenses Related To Defined Contribution Plans For Non-U.S. Employees) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Incurred Expenses	$ 3,039	$ 2,216	$ 2,057

Employee Benefit Plans (Post-Re

Employee Benefit Plans (Post-Retirement Benefit Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Post-retirement benefit expenses	$ 1,334	$ 1,231	$ 1,829

Dividend Restrictions And Sta_3

Dividend Restrictions And Statutory Financial Information (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Dividend Restrictions And Statutory Financial Information [Line Items]
Minimum solvency margin	$ 250
Prior approval of the Bermuda Monetary Authority is required for dividend payments, if percentage exceeds in prior-year end total statutory capital	0.25
Dividend payment restrictions, period in months	12 months
Dividend payment restrictions, percentage of statutory surplus required	0.10
Minimum percent of total adjusted capital	200.00%
Bermuda Re [Member]
Dividend Restrictions And Statutory Financial Information [Line Items]
Statutory capital and surplus	$ 2,944,455	$ 3,197,418
Statutory net income (loss)	$ 222,765	503,610	$ 873,111
Target capital level, percent of the enhanced capital requirement	1.20
Everest Re [Member]
Dividend Restrictions And Statutory Financial Information [Line Items]
Available for payment of dividends in 2016 without need for prior regulatory approval	$ 592,082
Statutory capital and surplus	5,276,003	3,739,140
Statutory net income (loss)	$ 595,077	$ 363,034	$ (1,317,991)

Dividend Restrictions And Sta_4

Dividend Restrictions And Statutory Financial Information (Regulatory Targeted Capital And The Actual Statutory Capital) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Minimum percent of total adjusted capital	200.00%
Bermuda Re [Member]
ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Regulatory targeted capital		$ 2,061,065
Actual capital	2,944,455	3,197,418
Everest Re [Member]
ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Regulatory targeted capital	2,489,772	2,001,226
Actual capital	$ 5,276,003	$ 3,739,140

Commitments And Contingencies_2

Commitments And Contingencies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020USD ($)Item$ / Item	Dec. 31, 2005Item
Derivative [Line Items]
Number of equity index put option contracts | Item		7
Equity Index Put Option [Member] | Standard & Poor's 500 [Member]
Derivative [Line Items]
Number of equity index put option contracts | Item	1
Probability of falling below strike price, percentage	0.20%
Index | $ / Item	3,756.07
Equity Index Put Option [Member] | Standard & Poor's 500 [Member] | Theoretical [Member]
Derivative [Line Items]
Maximum discount factor	3.00%
Maximum payout occurs based on index value | $	$ 147,894,000
Equity Index Put Option [Member] | Standard & Poor's 500 [Member] | If Contracts Expire [Member]
Derivative [Line Items]
Settlement amount | $	$ 0

Commitments And Contingencies_3

Commitments And Contingencies (Summary Of Estimated Cost To Replace Annuities For Contingent Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
The Prudential [Member]
Loss Contingencies [Line Items]
Estimated cost to replace annuities	$ 140,773	$ 141,703
Unaffiliated Life Insurance Company [Member]
Loss Contingencies [Line Items]
Estimated cost to replace annuities	$ 35,128	$ 35,082

