RenaissanceRe (RNR) 10-K 7 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 04, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	RENAISSANCERE HOLDINGS LTD.
Trading Symbol	RNR
Entity Central Index Key	913,144
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		42,207,390
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 4,752.5

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Fixed maturity investments trading, at fair value - amortized cost $8,163,962 at December 31, 2018 (2017 - $7,434,870) (Notes 4 and 5)	$ 8,088,870	$ 7,426,555
Short term investments, at fair value (Notes 4 and 5)	2,586,520	991,863
Equity investments trading, at fair value (Notes 4 and 5)	310,252	388,254
Other investments, at fair value (Notes 4 and 5)	784,933	594,793
Investments in other ventures, under equity method (Note 4)	115,172	101,974
Total investments	11,885,747	9,503,439
Cash and cash equivalents	1,107,922	1,361,592
Premiums receivable	1,537,188	1,304,622
Prepaid reinsurance premiums (Note 6)	616,185	533,546
Reinsurance recoverable (Notes 6 and 7)	2,372,221	1,586,630
Accrued investment income	51,311	42,235
Deferred acquisition costs	476,661	426,551
Receivable for investments sold	256,416	103,145
Other assets	135,127	121,226
Goodwill and other intangible assets (Note 3)	237,418	243,145
Total assets	18,676,196	15,226,131
Liabilities
Reserve for claims and claim expenses (Note 7)	6,076,271	5,080,408
Unearned premiums	1,716,021	1,477,609
Debt (Note 8)	991,127	989,623
Reinsurance balances payable	1,902,056	989,090
Payable for investments purchased	380,332	208,749
Other liabilities	513,609	792,771
Total liabilities	11,579,416	9,538,250
Commitments and Contingencies (Note 19)
Redeemable noncontrolling interests (Note 9)	2,051,700	1,296,506
Shareholders’ Equity (Note 11)
Preference shares: $1.00 par value – 16,010,000 shares issued and outstanding at December 31, 2018 (2017 – 16,000,000)	650,000	400,000
Common shares: $1.00 par value – 42,207,390 shares issued and outstanding at December 31, 2018 (2017 – 40,023,789)	42,207	40,024
Additional paid-in capital	296,099	37,355
Accumulated other comprehensive (loss) income	(1,433)	224
Retained earnings	4,058,207	3,913,772
Total shareholders’ equity attributable to RenaissanceRe	5,045,080	4,391,375
Total liabilities, noncontrolling interests and shareholders’ equity	$ 18,676,196	$ 15,226,131

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturity investments trading, amortized cost	$ 8,163,962	$ 7,434,870
Preference shares, par value (in usd per share)	$ 1	$ 1
Preference shares, shares issued (in shares)	16,010,000	16,000,000
Preference shares, shares outstanding (in shares)	16,010,000	16,000,000
Common shares, par value (in usd per share)	$ 1	$ 1
Common shares, shares issued (in shares)	42,207,390	40,023,789
Common shares, shares outstanding (in shares)	42,207,390	40,023,789

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Gross premiums written	$ 547,755	$ 625,677	$ 977,343	$ 1,159,652	$ 407,766	$ 640,269	$ 827,415	$ 922,090	$ 3,310,427	$ 2,797,540	$ 2,374,576
Net premiums written (Note 6)	411,094	453,255	604,509	663,044	288,223	483,221	555,745	544,136	2,131,902	1,871,325	1,535,312
Increase in unearned premiums	163,519	78,594	(175,124)	(222,762)	133,250	64,571	(173,480)	(178,091)	(155,773)	(153,750)	(131,882)
Net premiums earned (Note 6)	574,613	531,849	429,385	440,282	421,473	547,792	382,265	366,045	1,976,129	1,717,575	1,403,430
Net investment income (Note 4)	53,338	80,696	71,356	56,476	73,464	40,257	54,163	54,325	261,866	222,209	181,726
Net foreign exchange (losses) gains	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Equity in earnings of other ventures (Note 4)	4,143	7,648	5,826	857	2,200	1,794	5,543	(1,507)	18,474	8,030	963
Other income	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments (Note 4)	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Total revenues	547,997	629,754	479,204	417,986	491,293	634,735	505,585	472,066	2,074,941	2,103,679	1,727,837
Expenses
Net claims and claim expenses incurred (Notes 6 and 7)	477,638	410,510	60,167	171,703	304,064	1,221,696	142,587	193,081	1,120,018	1,861,428	530,831
Acquisition expenses	120,465	109,761	105,052	97,711	98,598	76,761	88,251	83,282	432,989	346,892	289,323
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Corporate expenses	12,108	6,841	8,301	6,733	4,237	4,413	4,636	5,286	33,983	18,572	37,402
Interest expense (Note 8)	11,765	11,769	11,768	11,767	11,777	11,799	10,091	10,526	47,069	44,193	42,144
Total expenses	680,835	579,474	222,831	329,186	447,868	1,357,206	287,331	339,458	1,812,326	2,431,863	1,097,449
Income (loss) before taxes	(132,838)	50,280	256,373	88,800	43,425	(722,471)	218,254	132,608	262,615	(328,184)	630,388
Income tax benefit (expense) (Note 14)	8,852	(1,451)	(4,506)	3,407	(41,226)	18,977	(3,904)	(334)	6,302	(26,487)	(340)
Net income (loss)	(123,986)	48,829	251,867	92,207	2,199	(703,494)	214,350	132,274	268,917	(354,671)	630,048
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	49,269	(6,440)	(54,483)	(29,899)	(56)	204,277	(37,612)	(34,327)	(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe	(74,717)	42,389	197,384	62,308	2,143	(499,217)	176,738	97,947	227,364	(222,389)	502,962
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	$ 197,276	$ (244,770)	$ 480,581
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic (Note 12) (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.25	$ 2.26	$ 4.91	$ (6.15)	$ 11.50
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted (Note 12) (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.24	$ 2.25	$ 4.91	$ (6.15)	$ 11.43

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Comprehensive income (loss)
Net income (loss)	$ 268,917	$ (354,671)	$ 630,048
Change in net unrealized (losses) gains on investments	(1,657)	(909)	(975)
Comprehensive income (loss)	267,260	(355,580)	629,073
Net (income) loss attributable to redeemable noncontrolling interests	(41,553)	132,282	(127,086)
Comprehensive (income) loss attributable to redeemable noncontrolling interests	(41,553)	132,282	(127,086)
Comprehensive income (loss) attributable to RenaissanceRe	225,707	(223,298)	501,987
Disclosure regarding net unrealized (losses) gains
Total net realized and unrealized holding (losses) gains on investments	(1,657)	(909)	403
Net realized losses on fixed maturity investments available for sale	0	0	(1,378)
Change in net unrealized (losses) gains on investments	$ (1,657)	$ (909)	$ (975)

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preference shares	Common shares	Additional paid-in capital	Accumulated other comprehensive (loss) income	Retained earnings
Beginning balance at Dec. 31, 2015		$ 400,000	$ 43,701	$ 507,674	$ 2,108	$ 3,778,701
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 11)		0	0	0
Repurchase of shares			(2,741)	(306,693)
Change in redeemable noncontrolling interest				(1,655)
Exercise of options and issuance of restricted stock awards (Notes 12 and 16)			227	17,232
Change in net unrealized (losses) gains on investments	$ 975				(975)
Net income (loss)	630,048					630,048
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	(127,086)					(127,086)
Dividends on common shares						(51,583)
Dividends on preference shares	(22,381)					(22,381)
Ending balance at Dec. 31, 2016	4,866,577	400,000	41,187	216,558	1,133	4,207,699
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 11)		0	0	0
Repurchase of shares			(1,322)	(187,269)
Offering expenses				0
Change in redeemable noncontrolling interest				119
Exercise of options and issuance of restricted stock awards (Notes 12 and 16)			159	7,947
Change in net unrealized (losses) gains on investments	909				(909)
Net income (loss)	(354,671)					(354,671)
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	132,282					132,282
Dividends on common shares						(51,370)
Dividends on preference shares	(22,381)					(22,381)
Ending balance at Dec. 31, 2017	4,391,375	400,000	40,024	37,355	224	3,913,772
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 11)		250,000	1,947	248,053
Repurchase of shares			0	0
Offering expenses				(8,552)
Change in redeemable noncontrolling interest				837
Exercise of options and issuance of restricted stock awards (Notes 12 and 16)			236	18,406
Change in net unrealized (losses) gains on investments	1,657				(1,657)
Net income (loss)	268,917					268,917
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	(41,553)					(41,553)
Dividends on common shares						(52,841)
Dividends on preference shares	(30,088)					(30,088)
Ending balance at Dec. 31, 2018	$ 5,045,080	$ 650,000	$ 42,207	$ 296,099	$ (1,433)	$ 4,058,207

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows provided by operating activities
Net income (loss)	$ 268,917	$ (354,671)	$ 630,048
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Amortization, accretion and depreciation	123	31,242	29,304
Equity in undistributed (earnings) losses of other ventures	(3,772)	6,295	5,504
Net realized and unrealized losses (gains) on investments	175,069	(135,822)	(141,328)
Net unrealized losses (gains) included in net investment income	8,309	(24,737)	(11,542)
Change in:
Premiums receivable	(232,566)	(317,299)	(209,314)
Prepaid reinsurance premiums	(82,639)	(92,286)	(210,589)
Reinsurance recoverable	(785,591)	(1,307,066)	(145,038)
Deferred acquisition costs	(50,110)	(91,226)	(135,945)
Reserve for claims and claim expenses	995,863	2,232,114	81,249
Unearned premiums	238,412	246,036	342,471
Reinsurance balances payable	912,966	315,107	150,009
Other	(223,280)	518,100	99,943
Net cash provided by operating activities	1,221,701	1,025,787	484,772
Cash flows used in investing activities
Proceeds from sales and maturities of fixed maturity investments trading	11,585,576	9,490,669	8,102,514
Purchases of fixed maturity investments trading	(12,489,972)	(10,093,532)	(8,282,720)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	17,692
Net sales of equity investments trading	14,156	115,837	184,788
Net (purchases) sales of short term investments	(1,436,389)	364,011	(118,617)
Net purchases of other investments	(199,475)	(19,419)	(68,589)
Net purchases of investments in other ventures	(21,473)	0	0
Return of investment from investment in other ventures	8,464	20,000	0
Net sales of other assets	2,500	0	400
Net cash used in investing activities	(2,536,613)	(122,434)	(164,532)
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases	0	(188,591)	(309,434)
RenaissanceRe common share issuance	250,000	0	0
Issuance of debt, net of expenses	0	295,866	0
Repayment of debt	0	(250,000)	0
Net third party redeemable noncontrolling interest share transactions	665,683	260,475	(2,990)
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	1,066,340	28,860	(401,331)
Effect of exchange rate changes on foreign currency cash	(5,098)	8,222	(4,637)
Net (decrease) increase in cash and cash equivalents	(253,670)	940,435	(85,728)
Cash and cash equivalents, beginning of period	1,361,592	421,157	506,885
Cash and cash equivalents, end of period	1,107,922	1,361,592	421,157
Supplemental Cash Flow Information
Income taxes paid (refunded)	341	343	(1,118)
Interest paid	$ 50,775	$ 44,171	$ 53,977

Organization

Organization	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	ORGANIZATION RenaissanceRe Holdings Ltd. (“RenaissanceRe”) was formed under the laws of Bermuda on June 7, 1993. Together with its wholly owned and majority-owned subsidiaries and DaVinciRe (as defined below), which are collectively referred to herein as the “Company”, RenaissanceRe provides property, casualty and specialty reinsurance and certain insurance solutions to customers. • Renaissance Reinsurance Ltd. (“Renaissance Reinsurance”), a Bermuda-domiciled reinsurance company, is the Company’s principal reinsurance subsidiary and provides property, casualty and specialty reinsurance coverages to insurers and reinsurers on a worldwide basis. Effective October 1, 2016, each of Renaissance Reinsurance Specialty Risks Ltd. (“RenaissanceRe Specialty Risks”) and Platinum Underwriters Bermuda, Ltd. (“Platinum Bermuda”) merged into Renaissance Reinsurance, with Renaissance Reinsurance being the sole surviving entity. • Renaissance Reinsurance U.S. Inc. (“Renaissance Reinsurance U.S.”) is a reinsurance company domiciled in the state of Maryland that provides property, casualty and specialty reinsurance coverages to insurers and reinsurers, primarily in the Americas. • RenaissanceRe Underwriting Managers U.S. LLC, a specialty reinsurance agency domiciled in the state of Connecticut, provides specialty treaty reinsurance solutions on both a quota share and excess of loss basis; and writes business on behalf of RenaissanceRe Specialty U.S. Ltd. (“RenaissanceRe Specialty U.S.”), a Bermuda-domiciled reinsurer, which operates subject to U.S. federal income tax, and RenaissanceRe Syndicate 1458 (“Syndicate 1458”). • Syndicate 1458 is the Company’s Lloyd’s syndicate. RenaissanceRe Corporate Capital (UK) Limited (“RenaissanceRe CCL”), a wholly owned subsidiary of RenaissanceRe, is Syndicate 1458’s sole corporate member and RenaissanceRe Syndicate Management Ltd. (“RSML”), a wholly owned subsidiary of RenaissanceRe, is the managing agent for Syndicate 1458. • The Company also manages property, casualty and specialty reinsurance business written on behalf of joint ventures, which principally include Top Layer Reinsurance Ltd. (“Top Layer Re”), recorded under the equity method of accounting, and DaVinci Reinsurance Ltd. (“DaVinci”). Because the Company owns a noncontrolling equity interest in, but controls a majority of the outstanding voting power of DaVinci’s parent, DaVinciRe Holdings Ltd. (“DaVinciRe”), the results of DaVinci and DaVinciRe are consolidated in the Company’s consolidated financial statements and all significant intercompany transactions have been eliminated. Redeemable noncontrolling interest – DaVinciRe represents the interests of external parties with respect to the net income and shareholders’ equity of DaVinciRe. Renaissance Underwriting Managers, Ltd. (“RUM”), a wholly owned subsidiary of RenaissanceRe, acts as exclusive underwriting manager for these joint ventures in return for fee-based income and profit participation. • RenaissanceRe Medici Fund Ltd. (“Medici”) is an exempted fund, incorporated under the laws of Bermuda. Medici’s objective is to seek to invest substantially all of its assets in various insurance based investment instruments that have returns primarily tied to property catastrophe risk. Third party investors have subscribed for a portion of the participating, non-voting common shares of Medici. Because the Company owns a noncontrolling equity interest in, but controls a majority of the outstanding voting power of Medici’s parent, RenaissanceRe Fund Holdings Ltd. (“Fund Holdings”), the results of Medici and Fund Holdings are consolidated in the Company’s consolidated financial statements and all significant inter-company transactions have been eliminated. Redeemable noncontrolling interest - Medici represents the interests of external parties with respect to the net income and shareholders’ equity of Medici. • Upsilon RFO Re Ltd., formerly known as Upsilon Reinsurance II Ltd. (“Upsilon RFO”), a Bermuda domiciled special purpose insurer (“SPI”), is a managed joint venture formed by the Company primarily to provide additional capacity to the worldwide aggregate and per-occurrence primary and retrocessional property catastrophe excess of loss market. Upsilon RFO is considered a variable interest entity (“VIE”) and the Company is considered the primary beneficiary. As a result, Upsilon RFO is consolidated by the Company and all significant inter-company transactions have been eliminated. • RenaissanceRe Upsilon Fund Ltd. (“Upsilon Fund”), an exempted Bermuda segregated accounts company was formed by the Company to provide a fund structure through which third party investors can invest in reinsurance risk managed by the Company. As a segregated accounts company, Upsilon Fund is permitted to establish segregated accounts to invest in and hold identified pools of assets and liabilities. Each pool of assets and liabilities in each segregated account is structured to be ring-fenced from any claims from the creditors of Upsilon Fund’s general account and from the creditors of other segregated accounts within Upsilon Fund. Third party investors purchase redeemable, non-voting preference shares linked to specific segregated accounts of Upsilon Fund and own 100% of these shares. Upsilon Fund is an investment company and is considered a VIE. The Company is not considered the primary beneficiary of Upsilon Fund and, as a result, the Company does not consolidate the financial position and results of operations of Upsilon Fund. • Effective November 7, 2016 , Fibonacci Reinsurance Ltd. ("Fibonacci Re"), a Bermuda-domiciled SPI, was formed to provide collateralized capacity to Renaissance Reinsurance and its affiliates. Fibonacci Re raises capital from third party investors and the Company, via private placements of participating notes which are listed on the Bermuda Stock Exchange. Fibonacci Re is considered a VIE. The Company is not considered the primary beneficiary of Fibonacci Re and, as a result, the Company does not consolidate the financial position and results of operations of Fibonacci Re. • Effective December 22, 2017, the Company and Reinsurance Group of America, Incorporated closed an initiative (“Langhorne”) to source third party capital to support reinsurers targeting large in-force life and annuity blocks. Langhorne Holdings LLC (“Langhorne Holdings”) is a company that owns and manages certain reinsurance entities within Langhorne. Langhorne Partners LLC (“Langhorne Partners”) is the general partner for Langhorne and the entity which manages the third-party investors investing into Langhorne Holdings. The Company concluded that Langhorne Holdings meets the definition of a VIE. The Company is not the primary beneficiary of Langhorne Holdings and as a result, the Company does not consolidate the financial position or results of operations of Langhorne Holdings. The Company concluded that Langhorne Partners is not a VIE. The Company will account for its investments in Langhorne Holdings and Langhorne Partners under the equity method of accounting, one quarter in arrears. • Effective December 17, 2018 , the Company formed Vermeer Reinsurance Ltd. (“Vermeer”), an exempted Bermuda reinsurer, with PGGM, a Dutch pension fund manager. Vermeer provides capacity focused on risk remote layers in the U.S. property catastrophe market. Vermeer is managed by RUM in return for a management fee. The Company maintains a majority voting control of Vermeer, while PGGM retains economic benefits. Vermeer is considered a VIE, as it has voting rights that are not proportional to its participating rights and the Company is the primary beneficiary. As a result, the Company consolidates Vermeer and all significant inter-company transactions have been eliminated. The Company does not currently expect its voting or economic interest in Vermeer to fluctuate. • On October 30, 2018, the Company entered into a Stock Purchase Agreement by and among the Company, Tokio Marine & Nichido Fire Insurance Co. Ltd. (“Tokio”) and, with respect to certain sections only, Tokio Marine Holdings, Inc. (the “TMR Stock Purchase Agreement”), pursuant to which the Company agreed, subject to the terms and conditions therein, to cause its wholly owned subsidiary RenaissanceRe Specialty Holdings (UK) Limited to purchase all of the share capital of Tokio Millennium Re AG (“TMR AG”), Tokio Millennium Re (UK) Limited (“TMR UK” and, together with TMR AG and their respective subsidiaries, the “TMR Group Entities”) (the “TMR Stock Purchase”). The TMR Stock Purchase is expected to close in the first half of 2019, subject to the closing conditions set forth in the TMR Stock Purchase Agreement, including the receipt of required regulatory approvals. Refer to “Note 20 . Acquisition of Tokio Millennium Re” for additional information regarding the TMR Stock Purchase.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION These consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated from these statements. Certain comparative information has been reclassified to conform to the current presentation. USE OF ESTIMATES IN FINANCIAL STATEMENTS The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. The major estimates reflected in the Company’s consolidated financial statements include, but are not limited to, the reserve for claims and claim expenses; reinsurance recoverables, including allowances for reinsurance recoverables deemed uncollectible; estimates of written and earned premiums; fair value, including the fair value of investments, financial instruments and derivatives; impairment charges; and the Company’s deferred tax valuation allowance. PREMIUMS AND RELATED EXPENSES Premiums are recognized as income, net of any applicable reinsurance or retrocessional coverage purchased, over the terms of the related contracts and policies. Premiums written are based on contract and policy terms and include estimates based on information received from both insureds and ceding companies. Subsequent differences arising on such estimates are recorded in the period in which they are determined. Unearned premiums represent the portion of premiums written that relate to the unexpired terms of contracts and policies in force. Amounts are computed by pro rata methods based on statistical data or reports received from ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written. Acquisition costs are incurred when a contract or policy is issued and only the costs directly related to the successful acquisition of new and renewal contract or policies are deferred and amortized over the same period in which the related premiums are earned. Acquisition costs are shown net of commissions and profit commissions earned on ceded reinsurance, and consist principally of commissions, brokerage and premium tax expenses incurred at the time a contract or policy is issued. Deferred policy acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated claims and claim expenses, based on historical and current experience, and anticipated investment income related to those premiums are considered in determining the recoverability of deferred acquisition costs. CLAIMS AND CLAIM EXPENSES The reserve for claims and claim expenses includes estimates for unpaid claims and claim expenses on reported losses as well as an estimate of losses incurred but not reported. The reserve is based on individual claims, case reserves and other reserve estimates reported by insureds and ceding companies as well as management estimates of ultimate losses. Inherent in the estimates of ultimate losses are expected trends in claim severity and frequency and other factors which could vary significantly as claims are settled. Also, during the past few years, the Company has increased its casualty and specialty reinsurance businesses, but does not have the benefit of a significant amount of its own historical experience in certain of these lines of business. Accordingly, the reserving for incurred losses in these lines of business could be subject to greater variability. Ultimate losses may vary materially from the amounts provided in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, are reflected in the consolidated statements of operations in the period in which they become known and are accounted for as changes in estimates. REINSURANCE Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. For multi-year retrospectively rated contracts, the Company accrues amounts (either assets or liabilities) that are due to or from assuming companies based on estimated contract experience. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the period in which they are determined. Reinsurance recoverables on dual trigger reinsurance contracts require the Company to estimate its ultimate losses applicable to these contracts as well as estimate the ultimate amount of insured industry losses that will be reported by the applicable statistical reporting agency, as per the contract terms. Amounts recoverable from reinsurers are recorded net of a valuation allowance for estimated uncollectible recoveries. Assumed and ceded reinsurance contracts that lack a significant transfer of risk are treated as deposits. Certain assumed and ceded reinsurance contracts that do not meet all of the criteria to be accounted for as reinsurance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic Financial Services - Insurance have been accounted for at fair value under the fair value option in accordance with FASB ASC Topic Financial Instruments. INVESTMENTS, CASH AND CASH EQUIVALENTS Fixed Maturity Investments Investments in fixed maturities are classified as trading or available for sale and are reported at fair value. Investment transactions are recorded on the trade date with balances pending settlement reflected in the balance sheet as a receivable for investments sold or a payable for investments purchased. Net investment income includes interest and dividend income together with amortization of market premiums and discounts and is net of investment management and custody fees. The amortization of premium and accretion of discount for fixed maturity securities is computed using the effective yield method. For mortgage-backed securities and other holdings for which there is prepayment risk, prepayment assumptions are evaluated quarterly and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments. Fair values of investments are based on quoted market prices, or when such prices are not available, by reference to broker or underwriter bid indications and/or internal pricing valuation techniques. The net unrealized appreciation or depreciation on fixed maturity investments trading is included in net realized and unrealized gains (losses) on investments in the consolidated statements of operations. The net unrealized appreciation or depreciation on fixed maturity investments available for sale is included in accumulated other comprehensive income. Realized gains or losses on the sale of investments are determined on the basis of the first in first out cost method and, for fixed maturity investments available for sale, include adjustments to the cost basis of investments for declines in value that are considered to be other-than-temporary. Short Term Investments Short term investments, which are managed as part of the Company’s investment portfolio and have a maturity of one year or less when purchased, are carried at fair value. The net unrealized appreciation or depreciation on short term investments is included in net realized and unrealized gains on investments in the consolidated statements of operations. Equity Investments, Classified as Trading Equity investments are accounted for at fair value in accordance with FASB ASC Topic Financial Instruments. Fair values are primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. Net investment income includes dividend income and the net realized and unrealized appreciation or depreciation on equity investments is included in net realized and unrealized gains (losses) on investments in the consolidated statements of operations. Other Investments The Company accounts for its other investments at fair value in accordance with FASB ASC Topic Financial Instruments with interest, dividend income, income distributions and realized and unrealized gains and losses included in net investment income. The fair value of certain of the Company’s fund investments, which principally include private equity investments, senior secured bank loan funds and hedge funds, is recorded on its balance sheet in other investments, and is generally established on the basis of the net valuation criteria established by the managers of such investments, if applicable. The net valuation criteria established by the managers of such investments is established in accordance with the governing documents of such investments. Certain of the Company’s fund managers, fund administrators, or both, are unable to provide final fund valuations as of the Company’s current reporting date. The typical reporting lag experienced by the Company to receive a final net asset value report is one month for hedge funds and senior secured bank loan funds and three months for private equity investments, although, in the past, in respect of certain of the Company’s private equity investments, the Company has on occasion experienced delays of up to six months at year end, as the private equity investments typically complete their respective year-end audits before releasing their final net asset value statements. In circumstances where there is a reporting lag between the current period end reporting date and the reporting date of the latest fund valuation, the Company estimates the fair value of these funds by starting with the prior month or quarter-end fund valuations, adjusting these valuations for actual capital calls, redemptions or distributions, as well as the impact of changes in foreign currency exchange rates, and then estimating the return for the current period. In circumstances in which the Company estimates the return for the current period, all information available to the Company is utilized. This principally includes preliminary estimates reported to the Company by its fund managers, obtaining the valuation of underlying portfolio investments where such underlying investments are publicly traded and therefore have a readily observable price, using information that is available to the Company with respect to the underlying investments, reviewing various indices for similar investments or asset classes, as well as estimating returns based on the results of similar types of investments for which the Company has obtained reported results, or other valuation methods, where possible. Actual final fund valuations may differ, perhaps materially so, from the Company’s estimates and these differences are recorded in the Company’s statement of operations in the period in which they are reported to the Company as a change in estimate. The Company’s other investments also include investments in catastrophe bonds which are recorded at fair value and the fair value is based on broker or underwriter bid indications. Investments in Other Ventures, Under Equity Method Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in other ventures, under equity method, and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period. Any decline in value of investments in other ventures, under equity method considered by management to be other-than-temporary is charged to income in the period in which it is determined. Cash and Cash Equivalents Cash equivalents include money market instruments with a maturity of ninety days or less when purchased. STOCK INCENTIVE COMPENSATION The Company is authorized to issue restricted stock awards and units, performance shares, stock options and other equity-based awards to its employees and directors. The fair value of the compensation cost is measured at the grant date and expensed over the period for which the employee is required to provide services in exchange for the award. In addition, the Company is authorized to issue cash settled restricted stock units (“CSRSU”) to its employees. The fair value of CSRSUs is determined using the fair market value of RenaissanceRe common shares at the end of each reporting period and is expensed over the period for which the employee is required to provide service in exchange for the award. The fair value of these awards is recorded on the Company’s consolidated balance sheet as a liability as it is expensed and until the point payment is made to the employee. The Company has elected to recognize forfeitures as they occur rather than estimating service-based forfeitures over the requisite service period. DERIVATIVES The Company enters into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts in order to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company accounts for its derivatives in accordance with FASB ASC Topic Derivatives and Hedging , which requires all derivatives to be recorded at fair value on the Company’s balance sheet as either assets or liabilities, depending on their rights or obligations, with changes in fair value reflected in current earnings. The Company does not currently apply hedge accounting. The fair value of the Company’s derivatives is estimated by reference to quoted prices or broker quotes, where available, or in the absence of quoted prices or broker quotes, the use of industry or internal valuation models. FAIR VALUE The Company accounts for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurement s and Disclosures . The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income in shareholders’ equity. BUSINESS COMBINATIONS, GOODWILL AND OTHER INTANGIBLE ASSETS The Company accounts for business combinations in accordance with FASB ASC Topic Business Combinations , and goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles – Goodwill and Other . A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill, and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful life of the asset. Other intangible assets with an indefinite useful life are not amortized. Goodwill and other indefinite life intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable. Finite life intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable, and tested for impairment if appropriate. For purposes of the annual impairment evaluation, goodwill is assigned to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill and other intangible assets recorded in connection with investments accounted for under the equity method, are recorded as “Investments in other ventures, under equity method” on the Company’s consolidated balance sheets. The Company has established the beginning of the fourth quarter as the date for performing its annual impairment tests. The Company has the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative goodwill impairment test. Under this option, the Company would not be required to calculate the fair value of a reporting unit unless the Company determines, based on its qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. If goodwill or other intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense reflected in the Company’s consolidated statements of operations. NONCONTROLLING INTERESTS The Company accounts for redeemable noncontrolling interests in the mezzanine section of the Company’s consolidated balance sheet in accordance with United States Securities and Exchange Commission (“SEC”) guidance which is applicable to SEC registrants. The SEC guidance requires shares, not required to be accounted for in accordance with FASB ASC Topic Distinguishing Liabilities from Equity , and having redemption features that are not solely within the control of the issuer, to be classified outside of permanent equity in the mezzanine section of the balance sheet. Because the share classes related to the redeemable noncontrolling interest portion of the issuer are not considered liabilities in accordance with FASB ASC Topic Distinguishing Liabilities from Equity and have redemption features that are not solely within the control of the issuer, the redeemable noncontrolling interests are presented in the mezzanine section on the Company’s consolidated balance sheet in accordance with the SEC guidance noted above. The SEC guidance does not impact the accounting for redeemable noncontrolling interest on the consolidated statements of operations; therefore, the provisions of FASB ASC Topic Consolidation with respect to the consolidated statements of operations still apply, and net income attributable to redeemable noncontrolling interests is presented separately in the Company’s consolidated statements of operations. VARIABLE INTEREST ENTITIES The Company accounts for VIEs in accordance with FASB ASC Topic Consolidation , which requires the consolidation of all VIEs by the primary beneficiary, that being the investor that has the power to direct the activities of the VIE and that will absorb a portion of the VIE’s expected losses or residual returns that could potentially be significant to the VIE. For VIEs the Company determines it has a variable interest in, it determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment. EARNINGS PER SHARE The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share. Basic earnings per share are based on weighted average common shares and exclude any dilutive effects of options and restricted stock. Diluted earnings per share assumes the exercise of all dilutive stock options and restricted stock grants. The two-class method is used to determine earnings per share based on dividends declared on common shares and participating securities (i.e., distributed earnings) and participation rights of participating securities in any undistributed earnings. Each unvested restricted share granted by the Company to its employees is considered a participating security and the Company uses the two-class method to calculate its net income available to RenaissanceRe common shareholders per common share – basic and diluted. FOREIGN EXCHANGE The Company’s functional currency is the U.S. dollar. Revenues and expenses denominated in foreign currencies are revalued at the prevailing exchange rate at the transaction date. Monetary assets and liabilities denominated in foreign currencies are remeasured at exchange rates in effect at the balance sheet date, which may result in the recognition of exchange gains or losses which are included in the determination of net income. TAXATION Income taxes have been provided for in accordance with the provisions of FASB ASC Topic Income Taxes . Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the consolidated financial statements and the tax basis of the Company’s assets and liabilities. Such temporary differences are primarily due to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to interest expense, underwriting results, accrued expenses and investments. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to deferred tax assets will not be realized. Uncertain tax positions are also accounted for in accordance with FASB ASC Topic Income Taxes . Uncertain tax positions must meet a more likely than not recognition threshold to be recognized. RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 was issued to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, treatment of forfeitures, classification of awards as either equity or liabilities, and the classification of taxes paid on the statements of cash flows. ASU 2016-09 became effective for the Company in annual and interim periods beginning after December 15, 2016. The cumulative effect of the adoption of ASU 2016-09 was a $2.2 million increase to opening retained earnings as of January 1, 2017. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also provides guidance on accounting for certain contract costs and had also required new disclosures. ASU 2014-09 was to be effective for public business entities in annual and interim periods beginning after December 15, 2016, however in July 2015, the FASB decided to defer by one year the effective dates of ASU 2014-09, and as a result, ASU 2014-09 is effective for public business entities in annual and interim periods beginning after December 15, 2017. ASU 2014-09 notably excludes the accounting for insurance contracts, leases, financial instruments and guarantees. As a result, the Company’s implementation efforts primarily focused on other income and operational expenses on its consolidated statements of operations. The adoption of ASU 2014-09 did not have a material impact on the Company’s consolidated statements of operations and financial position. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or those that result in the consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option, requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and clarifies that the reporting organization should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the organization’s other deferred tax assets. ASU 2016-01 is effective for public business entities in annual and interim periods beginning after December 15, 2017. The adoption of ASU 2016-01 did not have a material impact on the Company’s consolidated statements of operations and financial position. Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 clarifies the classification of receipts and payments in the statement of cash flows. ASU 2016-15 provides guidance related to (1) settlement and payment of zero coupon debt instruments, (2) contingent consideration, (3) proceeds from settlement of insurance claims, (4) proceeds from settlement of corporate and bank owned life insurance policies, (5) distributions from equity method investees, (6) cash receipts from beneficial interests obtained by a transferor, and (7) general guidelines for cash receipts and payments that have more than one aspect of classification. ASU 2016-15 is effective for public business entities for annual periods beginning after December 15, 2017, and interim periods within those fiscal years. The adoption of ASU 2016-15 resulted in the reclassification of $20.0 million of cash inflows from cash flows provided by operating activities, to cash flows used in investing activities for 2017 . This amount related to a return of investment associated with the Company’s investment in Top Layer Reinsurance Ltd, recorded under the equity method of accounting. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 requires lessees to recognize lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous guidance. ASU 2016-02 is effective for public business entities for annual and interim periods beginning after December 15, 2018. Early application is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 modifies the recognition of credit losses by replacing the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 is applicable to financial assets such as loans, debt securities, trade receivables, off-balance sheet credit exposures, reinsurance receivables, and other financial assets that have the contractual right to receive cash. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The Company's invested assets are measured at fair value through net income, and therefore those invested assets would not be impacted by the adoption of ASU 2016-13. The Company has other financial assets, such as reinsurance recoverables, that could be impacted by the adoption of ASU 2016-13. ASU 2016-13 is effective for public business entities that are SEC filers for annual and interim periods beginning after December 15, 2019. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Intra-Entity Transfers of Assets Other Than Inventory In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). ASU 2016-16 requires entities to recognize the income tax consequences of intra-entity transfers of assets other than inventory when the transfers occur; this is a change from current guidance which prohibits the recognition of current and deferred income taxes until the underlying assets have been sold to outside entities. ASU 2016-16 is effective for public business entities for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). Among other things, ASU 2017-04 requires the following: (1) the elimination of step two of the goodwill impairment test; entities will no longer utilize the implied fair value of their assets and liabilities for purposes of testing goodwill for impairment, (2) the quantitative portion of the goodwill impairment test will be performed by comparing the fair value of a reporting unit with its carrying amount; an impairment charge is to be recognized for the excess of carrying amount over fair value, but only to the extent of the amount of goodwill allocated to that reporting unit, and (3) foreign currency translation adjustments are not to be allocated to a reporting unit from an entity’s accumulated other comprehensive income; the reporting unit’s carrying amount should include only the currently translated balances of the assets and liabilities assigned to the reporting unit. ASU 2017-04 is effective for public business entities that are SEC filers for annual periods, or any interim goodwill impairment tests in annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS The following table shows an analysis of goodwill and other intangible assets: Goodwill and other intangible assets Goodwill Other intangible assets Total Balance as of December 31, 2016 Gross amount $ 199,889 $ 96,599 $ 296,488 Accumulated impairment losses and amortization (2,299 ) (43,003 ) (45,302 ) 197,590 53,596 251,186 Amortization — (8,041 ) (8,041 ) Balance as of December 31, 2017 Gross amount 199,889 96,599 296,488 Accumulated impairment losses and amortization (2,299 ) (51,044 ) (53,343 ) 197,590 45,555 243,145 Amortization — (5,727 ) (5,727 ) Balance as of December 31, 2018 Gross amount 199,889 96,599 296,488 Accumulated impairment losses and amortization (2,299 ) (56,771 ) (59,070 ) $ 197,590 $ 39,828 $ 237,418 The following table shows an analysis of goodwill and other intangible assets included in investments in other ventures, under equity method: Goodwill and other intangible assets included in investments in other ventures, under equity method Goodwill Other intangible assets Total Balance as of December 31, 2016 Gross amount $ 12,318 $ 51,796 $ 64,114 Accumulated impairment losses and amortization (4,500 ) (39,934 ) (44,434 ) 7,818 11,862 19,680 Amortization — (2,946 ) (2,946 ) Balance as of December 31, 2017 Gross amount 12,318 51,796 64,114 Accumulated impairment losses and amortization (4,500 ) (42,880 ) (47,380 ) 7,818 8,916 16,734 Acquired during the year 2,780 11,108 13,888 Amortization — (2,886 ) (2,886 ) Balance as of December 31, 2018 Gross amount 15,098 62,904 78,002 Accumulated impairment losses and amortization (4,500 ) (45,766 ) (50,266 ) $ 10,598 $ 17,138 $ 27,736 On March 23, 2018, the Company made an equity investment in TWFG Holding Company LLC (“TWFG”) and the transaction was accounted under the equity method of accounting . Total consideration paid was allocated to the Company’s proportionate share of the net assets of TWFG, other identifiable intangible assets and goodwill. In connection with the acquisition of TWFG, the Company recognized identifiable finite lived intangible assets of $2.0 million and identifiable indefinite lived intangible assets of $9.1 million . In addition, the Company recognized goodwill of $2.8 million . In accordance with the Company’s established accounting policy, the beginning of the fourth quarter was used as the date for performing the annual impairment test. The Company first assessed qualitative factors to determine whether it was necessary to perform a quantitative impairment test. Based on its qualitative assessment, the Company determined it was not more likely than not that the fair value of the goodwill and other intangible assets in question were less than their respective carrying amounts. The qualitative assessment included the following factors which the Company determined had not significantly deteriorated given specific facts and circumstances: macroeconomic conditions; industry and market conditions; costs factors; and overall financial performance. The Company also performed a quantitative analysis using a discounted cash flow model and concluded that the full amount of the goodwill and other intangible assets were not impaired. Other than the goodwill and other intangible assets acquired during the year as noted above and normal course amortization of intangible assets, in accordance with the Company’s established accounting policy, there were no adjustments to carried goodwill and other intangible assets during the year ended December 31, 2018 . The gross carrying value and accumulated amortization by major category of other intangible assets is shown below: Other intangible assets At December 31, 2018 Gross carrying value Accumulated amortization and impairment losses Total Customer relationships and customer lists $ 97,419 $ (60,221 ) $ 37,198 Value of business acquired 20,200 (20,200 ) — Software 12,230 (12,230 ) — Licenses 19,414 — 19,414 Patents and intellectual property 4,500 (4,500 ) — Covenants not-to-compete 4,030 (4,030 ) — Trademarks and trade names 1,710 (1,356 ) 354 $ 159,503 $ (102,537 ) $ 56,966 Other intangible assets At December 31, 2017 Gross carrying value Accumulated amortization and impairment losses Total Customer relationships and customer lists $ 95,458 $ (51,633 ) $ 43,825 Value of business acquired 20,200 (20,200 ) — Software 12,230 (12,230 ) — Licenses 10,267 — 10,267 Patents and intellectual property 4,500 (4,500 ) — Covenants not-to-compete 4,030 (4,030 ) — Trademarks and trade names 1,710 (1,331 ) 379 $ 148,395 $ (93,924 ) $ 54,471 The remaining useful life of intangible assets with finite lives ranges from 2 to 15 years, with a weighted-average amortization period of 6.6 years. Expected amortization of the other intangible assets, including other intangible assets recorded in investments in other ventures, under equity method, is shown below: Other intangibles Other intangible assets included in investments in other ventures, under equity method Total 2019 $ 5,446 $ 2,815 $ 8,261 2020 5,237 1,955 7,192 2021 4,910 1,095 6,005 2022 4,522 1,095 5,617 2023 4,093 631 4,724 2024 and thereafter 5,353 400 5,753 Total remaining amortization expense 29,561 7,991 37,552 Indefinite lived 10,267 9,147 19,414 Total $ 39,828 $ 17,138 $ 56,966

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments [Abstract]
Investments	INVESTMENTS Fixed Maturity Investments Trading The following table summarizes the fair value of fixed maturity investments trading: December 31, December 31, U.S. treasuries $ 3,331,411 $ 3,168,763 Agencies 174,883 47,646 Municipal 6,854 509,802 Non-U.S. government 279,818 287,660 Non-U.S. government-backed corporate 160,063 163,651 Corporate 2,450,244 2,063,459 Agency mortgage-backed 817,880 500,456 Non-agency mortgage-backed 278,680 300,331 Commercial mortgage-backed 282,294 202,062 Asset-backed 306,743 182,725 Total fixed maturity investments trading $ 8,088,870 $ 7,426,555 Contractual maturities of fixed maturity investments trading are described in the following table. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. At December 31, 2018 Amortized Cost Fair Value Due in less than one year $ 511,932 $ 507,728 Due after one through five years 4,799,196 4,762,712 Due after five through ten years 1,086,697 1,056,087 Due after ten years 79,084 76,746 Mortgage-backed 1,376,565 1,378,854 Asset-backed 310,488 306,743 Total $ 8,163,962 $ 8,088,870 Equity Investments Trading The following table summarizes the fair value of equity investments trading: December 31, December 31, Financials $ 200,357 $ 253,543 Communications and technology 42,333 49,526 Industrial, utilities and energy 24,520 34,325 Consumer 20,639 24,779 Healthcare 18,925 21,364 Basic materials 3,478 4,717 Total $ 310,252 $ 388,254 Pledged Investments At December 31, 2018 , $5.7 billion of cash and investments at fair value were on deposit with, or in trust accounts for the benefit of, various counterparties, including with respect to the Company’s letter of credit facilities ( 2017 - $4.4 billion ). Of this amount, $2.0 billion is on deposit with, or in trust accounts for the benefit of, U.S. state regulatory authorities ( 2017 - $1.7 billion ). Reverse Repurchase Agreements At December 31, 2018 , the Company held $3.7 million ( 2017 - $30.0 million ) of reverse repurchase agreements. These loans are fully collateralized, are generally outstanding for a short period of time and are presented on a gross basis as part of short term investments on the Company’s consolidated balance sheets. The required collateral for these loans typically includes high-quality, readily marketable instruments at a minimum amount of 102% of the loan principal. Upon maturity, the Company receives principal and interest income. Net Investment Income The components of net investment income are as follows: Year ended December 31, 2018 2017 2016 Fixed maturity investments $ 211,973 $ 179,624 $ 160,661 Short term investments 33,571 11,082 5,127 Equity investments 4,474 3,628 4,235 Other investments Private equity investments 477 33,999 6,155 Other 22,475 8,067 20,181 Cash and cash equivalents 3,810 1,196 788 276,780 237,596 197,147 Investment expenses (14,914 ) (15,387 ) (15,421 ) Net investment income $ 261,866 $ 222,209 $ 181,726 Net Realized and Unrealized (Losses) Gains on Investments Net realized and unrealized (losses) gains on investments are as follows: Year ended December 31, 2018 2017 2016 Gross realized gains $ 21,284 $ 49,121 $ 72,739 Gross realized losses (91,098 ) (38,832 ) (38,315 ) Net realized (losses) gains on fixed maturity investments (69,814 ) 10,289 34,424 Net unrealized (losses) gains on fixed maturity investments trading (57,310 ) 8,479 26,954 Net realized and unrealized losses on investments-related derivatives (8,784 ) (2,490 ) (15,414 ) Net realized gains on equity investments trading sold during the period 27,739 80,027 14,190 Net unrealized (losses) gains on equity investments trading still held at reporting date (66,900 ) 39,517 81,174 Net realized and unrealized (losses) gains on equity investments trading (39,161 ) 119,544 95,364 Net realized and unrealized (losses) gains on investments $ (175,069 ) $ 135,822 $ 141,328 Other Investments The table below shows the fair value of the Company’s portfolio of other investments: At December 31, 2018 2017 Catastrophe bonds $ 516,571 $ 380,475 Private equity investments 242,647 196,220 Senior secured bank loan funds 14,482 17,574 Hedge funds 11,233 524 Total other investments $ 784,933 $ 594,793 Interest income, income distributions and net realized and unrealized gains on other investments are included in net investment income and totaled $23.0 million ( 2017 – $42.1 million , 2016 – $26.3 million ) of which $8.3 million related to net unrealized losses ( 2017 – gains of $24.7 million , 2016 – gains of $11.5 million ). Included in net investment income for 2018 is income of $0.3 million ( 2017 - $1.9 million , 2016 - $3.4 million ) representing the change in estimate during the period related to the difference between the Company’s estimated fair value due to the lag in reporting, as discussed in “Note 2 . Significant Accounting Policies,” and the actual amount as reported in the final net asset values provided by the Company’s fund managers. The Company has committed capital to private equity investments, other investments and investments in other ventures of $1.2 billion , of which $686.4 million has been contributed at December 31, 2018 . The Company’s remaining commitments to these investments at December 31, 2018 totaled $470.8 million . In the future, the Company may enter into additional commitments in respect of private equity investments or individual portfolio company investment opportunities. Investments in Other Ventures, under Equity Method The table below shows the Company’s portfolio of investments in other ventures, under equity method: 2018 2017 At December 31, Investment Ownership % Carrying Value Investment Ownership % Carrying Value Tower Hill Companies 64,750 24.9 % 38,241 64,750 26.3 % 42,167 Top Layer Re 65,375 50.0 % 46,562 65,375 50.0 % 50,211 Other 35,862 30.6 % 30,369 13,650 40.4 % 9,596 Total investments in other ventures, under equity method $ 165,987 $ 115,172 $ 143,775 $ 101,974 On July 1, 2008, the Company invested $50.0 million in Tower Hill Insurance Group, LLC (included in the Tower Hill Companies in the table above) representing a 25.0% equity ownership. Included in the purchase price was $40.0 million of other intangibles and $7.8 million of goodwill, which, in accordance with generally accepted accounting principles, are recorded as “Investments in other ventures, under equity method” rather than “Goodwill and other intangibles” on the Company’s consolidated balance sheet. The Company originally invested $13.1 million in Top Layer Re, representing a 50.0% ownership. In December 2010, March 2011 and December 2011, primarily as a result of net claims and claim expenses incurred by Top Layer Re with respect to the September 2010 New Zealand Earthquake, the February 2011 New Zealand Earthquake and the Tohoku Earthquake and Tsunami, respectively, the Company invested an additional $13.8 million , $20.5 million and $18.0 million , respectively, in Top Layer Re, maintaining the Company’s 50.0% ownership interest. The table below shows the Company’s equity in earnings of other ventures, under equity method: Year ended December 31, 2018 2017 2016 Tower Hill Companies $ 9,605 $ (1,647 ) $ 10,379 Top Layer Re 8,852 9,851 (8,576 ) Other 17 (174 ) (840 ) Total equity in earnings of other ventures $ 18,474 $ 8,030 $ 963 During 2018 , the Company received $26.1 million of distributions from its investments in other ventures, under equity method ( 2017 – $29.7 million , 2016 – $9.4 million ). Earnings from the Company’s investments in other ventures, under equity method, net of distributions received, were $3.8 million at December 31, 2018 ( 2017 - losses of $6.3 million ). Except for Top Layer Re, the equity in earnings of the Company’s investments in other ventures are reported one quarter in arrears.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The use of fair value to measure certain assets and liabilities with resulting unrealized gains or losses is pervasive within the Company’s consolidated financial statements. Fair value is defined under accounting guidance currently applicable to the Company to be the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between open market participants at the measurement date. The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its consolidated statements of operations. FASB ASC Topic Fair Value Measurements and Disclosures prescribes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to valuation techniques that use at least one significant input that is unobservable (Level 3). The three levels of the fair value hierarchy are described below: • Fair values determined by Level 1 inputs utilize unadjusted quoted prices obtained from active markets for identical assets or liabilities for which the Company has access. The fair value is determined by multiplying the quoted price by the quantity held by the Company; • Fair values determined by Level 2 inputs utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals, broker quotes and certain pricing indices; and • Level 3 inputs are based all or in part on significant unobservable inputs for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In these cases, significant management assumptions can be used to establish management’s best estimate of the assumptions used by other market participants in determining the fair value of the asset or liability. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement of the asset or liability. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and the Company considers factors specific to the asset or liability. In order to determine if a market is active or inactive for a security, the Company considers a number of factors, including, but not limited to, the spread between what a seller is asking for a security and what a buyer is bidding for the same security, the volume of trading activity for the security in question, the price of the security compared to its par value (for fixed maturity investments), and other factors that may be indicative of market activity. There have been no material changes in the Company’s valuation techniques, nor have there been any transfers between Level 1 and Level 2, or Level 2 and Level 3 during the period represented by these consolidated financial statements. Below is a summary of the assets and liabilities that are measured at fair value on a recurring basis and also represents the carrying amount on the Company’s consolidated balance sheets: At December 31, 2018 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fixed maturity investments U.S. treasuries $ 3,331,411 $ 3,331,411 $ — $ — Agencies 174,883 — 174,883 — Municipal 6,854 — 6,854 — Non-U.S. government 279,818 — 279,818 — Non-U.S. government-backed corporate 160,063 — 160,063 — Corporate 2,450,244 — 2,450,244 — Agency mortgage-backed 817,880 — 817,880 — Non-agency mortgage-backed 278,680 — 278,680 — Commercial mortgage-backed 282,294 — 282,294 — Asset-backed 306,743 — 306,743 — Total fixed maturity investments 8,088,870 3,331,411 4,757,459 — Short term investments 2,586,520 — 2,586,520 — Equity investments trading 310,252 310,252 — — Other investments Catastrophe bonds 516,571 — 516,571 — Private equity investments (1) 242,647 — — 54,545 Senior secured bank loan funds (1) 14,482 — — — Hedge funds (1) 11,233 — — — Total other investments 784,933 — 516,571 54,545 Other assets and (liabilities) Assumed and ceded (re)insurance contracts (2) (8,359 ) — — (8,359 ) Derivatives (3) 12,399 484 11,915 — Total other assets and (liabilities) 4,040 484 11,915 (8,359 ) $ 11,774,615 $ 3,642,147 $ 7,872,465 $ 46,186 (1) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (2) Included in assumed and ceded (re)insurance contracts at December 31, 2018 was $5.0 million and $13.3 million of other assets and other liabilities, respectively. (3) See “Note 18 . Derivative Instruments” for additional information related to the fair value, by type of contract, of derivatives entered into by the Company. At December 31, 2017 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fixed maturity investments U.S. treasuries $ 3,168,763 $ 3,168,763 $ — $ — Agencies 47,646 — 47,646 — Municipal 509,802 — 509,802 — Non-U.S. government 287,660 — 287,660 — Non-U.S. government-backed corporate 163,651 — 163,651 — Corporate 2,063,459 — 2,063,459 — Agency mortgage-backed 500,456 — 500,456 — Non-agency mortgage-backed 300,331 — 300,331 — Commercial mortgage-backed 202,062 — 202,062 — Asset-backed 182,725 — 182,725 — Total fixed maturity investments 7,426,555 3,168,763 4,257,792 — Short term investments 991,863 — 991,863 — Equity investments trading 388,254 388,254 — — Other investments Catastrophe bonds 380,475 — 380,475 — Private equity investments (1) 196,220 — — — Senior secured bank loan fund (1) 17,574 — — — Hedge funds (1) 524 — — — Total other investments 594,793 — 380,475 — Other assets and (liabilities) Assumed and ceded (re)insurance contracts (2) (2,952 ) — — (2,952 ) Derivatives (3) 4,636 (45 ) 4,681 — Total other assets and (liabilities) 1,684 (45 ) 4,681 (2,952 ) $ 9,403,149 $ 3,556,972 $ 5,634,811 $ (2,952 ) (1) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (2) Included in assumed and ceded (re)insurance contracts at December 31, 2017 was $2.5 million and $5.5 million of other assets and other liabilities, respectively. (2) See “Note 18 . Derivative Instruments” for additional information related to the fair value, by type of contract, of derivatives entered into by the Company. Level 1 and Level 2 Assets and Liabilities Measured at Fair Value Fixed Maturity Investments Fixed maturity investments included in Level 1 consist of the Company’s investments in U.S. treasuries. Fixed maturity investments included in Level 2 are agencies, municipal, non-U.S. government, non-U.S. government-backed corporate, corporate, agency mortgage-backed, non-agency mortgage-backed, commercial mortgage-backed and asset-backed. The Company’s fixed maturity investments are primarily priced using pricing services, such as index providers and pricing vendors, as well as broker quotations. In general, the pricing vendors provide pricing for a high volume of liquid securities that are actively traded. For securities that do not trade on an exchange, the pricing services generally utilize market data and other observable inputs in matrix pricing models to determine month end prices. Observable inputs include benchmark yields, reported trades, broker-dealer quotes, issuer spreads, bids, offers, reference data and industry and economic events. Index pricing generally relies on market traders as the primary source for pricing; however, models are also utilized to provide prices for all index eligible securities. The models use a variety of observable inputs such as benchmark yields, transactional data, dealer runs, broker-dealer quotes and corporate actions. Prices are generally verified using third-party data. Securities which are priced by an index provider are generally included in the index. In general, broker-dealers value securities through their trading desks based on observable inputs. The methodologies include mapping securities based on trade data, bids or offers, observed spreads, and performance on newly issued securities. Broker-dealers also determine valuations by observing secondary trading of similar securities. Prices obtained from broker quotations are considered non-binding, however they are based on observable inputs and by observing secondary trading of similar securities obtained from active, non-distressed markets. The Company considers these broker quotations to be Level 2 inputs as they are corroborated with other market observable inputs. The techniques generally used to determine the fair value of the Company’s fixed maturity investments are detailed below by asset class. U.S. treasuries Level 1 - At December 31, 2018 , the Company’s U.S. treasuries fixed maturity investments were primarily priced by pricing services and had a weighted average yield to maturity of 2.5% and a weighted average credit quality of AA ( 2017 - 1.9% and AA, respectively). When pricing these securities, the pricing services utilize daily data from many real time market sources, including active broker dealers. Certain data sources are regularly reviewed for accuracy to attempt to ensure the most reliable price source is used for each issue and maturity date. Agencies Level 2 - At December 31, 2018 , the Company’s agency fixed maturity investments had a weighted average yield to maturity of 3.0% and a weighted average credit quality of AA ( 2017 - 2.1% and AA, respectively). The issuers of the Company’s agency fixed maturity investments primarily consist of the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and other agencies. Fixed maturity investments included in agencies are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources and integrate other observations from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The fair value of each security is individually computed using analytical models which incorporate option adjusted spreads and other daily interest rate data. Municipal Level 2 - At December 31, 2018 , the Company’s municipal fixed maturity investments had a weighted average yield to maturity of 4.8% and a weighted average credit quality of A ( 2017 - 2.2% and AA, respectively). The Company’s municipal fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information regarding the security from third party sources such as trustees, paying agents or issuers. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. In certain instances, securities are individually evaluated using a spread over widely accepted market benchmarks. Non-U.S. government Level 2 - At December 31, 2018 , the Company’s non-U.S. government fixed maturity investments had a weighted average yield to maturity of 2.7% and a weighted average credit quality of AAA ( 2017 - 2.0% and AAA, respectively). The issuers of securities in this sector are non-U.S. governments and their respective agencies as well as supranational organizations. Securities held in these sectors are primarily priced by pricing services that employ proprietary discounted cash flow models to value the securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high issuance credits. The pricing services then apply a credit spread for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets. Non-U.S. government-backed corporate Level 2 - At December 31, 2018 , the Company’s non-U.S. government-backed corporate fixed maturity investments had a weighted average yield to maturity of 2.8% and a weighted average credit quality of AA ( 2017 - 2.3% and AA, respectively). Non-U.S. government-backed fixed maturity investments are primarily priced by pricing services that employ proprietary discounted cash flow models to value the securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high issuance credits. The pricing services then apply a credit spread to the respective curve for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets. Corporate Level 2 - At December 31, 2018 , the Company’s corporate fixed maturity investments principally consisted of U.S. and international corporations and had a weighted average yield to maturity of 4.9% and a weighted average credit quality of BBB ( 2017 - 3.8% and BBB, respectively). The Company’s corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. In certain instances, securities are individually evaluated using a spread which is added to the U.S. treasury curve or a security specific swap curve as appropriate. Agency mortgage-backed Level 2 - At December 31, 2018 , the Company’s agency mortgage-backed fixed maturity investments included agency residential mortgage-backed securities with a weighted average yield to maturity of 3.5% , a weighted average credit quality of AA and a weighted average life of 7.1 years ( 2017 - 3.0% , AA and 6.4 years, respectively). The Company’s agency mortgage-backed fixed maturity investments are primarily priced by pricing services using a mortgage pool specific model which utilizes daily inputs from the active to be announced market which is very liquid, as well as the U.S. treasury market. The model also utilizes additional information, such as the weighted average maturity, weighted average coupon and other available pool level data which is provided by the sponsoring agency. Valuations are also corroborated with daily active market quotes. Non-agency mortgage-backed Level 2 - The Company’s non-agency mortgage-backed fixed maturity investments include non-agency prime, non-agency Alt-A and other non-agency residential mortgage-backed securities. At December 31, 2018 , the Company’s non-agency prime residential mortgage-backed fixed maturity investments had a weighted average yield to maturity of 4.4% , a weighted average credit quality of non-investment grade, and a weighted average life of 4.7 years ( 2017 - 3.7% , BBB and 5.1 years, respectively). The Company’s non-agency Alt-A fixed maturity investments held at December 31, 2018 had a weighted average yield to maturity of 4.7% , a weighted average credit quality of non-investment grade and a weighted average life of 6.3 years ( 2017 - 3.7% , non-investment grade and 6.2 years, respectively). Securities held in these sectors are primarily priced by pricing services using an option adjusted spread model or other relevant models, which principally utilize inputs including benchmark yields, available trade information or broker quotes, and issuer spreads. The pricing services also review collateral prepayment speeds, loss severity and delinquencies among other collateral performance indicators for the securities valuation, when applicable. Commercial mortgage-backed Level 2 - At December 31, 2018 , the Company’s commercial mortgage-backed fixed maturity investments had a weighted average yield to maturity of 3.6% , a weighted average credit quality of AAA, and a weighted average life of 5.0 years ( 2017 - 2.9% , AAA and 4.5 years, respectively). Securities held in these sectors are primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services discount the expected cash flows for each security held in this sector using a spread adjusted benchmark yield based on the characteristics of the security. Asset-backed Level 2 - At December 31, 2018 , the Company’s asset-backed fixed maturity investments had a weighted average yield to maturity of 4.3% , a weighted average credit quality of AAA and a weighted average life of 3.2 years ( 2017 - 2.8% , AAA and 3.0 years, respectively). The underlying collateral for the Company’s asset-backed fixed maturity investments primarily consists of bank loans, student loans, credit card receivables, auto loans and other receivables. Securities held in these sectors are primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services determine the expected cash flows for each security held in this sector using historical prepayment and default projections for the underlying collateral and current market data. In addition, a spread is applied to the relevant benchmark and used to discount the cash flows noted above to determine the fair value of the securities held in this sector. Short Term Investments Level 2 - At December 31, 2018 , the Company’s short term investments had a weighted average yield to maturity of 2.1% and a weighted average credit quality of AAA ( 2017 - 1.4% and AAA, respectively). The fair value of the Company’s portfolio of short term investments is generally determined using amortized cost which approximates fair value and, in certain cases, in a manner similar to the Company’s fixed maturity investments noted above. Equity Investments, Classified as Trading Level 1 - The fair value of the Company’s portfolio of equity investments, classified as trading is primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. When pricing these securities, the pricing services utilize daily data from many real time market sources, including applicable securities exchanges. All data sources are regularly reviewed for accuracy to attempt to ensure the most reliable price source was used for each security. Other investments Catastrophe bonds Level 2 - The Company’s other investments include investments in catastrophe bonds which are recorded at fair value based on broker or underwriter bid indications. Other assets and liabilities Derivatives Level 1 and Level 2 - Other assets and liabilities include certain derivatives entered into by the Company. The fair value of these transactions includes certain exchange traded futures contracts which are considered Level 1, and foreign currency contracts and certain credit derivatives, determined using standard industry valuation models and considered Level 2, as the inputs to the valuation model are based on observable market inputs. For credit derivatives, these inputs include credit spreads, credit ratings of the underlying referenced security, the risk free rate and the contract term. For foreign currency contracts, these inputs include spot rates and interest rate curves. Level 3 Assets and Liabilities Measured at Fair Value Below is a summary of quantitative information regarding the significant observable and unobservable inputs (Level 3) used in determining the fair value of assets and liabilities measured at fair value on a recurring basis: December 31, 2018 Fair Value Valuation Technique Unobservable Inputs Low High Weighted Average or Actual Other investments Private equity investments $ 54,545 Internal valuation model Discount rate 16.8 % 29.6 % 23.2 % Total other investments 54,545 Other assets and (liabilities) Assumed and ceded (re)insurance contracts 550 Internal valuation model Bond price $ 100.74 $ 107.82 $ 104.66 Liquidity discount n/a n/a 1.3 % Assumed and ceded (re)insurance contracts (8,909 ) Internal valuation model Net undiscounted cash flows n/a n/a $ (10,528 ) Expected loss ratio n/a n/a 36.1 % Discount rate n/a n/a 2.5 % Total other assets and (liabilities) $ (8,359 ) $ 46,186 Below is a reconciliation of the beginning and ending balances, for the periods shown, of assets and liabilities measured at fair value on a recurring basis using Level 3 inputs. Interest and dividend income are included in net investment income and are excluded from the reconciliation. Other investments Other assets and (liabilities) Total Balance - January 1, 2018 $ — $ (2,952 ) $ (2,952 ) Total realized and unrealized gains Included in other income — 2,901 2,901 Purchases 54,545 (9,291 ) 45,254 Settlements — 983 983 Balance - December 31, 2018 $ 54,545 $ (8,359 ) $ 46,186 Other assets and (liabilities) Balance - January 1, 2017 $ (13,004 ) Total realized and unrealized gains Included in other income 3,761 Purchases 354 Settlements 5,937 Balance - December 31, 2017 $ (2,952 ) Other investments Private equity investment Level 3 - At December 31, 2018 , the Company’s other investments included a $54.5 million private equity investment which is recorded at fair value, with the fair value obtained through the use of an internal valuation model. The Company measured the fair value of this investment using multiples of net tangible book value of the underlying entity. The significant unobservable inputs used in the fair value measurement of this investment are discount rates applied to each of the net tangible book value multiples used in the internal valuation model. These unobservable inputs in isolation can cause significant increases or decreases in fair value. The discount rates are applied to each of the comparable net tangible book value multiples which are used to determine fair value. The comparable net tangible book value multiples are observable and based on the trading multiples of public industry peers of the underlying entity as well as multiples observed in precedent merger and acquisition transactions in the underlying entity’s sector. Generally, an increase in the discount rate would result in a decrease in the fair value of this private equity investment. Other assets and liabilities Assumed and ceded (re)insurance contracts Level 3 - At December 31, 2018 , the Company had a $0.6 million net asset related to an assumed reinsurance contract accounted for at fair value, with the fair value obtained through the use of an internal valuation model. The inputs to the internal valuation model are principally based on indicative pricing obtained from independent brokers and pricing vendors for similarly structured marketable securities. The most significant unobservable inputs include prices for similar marketable securities and a liquidity premium. The Company considers the prices for similar securities to be unobservable, as there is little, if any market activity for these similar assets. In addition, the Company has estimated a liquidity premium that would be required if the Company attempted to effectively exit its position by executing a short sale of these securities. Generally, an increase in the prices for similar marketable securities or a decrease in the liquidity premium would result in an increase in the expected profit and ultimate fair value of this assumed reinsurance contract. Level 3 - At December 31, 2018 , the Company had a $8.9 million net liability related to assumed and ceded (re)insurance contracts accounted for at fair value, with the fair value obtained through the use of an internal valuation model. The inputs to the internal valuation model are principally based on proprietary data as observable market inputs are generally not available. The most significant unobservable inputs include the assumed and ceded expected net cash flows related to the contracts, including the expected premium, acquisition expenses and losses; the expected loss ratio and the relevant discount rate used to present value the net cash flows. The contract period and acquisition expense ratio are considered an observable input as each is defined in the contract. Generally, an increase in the net expected cash flows and expected term of the contract and a decrease in the discount rate, expected loss ratio or acquisition expense ratio, would result in an increase in the expected profit and ultimate fair value of these assumed and ceded (re)insurance contracts. Financial Instruments Disclosed, But Not Carried, at Fair Value The Company uses various financial instruments in the normal course of its business. The Company’s insurance contracts are excluded from the fair value of financial instruments accounting guidance, unless the Company elects the fair value option, and therefore, are not included in the amounts discussed herein. The carrying values of cash and cash equivalents, accrued investment income, receivables for investments sold, certain other assets, payables for investments purchased, certain other liabilities, and other financial instruments not included herein approximated their fair values. Debt Included on the Company’s consolidated balance sheet at December 31, 2018 were debt obligations of $991.1 million ( 2017 - $989.6 million ). At December 31, 2018 , the fair value of the Company’s debt obligations was $974.7 million ( 2017 – $1,018.2 million ). The fair value of the Company’s debt obligations is determined using indicative market pricing obtained from third-party service providers, which the Company considers Level 2 in the fair value hierarchy. There have been no changes during the period in the Company’s valuation technique used to determine the fair value of the Company’s debt obligations. Refer to “Note 8 . Debt and Credit Facilities” for additional information related to the Company’s debt obligations. The Fair Value Option for Financial Assets and Financial Liabilities The Company has elected to account for certain financial assets and financial liabilities at fair value using the guidance under FASB ASC Topic Financial Instruments as the Company believes it represents the most meaningful measurement basis for these assets and liabilities. Below is a summary of the balances the Company has elected to account for at fair value: 2018 2017 Other investments $ 784,933 $ 594,793 Other assets $ 4,968 $ 2,542 Other liabilities $ 13,327 $ 5,494 Included in net investment income for 2018 was net unrealized losses of $8.3 million related to the changes in fair value of other investments ( 2017 – gains of $24.7 million , 2016 – gains of $11.5 million ). Included in other income for 2018 were net unrealized gains of $Nil related to the changes in the fair value of other assets and liabilities ( 2017 – $Nil , 2016 – $Nil ). Measuring the Fair Value of Other Investments Using Net Asset Valuations The table below shows the Company’s portfolio of other investments measured using net asset valuations as a practical expedient: At December 31, 2018 Fair Value Unfunded Redemption Frequency Redemption Redemption Private equity investments $ 188,102 $ 393,700 See below See below See below Senior secured bank loan funds 14,482 20,121 See below See below See below Hedge funds 11,233 — See below See below See below Total other investments measured using net asset valuations $ 213,817 $ 413,821 Private equity investments – A significant portion of the Company’s investments in private equity investments include alternative asset limited partnerships (or similar corporate structures) that invest in certain private equity asset classes including U.S. and global leveraged buyouts, mezzanine investments, distressed securities, real estate, and oil, gas and power. The Company generally has no right to redeem its interest in any of these private equity investments in advance of dissolution of the applicable private equity investment. Instead, the nature of these investments is that distributions are received by the Company in connection with the liquidation of the underlying assets of the respective private equity investment. It is estimated that the majority of the underlying assets of the limited partnerships would liquidate over 7 to 10 years from inception of the respective limited partnership. Senior secured bank loan funds – At December 31, 2018 the Company had $14.5 million invested in closed end funds which invest primarily in loans. The Company has no right to redeem its investment in these funds. It is estimated that the majority of the underlying assets in these closed end funds would liquidate over 4 to 5 years from inception of the applicable fund. Hedge funds – At December 31, 2018 , the Company had $11.2 million of investments in hedge funds that pursue multiple strategies. This included an investment of $11.0 million in a fund primarily focused on global credit opportunities which is redeemable at the option of the shareholder. The remainder of the Company’s hedge fund investments consisted of so called “side pocket” investments which are not redeemable at the option of the shareholder.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Reinsurance	REINSURANCE The Company purchases reinsurance and other protection to manage its risk portfolio and to reduce its exposure to large losses. The Company currently has in place contracts that provide for recovery of a portion of certain claims and claim expenses, generally in excess of various retentions or on a proportional basis. In addition to loss recoveries, certain of the Company’s ceded reinsurance contracts provide for payments of additional premiums, for reinstatement premiums and for lost no-claims bonuses, which are incurred when losses are ceded to the respective reinsurance contracts. The Company remains liable to the extent that any reinsurer fails to meet its obligations. The following table sets forth the effect of reinsurance and retrocessional activity on premiums written and earned and on net claims and claim expenses incurred: Year ended December 31, 2018 2017 2016 Premiums written Direct $ 337,587 $ 290,730 $ 208,282 Assumed 2,972,840 2,506,810 2,166,294 Ceded (1,178,525 ) (926,215 ) (839,264 ) Net premiums written $ 2,131,902 $ 1,871,325 $ 1,535,312 Premiums earned Direct $ 292,219 $ 244,285 $ 157,112 Assumed 2,779,796 2,307,219 1,874,993 Ceded (1,095,886 ) (833,929 ) (628,675 ) Net premiums earned $ 1,976,129 $ 1,717,575 $ 1,403,430 Claims and claim expenses Gross claims and claim expenses incurred $ 2,578,536 $ 3,420,388 $ 710,651 Claims and claim expenses recovered (1,458,518 ) (1,558,960 ) (179,820 ) Net claims and claim expenses incurred $ 1,120,018 $ 1,861,428 $ 530,831 At December 31, 2018 , the Company’s reinsurance recoverable balance was $2.4 billion ( 2017 - $1.6 billion ). Of this amount, 60.8% is fully collateralized by our reinsurers, 38.0% is recoverable from reinsurers rated A- or higher by major rating agencies and 1.2% is recoverable from reinsurers rated lower than A- by major rating agencies ( 2017 - 54.5% , 44.5% and 1.0% , respectively). The reinsurers with the three largest balances accounted for 15.5% , 6.7% and 6.5% , respectively, of the Company’s reinsurance recoverable balance at December 31, 2018 ( 2017 - 10.4% , 7.5% and 7.3% , respectively). The valuation allowance recorded against reinsurance recoverable was $9.0 million at December 31, 2018 ( 2017 - $7.0 million ). The three largest company-specific components of the valuation allowance represented 16.2% , 14.8% and 12.3% , respectively, of the Company’s total valuation allowance at December 31, 2018 ( 2017 - 11.1% , 9.2% and 8.4% , respectively).