Share-Based Compensation Plan_2

Share-Based Compensation Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 18, 2020	Sep. 11, 2020	Feb. 26, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares, authorized				200,000,000	200,000,000
Grants in period					0
Share-based compensation awards, grant exercise price				$ 0
Share-based compensation expense				$ 39,209	$ 34,018	$ 32,369
Income tax benefit recorded				7,107	8,384	7,401
Additional paid-in capital due to tax benefit from dividends on restricted shares				583	484	403
Unrecognized compensation cost				88,233
Tax benefit from stock options vested				8,519
Fair value of shares vested				$ 38,745	$ 28,135	$ 25,317
Unrecognized compensation cost expected to be recognized over a weighted-average period, years				3 years 4 months 24 days
2020 Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares, authorized				1,400,000
Remaining shares				1,366,900
1995 and 2002 Employee Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period				0
2009 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares, authorized				37,439
Remaining shares				34,957
2003 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares, authorized				500,000
Remaining shares				316,702
Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares issued				2,718,140
Restricted shares cancelled				369,164
Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares, issued				593	459	480
Restricted shares issued				175,829
Restricted shares cancelled				0
Aggregate value of issuances				$ 125	$ 107	$ 113
Options and Restricted Shares [Member] | 2020 Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years				5 years
Options and Restricted Shares [Member] | 2020 Employee Plan [Member] | Share Based Compensation Award Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Options and Restricted Shares [Member] | 2003 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years				3 years
Options and Restricted Shares [Member] | 2003 Director Plan [Member] | Share Based Compensation Award Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				33.00%
Options and Restricted Shares [Member] | 2010 Employee Plan [Member] | Share Based Compensation Award Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Options and Restricted Shares [Member] | 2002 Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years				5 years
Options and Restricted Shares [Member] | 2002 Employee Plan [Member] | Share Based Compensation Award Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Options and Restricted Shares [Member] | Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock acquired for net-share settlement				66,289	71,437	65,974
Common stock values of shares acquired for net-share settlement				$ 17,889	$ 14,181	$ 14,202
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period				200,929
Weighted-average grant-date fair value of options granted	$ 238.0975	$ 207.505	$ 277.145
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period				16,120
Weighted-average grant-date fair value of options granted			$ 277.145
Performance Shares [Member] | 2020 Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				100.00%
Vesting period, years				3 years
Performance Shares [Member] | 2020 Employee Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock per unit awarded
Performance Shares [Member] | 2020 Employee Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock per unit awarded				1.75
Performance Shares [Member] | Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock acquired for net-share settlement				2,587	5,008	5,214
Common stock values of shares acquired for net-share settlement				$ 717	$ 1,119	$ 1,264
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period				0	0	0
Aggregate intrinsic value of options exercised				$ 9,982	$ 16,297	$ 11,737
Cash received from the exercised share options				4,613
Tax benefit realized from the options exercised				$ 1,904
Employee Stock Option [Member] | 2009 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years				10 years

Share-Based Compensation Plan_3

Share-Based Compensation Plans (Company's Shareholder Approved Plans) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-Based Compensation Plans [Abstract]
Outstanding at January 1, Shares	170,704	279,164	360,364
Granted, Shares		0
Exercised, Shares	53,833	108,460	81,200
Forfeited/Cancelled/Expired, Shares
Outstanding at December 31, Shares	116,871	170,704	279,164
Exercisable at December 31, Shares	116,871	170,704	279,164
Outstanding at January 1, Weighted-Average Exercise Price/Share	$ 87.18	$ 83.84	$ 84.10
Granted - Weighted- Average Exercise Price/Share	0
Exercised, Weighted- Average Exercise Price/Share	85.69	78.58	84.99
Forfeited/Cancelled/Expired, Weighted- Average Exercise Price/Share
Outstanding at December 31, Weighted-Average Exercise Price/Share	87.87	87.18	83.84
Exercisable at December 31, Weighted-Average Exercise Price/Share	$ 87.87	$ 87.18	$ 83.84
Outstanding at December 31, Weighted-Average Remaining Contractual Term	8 months 12 days	1 year 4 months 24 days	1 year 10 months 24 days
Exercisable at December 31, Weighted-Average Remaining Contractual Term	8 months 12 days	1 year 4 months 24 days	1 year 10 months 24 days
Outstanding at December 31, Aggregate Intrinsic Value	$ 17,089	$ 32,376	$ 37,386
Exercisable at December 31, Aggregate Intrinsic Value	$ 17,089	$ 32,376	$ 37,386