Reserve for Claims and Claim Ex

Reserve for Claims and Claim Expenses	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Reserve for Claims and Claim Expenses	RESERVE FOR CLAIMS AND CLAIM EXPENSES General Description The Company believes the most significant accounting judgment made by management is its estimate of claims and claim expense reserves. Claims and claim expense reserves represent estimates, including actuarial and statistical projections at a given point in time, of the ultimate settlement and administration costs for unpaid claims and claim expenses arising from the insurance and reinsurance contracts the Company sells. The Company establishes its claims and claim expense reserves by taking claims reported to the Company by insureds and ceding companies, but which have not yet been paid (“case reserves”), adding estimates for the anticipated cost of claims incurred but not yet reported to the Company, or incurred but not enough reported to the Company (collectively referred to as “IBNR”) and, if deemed necessary, adding costs for additional case reserves which represent the Company’s estimates for claims related to specific contracts previously reported to the Company which it believes may not be adequately estimated by the client as of that date, or adequately covered in the application of IBNR. On March 2, 2015 the Company acquired Platinum and the transaction was accounted for under the acquisition method of accounting in accordance with FASB ASC Topic Business Combinations . Total consideration paid was allocated among acquired assets and assumed liabilities based on their fair values, including Platinum’s claims and claim expense reserves, which totaled $1.4 billion at March 2, 2015 , and consisted of $179.7 million and $1.2 billion included in the Company’s Property and Casualty and Specialty segments, respectively. The following table summarizes the Company’s claims and claim expense reserves by segment, allocated between case reserves, additional case reserves and IBNR: At December 31, 2018 Case Reserves Additional Case Reserves IBNR Total Property $ 690,718 $ 1,308,307 $ 1,087,229 $ 3,086,254 Casualty and Specialty 771,537 116,877 2,096,979 2,985,393 Other 1,458 — 3,166 4,624 Total $ 1,463,713 $ 1,425,184 $ 3,187,374 $ 6,076,271 At December 31, 2017 Property $ 696,285 $ 896,522 $ 893,583 $ 2,486,390 Casualty and Specialty 689,962 124,923 1,760,607 2,575,492 Other 6,605 — 11,921 18,526 Total $ 1,392,852 $ 1,021,445 $ 2,666,111 $ 5,080,408 Activity in the liability for unpaid claims and claim expenses is summarized as follows: Year ended December 31, 2018 2017 2016 Net reserves as of January 1 $ 3,493,778 $ 2,568,730 $ 2,632,519 Net incurred related to: Current year 1,390,767 1,902,424 694,957 Prior years (270,749 ) (40,996 ) (164,126 ) Total net incurred 1,120,018 1,861,428 530,831 Net paid related to: Current year 391,061 450,527 83,015 Prior years 503,708 524,298 506,279 Total net paid 894,769 974,825 589,294 Foreign exchange (14,977 ) 38,445 (5,326 ) Net reserves as of December 31 3,704,050 3,493,778 2,568,730 Reinsurance recoverable as of December 31 2,372,221 1,586,630 279,564 Gross reserves as of December 31 $ 6,076,271 $ 5,080,408 $ 2,848,294 The Company’s reserving methodology for each line of business uses a loss reserving process that calculates a point estimate for its ultimate settlement and administration costs for claims and claim expenses. The Company does not calculate a range of estimates and does not discount any of its reserves for claims and claim expenses. The Company uses this point estimate, along with paid claims and case reserves, to record its best estimate of additional case reserves and IBNR in its consolidated financial statements. Under GAAP, the Company is not permitted to establish estimates for catastrophe claims and claim expense reserves until an event occurs that gives rise to a loss. Reserving for reinsurance claims involves other uncertainties, such as the dependence on information from ceding companies, the time lag inherent in reporting information from the primary insurer to the Company or to the Company’s ceding companies, and differing reserving practices among ceding companies. The information received from ceding companies is typically in the form of bordereaux, broker notifications of loss and/or discussions with ceding companies or their brokers. This information may be received on a monthly, quarterly or transactional basis and normally includes paid claims and estimates of case reserves. The Company sometimes also receives an estimate or provision for IBNR. This information is often updated and adjusted from time to time during the loss settlement period as new data or facts in respect of initial claims, client accounts, industry or event trends may be reported or emerge in addition to changes in applicable statutory and case laws. The Company’s estimates of losses from large events are based on factors including currently available information derived from claims information from certain customers and brokers, industry assessments of losses from the events, proprietary models, and the terms and conditions of the Company’s contracts. The uncertainty of the Company’s estimates for large events is also impacted by the preliminary nature of the information available, the magnitude and relative infrequency of the events, the expected duration of the respective claims development period, inadequacies in the data provided to the relevant date by industry participants and the potential for further reporting lags or insufficiencies; and in certain large events, significant uncertainty as to the form of the claims and legal issues, under the relevant terms of insurance and reinsurance contracts. In addition, a significant portion of the net claims and claim expenses associated with certain large events can be concentrated with a few large clients and therefore the loss estimates for these events may vary significantly based on the claims experience of those clients. The contingent nature of business interruption and other exposures will also impact losses in a meaningful way, which may give rise to significant complexity in respect of claims handling, claims adjustment and other coverage issues, over time. Given the magnitude of certain events, there can be meaningful uncertainty regarding total covered losses for the insurance industry and, accordingly, several of the key assumptions underlying the Company's loss estimates. Loss reserve estimation in respect of the Company's retrocessional contracts poses further challenges compared to directly assumed reinsurance. In addition, the Company’s actual net losses from these events may increase if the Company’s reinsurers or other obligors fail to meet their obligations. Because of the inherent uncertainties discussed above, the Company has developed a reserving philosophy that attempts to incorporate prudent assumptions and estimates, and the Company has generally experienced favorable net development on prior accident years net claims and claim expenses in the last several years. However, there is no assurance that this favorable development on prior accident years net claims and claim expenses will occur in future periods. The Company establishes a provision for unallocated loss adjustment expenses ("ULAE") when the related reserve for claims and claim expenses is established. ULAE are expenses that cannot be associated with a specific claim but are related to claims paid or in the process of settlement, such as internal costs of the claims function, and are included in the reserve for claims and claim expenses. The determination of the ULAE provision is subject to judgment. The Company reevaluates its actuarial reserving techniques on a periodic basis. Typically, the quarterly review procedures include reviewing paid and reported claims in the most recent reporting period, reviewing the development of paid and reported claims from prior periods, and reviewing the Company’s overall experience by underwriting year and in the aggregate. The Company monitors its expected ultimate claims and claim expense ratios and expected claims reporting assumptions on a quarterly basis and compares them to its actual experience. These actuarial assumptions are generally reviewed annually, based on input from the Company’s actuaries, underwriters, claims personnel and finance professionals, although adjustments may be made more frequently if needed. Assumption changes are made to adjust for changes in the pricing and terms of coverage the Company provides, changes in industry results for similar business, as well as its actual experience to the extent the Company has enough data to rely on its own experience. If the Company determines that adjustments to an earlier estimate are appropriate, such adjustments are recorded in the period in which they are identified. Incurred and Paid Claims Development and Reserving Methodology The information provided herein about incurred and paid accident year claims development for the years ended prior to December 31, 2018 on a consolidated basis and by segment is presented as supplementary information. The Company applied a retrospective approach with respect to its acquisition of Platinum, presenting all relevant historical information for all periods presented. In addition, included in the incurred claims and claim expenses and cumulated paid claims and claim expenses tables below is a reconciling item that represents the unamortized balance of fair value adjustments recorded in connection with the acquisition of Platinum to reflect an increase in net claims and claim expenses due to the addition of a market based risk margin that represented the cost of capital required by a market participant to assume the net claims and claim expenses of Platinum. For incurred and paid accident year claims denominated in foreign currency, the Company used the current year-end balance sheet foreign exchange rate for all periods provided, thereby eliminating the effects of changes in foreign currency translation rates from the incurred and paid accident year claims development information included in the tables below. The following table details the Company’s consolidated incurred claims and claim expenses and cumulative paid claims and claim expenses as of December 31, 2018 , net of reinsurance, as well as IBNR plus ACR included within the net incurred claims amounts. Incurred claims and claim expenses, net of reinsurance For the year ended December 31, At December 31, 2018 Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 IBNR and ACR (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 699,400 $ 634,400 $ 617,015 $ 577,285 $ 552,059 $ 530,876 $ 521,723 $ 516,888 $ 519,585 $ 521,739 $ 17,510 2010 — 992,376 950,984 902,908 871,664 869,959 860,517 868,441 866,529 855,132 52,575 2011 — — 1,646,568 1,573,930 1,493,095 1,412,886 1,384,912 1,348,620 1,334,068 1,337,445 76,002 2012 — — — 865,281 770,104 707,471 681,405 653,437 655,882 666,704 52,680 2013 — — — — 619,414 558,746 512,389 472,270 446,311 433,363 46,050 2014 — — — — — 660,836 613,786 601,727 582,473 558,619 117,354 2015 — — — — — — 639,151 627,702 629,211 590,591 136,328 2016 — — — — — — — 680,039 684,757 666,453 241,938 2017 — — — — — — — — 1,895,376 1,731,295 828,815 2018 — — — — — — — — — 1,367,413 923,976 Total $ 8,728,754 $ 2,493,228 Cumulative paid claims and claim expenses, net of reinsurance For the year ended December 31, Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 96,462 $ 269,714 $ 321,506 $ 365,731 $ 398,452 $ 437,232 $ 458,920 $ 465,244 $ 472,679 $ 481,632 2010 — 128,276 315,357 431,562 500,974 555,252 626,094 715,191 741,629 758,762 2011 — — 260,326 540,985 889,387 1,043,763 1,133,013 1,176,892 1,203,998 1,222,512 2012 — — — 166,564 266,980 357,821 417,628 461,035 525,736 551,846 2013 — — — — 86,998 179,709 243,544 289,144 326,807 348,436 2014 — — — — — 111,067 200,830 268,871 317,901 357,894 2015 — — — — — — 95,862 193,965 287,522 362,419 2016 — — — — — — — 79,577 217,746 324,224 2017 — — — — — — — — 450,034 548,619 2018 — — — — — — — — — 389,492 Total $ 5,345,836 Outstanding liabilities from accident year 2008 and prior, net of reinsurance 286,863 Claims and claim expenses, net of reinsurance, from the Company's former Bermuda-based insurance operations 368 Adjustment for unallocated claim expenses 28,956 Unamortized fair value adjustments recorded in connection with the acquisition of Platinum 4,945 Liability for claims and claim expenses, net of reinsurance $ 3,704,050 Property Segment Within the Property segment, the Company principally writes property catastrophe excess of loss reinsurance contracts to insure insurance and reinsurance companies against natural and man-made catastrophes. Under these contracts, the Company indemnifies an insurer or reinsurer when its aggregate paid claims and claim expenses from a single occurrence of a covered peril exceeds the attachment point specified in the contract, up to an amount per loss specified in the contract. The Company's most significant exposure is to losses from hurricanes, earthquakes and other windstorms, although the Company is also exposed to claims arising from other catastrophes, such as tsunamis, winter storms, freezes, floods, fires, tornadoes, explosions and acts of terrorism. The Company's predominant exposure under such coverage is to property damage. However, other risks, including business interruption and other non-property losses, may also be covered under the Company's catastrophe contracts when arising from a covered peril. The Company's coverages are offered on either a worldwide basis or are limited to selected geographic areas. Coverage can also vary from “all property” perils to limited coverage on selected perils, such as “earthquake only” coverage. The Company also enters into retrocessional contracts that provide property catastrophe coverage to other reinsurers or retrocedants. This coverage is generally in the form of excess of loss retrocessional contracts and may cover all perils and exposures on a worldwide basis or be limited in scope to selected geographic areas, perils and/or exposures. The exposures the Company assumes from retrocessional business can change within a contract term as the underwriters of a retrocedant may alter their book of business after the retrocessional coverage has been bound. The Company also offers dual trigger reinsurance contracts which require the Company to pay claims based on claims incurred by insurers and reinsurers in addition to the estimate of insured industry losses as reported by referenced statistical reporting agencies. Also included in the Property segment is property per risk, property (re)insurance, binding facilities and regional U.S. multi-line reinsurance. The Company's predominant exposure under such coverage is to property damage. However, other risks, including business interruption and other non-property losses, may also be covered when arising from a covered peril. The Company's coverages are offered on either a worldwide basis or are limited to selected geographic areas. The exposures assumed from retrocessional business can change within a contract term as the underwriters of a retrocedant may alter their book of business after the retrocessional coverage has been bound. The Company offers these products principally through proportional coverage. In a proportional reinsurance arrangement (also referred to as quota share reinsurance or pro rata reinsurance), the reinsurer shares a proportional part of the original premiums and losses of the reinsured. Claims and claim expenses in the Company's Property segment are generally characterized by loss events of low frequency and high severity. Initial reporting of paid and incurred claims in general, tends to be relatively prompt. The Company considers this business “short-tail” as compared to the reporting of claims for “long-tail” products, which tends to be slower. However, the timing of claims payment and reporting also varies depending on various factors, including: whether the claims arise under reinsurance of primary insurance companies or reinsurance of other reinsurance companies; the nature of the events (e.g., hurricanes, earthquakes or terrorism); the geographic area involved; post-event inflation which may cause the cost to repair damaged property to increase significantly from current estimates, or for property claims to remain open for a longer period of time, due to limitations on the supply of building materials, labor and other resources; complex policy coverage and other legal issues; and the quality of each client’s claims management and reserving practices. Management’s judgments regarding these factors are reflected in the Company's reserve for claims and claim expenses. Reserving for most of the Company's Property segment generally does not involve the use of traditional actuarial techniques. Rather, claims and claim expense reserves are estimated by management after a catastrophe occurs by completing an in-depth analysis of the individual contracts which may potentially be impacted by the catastrophic event. The in-depth analysis generally involves: 1) estimating the size of insured industry losses from the catastrophic event; 2) reviewing reinsurance contract portfolios to identify contracts which are exposed to the catastrophic event; 3) reviewing information reported by customers and brokers; 4) discussing the event with customers and brokers; and 5) estimating the ultimate expected cost to settle all claims and administrative costs arising from the catastrophic event on a contract-by-contract basis and in aggregate for the event. Once an event has occurred, during the then current reporting period, the Company records its best estimate of the ultimate expected cost to settle all claims arising from the event. The Company's estimate of claims and claim expense reserves is then determined by deducting cumulative paid losses from its estimate of the ultimate expected loss for an event. The Company’s estimate of IBNR is determined by deducting cumulative paid losses, case reserves and additional case reserves from its estimate of the ultimate expected loss for an event. Once the Company receives a valid notice of loss or payment request under a catastrophe reinsurance contract, it is generally able to process and pay such claims promptly. Because the events from which claims arise under policies written within the Property segment are typically prominent, public occurrences such as hurricanes and earthquakes, the Company is often able to use independent reports as part of its loss reserve estimation process. The Company also reviews catastrophe bulletins published by various statistical reporting agencies to assist in determining the size of the industry loss, although these reports may not be available for some time after an event. For smaller events including localized severe weather events such as windstorms, hail, ice, snow, flooding, freezing and tornadoes, which are not necessarily prominent, public occurrences, the Company initially places greater reliance on catastrophe bulletins published by statistical reporting agencies to assist in determining what events occurred during the reporting period than the Company does for large events. This includes reviewing catastrophe bulletins published by Property Claim Services (“PCS”) for U.S. catastrophes. The Company sets its initial estimates of reserves for claims and claim expenses for these smaller events based on a combination of its historical market share for these types of losses and the estimate of the total insured industry property losses as reported by statistical reporting agencies, although management may make significant adjustments based on the Company's current exposure to the geographic region involved as well as the size of the loss and the peril involved. This approach supplements the Company's approach for estimating losses for larger catastrophes, which as discussed above, includes discussions with brokers and ceding companies and reviewing individual contracts impacted by the event. Approximately one year from the date of loss for these small events, the Company typically estimates IBNR for these events by using the paid Bornhuetter-Ferguson actuarial method. The loss development factors for the paid Bornhuetter-Ferguson actuarial method are selected based on a review of the Company's historical experience. There were no significant changes to the Company's paid loss development factors over the last three years. In general, reserves for the Company's more recent reinsured catastrophic events are subject to greater uncertainty and, therefore, greater potential variability, and are likely to experience material changes from one period to the next. This is due to the uncertainty as to the size of the industry losses from the event, uncertainty as to which contracts have been exposed to the catastrophic event, uncertainty due to complex legal and coverage issues that can arise out of large or complex catastrophic events, and uncertainty as to the magnitude of claims incurred by the Company's customers. As the Company's claims age, more information becomes available and the Company believes its estimates become more certain. The following table details the Company’s Property segment incurred claims and claim expenses and cumulative paid claims and claim expenses as of December 31, 2018 , net of reinsurance, as well as IBNR plus ACR included within the net incurred claims amounts. Incurred claims and claim expenses, net of reinsurance For the year ended December 31, At December 31, 2018 Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 IBNR and ACR (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 219,979 $ 164,369 $ 145,207 $ 138,747 $ 134,490 $ 135,245 $ 134,539 $ 134,811 $ 134,355 $ 134,876 $ 74 2010 — 609,380 561,524 526,928 531,199 550,980 554,733 564,345 566,475 555,642 33,429 2011 — — 1,264,374 1,192,868 1,141,403 1,091,415 1,070,957 1,040,721 1,036,663 1,033,601 46,427 2012 — — — 437,940 344,487 311,648 293,873 275,910 264,532 257,246 16,299 2013 — — — — 227,268 196,729 174,335 152,715 141,197 137,660 1,971 2014 — — — — — 183,249 154,469 147,138 142,864 142,457 4,689 2015 — — — — — — 226,039 195,164 176,159 167,916 19,347 2016 — — — — — — — 252,556 254,151 241,296 64,136 2017 — — — — — — — — 1,342,161 1,167,013 454,395 2018 — — — — — — — — — 718,266 336,082 Total $ 4,555,973 $ 976,849 Cumulative paid claims and claim expenses, net of reinsurance For the year ended December 31, Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 56,142 $ 101,124 $ 115,459 $ 123,281 $ 129,204 $ 133,750 $ 134,770 $ 135,721 $ 135,729 $ 136,329 2010 — 93,423 216,504 295,243 337,060 372,499 398,691 474,179 483,738 497,547 2011 — — 212,259 427,501 743,745 868,489 926,747 952,780 966,304 971,324 2012 — — — 100,057 145,098 189,199 208,653 218,638 230,839 233,647 2013 — — — — 49,032 93,041 117,642 128,631 132,822 134,044 2014 — — — — — 55,090 96,074 118,768 123,790 126,897 2015 — — — — — — 62,169 108,679 127,509 138,283 2016 — — — — — — — 47,491 119,260 155,917 2017 — — — — — — — — 411,961 443,130 2018 — — — — — — — — — 354,616 Total $ 3,191,734 Outstanding liabilities from accident year 2008 and prior, net of reinsurance 4,222 Adjustment for unallocated claim expenses 4,028 Unamortized fair value adjustments recorded in connection with the acquisition of Platinum 636 Liability for claims and claim expenses, net of reinsurance $ 1,373,125 Casualty and Specialty Segment The Company offers its casualty and specialty reinsurance products principally on a proportional basis, and it also provides excess of loss coverage. The Company offers casualty and specialty reinsurance products to insurance and reinsurance companies and provides coverage for specific geographic regions or on a worldwide basis. Principally all of the business is reinsurance, although from time to time, the Company writes insurance business. As with the Company's Property segment, its Casualty and Specialty segment reinsurance contracts can include coverage for relatively large limits or exposures. As a result, the Company's casualty and specialty reinsurance business can be subject to significant claims volatility. In periods of low claims frequency or severity, the Company's results will generally be favorably impacted while in periods of high claims frequency or severity the Company's results will generally be negatively impacted. More recently, the Company has accepted a wider range of proportional risks, facilitating the Company's efforts to expand its product offerings. While the Company remains focused on underwriting discipline, and seeks to remain focused on opportunities amenable to stochastic representation and supported by strong data and analytics, the Company's expanded casualty and specialty product suite, may pose new, unmodelled or unforeseen risks for which the Company may not be adequately compensated and may also result in a higher level of attritional claims and claim expenses and the potential for reserve development, either adverse or favorable. The Company's processes and methodologies in respect of loss estimation for the coverages offered through its Casualty and Specialty segment differ from those used for its Property segment. For example, the Company's casualty and specialty coverages are more likely to be impacted by factors such as long-term inflation and changes in the social and legal environment, which the Company believes gives rise to greater uncertainty in its reserves for claims and claim expenses. Moreover, in many lines of business the Company does not have the benefit of a significant amount of its own historical experience and may have little or no related corporate reserving history in many of its newer or growing lines of business. The Company believes this makes its Casualty and Specialty segment reserving subject to greater uncertainty than its Property segment. The Company calculates multiple point estimates for claims and claim expense reserves using a variety of actuarial reserving techniques for many, but not all, of its classes of business for each underwriting year within the Casualty and Specialty segment. The Company does not believe that these multiple point estimates are, or should be considered a range. Rather, the Company considers each class of business and determines the most appropriate point estimate for each underwriting year based on the characteristics of the particular class including: (1) loss development patterns derived from historical data; (2) the credibility of the selected loss development pattern; (3) the stability of the loss development patterns; (4) how developed the underwriting year is; and (5) the observed loss development of other underwriting years for the same class. The Company also considers other relevant factors, including: (1) historical ultimate loss ratios; (2) the presence of individual large losses; and (3) known occurrences that have not yet resulted in reported losses. The Company makes determinations of the most appropriate point estimate of loss for each class based on an evaluation of relevant information and do not ascribe any particular portion of the estimate to a particular factor or consideration. In addition, the Company believes that a review of individual contract information improves the loss estimates for some classes of business. When developing claims and claims expense reserves for the Company's Casualty and Specialty segment, it considers several actuarial techniques such as the expected loss ratio method, the Bornhuetter-Ferguson actuarial method and the paid and reported chain ladder actuarial method. For classes of business and underwriting years where the Company has limited historical claims experience, estimates of ultimate losses that are not related to a specific event are generally initially determined based on the loss ratio method applied to each underwriting year and to each class of business. Unless the Company has credible claims experience or unfavorable development, it generally selects an ultimate loss based on its initial view of the loss. The selected ultimate losses are determined by multiplying the initial expected loss ratio by the earned premium. The initial expected loss ratios are key inputs that involve management judgment and are based on a variety of factors, including: (1) contract by contract expected loss ratios developed during the Company’s pricing process; (2) historical loss ratios and combined ratios adjusted for rate change and trend; and (3) industry benchmarks for similar business. These judgments take into account management’s view of past, current and future factors that may influence ultimate losses, including: (1) market conditions; (2) changes in the business underwritten; (3) changes in timing of the emergence of claims; and (4) other factors that may influence ultimate loss ratios and losses. The determination of when reported losses are sufficient and credible to warrant selection of an ultimate loss ratio different from the initial expected loss ratios also requires judgment. The Company generally makes adjustments for reported loss experience indicating unfavorable variances from initial expected loss ratios sooner than reported loss experience indicating favorable variances. This is because the reporting of losses in excess of expectations tends to have greater credibility than an absence or lower than expected level of reported losses. Over time, as a greater number of claims are reported and the credibility of reported losses improves, actuarial estimates of IBNR are typically based on the Bornhuetter-Ferguson actuarial method or the reported chain ladder actuarial method. The Bornhuetter-Ferguson method allows for greater weight to be applied to expected results in periods where little or no actual experience is available, and, hence, is less susceptible to the potential pitfall of being excessively swayed by one year or one quarter of actual paid and/or reported loss data, compared to the chain ladder actuarial method. The Bornhuetter-Ferguson method uses the initial expected loss ratio to estimate IBNR, and it assumes that past experience is not fully representative of the future. As the Company’s reserves for claims and claim expenses age, and actual claims experience becomes available, this method places less weight on expected experience and places more weight on actual experience. This experience, which represents the difference between expected reported claims and actual reported claims, is reflected in the respective reporting period as a change in estimate. The utilization of the Bornhuetter-Ferguson method requires the Company to estimate an expected ultimate claims and claim expense ratio and select an expected loss reporting pattern. The Company selects its estimates of the expected ultimate claims and claim expense ratios as described above and selects its expected loss reporting patterns by utilizing actuarial analysis, including management’s judgment, and historical patterns of paid losses and reporting of case reserves to the Company, as well as industry loss development patterns. The estimated expected claims and claim expense ratio may be modified to the extent that reported losses at a given point in time differ from what would be expected based on the selected loss reporting pattern. The reported chain ladder actuarial method utilizes actual reported losses and a loss development pattern to determine an estimate of ultimate losses that is independent of the initial expected ultimate loss ratio and earned premium. The Company believes this technique is most appropriate when there are a large number of reported losses with significant statistical credibility and a relatively stable loss development pattern. Information that may cause future loss development patterns to differ from historical loss development patterns is considered and reflected in the Company’s selected loss development patterns as appropriate. For certain reinsurance contracts, historical loss development patterns may be developed from ceding company data or other sources. In addition, certain specialty coverages may be impacted by natural and man-made catastrophes. The Company estimates reserves for claim and claim expenses f

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt and Credit Facilities	DEBT AND CREDIT FACILITIES Debt Obligations A summary of the Company’s debt obligations on its consolidated balance sheets is set forth below: December 31, 2018 December 31, 2017 Fair Value Carrying Value Fair Value Carrying Value 3.450% Senior Notes due 2027 $ 283,680 $ 295,797 $ 294,654 $ 295,303 3.700% Senior Notes due 2025 292,557 297,688 302,781 297,318 5.750% Senior Notes due 2020 255,938 249,602 263,750 249,272 4.750% Senior Notes due 2025 (DaVinciRe) (1) 142,539 148,040 157,050 147,730 $ 974,714 $ 991,127 $ 1,018,235 $ 989,623 (1) RenaissanceRe owns a noncontrolling economic interest in its joint venture DaVinciRe. Because RenaissanceRe controls a majority of DaVinciRe’s outstanding voting rights, the consolidated financial statements of DaVinciRe are included in the consolidated financial statements of RenaissanceRe. However, RenaissanceRe does not guarantee or provide credit support for DaVinciRe and RenaissanceRe’s financial exposure to DaVinciRe is limited to its investment in DaVinciRe’s shares and counterparty credit risk arising from reinsurance transactions. 3.450% Senior Notes due 2027 of RenaissanceRe Finance On June 29, 2017 , RenaissanceRe Finance issued $300.0 million of its 3.450% Senior Notes due July 1, 2027 , with interest on the notes payable on July 1 and January 1 of each year. The notes are fully and unconditionally guaranteed by RenaissanceRe and may be redeemed by RenaissanceRe Finance prior to maturity, subject to the payment of a “make-whole” premium if the notes are redeemed prior to April 1, 2027 . The notes contain various covenants, including limitations on mergers and consolidations, and restrictions as to the disposition of, and the placing of liens on, stock of designated subsidiaries. 3.700% Senior Notes due 2025 of RenaissanceRe Finance On March 24, 2015 , RenaissanceRe Finance issued $300.0 million of its 3.700% Senior Notes due April 1, 2025 , with interest on the notes payable on April 1 and October 1 of each year. The notes are fully and unconditionally guaranteed by RenaissanceRe and may be redeemed by RenaissanceRe Finance prior to maturity, subject to the payment of a “make-whole” premium if the notes are redeemed prior to January 1, 2025. The notes contain various covenants, including limitations on mergers and consolidations, and restrictions as to the disposition of, and the placing of liens on, stock of designated subsidiaries. The net proceeds from the offering of the notes (together with cash on hand) were applied by RenaissanceRe to repay in full a $300.0 million bridge loan that Barclays Bank PLC provided to RenaissanceRe on February 25, 2015 in order to finance a portion of the cash consideration paid by RenaissanceRe in connection with the acquisition of Platinum. 5.75% Senior Notes due 2020 of RenRe North America Holdings Inc. (“RRNAH”) and RenaissanceRe Finance On March 17, 2010, RenRe North America Holdings Inc. (“RRNAH”) issued $250.0 million of its 5.75% Senior Notes due March 15, 2020 (the “RRNAH Notes”), with interest on the notes payable on March 15 and September 15 of each year. RenaissanceRe Finance became a co-obligor of the notes as of July 3, 2015. The notes, which are senior obligations, are fully and unconditionally guaranteed by RenaissanceRe and may be redeemed prior to maturity, subject to the payment of a “make-whole” premium. The notes contain various covenants, including limitations on mergers and consolidations, and restrictions as to the disposition of, and the placing of liens on, stock of designated subsidiaries. Series B 7.50% Notes due 2017 of Platinum Underwriters Finance, Inc. On November 2, 2005, Platinum Underwriters Finance, Inc. (“Platinum Finance”) issued $250.0 million in aggregate principal amount of its Series B 7.50% Notes due June 1, 2017 (the “Platinum Finance Notes”). On June 1, 2017, the Platinum Finance Notes matured and the Company repaid the aggregate principal amount of $250.0 million plus applicable accrued interest in full. Platinum Finance was subsequently dissolved on November 30, 2017. Interest on the Platinum Finance Notes was payable on June 1 and December 1 of each year. The Platinum Finance Notes, which were senior obligations, were fully and unconditionally guaranteed by RenaissanceRe, and were redeemable by Platinum Finance prior to maturity, subject to the payment of a “make-whole” premium. The Platinum Finance Notes contained various covenants, including limitations on mergers and consolidations, and restrictions as to the disposition of, and the placing of liens on, the stock of designated subsidiaries. DaVinciRe Senior Notes On May 4, 2015 , DaVinciRe issued $150.0 million of its 4.750% Senior Notes due May 1, 2025 , with interest on the notes payable on May 1 and November 1, commencing with November 1, 2015 (the “DaVinciRe Senior Notes”). The DaVinciRe Senior Notes, which are senior obligations, may be redeemed prior to maturity, subject to the payment of a “make-whole” premium if the notes are redeemed before February 1, 2025. The DaVinciRe Senior Notes contain various covenants including restrictions as to the disposition of, and the placing of liens on, the stock of designated subsidiaries, limitations on mergers, amalgamations and consolidations, limitations on third party investor redemptions, a leverage covenant and a covenant to maintain certain ratings. The net proceeds from this offering were used to repay, in full, $100.0 million outstanding under the loan agreement, dated as of March 30, 2011, between DaVinciRe and RenaissanceRe, and the remainder of the net proceeds may be used to repurchase DaVinciRe shares or for general corporate purposes. Credit Facilities The outstanding amounts issued or drawn under each of the Company’s significant credit facilities is set forth below: At December 31, 2018 Issued or Drawn RenaissanceRe Revolving Credit Facility (1) $ — Uncommitted Standby Letter of Credit Facility with Wells Fargo 86,861 Bilateral Letter of Credit Facility with Citibank Europe 243,696 Renaissance Reinsurance FAL Facility 180,000 Total credit facilities in U.S. dollars $ 510,557 Specialty Risks FAL Facility (1) £ — Total credit facilities in pound sterling £ — (1) At December 31, 2018 , no amounts were issued or drawn under these facilities. RenaissanceRe Revolving Credit Facility On November 9, 2018, RenaissanceRe, Renaissance Reinsurance, RenaissanceRe Specialty U.S. and Renaissance Reinsurance U.S. (collectively with RenaissanceRe, the “Account Parties”) entered into a second amended and restated credit agreement (the “Revolving Credit Agreement”) with various banks, financial institutions and Wells Fargo Bank, National Association (“Wells Fargo”) as administrative agent, which amended and restated the credit agreement, dated as of May 15, 2015. The Revolving Credit Agreement provides for a revolving commitment to RenaissanceRe of $500.0 million . RenaissanceRe has the right, subject to satisfying certain conditions, to increase the size of the facility to $750.0 million . Amounts borrowed under the Revolving Credit Agreement bear interest at a rate selected by RenaissanceRe equal to the Base Rate or LIBOR (each as defined in the Revolving Credit Agreement) plus a margin, as more fully set forth in the Revolving Credit Agreement. In addition to revolving loans, the Revolving Credit Agreement provides that the entire facility will also be available for the issuance of standby letters of credit, subject to the terms and conditions set forth therein. Swingline Loans (as defined in the Credit Agreement) are capped at $50.0 million for each of the Swingline Lenders (as defined in the Credit Agreement). At December 31, 2018 , RenaissanceRe had $Nil outstanding under the Revolving Credit Agreement. The Revolving Credit Agreement contains representations, warranties and covenants customary for bank loan facilities of this type, including limits on the ability of RenaissanceRe and its subsidiaries to merge, consolidate, sell a substantial amount of assets, incur liens and declare or pay dividends under certain circumstances. The Revolving Credit Agreement also contains certain financial covenants which generally provide that the ratio of consolidated debt to capital shall not exceed 0.35 : 1 and that the consolidated net worth of RenaissanceRe shall equal or exceed approximately $2.9 billion . The net worth requirement is recalculated effective as of the end of each fiscal year. If certain events of default occur, in some circumstances the lenders’ obligations to make loans may be terminated and the outstanding obligations of RenaissanceRe under the Revolving Credit Agreement may be accelerated. The scheduled commitment maturity date of the Revolving Credit Agreement is November 9, 2023. RRNAH and RenaissanceRe Finance guarantee RenaissanceRe’s obligations under the Revolving Credit Agreement. Subject to certain exceptions, additional subsidiaries of RenaissanceRe are required to become guarantors if such subsidiaries issue or incur certain types of indebtedness. Uncommitted Standby Letter of Credit Facility with Wells Fargo Bank, National Association Renaissance Reinsurance, DaVinci and Renaissance Reinsurance U.S. (collectively, the “Applicants”) and RenaissanceRe are parties to a Standby Letter of Credit Agreement, as amended (the “Standby Letter of Credit Agreement”) with Wells Fargo which provides for a secured, uncommitted facility under which letters of credit may be issued from time to time for the respective accounts of the Applicants. RenaissanceRe has unconditionally guaranteed the payment obligations of the Applicants, other than DaVinci. The Standby Letter of Credit Agreement contains representations, warranties and covenants that are customary for facilities of this type. At all times during which it is a party to the Standby Letter of Credit Agreement, each Applicant is required to pledge to Wells Fargo eligible collateral having a value (determined as provided in such agreement) that equals or exceeds the aggregate face amount of the outstanding letters of credit issued for its account plus all of such Applicant’s payment and reimbursement obligations in respect of such letters of credit. In the case of an event of default, Wells Fargo may exercise certain remedies, including conversion of collateral of a defaulting Applicant into cash. Effective October 12, 2016, in connection with the merger of RenaissanceRe Specialty Risks and Platinum Bermuda into Renaissance Reinsurance, Renaissance Reinsurance assumed all of the obligations of RenaissanceRe Specialty Risks and Platinum Bermuda under the Standby Letter of Credit Agreement. At December 31, 2018 , the Applicants had $86.9 million of letters of credit outstanding under the Standby Letter of Credit Agreement. National Australia Bank Limited Standby Letter of Credit Agreement Effective as of March 23, 2018, the Company terminated the Standby Letter of Credit Agreement, dated as of May 19, 2015, among National Australia Bank Limited (“NAB”) and Renaissance Reinsurance, RenaissanceRe Specialty Risks, DaVinci and Platinum Bermuda (collectively, the “NAB Facility Applicants”) (the “NAB Standby Letter of Credit Agreement”). The NAB Standby Letter of Credit Agreement provided for a secured, uncommitted facility under which letters of credit were issued from time to time for the respective accounts of the NAB Facility Applicants in multiple currencies. RenaissanceRe unconditionally guaranteed the payment obligations of the NAB Facility Applicants, other than DaVinci. Bilateral Letter of Credit Facility with Citibank Europe Pursuant to the facility letter, dated September 17, 2010, as amended, among Citibank Europe plc (“CEP”) and certain subsidiaries and affiliates of RenaissanceRe (the “Facility Letter”), CEP has established a letter of credit facility (the “Bilateral Facility”) under which CEP provides a commitment to issue letters of credit for the account of one or more of the Bilateral Facility Participants (as defined below) and their respective subsidiaries in multiple currencies. The “Bilateral Facility Participants” currently include Renaissance Reinsurance, DaVinci, Renaissance Reinsurance of Europe, RenaissanceRe Specialty U.S. and Renaissance Reinsurance U.S. The aggregate commitment amount is $300.0 million , subject to a sublimit of $25.0 million for letters of credit issued for the account of Renaissance Reinsurance U.S. The Bilateral Facility is scheduled to expire on December 31, 2020. At all times during which it is a party to the Bilateral Facility, each Bilateral Facility Participant is obligated to pledge to CEP securities with a value (determined as provided in such facility) that equals or exceeds the aggregate face amount of its then-outstanding letters of credit. In the case of an event of default under the Bilateral Facility with respect to a Bilateral Facility Participant, CEP may exercise certain remedies, including terminating its commitment to such Bilateral Facility Participant and taking certain actions with respect to the collateral pledged by such Bilateral Facility Participant (including the sale thereof). In the Facility Letter, each Bilateral Facility Participant makes representations and warranties that are customary for facilities of this type and agrees that it will comply with certain informational and other undertakings, including those regarding the delivery of quarterly and annual financial statements. Effective October 1, 2016, in connection with the merger of RenaissanceRe Specialty Risks and Platinum Bermuda into Renaissance Reinsurance, Renaissance Reinsurance assumed all of the obligations of RenaissanceRe Specialty Risks and Platinum Bermuda under the Bilateral Facility. At December 31, 2018 , $243.7 million aggregate face amount of letters of credit was outstanding and, subject to the sublimits described above, $56.3 million remained unused and available to the Bilateral Facility Participants under the Bilateral Facility. Funds at Lloyd’s Letter of Credit Facilities Effective November 23, 2015, Renaissance Reinsurance entered into a letter of credit facility with Bank of Montreal (“BMO”), CEP and ING Bank N.V. (“ING”) as lenders (the “Renaissance Reinsurance FAL Facility”), evidenced by a letter of credit reimbursement agreement (the “Reimbursement Agreement”), which provides for the issuance by the lenders of letters of credit to support business written by Syndicate 1458. Effective May 31, 2016 the Funds at Lloyd’s letters of credit issued for the account of Renaissance Reinsurance were increased from $360.0 million and £85.0 million to $380.0 million and £90.0 million , respectively, and effective as of May 25, 2017, the stated amount of the $380.0 million letter of credit was reduced to $180.0 million and the £90.0 million letter of credit was cancelled. Renaissance Reinsurance may request that the Renaissance Reinsurance FAL Facility be amended to increase the stated amount of the letter of credit, or issue a new letter or credit denominated in British Pounds, in an aggregate amount for all such increases or issuances not to exceed $150.0 million or the equivalent thereof. At all times during the term of the Renaissance Reinsurance FAL Facility, Renaissance Reinsurance is obligated to pledge to the lenders certain eligible securities with a collateral value (determined as provided in the Reimbursement Agreement) that, until a Full Collateralization Event (as defined in the Reimbursement Agreement) occurs, is at Renaissance Reinsurance’s election, either (i) greater than or equal to 100% of the aggregate amount of its then-outstanding letters of credit or (ii) greater than or equal to 60% but less than 100% of the aggregate amount of its then-outstanding letters of credit. Upon the occurrence of a Full Collateralization Event, Renaissance Reinsurance is obligated to collateralize the Renaissance Reinsurance FAL Facility at 100% . The latest date upon which Renaissance Reinsurance will become obligated to collateralize the Facility at 100% is December 31, 2019. In the Reimbursement Agreement, Renaissance Reinsurance makes representations and warranties that are customary for facilities of this type and agrees that it will comply with certain informational undertakings and other covenants, including maintaining a minimum net worth. In the case of an event of default under the Renaissance Reinsurance FAL Facility, the lenders may exercise certain remedies, including declaring all outstanding obligations of Renaissance Reinsurance under the Reimbursement Agreement and related credit documents due and payable and taking certain actions with respect to the collateral pledged by Renaissance Reinsurance (including the sale thereof). At December 31, 2018 , the face amount of the outstanding letter of credit issued by CEP under the Renaissance Reinsurance FAL Facility was $180.0 million . Effective November 24, 2014, RenaissanceRe Specialty Risks and CEP entered into a letter of credit facility (the “Specialty Risks FAL Facility”), evidenced by a Master Agreement (the “Specialty Risks Master Agreement”), and a related Pledge Agreement (the “Specialty Risks Pledge Agreement”), which provided for the issuance and renewal by CEP for the account of RenaissanceRe Specialty Risks of letters of credit that are used to support business written by RenaissanceRe Specialty Risks and Syndicate 1458. Effective October 1, 2016, in connection with the merger of RenaissanceRe Specialty Risks and Platinum Bermuda into Renaissance Reinsurance, Renaissance Reinsurance assumed all of the obligations of RenaissanceRe Specialty Risks under the Specialty Risks FAL Facility. At all times during the term of the Specialty Risks FAL Facility, RenaissanceRe Specialty Risks has agreed to pledge to CEP certain qualifying securities with a value (determined as provided in the Specialty Risks Pledge Agreement) equal to the aggregate face amount of the then-outstanding letters of credit. The Specialty Risks Master Agreement and the Specialty Risks Pledge Agreement contain representations, warranties and covenants that are customary for facilities of this type. At December 31, 2018 , letters of credit issued by CEP under the Specialty Risks FAL Facility were outstanding in the face amount of £nil . Top Layer Re Renaissance Reinsurance is party to a collateralized letter of credit and reimbursement agreement in the amount of $37.5 million that supports the Company’s Top Layer Re joint venture. Renaissance Reinsurance is obligated to make a mandatory capital contribution of up to $50.0 million in the event that a loss reduces Top Layer Re’s capital below a specified level. Scheduled Debt Maturity The following table sets forth the scheduled maturity of the Company’s aggregate amount of its debt obligation reflected on its consolidated balance sheet at December 31, 2018 : 2019 $ — 2020 250,000 2021 — 2022 — 2023 — After 2023 750,000 Unamortized discount and debt issuance expenses (8,873 ) $ 991,127