Share-Based Compensation Plan_4

Share-Based Compensation Plans (Share Options Outstanding And Exercisable) (Details)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding | shares	116,871
Options Outstanding, Weighted Average-Remaining Contractual Life	8 months 12 days
Options Outstanding, Weighted Average Exercise Price	$ 87.87
Options Exercisable, Number Exercisable | shares	116,871
Options Exercisable, Weighted-Average Exercise Price	$ 87.87
Exercise Prices Range 1 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Ranges of Exercise Prices, Lower range limit	86.62
Ranges of Exercise Prices, Upper range limit	$ 88.31
Options Outstanding, Number Outstanding | shares	44,000
Options Outstanding, Weighted Average-Remaining Contractual Life	2 months 12 days
Options Outstanding, Weighted Average Exercise Price	$ 86.62
Options Exercisable, Number Exercisable | shares	44,000
Options Exercisable, Weighted-Average Exercise Price	$ 86.62
Exercise Prices Range 2 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Ranges of Exercise Prices, Lower range limit	88.32
Ranges of Exercise Prices, Upper range limit	$ 90.48
Options Outstanding, Number Outstanding | shares	66,917
Options Outstanding, Weighted Average-Remaining Contractual Life	1 year 1 month 6 days
Options Outstanding, Weighted Average Exercise Price	$ 88.32
Options Exercisable, Number Exercisable | shares	66,917
Options Exercisable, Weighted-Average Exercise Price	$ 88.32
Exercise Prices Range 3 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Ranges of Exercise Prices, Lower range limit	90.49
Ranges of Exercise Prices, Upper range limit	$ 110.13
Options Outstanding, Number Outstanding | shares	5,954
Options Outstanding, Weighted Average-Remaining Contractual Life	6 months
Options Outstanding, Weighted Average Exercise Price	$ 91.99
Options Exercisable, Number Exercisable | shares	5,954
Options Exercisable, Weighted-Average Exercise Price	$ 91.99

Share-Based Compensation Plan_5

Share-Based Compensation Plans (Summary Of Company's Non-Vested Shares And Changes) (Details) - Restricted Shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at January 1, Shares	495,137	414,407	421,261
Granted, Shares	200,929	232,601	173,065
Vested, Shares	175,413	138,322	141,982
Forfeited, Shares	37,226	13,549	37,937
Outstanding at December 31, Shares	483,427	495,137	414,407
Outstanding at January 1, Weighted Average Grant Date Fair Value	$ 228.02	$ 217.15	$ 194.01
Granted, Weighted Average Grant Date Fair Value	269.86	232.36	240.59
Vested, Weighted Average Grant Date Fair Value	220.88	203.41	178.31
Forfeited, Weighted Average Grant Date Fair Value	246.20	221.35	212.48
Outstanding at December 31, Weighted Average Grant Date Fair Value	$ 246.60	$ 228.02	$ 217.15

Share-Based Compensation Plan_6

Share-Based Compensation Plans (Company's Non-Vested Performance Share Unit Awards) (Details) - Performance Shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at January 1, Shares	34,850	32,382	33,454
Granted, Shares	16,120	16,855	13,325
Increase/(Decrease) on vesting units due to performance, Shares	(2,227)	(3,455)	(267)
Vested, Shares	6,157	10,922	12,435
Forfeited, Shares	3,695		1,695
Outstanding at December 31, Shares	38,891	34,850	32,382
Outstanding at January 1, Weighted Average Grant Date Fair Value
Granted, Weighted Average Grant Date Fair Value	277.15	223.45	242.39
Vested, Weighted Average Grant Date Fair Value	277.15	223.45	242.39
Forfeited, Weighted Average Grant Date Fair Value
Outstanding at December 31, Weighted Average Grant Date Fair Value

Segment Reporting (Narrative) (

Segment Reporting (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Percentage threshold of Company revenue not exceeded by any other country	20.10%	23.10%	19.70%

Segment Reporting (Schedule Of

Segment Reporting (Schedule Of Underwriting Results For Operating Segments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Gross written premiums									$ 3,217,999	$ 2,783,036	$ 2,240,951
Net written premiums	$ 2,449,346	$ 2,448,680	$ 2,017,478	$ 2,201,479	$ 2,120,186	$ 2,068,557	$ 1,783,983	$ 1,851,698	9,116,983	7,824,424	7,414,428
Premiums earned	$ 2,396,483	$ 2,205,811	$ 2,042,405	$ 2,036,814	$ 1,948,071	$ 1,905,619	$ 1,817,299	$ 1,732,697	8,681,513	7,403,686	6,931,699
Incurred losses and LAE									6,550,837	4,922,898	5,651,403
Commission and brokerage									1,873,250	1,703,726	1,519,030
Other Underwriting Expenses									511,237	440,899	371,541
Underwriting gain (loss)									(253,811)	336,163	(610,275)
Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums									7,281,716	6,355,889	6,224,601
Net written premiums									6,767,579	5,732,272	5,706,453
Premiums earned									6,466,106	5,491,296	5,293,071
Incurred losses and LAE									4,933,411	3,675,178	4,585,602
Commission and brokerage									1,552,371	1,400,247	1,251,581
Other Underwriting Expenses									175,734	160,834	142,874
Underwriting gain (loss)									(195,410)	255,037	(686,986)
Insurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums									3,200,645	2,777,475	2,250,552
Net written premiums									2,349,404	2,092,152	1,707,975
Premiums earned									2,215,407	1,912,390	1,638,628
Incurred losses and LAE									1,617,426	1,247,720	1,065,801
Commission and brokerage									320,879	303,479	267,449
Other Underwriting Expenses									335,503	280,065	228,667
Underwriting gain (loss)									$ (58,401)	$ 81,126	$ 76,711