Noncontrolling Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2018
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest [Abstract]
Noncontrolling Interests	NONCONTROLLING INTERESTS A summary of the Company’s redeemable noncontrolling interests on its consolidated balance sheets is set forth below: December 31, December 31, Redeemable noncontrolling interest - DaVinciRe $ 1,034,946 $ 1,011,659 Redeemable noncontrolling interest - Medici 416,765 284,847 Redeemable noncontrolling interest - Vermeer 599,989 — Redeemable noncontrolling interests $ 2,051,700 $ 1,296,506 A summary of the Company’s redeemable noncontrolling interests on its consolidated statements of operations is set forth below: 2018 2017 2016 Redeemable noncontrolling interest - DaVinciRe $ 27,638 $ (134,860 ) $ 118,748 Redeemable noncontrolling interest - Medici 13,926 2,578 8,338 Redeemable noncontrolling interest - Vermeer (11 ) — — Net income (loss) attributable to redeemable noncontrolling interests $ 41,553 $ (132,282 ) $ 127,086 Redeemable Noncontrolling Interest – DaVinciRe RenaissanceRe owns a noncontrolling economic interest in DaVinciRe; however, because RenaissanceRe controls a majority of DaVinciRe’s outstanding voting rights, the consolidated financial statements of DaVinciRe are included in the consolidated financial statements of the Company. The portion of DaVinciRe’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to redeemable noncontrolling interests. The Company’s noncontrolling economic ownership in DaVinciRe was 22.1% at December 31, 2018 ( 2017 - 22.1% ). DaVinciRe shareholders are party to a shareholders agreement which provides DaVinciRe shareholders, excluding RenaissanceRe, with certain redemption rights that enable each shareholder to notify DaVinciRe of such shareholder’s desire for DaVinciRe to repurchase up to half of such shareholder’s initial aggregate number of shares held, subject to certain limitations, such as limiting the aggregate of all share repurchase requests to 25% of DaVinciRe’s capital in any given year and satisfying all applicable regulatory requirements. If total shareholder requests exceed 25% of DaVinciRe’s capital, the number of shares repurchased will be reduced among the requesting shareholders pro-rata, based on the amounts desired to be repurchased. Shareholders desiring to have DaVinci repurchase their shares must notify DaVinciRe before March 1 of each year. The repurchase price will be based on GAAP book value as of the end of the year in which the shareholder notice is given, and the repurchase will be effective as of January 1 of the following year. The repurchase price is generally subject to a true-up for potential development on outstanding loss reserves after settlement of all claims relating to the applicable years. 2017 During January 2017, DaVinciRe redeemed $75.0 million of its outstanding shares from certain existing DaVinciRe shareholders, including RenaissanceRe. In connection with the redemption, DaVinciRe retained a $7.5 million holdback. In addition, RenaissanceRe sold an aggregate of $24.0 million of its shares in DaVinciRe to an existing shareholder and a new shareholder. The Company’s noncontrolling economic ownership in DaVinciRe subsequent to these transactions was 22.6% , effective January 1, 2017. During July 2017, RenaissanceRe purchased $12.0 million of DaVinciRe’s outstanding shares from an existing third-party shareholder. The Company’s noncontrolling economic ownership in DaVinciRe subsequent to these transactions was 23.5% , effective July 1, 2017. Effective October 1, 2017, DaVinciRe completed an equity capital raise of $248.6 million from third-party investors and RenaissanceRe. In addition, RenaissanceRe sold an aggregate of $49.7 million of its shares in DaVinciRe to third-party investors. The Company’s noncontrolling economic ownership in DaVinciRe subsequent to these transactions was 22.1% , effective October 1, 2017. The Company expects its noncontrolling economic ownership in DaVinciRe to fluctuate over time. The activity in redeemable noncontrolling interest – DaVinciRe is detailed in the table below: 2018 2017 Balance – January 1 $ 1,011,659 $ 994,458 Redemption of shares from redeemable noncontrolling interest (4,351 ) (80,058 ) Sale of shares to redeemable noncontrolling interest — 232,119 Net income (loss) attributable to redeemable noncontrolling interest 27,638 (134,860 ) Balance – December 31 $ 1,034,946 $ 1,011,659 Redeemable Noncontrolling Interest - Medici Medici is an exempted company incorporated under the laws of Bermuda and its objective is to seek to invest substantially all of its assets in various insurance-based investment instruments that have returns primarily tied to property catastrophe risk. RenaissanceRe owns a noncontrolling economic interest in Medici; however, because RenaissanceRe controls all of Medici’s outstanding voting rights, the financial statements of Medici are included in the consolidated financial statements of the Company. The portion of Medici’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to redeemable noncontrolling interests. Any shareholder may redeem all or any portion of its shares as of the last day of any calendar month, upon at least 30 calendar days’ prior irrevocable written notice to Medici. 2017 During 2017 , third-party investors subscribed for $149.2 million and redeemed $48.0 million of the participating, non-voting common shares of Medici. As a result of these net subscriptions, the Company’s noncontrolling economic ownership in Medici was 26.8% , effective December 31, 2017 . 2018 During 2018 , third-party investors subscribed for $208.5 million and redeemed $90.5 million of the participating, non-voting common shares of Medici. As a result of these net subscriptions, the Company’s noncontrolling economic ownership in Medici was 16.6% at December 31, 2018 . The Company expects its noncontrolling economic ownership in Medici to fluctuate over time. The activity in redeemable noncontrolling interest – Medici is detailed in the table below: 2018 2017 Balance – January 1 $ 284,847 $ 181,136 Redemption of shares from redeemable noncontrolling interest (90,490 ) (48,049 ) Sale of shares to redeemable noncontrolling interest 208,482 149,182 Net income attributable to redeemable noncontrolling interest 13,926 2,578 Balance – December 31 $ 416,765 $ 284,847 Redeemable Noncontrolling Interest – Vermeer Vermeer is an exempted Bermuda reinsurer that provides capacity focused on risk remote layers in the U.S. property catastrophe market. Vermeer is managed by RUM in return for a management fee. The Company maintains majority voting control of Vermeer, while PGGM retains economic benefits. The Company concluded that Vermeer is a VIE as it has voting rights that are not proportional to its participating rights, and the Company is the primary beneficiary. As a result, the Company consolidates Vermeer and all significant inter-company transactions have been eliminated. The portion of Vermeer’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to redeemable noncontrolling interests. The Company has not provided any financial or other support to Vermeer that it was not contractually required to provide. 2018 During 2018, a third-party investor subscribed for $600.0 million of the participating, non-voting common shares of Vermeer and the Company subscribed $1 thousand for all of the voting, non-participating shares of Vermeer. The activity in redeemable noncontrolling interest – Vermeer is detailed in the table below: 2018 2017 Balance – January 1 $ — $ — Sale of shares to redeemable noncontrolling interest 600,000 — Net loss attributable to redeemable noncontrolling interest (11 ) — Balance – December 31 $ 599,989 $ —

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES Upsilon RFO Upsilon RFO is a managed joint venture and a Bermuda domiciled SPI that was formed by the Company primarily to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market. The shareholders (other than the Class A shareholder) participate in substantially all of the profits or losses of Upsilon RFO while their shares remain outstanding. The shareholders (other than the Class A shareholder) indemnify Upsilon RFO against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance . Upsilon RFO is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company is the primary beneficiary of Upsilon RFO as it has the power over the activities that most significantly impact the economic performance of Upsilon RFO and has the obligation to absorb expected losses and the right to receive expected benefits that could be significant to Upsilon RFO, in accordance with the accounting guidance. As a result, the Company consolidates Upsilon RFO and all significant inter-company transactions have been eliminated. Other than its equity investment in Upsilon RFO, the Company has not provided financial or other support to Upsilon RFO that it was not contractually required to provide. 2017 During 2017, Upsilon RFO returned $84.3 million of capital to its investors, including $33.0 million to the Company. In addition, during 2017, $180.6 million of Upsilon RFO non-voting preference shares were issued to existing investors therein, including $27.2 million to the Company, and an existing third-party investor purchased $7.5 million of Upsilon RFO non-voting preference shares from the Company. At December 31, 2016, the Company’s participation in the risks assumed by Upsilon RFO was 20.8% . 2018 During 2018 , $856.7 million of Upsilon RFO non-voting preference shares were issued to existing investors, including $109.8 million to the Company. At December 31, 2018 , the Company’s participation in the risks assumed by Upsilon RFO was 14.0% . Payments for certain of the shares issued during 2018 were received by the Company prior to January 1, 2018 were included in other liabilities on the Company’s consolidated balance sheet at December 31, 2017, and in other operating cash flows on the Company’s consolidated statements of cash flows for 2017. During 2018, in connection with the issuance of the non-voting preference shares of Upsilon RFO, other liabilities were reduced by this amount, and reinsurance balances payable were increased by an offsetting amount, with corresponding impacts to other operating cash flows and the change in reinsurance balances payable on the Company consolidated statements of cash flows for the year ended December 31, 2018 . At December 31, 2018 , the Company’s consolidated balance sheet included total assets and total liabilities of Upsilon RFO of $2.2 billion and $2.2 billion , respectively ( December 31, 2017 - $1.2 billion and $1.2 billion , respectively). See “Note 23 . Subsequent Events” for additional information related to Upsilon RFO’s non-voting preference shares subsequent to December 31, 2018 . Mona Lisa Re Ltd. (“Mona Lisa Re”) Mona Lisa Re is licensed as a Bermuda domiciled SPI to provide reinsurance capacity to subsidiaries of RenaissanceRe, namely Renaissance Reinsurance and DaVinci, through reinsurance agreements which will be collateralized and funded by Mona Lisa Re through the issuance of one or more series of principal-at-risk variable rate notes to third-party investors. Upon issuance of a series of notes by Mona Lisa Re, all of the proceeds from the issuance were deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance and/or DaVinci underlying such series of notes. The outstanding principal amount of each series of notes generally will be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned will be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes. The Company concluded that Mona Lisa Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Mona Lisa Re and concluded it does not have a variable interest in Mona Lisa Re. As a result, the financial position and results of operations of Mona Lisa Re are not consolidated by the Company. The Company has not provided financial or other support to Mona Lisa Re that it was not contractually required to provide. On July 6, 2018, all remaining outstanding series of notes issued by Mona Lisa Re were redeemed and the proceeds were returned to the holders of such notes. At December 31, 2018 , the total assets and total liabilities of Mona Lisa Re were $41 thousand and $41 thousand , respectively ( 2017 - $25.9 million and $25.9 million , respectively). The only transactions related to Mona Lisa Re that are recorded in the Company’s consolidated financial statements are the ceded reinsurance agreements entered into by Renaissance Reinsurance and DaVinci which are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance . Renaissance Reinsurance and DaVinci have together entered into ceded reinsurance contracts with Mona Lisa Re with gross premiums ceded of $0.2 million and $0.2 million , respectively, during 2018 ( 2017 - $0.4 million and $0.4 million , respectively). In addition, Renaissance Reinsurance and DaVinci recognized ceded premiums earned related to the ceded reinsurance contracts with Mona Lisa Re of $0.2 million and $0.2 million , respectively, during 2018 ( 2017 - $4.1 million and $2.9 million , respectively). Fibonacci Re Effective November 7, 2016 , Fibonacci Re, a Bermuda-domiciled SPI, was formed to provide collateralized capacity to Renaissance Reinsurance and its affiliates. Upon issuance of a series of notes by Fibonacci Re, all of the proceeds from the issuance are deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance underlying such series of notes. The outstanding principal amount of each series of notes generally is expected to be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned is expected to be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes. RUM receives an origination and structuring fee in connection with the formation and operation of Fibonacci Re. The Company concluded that Fibonacci Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Fibonacci Re and concluded it is not the primary beneficiary of Fibonacci Re as it does not have power over the activities that most significantly impact the economic performance of Fibonacci Re. As a result, the Company does not consolidate the financial position or results of operations of Fibonacci Re. The only transactions related to Fibonacci Re that will be recorded in the Company’s consolidated financial statements will be the ceded reinsurance agreements entered into by Renaissance Reinsurance that are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance, and the fair value of the participating notes owned by the Company. Other than its investment in the participating notes of Fibonacci Re, the Company has not provided financial or other support to Fibonacci Re that it was not contractually required to provide. The fair value of the Company’s investment in the participating notes of Fibonacci Re is included in other investments. Net of third-party investors, the fair value of the Company’s investment in Fibonacci Re was $6.0 million at December 31, 2018 ( 2017 - $14.1 million ). Renaissance Reinsurance entered into ceded reinsurance contracts with Fibonacci Re with ceded premiums of $9.1 million and ceded premiums earned of $10.0 million during 2018 ( 2017 - $9.0 million and $8.2 million , respectively). Langhorne Effective December 22, 2017, the Company and Reinsurance Group of America, Incorporated closed Langhorne, an initiative to source third party capital to support reinsurers targeting large in-force life and annuity blocks. In connection with Langhorne, as of December 31, 2018 the Company has invested $1.3 million in Langhorne Holdings ( 2017 - $0.6 million ), a company that owns and manages certain reinsurance entities within Langhorne. In addition, as of December 31, 2018 the Company had invested $0.1 million in Langhorne Partners ( 2017 - $Nil ), the general partner for Langhorne and the entity which manages the third-party investors investing into Langhorne Holdings. The Company concluded that Langhorne Holdings meets the definition of a VIE as the voting rights are not proportional with the obligations to absorb losses and rights to receive residual returns. The Company evaluated its relationship with Langhorne Holdings and concluded it is not the primary beneficiary of Langhorne Holdings, as it does not have power over the activities that most significantly impact the economic performance of Langhorne Holdings. As a result, the Company does not consolidate the financial position or results of operations of Langhorne Holdings. The Company separately evaluated Langhorne Partners and concluded that it was not a VIE. The Company accounts for its investments in Langhorne Holdings and Langhorne Partners under the equity method of accounting, one quarter in arrears. The Company anticipates that its absolute investment in Langhorne will increase, perhaps materially, as in-force life and annuity blocks of businesses are written. The Company expects its absolute and relative ownership in Langhorne Partners to remain stable. Other than its current and committed future equity investment in Langhorne, the Company has not provided financial or other support to Langhorne that it was not contractually required to provide. Vermeer Vermeer is an exempted Bermuda reinsurer that provides capacity focused on risk remote layers in the U.S. property catastrophe market. Vermeer is considered a VIE as it has voting rights that are not proportional to its participating rights. The Company is the primary beneficiary of Vermeer as it has the power over the activities that most significantly impact the economic performance of Vermeer and has the obligation to absorb expected losses and the right to receive expected benefits that could be significant to Vermeer, in accordance with the accounting guidance. The portion of Vermeer’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to redeemable noncontrolling interests. Refer to “Note 9 . Noncontrolling Interests” for additional information regarding Vermeer. Other than the Company’s minimal equity investment, it has not provided any financial or other support to Vermeer that it was not contractually required to provide. At December 31, 2018 , the Company’s consolidated balance sheet included total assets and total liabilities of Vermeer of $600.4 million and $0.4 million , respectively. In addition, the Company’s consolidated balance sheet included redeemable noncontrolling interests associated with Vermeer of $600.0 million at December 31, 2018 .

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY Authorized Capital The aggregate authorized capital of RenaissanceRe is 325 million shares consisting of 225 million common shares and 100 million preference shares. The following table is a summary of changes in common shares issued and outstanding: Year ended December 31, 2018 2017 2016 (thousands of shares) Issued and outstanding shares – January 1 40,024 41,187 43,701 Issuance of shares 1,947 — — Repurchase of shares — (1,322 ) (2,741 ) Exercise of options and issuance of restricted stock awards 236 159 227 Issued and outstanding shares – December 31 42,207 40,024 41,187 Dividends The Board of Directors of RenaissanceRe declared dividends, payable to common shareholders of record on each of March 15, 2018, June 15, 2018, September 14, 2018 and December 14, 2018 , of $0.33 per common share, and the Company paid the dividends on March 29, 2018, June 29, 2018, September 28, 2018 and December 31, 2018 , respectively. The declaration and payment of dividends on the Company’s common shares are subject to the discretion of the Company’s Board of Directors and depend on the Company’s financial condition, general business conditions, legal, contractual and regulatory restrictions regarding the payment of dividends by the Company and its subsidiaries and other factors which the Board of Directors may consider to be relevant. The Board of Directors approved the payment of quarterly dividends on the Series C 6.08% Preference Shares, Series E 5.375% Preference Shares and 5.750% Series F Preference Shares to preference shareholders of record in the amounts and on the quarterly record dates and dividend payment dates set forth in the prospectus supplement and Certificate of Designation for the applicable series of preference shares, unless and until further action is taken by the Board of Directors. The dividend payment dates for the preference shares will be the first day of March, June, September and December of each year (or if this date is not a business day, on the business day immediately following this date). The record dates for the preference share dividends are one day prior to the dividend payment dates. The amount of the dividend on the Series C 6.08% Preference Shares is an amount per share equal to 6.08% of the liquidation preference per annum (the equivalent to $1.52 per share per annum, or $0.38 per share per quarter). The amount of the dividend on the Series E 5.375% Preference Shares is an amount per share equal to 5.375% of the liquidation preference per annum (the equivalent to $1.34375 per share per annum, or $0.3359375 per share per quarter). The amount of the dividend on the 5.750% Series F Preference Shares is an amount per share equal to 5.750% of the liquidation preference per annum (the equivalent to $1,437.50 per 5.750% Series F Preference Share per annum, or $359.375 per 5.750% Series F Preference Share per quarter, or $1.4375 per Depositary Share per annum, or $0.359375 per Depositary Share per quarter). During 2018 , the Company paid $30.1 million in preference share dividends ( 2017 - $22.4 million , 2016 - $22.4 million ) and $52.8 million in common share dividends ( 2017 - $51.4 million , 2016 - $51.6 million ). Common Shares On December 20, 2018, we issued 1,947,496 common shares of the Company to State Farm Mutual Automobile Insurance Company (“State Farm”) in exchange for $250.0 million in a private placement pursuant to an Investment Agreement between the Company and State Farm entered into on October 30, 2018. Preference Shares In March 2004, RenaissanceRe raised $250.0 million through the issuance of 10 million Series C Preference Shares at $25 per share and in May 2013, RenaissanceRe raised $275.0 million through the issuance of 11 million Series E Preference Shares at $25 per share. On June 27, 2013, RenaissanceRe redeemed 5 million Series C Preference Shares for $125.0 million plus accrued and unpaid dividends thereon. Following the redemption, 5 million Series C Preference Shares remain outstanding. In June 2018, RenaissanceRe raised $250.0 million through the issuance of 10,000 Series F Preference Shares at $25,000 share (equivalent to 10,000,000 Depositary Shares, each of which represents a 1/1,000th interest in a Series F Preference Share). The Series E Preference Shares and the remaining Series C Preference Shares may be redeemed at $25 per share plus declared and unpaid dividends at RenaissanceRe’s option on or after June 1, 2018 and March 23, 2009, respectively. The Series F Preference Shares may be redeemed at $25,000 per share (equivalent to $25 per Depositary Share), plus declared and unpaid dividends, at RenaissanceRe’s option on or after June 30, 2023, provided that no redemption may occur prior to June 30, 2028 unless certain redemption requirements are met. Dividends on the Series C Preference Shares are cumulative from the date of original issuance and are payable quarterly in arrears at 6.08% per annum, when, if, and as declared by the Board of Directors. Dividends on the Series E Preference Shares are payable from the date of original issuance on a non-cumulative basis, only when, as and if declared by the Board of Directors, quarterly in arrears at 5.375% per annum. Dividends on the Series F Preference Shares are payable on a non-cumulative basis, only when, as and if declared by the Board of Directors, quarterly in arrears at 5.750% per annum. Unless certain dividend payments are made on the preference shares, RenaissanceRe will be restricted from paying any dividends on its common shares. As stated above, the Board of Directors approved the payment of quarterly dividends on the Series C Preference Shares, Series E Preference Shares and Series F Preference Shares in the amounts and on the quarterly record dates and dividend payment dates set forth in the prospectus supplement and Certificate of Designation for the applicable series of preference shares, unless and until further action is taken by the Board of Directors. The preference shares have no stated maturity and are not convertible into any other securities of RenaissanceRe. Generally, the preference shares have no voting rights. Whenever dividends payable on the preference shares are in arrears (whether or not such dividends have been earned or declared) in an amount equivalent to dividends for six full dividend periods (whether or not consecutive), the holders of the preference shares, voting as a single class regardless of class or series, will have the right to elect two directors to the Board of Directors of RenaissanceRe. Share Repurchases The Company’s share repurchase program may be effected from time to time, depending on market conditions and other factors, through open market purchases and privately negotiated transactions. On November 10, 2017 , RenaissanceRe’s Board of Directors approved a renewal of its authorized share repurchase program for an aggregate amount of up to $500.0 million . Unless terminated earlier by RenaissanceRe’s Board of Directors, the program will expire when the Company has repurchased the full value of the common shares authorized. The Company’s decision to repurchase common shares will depend on, among other matters, the market price of the common shares and the capital requirements of the Company. During 2018 , the Company did not repurchase any of its common shares. At December 31, 2018 , $500.0 million remained available for repurchase under the share repurchase program.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table sets forth the computation of basic and diluted earnings per common share: Year ended December 31, 2018 2017 2016 (common shares in thousands) Numerator: Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 197,276 $ (244,770 ) $ 480,581 Amount allocated to participating common shareholders (1) (2,121 ) (457 ) (5,666 ) Net income (loss) allocated to RenaissanceRe common shareholders $ 195,155 $ (245,227 ) $ 474,915 Denominator: Denominator for basic income (loss) per RenaissanceRe common share - weighted average common shares 39,732 39,854 41,314 Per common share equivalents of employee stock options and performance shares 23 — 245 Denominator for diluted income (loss) per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions 39,755 39,854 41,559 Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic $ 4.91 $ (6.15 ) $ 11.50 Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted $ 4.91 $ (6.15 ) $ 11.43 (1) Represents earnings attributable to holders of unvested restricted shares issued pursuant to the Company’s 2001 Stock Incentive Plan, 2010 Performance-Based Equity Incentive Plan, 2016 Long-Term Incentive Plan and to the Company’s non-employee directors.