Segment Reporting (Schedule O_2

Segment Reporting (Schedule Of Underwriting Results For Operating Segments To Income (Loss) Before Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss)									$ (253,811)	$ 336,163	$ (610,275)
Net Investment Income	$ 222,349	$ 234,233	$ 38,083	$ 147,800	$ 146,077	$ 181,058	$ 179,028	$ 140,976	642,465	647,139	581,183
Net realized capital gains (losses)	$ 183,386	$ 110,203	$ 184,648	$ (210,588)	$ 75,443	$ (12,943)	$ 30,272	$ 92,232	267,649	185,004	(127,136)
Corporate expenses									(41,118)	(32,966)	(30,672)
Interest, fee and bond issue cost amortization expense									(36,323)	(31,693)	(31,031)
Other income (expense)									6,487	(4,660)	(24,251)
INCOME (LOSS) BEFORE TAXES									$ 585,349	$ 1,098,987	$ (242,182)

Segment Reporting (Schedule O_3

Segment Reporting (Schedule Of Gross Written Premiums Derived From Largest Non-U.S. Market) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Gross written premiums	$ 3,217,999	$ 2,783,036	$ 2,240,951
United Kingdom [Member]
Segment Reporting Information [Line Items]
Gross written premiums	$ 1,116,363	$ 964,358	$ 914,612

Unaudited Quarterly Financial_3

Unaudited Quarterly Financial Data (Summary Of Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unaudited Quarterly Financial Data [Abstract]
Gross written premiums	$ 2,750,548	$ 2,791,604	$ 2,369,338	$ 2,570,871	$ 2,436,327	$ 2,403,274	$ 2,166,655	$ 2,127,108
Net written premiums	2,449,346	2,448,680	2,017,478	2,201,479	2,120,186	2,068,557	1,783,983	1,851,698	$ 9,116,983	$ 7,824,424	$ 7,414,428
Premiums earned	2,396,483	2,205,811	2,042,405	2,036,814	1,948,071	1,905,619	1,817,299	1,732,697	8,681,513	7,403,686	6,931,699
Net investment income	222,349	234,233	38,083	147,800	146,077	181,058	179,028	140,976	642,465	647,139	581,183
Net realized capital gains (losses)	183,386	110,203	184,648	(210,588)	75,443	(12,943)	30,272	92,232	267,649	185,004	(127,136)
Total claims and underwriting expenses	2,615,223	2,320,417	1,991,462	2,008,222	1,976,943	1,933,158	1,620,413	1,537,009
Net income (loss)	$ 63,601	$ 243,057	$ 190,880	$ 16,612	$ 217,644	$ 104,398	$ 332,868	$ 354,551	$ 514,151	$ 1,009,461	$ 89,041
Basic	$ 1.59	$ 6.08	$ 4.78	$ 0.41	$ 5.34	$ 2.56	$ 8.17	$ 8.70	$ 12.81	$ 24.77	$ 2.18
Diluted	$ 1.59	$ 6.07	$ 4.77	$ 0.41	$ 5.32	$ 2.56	$ 8.15	$ 8.67	$ 12.78	$ 24.70	$ 2.17

Schedule I - Summary Of Inves_2

Schedule I - Summary Of Investments - Other Than Investments In Related Parties (Details) $ in Thousands	Dec. 31, 2020USD ($)
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	$ 24,287,685
Total investments and cash, Market Value	25,461,591
Total investments and cash, Amount Shown in Balance Sheet	25,461,591
Total Fixed Maturities Available For Sale [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	19,225,067
Total investments and cash, Market Value	20,040,173
Total investments and cash, Amount Shown in Balance Sheet	20,040,173
U S Treasury And Government [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	1,325,156
Total investments and cash, Market Value	1,367,106
Total investments and cash, Amount Shown in Balance Sheet	1,367,106
State, Municipalities and Political Subdivisions [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	543,895
Total investments and cash, Market Value	577,295
Total investments and cash, Amount Shown in Balance Sheet	577,295
Foreign Government Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	1,565,260
Total investments and cash, Market Value	1,645,375
Total investments and cash, Amount Shown in Balance Sheet	1,645,375
Foreign Corporate Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	3,297,898
Total investments and cash, Market Value	3,472,333
Total investments and cash, Amount Shown in Balance Sheet	3,472,333
Public Utilities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	305,922
Total investments and cash, Market Value	329,977
Total investments and cash, Amount Shown in Balance Sheet	329,977
All Other Corporate Bonds [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	9,051,540
Total investments and cash, Market Value	9,377,901
Total investments and cash, Amount Shown in Balance Sheet	9,377,901
Commercial Mortgage Backed Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	915,923
Total investments and cash, Market Value	990,303
Total investments and cash, Amount Shown in Balance Sheet	990,303
Agency Residential [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	2,206,139
Total investments and cash, Market Value	2,267,739
Total investments and cash, Amount Shown in Balance Sheet	2,267,739
Non-Agency Residential [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	5,187
Total investments and cash, Market Value	5,194
Total investments and cash, Amount Shown in Balance Sheet	5,194
Redeemable Preferred Stock [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	8,147
Total investments and cash, Market Value	6,950
Total investments and cash, Amount Shown in Balance Sheet	6,950
Fixed Maturities - Available For Sale At Fair Value [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost
Total investments and cash, Market Value
Total investments and cash, Amount Shown in Balance Sheet
Equity Securities - at Fair Value [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	1,113,298
Total investments and cash, Market Value	1,472,236
Total investments and cash, Amount Shown in Balance Sheet	1,472,236
Short-Term Investments [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	1,135,088
Total investments and cash, Market Value	1,134,950
Total investments and cash, Amount Shown in Balance Sheet	1,134,950
Other Invested Assets [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	2,012,581
Total investments and cash, Market Value	2,012,581
Total investments and cash, Amount Shown in Balance Sheet	2,012,581
Cash [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Total investments and cash, Cost	801,651
Total investments and cash, Market Value	801,651
Total investments and cash, Amount Shown in Balance Sheet	$ 801,651

Schedule II - Condensed Finan_2

Schedule II - Condensed Financial Information Of The Registrant (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 17, 2019
Debt Instrument [Line Items]
Other assets	$ 742,369,000	$ 612,997,000
Other income (expense)	6,487,000	(4,660,000)	$ (24,251,000)
Mt. Logan Re Segregated Accounts [Member]
Debt Instrument [Line Items]
Other assets	67,645,000	46,390,000
Other income (expense)	6,255,000	765,000	(4,695,000)
Parent Company [Member]
Debt Instrument [Line Items]
Other assets	64,692,000	44,646,000
Other income (expense)	$ 5,833,000	$ 458,000	$ (5,299,000)
Parent Company [Member] | Notes Payable Other Payables [Member]
Debt Instrument [Line Items]
Debt instrument face amount				$ 300,000,000
Maturity Date	Dec. 1, 2028
Debt instrument, stated interest rate				1.69%