Related Party Transactions and

Related Party Transactions and Major Customers	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions and Major Customers	RELATED PARTY TRANSACTIONS AND MAJOR CUSTOMERS The Company has equity interests in the Tower Hill Companies as described in “Note 4 . Investments”. The Company has entered into reinsurance arrangements with certain subsidiaries and affiliates of Tower Hill and has also entered into reinsurance arrangements with respect to business produced by the Tower Hill Companies. For 2018 , the Company recorded $45.5 million ( 2017 - $39.1 million , 2016 - $32.8 million ) of gross premium written assumed from the Tower Hill Companies and its subsidiaries and affiliates. Gross premiums earned totaled $43.8 million ( 2017 - $35.7 million , 2016 - $32.3 million ) and expenses incurred were $7.1 million ( 2017 - $5.1 million , 2016 - $3.8 million ) for 2018 . The Company had a net related outstanding receivable balance of $19.3 million as of December 31, 2018 ( 2017 - receivable of $14.1 million ). During 2018 , the Company assumed net claims and claim expenses of $111.2 million ( 2017 - assumed net claims and claim expenses of $94.4 million , 2016 - assumed net claims and claim expenses of $1.5 million ) and, as of December 31, 2018 , had a net reserve for claims and claim expenses of $98.8 million ( 2017 - $65.3 million ). In addition, the Company received distributions of $12.1 million from the Tower Hill Companies during 2018 ( 2017 - $8.3 million , 2016 - $9.0 million ). During 2018 , the Company received distributions from Top Layer Re of $4.0 million ( 2017 - $20.0 million , 2016 - $Nil ), and recorded a management fee of $2.7 million ( 2017 - $2.7 million , 2016 - $2.6 million ). The management fee reimburses the Company for services it provides to Top Layer Re. During 2018 , the Company received 75.2% of its gross premiums written ( 2017 - 76.4% , 2016 - 80.8% ) from three brokers. Subsidiaries and affiliates of AON, Marsh, and Willis Towers Watson accounted for 40.7% , 24.6% and 9.9% , respectively, of gross premiums written in 2018 ( 2017 - 42.8% , 23.8% and 9.8% , respectively, 2016 - 46.4% , 23.6% and 10.8% , respectively).

Taxation

Taxation	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Taxation	TAXATION Under current Bermuda law, RenaissanceRe and its Bermuda subsidiaries are not subject to any income or capital gains taxes. In the event that such taxes are imposed, RenaissanceRe and its Bermuda subsidiaries would be exempted from any such tax until March 2035 pursuant to the Bermuda Exempted Undertakings Tax Protection Act 1966, and Amended Acts of 1987 and 2011, respectively. RenaissanceRe Finance and its subsidiaries are subject to income taxes imposed by U.S. federal and state authorities and file a consolidated U.S. federal income tax return. Should the U.S. subsidiaries pay a dividend to RenaissanceRe, withholding taxes would apply to the extent of current year or accumulated earnings and profits at an expected tax rate of 5.0% . The Company also has operations in Ireland, the U.K., Singapore and Switzerland which are subject to income taxes imposed by the respective jurisdictions in which they operate. Withholding taxes would not be expected to apply to dividends paid to RenaissanceRe from its subsidiaries in Ireland, the U.K., Singapore and Switzerland. The following is a summary of the Company’s income (loss) before taxes allocated between domestic and foreign operations: Year ended December 31, 2018 2017 2016 Domestic Bermuda $ 349,959 $ (262,827 ) $ 652,758 Foreign U.S. (56,261 ) (11,897 ) (1,236 ) U.K. (28,574 ) (41,656 ) (24,278 ) Singapore (3,226 ) (12,421 ) 2,180 Ireland 551 617 964 Switzerland 166 — — Income (loss) before taxes $ 262,615 $ (328,184 ) $ 630,388 Income tax benefit (expense) is comprised as follows: Year ended December 31, 2018 Current Deferred Total Total income tax (expense) benefit $ (1,668 ) $ 7,970 $ 6,302 Year ended December 31, 2017 Total income tax expense $ (844 ) $ (25,643 ) $ (26,487 ) Year ended December 31, 2016 Total income tax (expense) benefit $ (2,090 ) $ 1,750 $ (340 ) The Company’s expected income tax provision computed on pre-tax income at the weighted average tax rate has been calculated as the sum of the pre-tax income in each jurisdiction multiplied by that jurisdiction’s applicable statutory tax rate. Statutory tax rates of 0.0% , 21.0% , 12.5% , 19.0% , 17.0% and 21.2% have been used for Bermuda, the U.S., Ireland, the U.K., Singapore and Switzerland, respectively. The Company’s effective income tax rate, which it calculates as income tax expense divided by net income before taxes, may fluctuate significantly from period to period depending on the geographic distribution of pre-tax net income (loss) in any given period between different jurisdictions with comparatively higher tax rates and those with comparatively lower tax rates. The geographic distribution of pre-tax net income (loss) can vary significantly between periods due to, but not limited to, the following factors: the business mix of net premiums written and earned; the geographic location, the size and the nature of net claims and claim expenses incurred; the amount and geographic location of operating expenses, net investment income, net realized and unrealized gains (losses) on investments; outstanding debt and related interest expense; and the amount of specific adjustments to determine the income tax basis in each of the Company’s operating jurisdictions. In addition, a significant portion of the Company’s gross and net premiums are currently written and earned in Bermuda, which does not have a corporate income tax, including the majority of the Company’s catastrophe business, which can result in significant volatility to its pre-tax net income (loss) in any given period. A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows: Year ended December 31, 2018 2017 2016 Expected income tax benefit $ 17,697 $ 14,216 $ 4,856 Tax exempt income 944 3,794 4,487 Non-taxable foreign exchange gains (losses) 586 2,574 (1,126 ) Effect of change in tax rate (708 ) (38,083 ) (1,421 ) U.S. base erosion and anti-abuse tax (1,271 ) — — Withholding tax (1,831 ) (216 ) (2,578 ) Transfer pricing (2,481 ) (11 ) 27 Change in valuation allowance (5,255 ) (11,718 ) (924 ) Other (1,379 ) 2,957 (3,661 ) Income tax benefit (expense) $ 6,302 $ (26,487 ) $ (340 ) As a result of the reduction in the U.S. corporate tax rate from 35% to 21% effective January 1, 2018 pursuant to the Tax Cuts and Jobs Act of 2017, the Company recorded a partial write-down of its U.S. deferred tax asset of $36.7 million in 2017. This adjustment is included in effect of change in tax rate in the table above. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: At December 31, 2018 2017 Deferred tax assets Tax loss and credit carryforwards $ 60,395 $ 62,643 Reserve for claims and claim expenses 17,345 13,992 Deferred finance charges 14,646 11,320 Unearned premiums 10,108 9,436 Investments 4,427 — Accrued expenses 4,292 2,641 Deferred underwriting results 3,514 3,407 114,727 103,439 Deferred tax liabilities Deferred acquisition expenses (11,801 ) (12,343 ) Amortization and depreciation (2,992 ) (3,340 ) Investments — (1,047 ) (14,793 ) (16,730 ) Net deferred tax asset before valuation allowance 99,934 86,709 Valuation allowance (35,271 ) (30,016 ) Net deferred tax asset $ 64,663 $ 56,693 The Company’s net deferred tax asset is included in other assets on its consolidated balance sheets. During 2018 , the Company recorded a net increase to the valuation allowance of $5.3 million ( 2017 – increase of $11.2 million , 2016 – increase of $0.9 million ). The Company’s net deferred tax asset primarily relates to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to reserves for claims and claim expenses, deferred finance charges, accrued expenses, unearned premiums, deferred underwriting results, deferred acquisition expenses, amortization and depreciation and investments. The Company’s valuation allowance assessment is based on all available information including projections of future GAAP taxable income from each tax-paying component in each tax jurisdiction. A valuation allowance has been provided against deferred tax assets in Ireland, the U.K., and Singapore. These deferred tax assets relate primarily to net operating loss carryforwards. In 2018 , the valuation allowance with respect to the Company’s U.K. operations increased by $4.0 million . In the U.S., the Company has net operating loss carryforwards of $164.2 million . Under applicable law, the U.S. net operating loss carryforwards will begin to expire in 2031 . The Company has net operating loss carryforwards of $114.4 million in the U.K., $21.7 million in Singapore and $4.8 million in Ireland. Under applicable law, the U.K., Singapore and Irish net operating losses can be carried forward for an indefinite period. The Company had a net payment for U.S. federal, Irish, U.K., Singapore and Switzerland income taxes of $0.3 million for the year ended 2018 ( 2017 – net payment of $0.3 million , 2016 – net refund of $1.1 million ). The Company has unrecognized tax benefits of $Nil as of December 31, 2018 ( 2017 – $Nil ). Interest and penalties related to unrecognized tax benefits would be recognized in income tax expense. At December 31, 2018 , interest and penalties accrued on unrecognized tax benefits were $Nil ( 2017 – $Nil ). Income tax returns filed for tax years 2015 through 2017, 2014 through 2017, 2017, 2014 through 2017, and 2017, are open for examination by the IRS, Irish tax authorities, U.K. tax authorities, Singapore and Switzerland tax authorities, respectively. The Company does not expect the resolution of these open years to have a significant impact on its results from operations and financial condition.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2018
Segment Reporting, Measurement Disclosures [Abstract]
Segment Reporting	SEGMENT REPORTING The Company’s reportable segments are defined as follows: (1) Property, which is comprised of catastrophe and other property reinsurance and insurance written on behalf of the Company’s operating subsidiaries and certain joint ventures managed by the Company’s ventures unit, and (2) Casualty and Specialty, which is comprised of casualty and specialty reinsurance and insurance written on behalf of the Company’s operating subsidiaries and certain joint ventures managed by the Company’s ventures unit. In addition to its reportable segments, the Company has an Other category, which primarily includes its strategic investments, investments unit, corporate expenses, capital servicing costs, noncontrolling interests and the remnants of its former Bermuda-based insurance operations. The Company’s Property segment is managed by the Chief Underwriting Officer - Property and the Casualty and Specialty segment is managed by the Chief Underwriting Officer - Casualty and Specialty, each of whom operate under the direction of the Company’s Group Chief Underwriting Officer, who in turn reports to the Company’s President and Chief Executive Officer. The Company does not manage its assets by segment; accordingly, net investment income and total assets are not allocated to the segments. A summary of the significant components of the Company’s revenues and expenses by segment is as follows: Year ended December 31, 2018 Property Casualty and Specialty Other Total Gross premiums written $ 1,760,926 $ 1,549,501 $ — $ 3,310,427 Net premiums written $ 1,055,188 $ 1,076,714 $ — $ 2,131,902 Net premiums earned $ 1,050,831 $ 925,298 $ — $ 1,976,129 Net claims and claim expenses incurred 497,895 622,320 (197 ) 1,120,018 Acquisition expenses 177,912 255,079 (2 ) 432,989 Operational expenses 112,954 64,883 430 178,267 Underwriting income (loss) $ 262,070 $ (16,984 ) $ (231 ) 244,855 Net investment income 261,866 261,866 Net foreign exchange losses (12,428 ) (12,428 ) Equity in earnings of other ventures 18,474 18,474 Other income 5,969 5,969 Net realized and unrealized losses on investments (175,069 ) (175,069 ) Corporate expenses (33,983 ) (33,983 ) Interest expense (47,069 ) (47,069 ) Income before taxes and redeemable noncontrolling interests 262,615 Income tax benefit 6,302 6,302 Net income attributable to redeemable noncontrolling interests (41,553 ) (41,553 ) Dividends on preference shares (30,088 ) (30,088 ) Net income available to RenaissanceRe common shareholders $ 197,276 Net claims and claim expenses incurred – current accident year $ 719,185 $ 671,582 $ — $ 1,390,767 Net claims and claim expenses incurred – prior accident years (221,290 ) (49,262 ) (197 ) (270,749 ) Net claims and claim expenses incurred – total $ 497,895 $ 622,320 $ (197 ) $ 1,120,018 Net claims and claim expense ratio – current accident year 68.4 % 72.6 % 70.4 % Net claims and claim expense ratio – prior accident years (21.0 )% (5.3 )% (13.7 )% Net claims and claim expense ratio – calendar year 47.4 % 67.3 % 56.7 % Underwriting expense ratio 27.7 % 34.5 % 30.9 % Combined ratio 75.1 % 101.8 % 87.6 % Year ended December 31, 2017 Property Casualty and Specialty Other Total Gross premiums written $ 1,440,437 $ 1,357,110 $ (7 ) $ 2,797,540 Net premiums written $ 978,014 $ 893,307 $ 4 $ 1,871,325 Net premiums earned $ 931,070 $ 786,501 $ 4 $ 1,717,575 Net claims and claim expenses incurred 1,297,985 565,026 (1,583 ) 1,861,428 Acquisition expenses 113,816 233,077 (1 ) 346,892 Operational expenses 94,194 66,548 36 160,778 Underwriting (loss) income $ (574,925 ) $ (78,150 ) $ 1,552 (651,523 ) Net investment income 222,209 222,209 Net foreign exchange gains 10,628 10,628 Equity in earnings of other ventures 8,030 8,030 Other income 9,415 9,415 Net realized and unrealized gains on investments 135,822 135,822 Corporate expenses (18,572 ) (18,572 ) Interest expense (44,193 ) (44,193 ) Loss before taxes and noncontrolling interests (328,184 ) Income tax expense (26,487 ) (26,487 ) Net loss attributable to noncontrolling interests 132,282 132,282 Dividends on preference shares (22,381 ) (22,381 ) Net loss attributable to RenaissanceRe common shareholders $ (244,770 ) Net claims and claim expenses incurred – current accident year $ 1,343,581 $ 558,843 $ — $ 1,902,424 Net claims and claim expenses incurred – prior accident years (45,596 ) 6,183 (1,583 ) (40,996 ) Net claims and claim expenses incurred – total $ 1,297,985 $ 565,026 $ (1,583 ) $ 1,861,428 Net claims and claim expense ratio – current accident year 144.3 % 71.1 % 110.8 % Net claims and claim expense ratio – prior accident years (4.9 )% 0.7 % (2.4 )% Net claims and claim expense ratio – calendar year 139.4 % 71.8 % 108.4 % Underwriting expense ratio 22.3 % 38.1 % 29.5 % Combined ratio 161.7 % 109.9 % 137.9 % Year ended December 31, 2016 Property Casualty and Specialty Other Total Gross premiums written $ 1,111,263 $ 1,263,313 $ — $ 2,374,576 Net premiums written $ 725,321 $ 809,848 $ 143 $ 1,535,312 Net premiums earned $ 720,951 $ 682,337 $ 142 $ 1,403,430 Net claims and claim expenses incurred 151,545 380,396 (1,110 ) 530,831 Acquisition expenses 97,594 191,729 — 289,323 Operational expenses 108,642 88,984 123 197,749 Underwriting income $ 363,170 $ 21,228 $ 1,129 385,527 Net investment income 181,726 181,726 Net foreign exchange losses (13,788 ) (13,788 ) Equity in earnings of other ventures 963 963 Other income 14,178 14,178 Net realized and unrealized gains on investments 141,328 141,328 Corporate expenses (37,402 ) (37,402 ) Interest expense (42,144 ) (42,144 ) Income before taxes and noncontrolling interests 630,388 Income tax expense (340 ) (340 ) Net income attributable to noncontrolling interests (127,086 ) (127,086 ) Dividends on preference shares (22,381 ) (22,381 ) Net income available to RenaissanceRe common shareholders $ 480,581 Net claims and claim expenses incurred – current accident year $ 256,421 $ 438,536 $ — $ 694,957 Net claims and claim expenses incurred – prior accident years (104,876 ) (58,140 ) (1,110 ) (164,126 ) Net claims and claim expenses incurred – total $ 151,545 $ 380,396 $ (1,110 ) $ 530,831 Net claims and claim expense ratio – current accident year 35.6 % 64.3 % 49.5 % Net claims and claim expense ratio – prior accident years (14.6 )% (8.6 )% (11.7 )% Net claims and claim expense ratio – calendar year 21.0 % 55.7 % 37.8 % Underwriting expense ratio 28.6 % 41.2 % 34.7 % Combined ratio 49.6 % 96.9 % 72.5 % The following is a summary of the Company’s gross premiums written allocated to the territory of coverage exposure: Year ended December 31, 2018 2017 2016 Property U.S. and Caribbean $ 978,063 $ 954,269 $ 743,226 Worldwide 464,311 305,915 210,168 Europe 144,857 49,486 37,611 Japan 71,601 49,821 44,536 Worldwide (excluding U.S.) (1) 66,872 48,182 55,043 Australia and New Zealand 19,273 14,151 13,729 Other 15,949 18,613 6,950 Total Property 1,760,926 1,440,437 1,111,263 Casualty and Specialty Worldwide 776,976 686,253 581,972 U.S. and Caribbean 667,125 622,757 646,381 Worldwide (excluding U.S.) (1) 31,734 10,104 13,840 Europe 15,296 9,752 5,541 Australia and New Zealand 3,667 4,141 5,073 Other 54,703 24,103 10,506 Total Casualty and Specialty 1,549,501 1,357,110 1,263,313 Other category — (7 ) — Total gross premiums written $ 3,310,427 $ 2,797,540 $ 2,374,576 (1) The category “Worldwide (excluding U.S.)” consists of contracts that cover more than one geographic region (other than the U.S.).

Stock Incentive Compensation an

Stock Incentive Compensation and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Incentive Compensation and Employee Benefit Plans	STOCK INCENTIVE COMPENSATION AND EMPLOYEE BENEFIT PLANS Stock Incentive Compensation Plans and Awards The Company is authorized to issue restricted stock awards, restricted stock units, performance share awards, stock options and other share-based awards to its employees and directors pursuant to various stock incentive compensation plans. On May 16, 2016, the Company’s shareholders approved the Company’s 2016 Long-Term Incentive Plan (the “2016 Long-Term Incentive Plan”). Pursuant to the 2016 Long-Term Incentive Plan, the Company is authorized to issue up to 1,625,000 common shares plus the number of shares that were subject to awards outstanding under the Company’s 2001 Stock Incentive Plan, as amended (the “2001 Stock Incentive Plan”) and the Company’s 2010 Performance-Based Equity Incentive Plan, as amended (the “2010 Performance Plan”) as of the effective date of the 2016 Long-Term Incentive Plan that are forfeited, canceled, settled in cash, or otherwise terminated without delivery after the effective date. The 2016 Long-Term Incentive Plan permits the grant of restricted stock awards, restricted stock units, performance share awards (including cash-based performance awards), stock options and other share-based awards to employees, officers, non-employee directors and consultants or advisors of the Company and its affiliates. The 2001 Stock Incentive Plan, which permitted the grant of stock options, restricted stock awards and other share-based awards to employees of RenaissanceRe and its subsidiaries, expired in accordance with its terms on February 6, 2016 and no additional awards may be made under this plan. The 2010 Performance Plan, pursuant to which the Company granted performance share awards, was terminated on May 16, 2016 upon approval of the 2016 Long-Term Incentive Plan, and no additional awards will be made under this plan. The terms and conditions of outstanding awards granted under the 2001 Share Incentive Plan and the 2010 Performance Plan were not affected by the respective expiration and termination of these plans. In 2010, the Company instituted a cash settled restricted stock unit (“CSRSU”) plan, the 2010 Restricted Stock Unit Plan, which allowed for the issuance of equity awards in the form of CSRSUs. In November 2016, the 2010 Restricted Stock Plan was terminated and replaced with a new cash settled restricted stock unit plan, the 2016 Restricted Stock Unit Plan. The terms and conditions of CSRSU awards outstanding under the 2010 Restricted Stock Unit Plan at the time of termination were not affected, but no additional awards will be made under the 2010 Restricted Stock Unit Plan. Stock Options The Company has not granted stock options since 2008. Stock options were granted pursuant to the 2001 Stock Incentive Plan and allowed for the purchase of RenaissanceRe common shares at a price that was equal to, or not less than, the fair market value of RenaissanceRe common shares as of the effective grant date. Stock options generally vested over four years and expired 10 years from the grant date. Restricted Stock Awards Restricted stock awards granted periodically under the 2001 Stock Incentive Plan and the 2016 Long-Term Incentive Plan generally vest ratably over a four year period. The Company has also granted restricted stock awards to non-employee directors, which generally vest ratably over a three year period. Performance Share Awards Performance share awards have been granted periodically to certain of the Company’s executive officers pursuant to the 2010 Performance Plan, 2001 Share Incentive Plan and 2016 Long-Term Incentive Plan. Outstanding performance share awards are subject to vesting conditions based on both continued service and the attainment of pre-established performance goals. If performance goals are achieved, the performance share awards will vest up to a maximum of 250% of target. Performance share awards generally cliff vest at the end of a three year vesting period based on the attainment of annual performance goals over the vesting period. The performance share awards granted prior to May 2018 have a market condition, which is the Company’s total shareholder return relative to its peer group. The performance share awards granted in May 2018 have a performance condition, which is the percentage change in the Company’s tangible book value per common share plus accumulated dividends, or, in the event of a change in control, a market condition, which is the Company’s total shareholder return relative to its peer group. Total shareholder return is calculated in accordance with the terms of the applicable award agreement and is generally based on the average closing share price over the 20 trading days preceding and including the start and end of the annual performance period. The percentage change in tangible book value per share plus accumulated dividends is calculated in accordance with the terms of the applicable award agreement. Cash Settled Restricted Stock Units CSRSUs are liability awards with fair value measurement based on the fair market value of the Company’s common shares at the end of each reporting period. CSRSUs granted periodically pursuant to the 2010 Restricted Stock Unit Plan and 2016 Restricted Stock Unit Plan generally vest ratably over four years. Valuation Assumptions Performance Share Awards Granted Prior to May 2018 The fair value of performance share awards granted prior to May 2018 is measured on the grant date using a Monte Carlo simulation model which requires the following inputs: share price; expected volatility; expected term; expected dividend yield; and risk-free interest rates. The following are the weighted average-assumptions used to estimate the fair value for all performance share awards issued in each respective year. Performance Share Awards Year ended December 31, 2018 2017 Expected volatility (1) 15.8% 14.3% Expected term (in years) n/a n/a Expected dividend yield n/a n/a Risk-free interest rate (1) 1.85% - 2.36% 0.93% - 1.69% (1) The expected volatility and risk-free interest rate applied are specific to each tranche of performance share awards. Expected volatility: The expected volatility is estimated by the Company based on RenaissanceRe’s historical stock volatility. Expected term: The expected term is not applicable as the length of the performance periods are fixed and not subject to future employee behavior. Each tranche of the performance share awards has a one year period during which performance is measured. Expected dividend yield: The expected dividend yield is not applicable to performance share awards as dividends are paid at the end of the vesting period and do not affect the value of the performance shares. Risk-free interest rate: The risk free rate is estimated based on the yield on a U.S. treasury zero-coupon issued with a remaining term equal to the vesting period of the performance share awards. For performance share awards granted before May 2018, the total cost of the performance share awards is determined on the grant date based on the fair value calculated by the Monte Carlo simulation model. The Company recognizes cost equal to fair value per performance share award multiplied by the target number of performance share awards on the grant date. The cost is then amortized as an expense over the requisite service period. The Company has elected to recognize forfeitures as they occurred rather than estimating service-based forfeitures over the requisite service period. Performance Share Awards Granted as of May 2018 For performance share awards granted as of May 2018, the performance metric relates to the percentage change in tangible book value per share plus accumulated dividends which is classified as a performance condition under ASC 718. As a result, the fair value of the performance share awards is determined based on the fair market value of RenaissanceRe’s common shares on the grant date. The estimated fair value of performance share awards is amortized as an expense over the requisite service period. Restricted Stock Awards The fair value of restricted stock awards is determined based on the fair market value of RenaissanceRe’s common shares on the grant date. The estimated fair value of restricted stock awards is amortized as an expense over the requisite service period. The Company has elected to recognize forfeitures as they occurred rather than estimating service-based forfeitures over the requisite service period. Cash Settled Restricted Stock Units CSRSUs are revalued at the end of each quarterly reporting period based on the then fair market value of RenaissanceRe’s common shares. The total cost is adjusted each quarter for unvested CSRSUs to reflect the current share price, and this total cost is amortized as an expense over the requisite service period. The Company has elected to recognize forfeitures as they occurred rather than estimating service-based forfeitures over the requisite service period. Summary of Stock Compensation Activity The following is a summary of activity under the Company’s stock compensation plans. Stock Options Weighted options outstanding Weighted average exercise price Weighted average remaining contractual life Aggregate intrinsic value Range of exercise prices Balance, December 31, 2015 408,212 $ 51.90 1.6 $ 25,020 $42.66 - $59.66 Options granted — — — Options forfeited — — Options expired — — Options exercised (201,417 ) 50.59 $ 14,806 — Balance, December 31, 2016 206,795 $ 53.17 0.9 $ 17,174 $50.71 - $59.66 Options granted — — — Options forfeited — — Options expired — — Options exercised (174,794 ) 53.04 $ 15,945 — Balance, December 31, 2017 32,001 $ 53.86 0.2 $ 2,295 53.86 Options granted — — — Options forfeited — — Options expired — — Options exercised (32,001 ) $ 53.86 $ 2,320 $ — Balance, December 31, 2018 — $ — 0.0 $ — $ — Total options exercisable at December 31, 2018 — $ — 0.0 $ — $ — Cash Settled Restricted Stock Units Number of shares Nonvested at December 31, 2015 326,078 Awards granted 135,119 Awards vested (133,278 ) Awards forfeited (19,575 ) Nonvested at December 31, 2016 308,344 Awards granted 98,067 Awards vested (122,088 ) Awards forfeited (21,993 ) Nonvested at December 31, 2017 262,330 Awards granted — Awards vested (108,344 ) Awards forfeited (7,069 ) Nonvested at December 31, 2018 146,917 Performance Share Awards Number of shares (1) Weighted average grant-date fair value Nonvested at December 31, 2015 230,271 $ 41.40 Awards granted 77,045 $ 48.31 Awards vested (58,032 ) $ 38.30 Awards forfeited (37,903 ) Nonvested at December 31, 2016 211,381 $ 44.63 Awards granted 64,947 $ 65.27 Awards vested (62,499 ) $ 43.51 Awards forfeited (46,156 ) Nonvested at December 31, 2017 167,673 $ 53.11 Awards granted 83,475 $ 60.69 Awards vested (16,456 ) $ 53.79 Awards forfeited (82,241 ) Nonvested at December 31, 2018 152,451 $ 57.21 (1) For performance share awards, the number of shares is stated at the maximum number that can be attained if the performance conditions are fully met. Forfeitures represent shares forfeited due to vesting below the maximum attainable as a result of the Company not fully meeting the performance conditions. Restricted Stock Awards Employee restricted stock awards Non-employee director restricted stock awards Total restricted stock awards Number of shares Weighted average grant date fair value Number of shares Weighted Number of shares Weighted Nonvested at December 31, 2015 479,040 $ 94.95 26,886 $ 97.61 505,926 $ 95.09 Awards granted 179,003 112.41 14,727 114.71 193,730 112.59 Awards vested (255,873 ) 93.98 (16,068 ) 96.83 (271,941 ) 94.15 Awards forfeited — — — — — — Nonvested at December 31, 2016 402,170 $ 103.34 25,545 $ 107.95 427,715 $ 103.61 Awards granted 116,345 148.66 12,193 150.05 128,538 148.79 Awards vested (185,478 ) 100.17 (17,612 ) 110.66 (203,090 ) 101.08 Awards forfeited — — — — — — Nonvested at December 31, 2017 333,037 $ 120.93 20,126 $ 131.09 353,163 $ 121.51 Awards granted 255,799 132.70 12,169 127.29 267,968 132.79 Awards vested (139,454 ) 112.70 (9,761 ) 123.59 (149,215 ) 113.41 Awards forfeited (1,642 ) 134.38 — — (1,642 ) 134.38 Nonvested at December 31, 2018 447,740 $ 130.37 22,534 $ 132.29 470,274 $ 130.46 There were 1.6 million shares available for issuance under the 2016 Long-Term Incentive Plan at December 31, 2018 and no shares available for issuance under the 2001 Stock Incentive Plan or 2010 Performance Share Plan at December 31, 2018 . The aggregate fair value of restricted stock awards, performance share awards and CSRSUs vested during 2018 was $37.2 million ( 2017 – $56.9 million , 2016 – $54.5 million ). Cash in the amount of $Nil was received from employees as a result of employee stock option exercises during 2018 ( 2017 – $Nil , 2016 – $Nil ). In connection with share vestings and option exercises, there was no excess windfall tax benefit realized by the Company due to its net operating loss position in the taxable jurisdictions in which it operates. RenaissanceRe issues new shares upon the exercise of an option. The total stock compensation expense recognized in the Company’s consolidated statements of operations during 2018 was $35.7 million ( 2017 – $37.2 million , 2016 – $47.4 million ). As of December 31, 2018 , there was $43.2 million of total unrecognized compensation cost related to restricted stock awards, $11.2 million related to CSRSUs and $4.8 million related to performance share awards, which will be recognized, on a weighted average basis, during the next 1.8 , 1.3 and 1.7 years, respectively. All of the Company’s employees are eligible for defined contribution pension plans. Contributions are primarily based upon a percentage of eligible compensation. The Company contributed $4.1 million to its defined contribution pension plans in 2018 ( 2017 – $4.4 million , 2016 – $4.0 million ).