Schedule II - Condensed Finan_3

Schedule II - Condensed Financial Information Of The Registrant (Condensed Balance Sheets) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Fixed maturities - available for sale, at market value	$ 20,040,173	$ 16,824,944
Other invested assets	2,012,581	1,763,531
Cash	801,651	808,036
Accrued investment income	141,304	116,804
Other assets	742,369	612,997
TOTAL ASSETS	32,788,357	27,324,051
Other liabilities	558,432	458,848
Total liabilities	23,062,181	18,191,126
Preferred shares, par value: $0.01; 50,000 shares authorized; no shares issued and outstanding
Common shares, par value	696	694
Additional paid-in capital	2,245,301	2,219,660
Accumulated other comprehensive income (loss), net of deferred income	534,899	28,152
Treasury shares, at cost;	(3,622,172)	(3,422,152)
Retained earnings	10,567,452	10,306,571
Total shareholders' equity	9,726,176	9,132,925	$ 7,860,797
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	32,788,357	27,324,051
Fixed maturities - available for sale, at market value, amortized cost	19,225,067	16,473,491
Other invested assets, at cost	$ 2,012,581	$ 1,763,531
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 Stock, Shares Authorized	200,000,000	200,000,000
Common shares, outstanding	69,620,000	69,464,000
Accumulated other comprehensive income (loss), net deferred income tax expense (benefit)	$ 80,451	$ 30,996
Treasury shares, at cost	29,636,000	28,665,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Fixed maturities - available for sale, at market value	$ 3	$ 201,666
Other invested assets	282,762	41,700
Cash	884	3,471
Investment in subsidiaries, at equity in the underlying net assets	9,660,713	9,134,038
Accrued investment income		652
Receivable from subsidiaries	18,424	9,361
Other assets	64,692	44,646
TOTAL ASSETS	10,027,478	9,435,534
Long term note payable - Affiliated	300,000	300,000
Due to subsidiaries	1,933	1,491
Other liabilities	(631)	1,118
Total liabilities	301,302	302,609
Preferred shares, par value: $0.01; 50,000 shares authorized; no shares issued and outstanding
Common shares, par value	696	694
Additional paid-in capital	2,245,301	2,219,660
Accumulated other comprehensive income (loss), net of deferred income	534,899	28,152
Treasury shares, at cost;	(3,622,172)	(3,422,152)
Retained earnings	10,567,452	10,306,571
Total shareholders' equity	9,726,176	9,132,925
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	10,027,478	9,435,534
Fixed maturities - available for sale, at market value, amortized cost	3	201,581
Other invested assets, at cost	$ 282,762	$ 41,700
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 Stock, Shares Authorized	200,000,000	200,000,000
Common shares, issued	69,620,000	69,464,000
Common shares, outstanding	69,620,000	69,464,000
Treasury shares, at cost	29,636,000	28,665,000
Parent Company [Member] | Notes Payable Other Payables [Member]
Condensed Financial Statements, Captions [Line Items]
Date due	Dec. 1, 2028

Schedule II - Condensed Finan_4

Schedule II - Condensed Financial Information Of The Registrant (Condensed Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Net Investment Income	$ 222,349	$ 234,233	$ 38,083	$ 147,800	$ 146,077	$ 181,058	$ 179,028	$ 140,976	$ 642,465	$ 647,139	$ 581,183
Net realized capital gains (losses)	183,386	110,203	184,648	(210,588)	75,443	(12,943)	30,272	92,232	267,649	185,004	(127,136)
Other income (expense)									6,487	(4,660)	(24,251)
Total revenues									9,598,114	8,231,169	7,361,495
Interest expense - affiliated									36,323	31,693	31,031
Total claims and expenses									9,012,765	7,132,182	7,603,677
INCOME (LOSS) BEFORE TAXES									585,349	1,098,987	(242,182)
Income tax expense (benefit)									(71,198)	(89,526)	331,223
NET INCOME (LOSS)	$ 63,601	$ 243,057	$ 190,880	$ 16,612	$ 217,644	$ 104,398	$ 332,868	$ 354,551	514,151	1,009,461	89,041
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period									423,210	496,430	(255,656)
Reclassification adjustment for realized losses (gains) included in net income (loss)									(3,476)	(12,613)	27,496
Total URA(D) on securities arising during the period									419,734	483,817	(228,160)
Foreign currency translation adjustments									86,327	14,030	(76,816)
Benefit plan actuarial net gain (loss) for the period									(5,615)	(12,591)	(510)
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)									6,300	5,453	5,021
Total benefit plan net gain (loss) for the period									685	(7,138)	4,511
Total other comprehensive income (loss), net of tax									506,746	490,709	(300,465)
COMPREHENSIVE INCOME (LOSS)									1,020,897	1,500,170	(211,424)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net Investment Income									1,121	3,484	3,790
Net realized capital gains (losses)									28	(66)	(57)
Other income (expense)									5,833	458	(5,299)
Net income (loss) of subsidiaries									535,866	1,026,233	112,859
Total revenues									542,848	1,030,109	111,293
Interest expense - affiliated									5,155	2,087	4,085
Other expenses									23,542	18,561	18,167
INCOME (LOSS) BEFORE TAXES									514,151	1,009,461	89,041
NET INCOME (LOSS)									514,151	1,009,461	89,041
Unrealized appreciation (depreciation) ("URA(D)") on securities arising during the period									423,210	496,430	(255,656)
Reclassification adjustment for realized losses (gains) included in net income (loss)									(3,476)	(12,613)	27,496
Total URA(D) on securities arising during the period									419,734	483,817	(228,160)
Foreign currency translation adjustments									86,327	14,030	(76,816)
Benefit plan actuarial net gain (loss) for the period									(5,615)	(12,591)	(510)
Reclassification adjustment for amortization of net (gain) loss included in net income (loss)									6,300	5,453	5,021
Total benefit plan net gain (loss) for the period									685	(7,138)	4,511
Total other comprehensive income (loss), net of tax									506,746	490,709	(300,465)
COMPREHENSIVE INCOME (LOSS)									$ 1,020,897	$ 1,500,170	$ (211,424)

Schedule II - Condensed Finan_5

Schedule II - Condensed Financial Information Of The Registrant (Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ 63,601	$ 243,057	$ 190,880	$ 16,612	$ 217,644	$ 104,398	$ 332,868	$ 354,551	$ 514,151	$ 1,009,461	$ 89,041
Change in other assets and liabilities, net									(95,968)	(54,176)	(322,107)
Amortization of bond premium (accrual of bond discount)									49,673	30,936	29,272
Realized capital losses (gains)	(183,386)	$ (110,203)	$ (184,648)	210,588	(75,443)	$ 12,943	$ (30,272)	(92,232)	(267,649)	(185,004)	127,136
Non-cash compensation expense									39,209	34,018	32,369
Net cash provided by (used in) operating activities									2,873,579	1,852,002	610,069
Proceeds from fixed maturities sold - available for sale, at market value									1,945,867	3,280,237	3,148,428
Distributions from other invested assets									309,912	284,558	3,102,018
Cost of fixed maturities acquired - available for sale, at market value									(7,189,301)	(6,613,917)	(5,909,504)
Cost of other invested assets acquired									(557,473)	(425,438)	(3,370,455)
Net change in short-term investments									(717,527)	(167,290)	455,350
Net cash provided by (used in) investing activities									(3,683,371)	(1,412,492)	(279,621)
Purchase of treasury shares									(200,020)	(24,604)	(75,304)
Dividends paid to shareholders									(249,097)	(234,322)	(216,221)
Net cash provided by (used in) financing activities									800,220	(275,687)	(316,594)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									514,151	1,009,461	89,041
Equity in retained (earnings) deficit of subsidiaries									(535,866)	(1,026,233)	(112,859)
Change in other assets and liabilities, net									(21,145)	564	4,824
Increase (decrease) in due to/from affiliate									(8,621)	(2,209)	683
Amortization of bond premium (accrual of bond discount)									(14)	(9)	(577)
Realized capital losses (gains)									(28)	66	57
Non-cash compensation expense									2,588	2,796	2,740
Net cash provided by (used in) operating activities									601,065	584,436	933,909
Additional investment in subsidiaries									(138,320)	(478,125)	(542,965)
Proceeds from fixed maturities matured/called - available for sale, at market value									1,356	63	93
Proceeds from fixed maturities sold - available for sale, at market value									200,264	74,841	24,856
Distributions from other invested assets									559,767	644,918	1,026,297
Cost of fixed maturities acquired - available for sale, at market value										(200,267)
Cost of other invested assets acquired									(800,828)	(686,528)	(923,828)
Net change in short-term investments
Net cash provided by (used in) investing activities									(177,761)	(645,098)	(415,547)
Common shares issued during the period, net									23,185	22,861	20,086
Purchase of treasury shares									(200,020)	(24,604)	(75,304)
Dividends paid to shareholders									(249,056)	(234,322)	(216,221)
Proceeds from issuance (cost or repayment) of long term note - affiliated										300,000	(250,000)
Net cash provided by (used in) financing activities									(425,891)	63,935	(521,439)
EFFECT OF EXCHANGE RATE CHANGES ON CASH
Net increase (decrease) in cash									(2,587)	3,273	(3,077)
Cash, beginning of period				$ 3,471				$ 198	3,471	198	3,275
Cash, end of period	$ 884				$ 3,471				884	3,471	198
Parent Company [Member] | Everest International [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends received from subsidiaries											200,000
Parent Company [Member] | Mt Logan Re [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends received from subsidiaries
Bermuda Re [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends received from subsidiaries									$ 650,000	$ 600,000	$ 750,000