Statutory Requirements

Statutory Requirements	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Statutory Requirements	STATUTORY REQUIREMENTS The Company’s (re)insurance operations are subject to insurance laws and regulations in the jurisdictions in which they operate, the most significant of which currently include Bermuda, the U.S. and the U.K. These regulations include certain restrictions on the amount of dividends or other distributions, such as loans or cash advances, available to shareholders without prior approval of the respective regulatory authorities. Group Supervision The Bermuda Monetary Authority (“BMA”) is the group supervisor of the Company. Under the Insurance Act 1978, amendments thereto and related regulations of Bermuda (collectively, the “Insurance Act”), the Company shall ensure that it can meet its minimum solvency margin (“MSM”), defined as the prescribed minimum amount by which the value of the assets of the Company must exceed the value of its liabilities, the breach of which represents an unacceptable level of risk and triggers the strongest supervisory actions. In addition, the Company is required to maintain statutory economic capital and surplus at a level equal to or in excess of its enhanced capital requirement (“ECR”) which is established by reference to the Bermuda Solvency Capital Requirement (the “BSCR”) model. The BSCR is a mathematical model designed to give the BMA robust methods for determining an insurer’s capital adequacy. The ECR is equal to the greater of the MSM or required capital calculated by reference to the BSCR. Effective January 1, 2016, the BMA embedded the Economic Balance Sheet (“EBS”) framework in the Bermuda legislative and regulatory regime. The EBS is an input to the BSCR which determines the Company’s ECR. The EBS regime prescribes the use of financial statements prepared in accordance with GAAP as the basis on which statutory financial statements are prepared, and those statutory financial statements form the starting basis for the EBS. The BMA has established a target capital level (“TCL”) which is set at 120% of the ECR. While the Company is not required to maintain statutory economic capital and surplus at this level, it serves as an early warning tool for the BMA, and failure to meet the TCL may result in additional reporting requirements or increased regulatory oversight. The Company is currently completing its 2018 group BSCR, which must be filed with the BMA on or before May 31, 2019 , and at this time, the Company believes it will exceed the target level of required statutory economic capital and surplus. The statutory economic capital and surplus, required minimum statutory capital and surplus and unrestricted net assets of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below: Bermuda (1) U.S. U.K. (2) (3) At December 31, 2018 2017 2018 2017 2018 2017 Statutory economic capital and surplus $ 4,256,830 $ 4,155,368 $ 502,803 $ 523,384 $ 519,689 $ 527,325 Required statutory capital and surplus 950,915 836,181 306,628 306,375 519,689 527,325 Unrestricted net assets 931,387 790,177 31,228 24,109 — — (1) The Company's Bermuda-domiciled insurance subsidiaries’ capital and surplus is based on the relevant insurer’s statutory financial statements and required statutory capital and surplus is based on the MSM. (2) With respect to statutory capital and surplus and required statutory capital and surplus, and as described below, underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as Funds at Lloyd’s (“FAL”). FAL is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirements as calculated through its internal model. (3) Syndicate 1458 is capitalized by its FAL, with the related assets not held on its balance sheet. As such, unrestricted net assets is not applicable to Syndicate 1458; however, the Company can make an application to obtain approval from Lloyd’s to have funds released to RenaissanceRe from Syndicate 1458, subject to passing a Lloyd’s release test. Statutory net income (loss) of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below: Statutory Net Income (Loss) Bermuda U.S. U.K. Year ended December 31, 2018 $ 326,386 $ 25,851 $ (6,692 ) Year ended December 31, 2017 (334,142 ) (3,627 ) (57,050 ) Year ended December 31, 2016 625,371 43,292 28,007 The difference between statutory financial statements and statements prepared in accordance with GAAP varies by jurisdiction; however, the primary difference is that for the Company’s regulated entities the statutory financial statements generally do not reflect goodwill and intangible assets. Also, in the U.S., fixed maturity investments are generally recorded at amortized cost and deferred income tax is charged directly to equity. In the U.S. and the U.K., deferred acquisition costs are generally not reflected in the statutory financial statements. None of the Company’s insurance subsidiaries used permitted practices that prevented the trigger of a regulatory event during the years ended December 31, 2018 , 2017 and 2016 . Dividend Restrictions of RenaissanceRe As a Bermuda-domiciled holding company, RenaissanceRe has limited operations of its own and its assets consist primarily of investments in subsidiaries, and to a degree, cash and securities. Accordingly, RenaissanceRe’s future cash flows largely depend on the availability of dividends or other statutorily permissible payments from subsidiaries. The ability to pay such dividends is limited by the applicable laws and regulations of the various countries and states in which these subsidiaries operate, including, among others, Bermuda, the U.S., the U.K. and Ireland. RenaissanceRe’s ability to pay dividends and distribute capital to shareholders is limited by the Bermuda Companies Act 1981, insofar as both before and after the payment, RenaissanceRe must still be able to pay its liabilities as they come due and the realizable value of its assets must be greater than its liabilities. Bermuda-Domiciled Insurance Entities Under the Insurance Act, certain subsidiaries of RenaissanceRe are required to prepare and file statutory financial statements. Effective January 1, 2016, the BMA prescribed the use of financial statements prepared in accordance with GAAP as the basis on which the statutory financial statements are prepared, subject to the application of certain prudential filters. These statutory financial statements are used to prepare the EBS. In addition, Bermuda insurance subsidiaries of RenaissanceRe are required to maintain certain measures of solvency and liquidity and file a BSCR return. Class 3B and Class 4 Insurers Under the Insurance Act, RenaissanceRe Specialty U.S. and Vermeer are defined as Class 3B insurers, and Renaissance Reinsurance and DaVinci are classified as Class 4 insurers, and therefore must maintain statutory economic capital and surplus at a level at least equal to its ECR which is the greater of its MSM and the required capital calculated by reference to the BSCR. Class 3B and Class 4 insurers are prohibited from declaring or paying any dividends if in breach of the required minimum solvency margin or minimum liquidity ratio (the “Relevant Margins”) or if the declaration or payment of such dividend would cause the insurer to fail to meet the Relevant Margins. Where an insurer fails to meet its Relevant Margins on the last day of any financial year, it is prohibited from declaring or paying any dividends during the next financial year without the prior approval of the BMA. Further, Class 3B and Class 4 insurers are prohibited from declaring or paying in any financial year dividends of more than 25% of its total statutory capital and surplus (as shown on its previous financial year’s statutory balance sheet) unless it files (at least seven days before payment of such dividends) with the BMA an affidavit stating that it will continue to meet its Relevant Margins. Class 3B and Class 4 insurers must obtain the BMA’s prior approval for a reduction by 15% or more of the total statutory capital as set forth in its previous year’s financial statements. These restrictions on declaring or paying dividends and distributions under the Insurance Act are in addition to the solvency requirements under the Bermuda Companies Act 1981 which apply to all Bermuda companies. In addition, an insurer engaged in general business is also required to maintain the value of its relevant assets at not less than 75% of the amount of its relevant liabilities. The Company is currently completing its 2018 Bermuda-domiciled statutory filings for Renaissance Reinsurance, DaVinci and RenaissanceRe Specialty U.S., which must be filed with the BMA on or before April 30, 2019 , and at this time, the Company believes each of Renaissance Reinsurance, DaVinci and RenaissanceRe Specialty U.S. will exceed the target level of required statutory economic capital. Vermeer applied for and received an exemption from the BMA with respect to filing its 2018 Bermuda-domiciled statutory filings. SPIs Under the Insurance Act, Upsilon RFO is considered an SPI. See “Note 10 . Variable Interest Entities” for additional information related to Upsilon RFO. Unlike other (re)insurers, such as the Class 3B and Class 4 insurers discussed above, SPIs are fully funded to meet their (re)insurance obligations and are not exposed to insolvency, therefore the application and supervision processes are streamlined to facilitate the transparent structure. Further, the BMA has the discretion to modify such insurer’s reporting requirements under the Insurance Act. Like other (re)insurers, the principal representative of an SPI has a duty to inform the BMA in relation to solvency matters, where applicable. Upsilon RFO applied for and received a direction from the BMA, which, subject to specified conditions, modified its filing requirements in respect of statutory financial statements for the year ended December 31, 2018 and 2017 . U.S.-Domiciled Insurance Entities The Company has a U.S.-domiciled insurance subsidiary, Renaissance Reinsurance U.S., which was acquired on March 2, 2015 and is subject to statutory accounting principles as defined by the National Association of Insurance Commissioners (the “NAIC”). The NAIC uses a risk-based capital ("RBC") model to monitor and regulate the solvency of licensed life, health, and property and casualty insurance and reinsurance companies. Renaissance Reinsurance U.S. is domiciled in Maryland, which has adopted the NAIC's model law. Laws and regulations in the U.S. establish minimum capital adequacy levels and grant regulators the authority to take specific actions based on the level of impairment. Based on Maryland’s adoption of the RBC model of the NAIC, the first level at which action is required is Company Action Level (“CAL”) RBC. If Renaissance Reinsurance U.S.’s total adjusted capital is less than CAL RBC (but greater than Regulatory Action Level (“RAL”) RBC), then Renaissance Reinsurance U.S. must file an RBC plan with the Maryland Insurance Commissioner (the "Commissioner"). If Renaissance Reinsurance U.S.’s total adjusted capital is less than RAL RBC, then the Commissioner must take certain regulatory actions. Under Maryland insurance law, Renaissance Reinsurance U.S. must notify the Commissioner within five business days after the declaration of any dividend or distribution, other than an extraordinary dividend or extraordinary distribution, and notify the Commissioner at least ten days prior to the payment or distribution thereof. The Commissioner has the right to prevent payment of such a dividend or such a distribution if the Commissioner determines, in the Commissioner's discretion, that after the payment thereof, the policyholders' surplus of Renaissance Reinsurance U.S. would be inadequate or could cause Renaissance Reinsurance U.S. to be in a hazardous financial condition. Renaissance Reinsurance U.S. must give at least 30 days prior notice to the Commissioner before paying an extraordinary dividend or making an extraordinary distribution. Extraordinary dividends and extraordinary distributions are dividends or distributions which, together with any other dividends and distributions paid during the immediately preceding twelve-month period, would exceed the lesser of: • 10% of the insurer's statutory policyholders' surplus (as determined under statutory accounting principles) as of December 31 of the prior year; or • the insurer's net investment income excluding realized capital gains (as determined under statutory accounting principles) for the twelve-month period ending on December 31 of the prior year and pro rata distributions of any class of the insurer's securities, plus any amounts of net investment income (subject to the foregoing exclusions) in the three calendar years prior to the preceding year which have not been paid out as dividends. At December 31, 2018 , Renaissance Reinsurance U.S. had an ordinary dividend capacity of $31.2 million which can be paid in 2019 . Renaissance Reinsurance U.S. is required to file statutory basis financial statements with the Maryland Insurance Administration, as its domestic regulator, with the NAIC and with insurance regulators in certain other states where it is licensed, authorized or accredited to do business. The operations of Renaissance Reinsurance U.S. are subject to examination by those state insurance regulators at any time. The Company is currently completing the 2018 statutory basis financial statements for Renaissance Reinsurance U.S., which must be filed with the NAIC, on or before March 1, 2019 . At this time, the Company believes Renaissance Reinsurance U.S. will exceed the CAL. U.K.-Domiciled Syndicate 1458 RenaissanceRe CCL and Syndicate 1458 are subject to oversight by the Council of Lloyd’s. RSML is authorized by the U.K.’s Prudential Regulation Authority and regulated by the Financial Conduct Authority under the Financial Services and Markets Act 2000. Underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as FAL. This amount is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirement as calculated through its internal model. In addition, if the FAL are not sufficient to cover all losses, the Lloyd’s Central Fund provides an additional discretionary level of security for policyholders. Multi-Beneficiary Reinsurance Trusts Each of Renaissance Reinsurance and DaVinci was approved as a Trusteed Reinsurer in the state of New York and established a multi-beneficiary reinsurance trust (“MBRT”) to collateralize its (re)insurance liabilities associated with U.S. domiciled cedants. The MBRTs are subject to the rules and regulations of the state of New York and the respective deed of trust, including but not limited to certain minimum capital funding requirements, investment guidelines, capital distribution restrictions and regulatory reporting requirements. Assets held under trust at December 31, 2018 with respect to the MBRTs totaled $1.2 billion and $385.8 million for Renaissance Reinsurance and DaVinci, respectively ( 2017 – $1.2 billion and $377.0 million , respectively), compared to the minimum amount required under U.S. state regulations of $1.1 billion and $356.9 million , respectively ( 2017 – $1.1 billion and $326.9 million , respectively). Multi-Beneficiary Reduced Collateral Reinsurance Trusts Each of Renaissance Reinsurance and DaVinci has been approved as a “certified reinsurer” eligible for collateral reduction in Connecticut, Delaware, Florida, Indiana, Maryland and New York, and are authorized to provide reduced collateral equal to 20% and 50% , respectively, of their net outstanding insurance liabilities to insurers domiciled in each of those states. Each of Renaissance Reinsurance and DaVinci has established a multi-beneficiary reduced collateral reinsurance trust (“RCT”) to collateralize its (re)insurance liabilities associated with cedants domiciled in those states. Because the RCTs were established in New York, they are subject to the rules and regulations of the state of New York including but not limited to certain minimum capital funding requirements, investment guidelines, capital distribution restrictions and regulatory reporting requirements. Assets held under trust at December 31, 2018 with respect to the RCTs totaled $50.3 million and $63.2 million for Renaissance Reinsurance and DaVinci, respectively ( 2017 - $49.4 million and $62.0 million , respectively), compared to the minimum amount required under U.S. state regulations of $36.8 million and $26.9 million , respectively ( 2017 - $39.7 million and $46.0 million , respectively).

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2018
Summary of Derivative Instruments [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS From time to time, the Company may enter into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts primarily to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company’s derivative instruments can be exchange traded or over-the-counter, with over-the-counter derivatives generally traded under International Swaps and Derivatives Association master agreements, which establish the terms of the transactions entered into with the Company’s derivative counterparties. In the event a party becomes insolvent or otherwise defaults on its obligations, a master agreement generally permits the non-defaulting party to accelerate and terminate all outstanding transactions and net the transactions’ marked-to-market values so that a single sum in a single currency will be owed by, or owed to, the non-defaulting party. Effectively, this contractual close-out netting reduces credit exposure from gross to net exposure. Where the Company has entered into master netting agreements with counterparties, or the Company has the legal and contractual right to offset positions, the derivative positions are generally netted by counterparty and are reported accordingly in other assets and other liabilities. The tables below show the gross and net amounts of recognized derivative assets and liabilities at fair value, including the location on the consolidated balance sheets of the Company’s principal derivative instruments: Derivative Assets At December 31, 2018 Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet Balance Sheet Location Collateral Net Amount Interest rate futures $ 2,361 1,660 $ 701 Other assets $ — $ 701 Interest rate swaps 860 — 860 Other assets — 860 Foreign currency forward contracts (1) 16,459 2,260 14,199 Other assets — 14,199 Foreign currency forward contracts (2) 3,194 71 3,123 Other assets — 3,123 Total $ 22,874 $ 3,991 $ 18,883 $ — $ 18,883 Derivative Liabilities At December 31, 2018 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet Balance Sheet Location Collateral Pledged Net Amount Interest rate futures $ 1,887 1,670 $ 217 Other liabilities $ 217 $ — Interest rate swaps 506 — 506 Other liabilities 254 252 Foreign currency forward contracts (1) 4,154 — 4,154 Other liabilities — 4,154 Foreign currency forward contracts (2) 72 71 1 Other liabilities — 1 Credit default swaps 1,606 — 1,606 Other liabilities 1,605 1 Total $ 8,225 $ 1,741 $ 6,484 $ 2,076 $ 4,408 (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations. Derivative Assets At December 31, 2017 Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet Balance Sheet Location Collateral Net Amount Interest rate futures $ 684 524 $ 160 Other assets $ — $ 160 Interest rate swaps 424 — 424 Other assets — 424 Foreign currency forward contracts (1) 3,865 358 3,507 Other assets — 3,507 Foreign currency forward contracts (2) 39 11 28 Other assets — 28 Credit default swaps 1,518 — 1,518 Other assets — 1,518 Total $ 6,530 $ 893 $ 5,637 $ — $ 5,637 Derivative Liabilities At December 31, 2017 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet Balance Sheet Location Collateral Pledged Net Amount Interest rate futures $ 729 524 $ 205 Other liabilities $ 205 $ — Foreign currency forward contracts (1) 670 — 670 Other liabilities — 670 Foreign currency forward contracts (2) 115 11 104 Other liabilities — 104 Credit default swaps 22 — 22 Other liabilities 22 — Total $ 1,536 $ 535 $ 1,001 $ 227 $ 774 (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations. Refer to “Note 4 . Investments” for information on reverse repurchase agreements. The location and amount of the gain (loss) recognized in the Company’s consolidated statements of operations related to its principal derivative instruments are shown in the following table: Location of gain (loss) recognized on derivatives Amount of gain (loss) recognized on derivatives Year ended December 31, 2018 2017 2016 Interest rate futures Net realized and unrealized (losses) gains on investments $ (5,594 ) $ (3,252 ) $ (17,379 ) Interest rate swaps Net realized and unrealized (losses) gains on investments (84 ) 436 — Foreign currency forward contracts (1) Net foreign exchange (losses) gains 3,840 9,628 (6,937 ) Foreign currency forward contracts (2) Net foreign exchange (losses) gains 5,736 (916 ) (1,591 ) Credit default swaps Net realized and unrealized (losses) gains on investments (3,106 ) 326 1,965 Total $ 792 $ 6,222 $ (23,942 ) (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations. The Company is not aware of the existence of any credit-risk related contingent features that it believes would be triggered in its derivative instruments that are in a net liability position at December 31, 2018 . Interest Rate Derivatives The Company uses interest rate futures and swaps within its portfolio of fixed maturity investments to manage its exposure to interest rate risk, which may result in increasing or decreasing its exposure to this risk. Interest Rate Futures The fair value of interest rate futures is determined using exchange traded prices. At December 31, 2018 , the Company had $1.9 billion of notional long positions and $545.8 million of notional short positions of primarily Eurodollar, U.S. treasury and non-U.S. dollar futures contracts ( 2017 – $1.5 billion and $801.1 million , respectively). Interest Rate Swaps The fair value of interest rate swaps is determined using the relevant exchange traded price where available or a discounted cash flow model based on the terms of the contract and inputs, including, where applicable, observable yield curves. At December 31, 2018 , the Company had $78.4 million of notional positions paying a fixed rate and $32.1 million receiving a fixed rate denominated in U.S. dollar swap contracts ( 2017 - $40.3 million and $Nil , respectively). Foreign Currency Derivatives The Company’s functional currency is the U.S. dollar. The Company writes a portion of its business in currencies other than U.S. dollars and may, from time to time, experience foreign exchange gains and losses in the Company’s consolidated financial statements. All changes in exchange rates, with the exception of non-monetary assets and liabilities, are recognized in the Company’s consolidated statements of operations. Underwriting Operations Related Foreign Currency Contracts The Company’s foreign currency policy with regard to its underwriting operations is generally to hold foreign currency assets, including cash, investments and receivables that approximate the foreign currency liabilities, including claims and claim expense reserves and reinsurance balances payable. When necessary, the Company may use foreign currency forward and option contracts to minimize the effect of fluctuating foreign currencies on the value of non-U.S. dollar denominated assets and liabilities associated with its underwriting operations. The fair value of the Company’s underwriting operations related foreign currency contracts is determined using indicative pricing obtained from counterparties or broker quotes. At December 31, 2018 , the Company had outstanding underwriting related foreign currency contracts of $354.1 million in notional long positions and $601.2 million in notional short positions, denominated in U.S. dollars ( 2017 – $215.4 million and $44.2 million , respectively). Investment Portfolio Related Foreign Currency Forward Contracts The Company’s investment operations are exposed to currency fluctuations through its investments in non-U.S. dollar fixed maturity investments, short term investments and other investments. From time to time, the Company may employ foreign currency forward contracts in its investment portfolio to either assume foreign currency risk or to economically hedge its exposure to currency fluctuations from these investments. The fair value of the Company’s investment portfolio related foreign currency forward contracts is determined using an interpolated rate based on closing forward market rates. At December 31, 2018 , the Company had outstanding investment portfolio related foreign currency contracts of $121.3 million in notional long positions and $42.9 million in notional short positions, denominated in U.S. dollars ( 2017 – $16.6 million and $5.1 million , respectively). Credit Derivatives The Company’s exposure to credit risk is primarily due to its fixed maturity investments, short term investments, premiums receivable and reinsurance recoverable. From time to time, the Company may purchase credit derivatives to hedge its exposures in the insurance industry, and to assist in managing the credit risk associated with ceded reinsurance. The Company also employs credit derivatives in its investment portfolio to either assume credit risk or hedge its credit exposure. The fair value of credit derivatives is determined using industry valuation models, broker bid indications or internal pricing valuation techniques. The fair value of these credit derivatives can change based on a variety of factors including changes in credit spreads, default rates and recovery rates, the correlation of credit risk between the referenced credit and the counterparty, and market rate inputs such as interest rates. At December 31, 2018 , the Company had outstanding credit derivatives of $1.0 million in notional positions to hedge credit risk and $126.2 million in notional positions to assume credit risk, denominated in U.S. dollars ( 2017 – $1.0 million and $18.8 million , respectively).

Commitments, Contingencies and

Commitments, Contingencies and Other Items	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Other Items	COMMITMENTS, CONTINGENCIES AND OTHER ITEMS CONCENTRATION OF CREDIT RISK Instruments which potentially subject the Company to concentration of credit risk consist principally of investments, including the Company’s equity method investments, cash, premiums receivable and reinsurance balances. The Company limits the amount of credit exposure to any one financial institution and, except for U.S. Government and money market securities, none of the Company’s investments exceeded 10% of shareholders’ equity at December 31, 2018 . See “Note 6 . Reinsurance”, for information with respect to reinsurance recoverable. EMPLOYMENT AGREEMENTS The Board of Directors has authorized the execution of employment agreements between the Company and certain officers. These agreements provide for, among other things, severance payments under certain circumstances, as well as accelerated vesting of options and certain restricted stock grants, upon a change in control, as defined in the employment agreements and the Company’s stock incentive plans. LETTERS OF CREDIT AND OTHER COMMITMENTS At December 31, 2018 , the Company’s banks have issued letters of credit of $510.6 million in favor of certain ceding companies. In connection with the Company’s Top Layer Re joint venture, Renaissance Reinsurance has committed $37.5 million of collateral to support a letter of credit and is obligated to make a mandatory capital contribution of up to $50.0 million in the event that a loss reduces Top Layer Re’s capital and surplus below a specified level. The letters of credit are secured by cash and investments of similar amounts. See “Note 8 . Debt and Credit Facilities” for additional information related to the Company’s debt and credit facilities. PRIVATE EQUITY AND INVESTMENT COMMITMENTS The Company has committed capital to private equity investments, other investments and investments in other ventures of $1.2 billion , of which $686.4 million has been contributed at December 31, 2018 . The Company’s remaining commitments to these investments at December 31, 2018 totaled $470.8 million . These commitments do not have a defined contractual commitment date. INDEMNIFICATIONS AND WARRANTIES In the ordinary course of its business, the Company may enter into contracts or agreements that contain indemnifications or warranties. Future events could occur that lead to the execution of these provisions against the Company. Based on past experience, management currently believes that the likelihood of such an event is remote. OPERATING AND CAPITAL LEASES The Company leases office space under operating leases which expire at various dates through 2027 . Future minimum lease payments under existing operating leases are expected to be as follows: Minimum lease payments 2019 $ 7,137 2020 5,294 2021 4,934 2022 4,225 2023 1,530 After 2023 298 Future minimum lease payments under existing operating leases $ 23,418 The Company’s capital leases primarily relate to office space in Bermuda with an initial lease term of 20 years, ending in 2028, and a bargain renewal option for an additional 30 years. The future minimum lease payments of the Company’s capital leases are detailed below, and relate principally to the transaction noted above, excluding the bargain renewal option. Minimum lease payments 2019 $ 3,331 2020 3,336 2021 3,336 2022 3,336 2023 2,830 After 2023 12,790 Future minimum lease payments under existing capital leases $ 28,959 LITIGATION The Company and its subsidiaries are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on reinsurance treaties or contracts or direct surplus lines insurance policies. In the Company’s industry, business litigation may involve allegations of underwriting or claims-handling errors or misconduct, disputes relating to the scope of, or compliance with, the terms of delegated underwriting agreements, employment claims, regulatory actions or disputes arising from the Company’s business ventures. The Company’s operating subsidiaries are subject to claims litigation involving, among other things, disputed interpretations of policy coverages. Generally, the Company’s direct surplus lines insurance operations are subject to greater frequency and diversity of claims and claims-related litigation than its reinsurance operations and, in some jurisdictions, may be subject to direct actions by allegedly injured persons or entities seeking damages from policyholders. These lawsuits, involving or arising out of claims on policies issued by the Company’s subsidiaries which are typical to the insurance industry in general and in the normal course of business, are considered in its loss and loss expense reserves which are discussed in “Note 7 . Reserve for Claims and Claim Expenses”. In addition, the Company may from time to time engage in litigation or arbitration related to its claims for payment in respect of ceded reinsurance, including disputes that challenge the Company’s ability to enforce its underwriting intent. Such matters could result, directly or indirectly, in providers of protection not meeting their obligations to the Company or not doing so on a timely basis. The Company may also be subject to other disputes from time to time, relating to operational or other matters distinct from insurance or reinsurance claims. Any litigation or arbitration, or regulatory process, contains an element of uncertainty, and the value of an exposure or a gain contingency related to a dispute is difficult to estimate accordingly. Currently, the Company believes that no individual litigation or arbitration to which it is presently a party is likely to have a material adverse effect on its financial condition, business or operations. ACQUISITION OF TOKIO MILLENNIUM RE See “Note 20 . Acquisition of Tokio Millennium Re” for information related to the obligations of the Company with respect to the TMR Stock Purchase.