Schedule III - Supplementary _2

Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	$ 622,053	$ 581,863	$ 511,573
Reverse for Losses and Loss Adjustment Expenses	16,398,997	13,611,313	13,119,090
Unearned Premium Reserves	3,501,359	3,056,735	2,517,612
Premiums Earned	8,681,513	7,403,686	6,931,699
Net Investment Income	642,465	647,139	581,183
Incurred Loss and Loss Adjustment Expenses	6,550,837	4,922,898	5,651,403
Amortization of Deferred Acquisition Costs	1,873,250	1,703,726	1,519,030
Other Operating Expenses	511,237	440,899	371,541
Net Written Premium	9,116,983	7,824,424	7,414,428
Domestic Country [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	341,836	358,108	334,818
Reverse for Losses and Loss Adjustment Expenses	9,501,573	7,823,095	8,154,003
Unearned Premium Reserves	2,206,378	2,014,712	1,695,208
Premiums Earned	5,123,460	4,383,837	4,167,619
Net Investment Income	341,797	320,923	287,002
Incurred Loss and Loss Adjustment Expenses	3,920,837	2,761,871	3,849,982
Amortization of Deferred Acquisition Costs	1,063,266	1,007,282	835,823
Other Operating Expenses	409,912	348,861	288,933
Net Written Premium	5,313,490	4,605,731	4,350,157
International Country [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	85,678	66,183	54,253
Reverse for Losses and Loss Adjustment Expenses	2,781,210	2,655,458	2,209,202
Unearned Premium Reserves	430,227	344,222	261,611
Premiums Earned	1,752,244	1,475,669	1,439,882
Net Investment Income	37,208	37,297	34,965
Incurred Loss and Loss Adjustment Expenses	1,074,727	1,193,816	992,704
Amortization of Deferred Acquisition Costs	399,908	342,400	364,010
Other Operating Expenses	45,757	41,690	39,042
Net Written Premium	1,854,813	1,551,753	1,458,745
Bermuda Country [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	194,539	157,572	122,502
Reverse for Losses and Loss Adjustment Expenses	4,116,214	3,132,760	2,755,885
Unearned Premium Reserves	864,754	697,801	560,793
Premiums Earned	1,805,809	1,544,180	1,324,198
Net Investment Income	263,460	288,919	259,216
Incurred Loss and Loss Adjustment Expenses	1,555,273	967,211	808,717
Amortization of Deferred Acquisition Costs	410,076	354,044	319,197
Other Operating Expenses	55,568	50,348	43,566
Net Written Premium	$ 1,948,680	$ 1,666,940	$ 1,605,526

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount									$ 3,028,095	$ 2,551,662	$ 2,129,320
Ceded to Other Companies									1,401,262	1,207,198	1,004,953
Assumed from Other Companies									7,054,680	6,059,222	5,807,332
Net Amount	$ 2,396,483	$ 2,205,811	$ 2,042,405	$ 2,036,814	$ 1,948,071	$ 1,905,619	$ 1,817,299	$ 1,732,697	8,681,513	7,403,686	6,931,699
Total Property And Liability Insurance Premiums Earned [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount									3,028,095	2,556,386	2,129,320
Ceded to Other Companies									1,401,262	1,207,198	1,004,953
Assumed from Other Companies									7,054,680	6,054,498	5,807,332
Net Amount									$ 8,681,513	$ 7,403,686	$ 6,931,699
Assumed to Net	81.30%				81.80%				81.30%	81.80%	83.80%