Acquisition of Tokio Millennium

Acquisition of Tokio Millennium RE	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisition of Tokio Millennium RE	ACQUISITION OF TOKIO MILLENNIUM RE Pursuant to the TMR Stock Purchase Agreement, the aggregate consideration for the TMR Stock Purchase consists of: (i) an amount in cash equal to the product of (x) the closing tangible book value of the TMR Group Entities (calculated as set forth in the TMR Stock Purchase Agreement) prior to taking into account the pre-closing dividend (if any) (as described in the paragraph below) and the amounts payable to Tokio at the closing under the Reserve Development Agreement and Third Party Capital Agreement (as defined in the TMR Stock Purchase Agreement) (the “ADC/TPC Amount”) and (y) 1.02 , less an amount equal to the sum of (1) the amount of the pre-closing dividend (if any), and (2) the ADC/TPC Amount, plus solely in the event the 30 trading day volume-weighted average closing RenaissanceRe share price (the “Closing RenaissanceRe Share Price”) is less than or equal to $128.37 (the “Signing RenaissanceRe Share Price”), the amount by which (A) $250.0 million exceeds (B) the product of (I) the RenaissanceRe Share Amount (as defined below) and (II) the Closing RenaissanceRe Share Price; and (ii) a number of common shares of the Company equal to (a) if the Closing RenaissanceRe Share Price is less than or equal to the Signing RenaissanceRe Share Price, an amount equal to the quotient obtained by dividing (1) $250.0 million by (2) the Signing RenaissanceRe Share Price, or (b) if the Signing RenaissanceRe Share Price is less than the Closing RenaissanceRe Share Price, an amount equal to the quotient obtained by dividing (1) $250.0 million by (2) the Closing RenaissanceRe Share Price, in either case of clause (a) or (b), rounded down to the nearest whole number (the “RenaissanceRe Share Amount”). Under the terms of the TMR Stock Purchase Agreement, Tokio will use its reasonable best efforts to cause TMR AG and/or TMR UK to, subject to regulatory approvals, pay to Tokio, prior to closing, one or more dividends in an aggregate amount equal to $275.0 million (or a lesser amount as mutually agreed by the Company and Tokio), provided that Tokio shall use its reasonable best efforts to maximize the amount of such dividend in an amount up to $500.0 million (or a lesser amount as mutually agreed by the Company and Tokio). In connection with the TMR Stock Purchase Agreement, Tokio, TMR AG and TMR UK have agreed to enter into a Reserve Development Agreement at the closing whereby TMR AG and TMR UK will agree to cede to Tokio, and Tokio will agree to indemnify and reimburse TMR AG and TMR UK for, substantially all of TMR AG and TMR UK’s adverse development on stated reserves at time of Closing including unearned premium reserves, subject to the terms and conditions of the Reserve Development Agreement. The TMR Stock Purchase is expected to close in the first half of 2019, subject to the closing conditions described above and contained in the TMR Stock Purchase Agreement.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data [Abstract]
Quarterly Financial Information (Unaudited)	QUARTERLY FINANCIAL INFORMATION (UNAUDITED) Quarter Ended March 31, Quarter Ended June 30, Quarter Ended September 30, Quarter Ended December 31, 2018 2017 2018 2017 2018 2017 2018 2017 Revenues Gross premiums written $ 1,159,652 $ 922,090 $ 977,343 $ 827,415 $ 625,677 $ 640,269 $ 547,755 $ 407,766 Net premiums written $ 663,044 $ 544,136 $ 604,509 $ 555,745 $ 453,255 $ 483,221 $ 411,094 $ 288,223 (Increase) decrease in unearned premiums (222,762 ) (178,091 ) (175,124 ) (173,480 ) 78,594 64,571 163,519 133,250 Net premiums earned 440,282 366,045 429,385 382,265 531,849 547,792 574,613 421,473 Net investment income 56,476 54,325 71,356 54,163 80,696 40,257 53,338 73,464 Net foreign exchange gains (losses) 3,757 8,165 (10,687 ) 3,109 (4,566 ) (156 ) (932 ) (490 ) Equity in earnings (losses) of other ventures 857 (1,507 ) 5,826 5,543 7,648 1,794 4,143 2,200 Other (loss) income (1,242 ) 1,665 1,225 2,392 497 2,996 5,489 2,362 Net realized and unrealized (losses) gains on investments (82,144 ) 43,373 (17,901 ) 58,113 13,630 42,052 (88,654 ) (7,716 ) Total revenues 417,986 472,066 479,204 505,585 629,754 634,735 547,997 491,293 Expenses Net claims and claim expenses incurred 171,703 193,081 60,167 142,587 410,510 1,221,696 477,638 304,064 Acquisition costs 97,711 83,282 105,052 88,251 109,761 76,761 120,465 98,598 Operational expenses 41,272 47,283 37,543 41,766 40,593 42,537 58,859 29,192 Corporate expenses 6,733 5,286 8,301 4,636 6,841 4,413 12,108 4,237 Interest expense 11,767 10,526 11,768 10,091 11,769 11,799 11,765 11,777 Total expenses 329,186 339,458 222,831 287,331 579,474 1,357,206 680,835 447,868 Income (loss) before taxes 88,800 132,608 256,373 218,254 50,280 (722,471 ) (132,838 ) 43,425 Income tax benefit (expense) 3,407 (334 ) (4,506 ) (3,904 ) (1,451 ) 18,977 8,852 (41,226 ) Net income (loss) 92,207 132,274 251,867 214,350 48,829 (703,494 ) (123,986 ) 2,199 Net (income) loss attributable to redeemable noncontrolling interests (29,899 ) (34,327 ) (54,483 ) (37,612 ) (6,440 ) 204,277 49,269 (56 ) Net income (loss) available (attributable) to RenaissanceRe 62,308 97,947 197,384 176,738 42,389 (499,217 ) (74,717 ) 2,143 Dividends on preference shares (5,595 ) (5,595 ) (5,596 ) (5,596 ) (9,708 ) (5,595 ) (9,189 ) (5,595 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 56,713 $ 92,352 $ 191,788 $ 171,142 $ 32,681 $ (504,812 ) $ (83,906 ) $ (3,452 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic $ 1.42 $ 2.26 $ 4.78 $ 4.25 $ 0.82 $ (12.75 ) $ (2.10 ) $ (0.09 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted $ 1.42 $ 2.25 $ 4.78 $ 4.24 $ 0.82 $ (12.75 ) $ (2.10 ) $ (0.09 ) Average shares outstanding – basic 39,552 40,408 39,641 39,937 39,624 39,591 40,111 39,478 Average shares outstanding – diluted 39,599 40,623 39,654 40,024 39,637 39,591 40,111 39,478

Condensed Consolidating Financi

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries	12 Months Ended
	Dec. 31, 2018
Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries	CONDENSED CONSOLIDATING FINANCIAL INFORMATION PROVIDED IN CONNECTION WITH OUTSTANDING DEBT OF SUBSIDIARIES The following tables present condensed consolidating balance sheets at December 31, 2018 and 2017 , condensed consolidating statements of operations, condensed consolidating statements of comprehensive income (loss) and condensed consolidating statements of cash flows for the years ended December 31, 2018 , 2017 and 2016 , respectively. Each of RRNAH and RenaissanceRe Finance is a 100% owned subsidiary of RenaissanceRe. On June 1, 2017, the Platinum Finance Notes matured and the Company repaid the aggregate principal amount plus applicable accrued interest in full. Platinum Finance was subsequently dissolved on November 30, 2017. Prior to the liquidation of Platinum Finance, it was a 100% owned subsidiary of RenaissanceRe. For additional information related to the terms of the Company’s outstanding debt securities, see “Note 8 . Debt and Credit Facilities”. Condensed Consolidating Balance Sheet at December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Assets Total investments $ 313,360 $ 77,842 $ 28,885 $ 11,465,660 $ — $ 11,885,747 Cash and cash equivalents 3,534 3,350 9,604 1,091,434 — 1,107,922 Investments in subsidiaries 4,414,475 58,458 1,215,663 — (5,688,596 ) — Due from subsidiaries and affiliates 57,039 101,579 — — (158,618 ) — Premiums receivable — — — 1,537,188 — 1,537,188 Prepaid reinsurance premiums — — — 616,185 — 616,185 Reinsurance recoverable — — — 2,372,221 — 2,372,221 Accrued investment income 1,046 310 127 49,828 — 51,311 Deferred acquisition costs — — — 476,661 — 476,661 Receivable for investments sold 203 23,885 — 232,328 — 256,416 Other assets 458,842 22,571 313,636 (1,403,636 ) 743,714 135,127 Goodwill and other intangible assets 120,476 — — 116,942 — 237,418 Total assets $ 5,368,975 $ 287,995 $ 1,567,915 $ 16,554,811 $ (5,103,500 ) $ 18,676,196 Liabilities, Noncontrolling Interests and Shareholders’ Equity Liabilities Reserve for claims and claim expenses $ — $ — $ — $ 6,076,271 $ — $ 6,076,271 Unearned premiums — — — 1,716,021 — 1,716,021 Debt 300,000 — 843,086 148,041 (300,000 ) 991,127 Amounts due to subsidiaries and affiliates 6,453 217 102,243 — (108,913 ) — Reinsurance balances payable — — — 1,902,056 — 1,902,056 Payable for investments purchased — 24 — 380,308 — 380,332 Other liabilities 17,442 5,362 13,918 482,422 (5,535 ) 513,609 Total liabilities 323,895 5,603 959,247 10,705,119 (414,448 ) 11,579,416 Redeemable noncontrolling interests — — — 2,051,700 — 2,051,700 Shareholders’ Equity Total shareholders’ equity 5,045,080 282,392 608,668 3,797,992 (4,689,052 ) 5,045,080 Total liabilities, noncontrolling interests and shareholders’ equity $ 5,368,975 $ 287,995 $ 1,567,915 $ 16,554,811 $ (5,103,500 ) $ 18,676,196 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Balance Sheet at December 31, 2017 RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Assets Total investments $ 225,266 $ 129,732 $ 31,255 $ 9,117,186 $ — $ 9,503,439 Cash and cash equivalents 14,656 139 1,469 1,345,328 — 1,361,592 Investments in subsidiaries 4,105,760 36,140 1,141,733 — (5,283,633 ) — Due from subsidiaries and affiliates 4,602 91,891 — — (96,493 ) — Premiums receivable — — — 1,304,622 — 1,304,622 Prepaid reinsurance premiums — — — 533,546 — 533,546 Reinsurance recoverable — — — 1,586,630 — 1,586,630 Accrued investment income 405 428 82 41,320 — 42,235 Deferred acquisition costs — — — 426,551 — 426,551 Receivable for investments sold 135 51 8 102,951 — 103,145 Other assets 433,468 21,342 430,481 76,703 (840,768 ) 121,226 Goodwill and other intangible assets 124,960 — — 118,185 — 243,145 Total assets $ 4,909,252 $ 279,723 $ 1,605,028 $ 14,653,022 $ (6,220,894 ) $ 15,226,131 Liabilities, Redeemable Noncontrolling Interest and Shareholders’ Equity Liabilities Reserve for claims and claim expenses $ — $ — $ — $ 5,080,408 $ — $ 5,080,408 Unearned premiums — — — 1,477,609 — 1,477,609 Debt 417,000 — 841,892 147,731 (417,000 ) 989,623 Amounts due to subsidiaries and affiliates 82,579 54 92,794 — (175,427 ) — Reinsurance balances payable — — — 989,090 — 989,090 Payable for investments purchased — — — 208,749 — 208,749 Other liabilities 18,298 1,053 14,117 764,432 (5,129 ) 792,771 Total liabilities 517,877 1,107 948,803 8,668,019 (597,556 ) 9,538,250 Redeemable noncontrolling interests — — — 1,296,506 — 1,296,506 Shareholders’ Equity Total shareholders’ equity 4,391,375 278,616 656,225 4,688,497 (5,623,338 ) 4,391,375 Total liabilities, redeemable noncontrolling interest and shareholders’ equity $ 4,909,252 $ 279,723 $ 1,605,028 $ 14,653,022 $ (6,220,894 ) $ 15,226,131 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Operations for RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Revenues Net premiums earned $ — $ — $ — $ 1,976,129 $ — $ 1,976,129 Net investment income 24,791 2,193 6,219 261,192 (32,529 ) 261,866 Net foreign exchange losses (3 ) — — (12,425 ) — (12,428 ) Equity in earnings of other ventures — — 3,065 15,409 — 18,474 Other income — — — 5,969 — 5,969 Net realized and unrealized gains (losses) on investments 633 (4,360 ) (329 ) (171,013 ) — (175,069 ) Total revenues 25,421 (2,167 ) 8,955 2,075,261 (32,529 ) 2,074,941 Expenses Net claims and claim expenses incurred — — — 1,120,018 — 1,120,018 Acquisition expenses — — — 432,989 — 432,989 Operational expenses 7,679 110 34,534 164,605 (28,661 ) 178,267 Corporate expenses 25,190 — 7 3,103 5,683 33,983 Interest expense 5,683 — 37,019 4,367 — 47,069 Total expenses 38,552 110 71,560 1,725,082 (22,978 ) 1,812,326 (Loss) income before equity in net income of subsidiaries and taxes (13,131 ) (2,277 ) (62,605 ) 350,179 (9,551 ) 262,615 Equity in net income of subsidiaries 240,495 5,631 9,091 — (255,217 ) — Income (loss) before taxes 227,364 3,354 (53,514 ) 350,179 (264,768 ) 262,615 Income tax benefit (expense) — 582 6,119 (399 ) — 6,302 Net income (loss) 227,364 3,936 (47,395 ) 349,780 (264,768 ) 268,917 Net income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Net income (loss) attributable to RenaissanceRe 227,364 3,936 (47,395 ) 308,227 (264,768 ) 227,364 Dividends on preference shares (30,088 ) — — — — (30,088 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 197,276 $ 3,936 $ (47,395 ) $ 308,227 $ (264,768 ) $ 197,276 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor, Subsidiary Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Comprehensive income (loss) Net income (loss) $ 227,364 $ 3,936 $ (47,395 ) $ 349,780 $ (264,768 ) $ 268,917 Change in net unrealized gains on investments — — — (1,657 ) — (1,657 ) Comprehensive income (loss) 227,364 3,936 (47,395 ) 348,123 (264,768 ) 267,260 Net income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income (loss) available (attributable) to RenaissanceRe $ 227,364 $ 3,936 $ (47,395 ) $ 306,570 $ (264,768 ) $ 225,707 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor, Subsidiary Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Operations for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Revenues Net premiums earned $ — $ — $ — $ — $ 1,717,575 $ — $ 1,717,575 Net investment income 23,109 1,947 1,373 3,090 219,490 (26,800 ) 222,209 Net foreign exchange (losses) gains (1 ) — — — 10,629 — 10,628 Equity in (losses) earnings of other ventures — — — (223 ) 8,253 — 8,030 Other income — — — — 9,415 — 9,415 Net realized and unrealized (losses) gains on investments (1,357 ) 9,621 4,916 (479 ) 123,121 — 135,822 Total revenues 21,751 11,568 6,289 2,388 2,088,483 (26,800 ) 2,103,679 Expenses Net claims and claim expenses incurred — — — — 1,861,428 — 1,861,428 Acquisition expenses — — — — 346,892 — 346,892 Operational expenses 11,314 103 85 26,063 141,572 (18,359 ) 160,778 Corporate expenses 18,546 — — — 26 — 18,572 Interest expense 1,572 — 2,461 31,657 10,075 (1,572 ) 44,193 Total expenses 31,432 103 2,546 57,720 2,359,993 (19,931 ) 2,431,863 (Loss) income before equity in net (loss) income of subsidiaries and taxes (9,681 ) 11,465 3,743 (55,332 ) (271,510 ) (6,869 ) (328,184 ) Equity in net (loss) income of subsidiaries (212,708 ) 756 28,028 9,298 — 174,626 — (Loss) income before taxes (222,389 ) 12,221 31,771 (46,034 ) (271,510 ) 167,757 (328,184 ) Income tax (expense) benefit — (18,147 ) (1,175 ) 7,163 (14,328 ) — (26,487 ) Net (loss) income (222,389 ) (5,926 ) 30,596 (38,871 ) (285,838 ) 167,757 (354,671 ) Net loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Net (loss) income attributable to RenaissanceRe (222,389 ) (5,926 ) 30,596 (38,871 ) (153,556 ) 167,757 (222,389 ) Dividends on preference shares (22,381 ) — — — — — (22,381 ) Net (loss) income (attributable) available to RenaissanceRe common shareholders $ (244,770 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (153,556 ) $ 167,757 $ (244,770 ) (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive (Loss) Income for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Comprehensive (loss) income Net (loss) income $ (222,389 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (285,838 ) $ 167,757 $ (354,671 ) Change in net unrealized gains on investments — — — — (909 ) — (909 ) Comprehensive (loss) income (222,389 ) (5,926 ) 30,596 (38,871 ) (286,747 ) 167,757 (355,580 ) Net loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Comprehensive loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Comprehensive (loss) income (attributable) available to RenaissanceRe $ (222,389 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (154,465 ) $ 167,757 $ (223,298 ) (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Operations RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North America Holdings Inc. (Subsidiary Issuer) Platinum RenaissanceRe Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Revenues Net premiums earned $ — $ — $ — $ — $ 1,403,430 $ — $ 1,403,430 Net investment income 24,178 1,852 3,989 569 175,407 (24,269 ) 181,726 Net foreign exchange losses (2 ) — — — (13,786 ) — (13,788 ) Equity in earnings of other ventures — — — — 963 — 963 Other (loss) income (772 ) — — — 14,950 — 14,178 Net realized and unrealized gains on investments 4,151 4,659 8,193 46 124,279 — 141,328 Total revenues 27,555 6,511 12,182 615 1,705,243 (24,269 ) 1,727,837 Expenses Net claims and claim expenses incurred — — — — 530,831 — 530,831 Acquisition expenses — — — — 289,323 — 289,323 Operational expenses 13,716 (112 ) 296 22,152 176,041 (14,344 ) 197,749 Corporate expenses 26,848 203 — 7 10,344 — 37,402 Interest expense 562 — 5,906 26,176 10,062 (562 ) 42,144 Total expenses 41,126 91 6,202 48,335 1,016,601 (14,906 ) 1,097,449 (Loss) income before equity in net income of subsidiaries and taxes (13,571 ) 6,420 5,980 (47,720 ) 688,642 (9,363 ) 630,388 Equity in net income of subsidiaries 516,533 3,857 25,073 38,628 — (584,091 ) — Income (loss) before taxes 502,962 10,277 31,053 (9,092 ) 688,642 (593,454 ) 630,388 Income tax (expense) benefit — (2,275 ) (1,462 ) 11,014 (7,617 ) — (340 ) Net income 502,962 8,002 29,591 1,922 681,025 (593,454 ) 630,048 Net income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Net income attributable to RenaissanceRe 502,962 8,002 29,591 1,922 553,939 (593,454 ) 502,962 Dividends on preference shares (22,381 ) — — — — — (22,381 ) Net income available to RenaissanceRe common shareholders $ 480,581 $ 8,002 $ 29,591 $ 1,922 $ 553,939 $ (593,454 ) $ 480,581 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income for the year ended December 31, 2016 RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North America Holdings Inc. (Subsidiary Issuer) Platinum RenaissanceRe Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Comprehensive income Net income $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 681,025 $ (593,454 ) $ 630,048 Change in net unrealized gains on investments — — — — (975 ) — (975 ) Comprehensive income 502,962 8,002 29,591 1,922 680,050 (593,454 ) 629,073 Net income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to RenaissanceRe $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 552,964 $ (593,454 ) $ 501,987 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Consolidated Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (9,659 ) $ 6,315 $ 62,645 $ 1,162,400 $ 1,221,701 Cash flows used in investing activities Proceeds from sales and maturities of fixed maturity investments trading 384,818 97,272 56,518 11,046,968 11,585,576 Purchases of fixed maturity investments trading (520,935 ) (72,292 ) (55,932 ) (11,840,813 ) (12,489,972 ) Net (purchases) sales of equity investments trading — (1,308 ) — 15,464 14,156 Net sales (purchases) of short term investments 48,600 (404 ) 455 (1,485,040 ) (1,436,389 ) Net purchases of other investments — — — (199,475 ) (199,475 ) Net purchases of investments in other ventures — — — (21,473 ) (21,473 ) Return of investment from investment in other ventures — — — 8,464 8,464 Net sales of other assets — — — 2,500 2,500 Dividends and return of capital from subsidiaries 672,098 — — (672,098 ) — Contributions to subsidiaries (785,785 ) (16,847 ) (65,000 ) 867,632 — Due (from) to subsidiary (200,916 ) (9,525 ) 9,449 200,992 — Net cash used in investing activities (402,120 ) (3,104 ) (54,510 ) (2,076,879 ) (2,536,613 ) Cash flows provided by financing activities Dividends paid – RenaissanceRe common shares (52,841 ) — — — (52,841 ) Dividends paid – preference shares (30,088 ) — — — (30,088 ) RenaissanceRe common share issuance 250,000 — — — 250,000 Issuance of preference shares, net of expenses 241,448 — — — 241,448 Net third party redeemable noncontrolling interest share transactions — — — 665,683 665,683 Taxes paid on withholding shares (7,862 ) — — — (7,862 ) Net cash provided by financing activities 400,657 — — 665,683 1,066,340 Effect of exchange rate changes on foreign currency cash — — — (5,098 ) (5,098 ) Net (decrease) increase in cash and cash equivalents (11,122 ) 3,211 8,135 (253,894 ) (253,670 ) Cash and cash equivalents, beginning of period 14,656 139 1,469 1,345,328 1,361,592 Cash and cash equivalents, end of period $ 3,534 $ 3,350 $ 9,604 $ 1,091,434 $ 1,107,922 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) RenaissanceRe Consolidated Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (4,109 ) $ (8,253 ) $ (2,272 ) $ (347,890 ) $ 1,388,311 $ 1,025,787 Cash flows provided by (used in) investing activities Proceeds from sales and maturities of fixed maturity investments trading 261,601 100,248 289,741 288,900 8,550,179 9,490,669 Purchases of fixed maturity investments trading (344,463 ) (99,568 ) (143,991 ) (275,778 ) (9,229,732 ) (10,093,532 ) Net (purchases) sales of equity investments trading — (1,752 ) 85,324 — 32,265 115,837 Net sales (purchases) of short term investments 243,571 114 41,299 (493 ) 79,520 364,011 Net purchases of other investments — — — — (19,419 ) (19,419 ) Return of investment from investment in other ventures — — — — 20,000 20,000 Dividends and return of capital from subsidiaries 478,496 9,175 — 41,866 (529,537 ) — Contributions to subsidiaries (669,672 ) — (26,649 ) (9,890 ) 706,211 — Due to (from) subsidiaries 319,646 13 (123 ) (509 ) (319,027 ) — Net cash provided by (used in) investing activities 289,179 8,230 245,601 44,096 (709,540 ) (122,434 ) Cash flows (used in) provided by financing activities Dividends paid – RenaissanceRe common shares (51,370 ) — — — — (51,370 ) Dividends paid – preference shares (22,381 ) — — — — (22,381 ) RenaissanceRe common share repurchases (188,591 ) — — — — (188,591 ) Issuance of debt, net of expenses — — — 295,866 — 295,866 Repayment of debt — — (250,000 ) — — (250,000 ) Net third party redeemable noncontrolling interest share transactions — — — — 260,475 260,475 Taxes paid on withholding shares (15,139 ) — — — — (15,139 ) Net cash (used in) provided by financing activities (277,481 ) — (250,000 ) 295,866 260,475 28,860 Effect of exchange rate changes on foreign currency cash — — — — 8,222 8,222 Net increase (decrease) in cash and cash equivalents 7,589 (23 ) (6,671 ) (7,928 ) 947,468 940,435 Cash and cash equivalents, beginning of period 7,067 162 6,671 9,397 397,860 421,157 Cash and cash equivalents, end of period $ 14,656 $ 139 $ — $ 1,469 $ 1,345,328 $ 1,361,592 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2016 RenaissanceRe RenRe North Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (3,509 ) $ 1,477 $ (14,501 ) $ (34,607 ) $ 535,912 $ 484,772 Cash flows provided by (used in) investing activities Proceeds from sales and maturities of fixed maturity investments trading 314,568 69,941 145,082 — 7,572,923 8,102,514 Purchases of fixed maturity investments trading (336,345 ) (123,046 ) (291,053 ) — (7,532,276 ) (8,282,720 ) Proceeds from sales and maturities of fixed maturity investments available for sale — — — — 17,692 17,692 Net (purchases) sales of equity investments trading — (2,389 ) 193,022 — (5,845 ) 184,788 Net (purchases) sales of short term investments (111,814 ) 67,684 (32,901 ) — (41,586 ) (118,617 ) Net purchases of other investments — — — — (68,589 ) (68,589 ) Net sales of other assets — — — — 400 400 Dividends and return of capital from subsidiaries 617,239 2,900 — 13,125 (633,264 ) — Contributions to subsidiaries (108,674 ) — — — 108,674 — Due to (from) subsidiary 23,758 (22,313 ) (81 ) 30,202 (31,566 ) — Net cash provided by (used in) investing activities 398,732 (7,223 ) 14,069 43,327 (613,437 ) (164,532 ) Cash flows used in financing activities Dividends paid – RenaissanceRe common shares (51,583 ) — — — — (51,583 ) Dividends paid – preference shares (22,381 ) — — — — (22,381 ) RenaissanceRe common share repurchases (309,434 ) — — — — (309,434 ) Net third party redeemable noncontrolling interest share transactions — — — — (2,990 ) (2,990 ) Taxes paid on withholding shares (14,943 ) — — — — (14,943 ) Net cash used in financing activities (398,341 ) — — — (2,990 ) (401,331 ) Effect of exchange rate changes on foreign currency cash — — — — (4,637 ) (4,637 ) Net (decrease) increase in cash and cash equivalents (3,118 ) (5,746 ) (432 ) 8,720 (85,152 ) (85,728 ) Cash and cash equivalents, beginning of year 10,185 5,908 7,103 677 483,012 506,885 Cash and cash equivalents, end of year $ 7,067 $ 162 $ 6,671 $ 9,397 $ 397,860 $ 421,157 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Effective January 1, 2019, Upsilon RFO issued $456.8 million of non-voting preference shares to investors, including $100.0 million to the Company. Of the total amount, $400.0 million was received by the Company prior to December 31, 2018. At December 31, 2018, $300.0 million , representing the amount received from investors other than the Company prior to December 31, 2018, is included in other liabilities on the Company’s consolidated balance sheet, and also included in other operating cash flows on the Company’s consolidated statements of cash flows for the year ended December 31, 2018. Effective January 1, 2019, the Company’s participation in the risks assumed by Upsilon RFO was 16.9% .

Schedule I. Summary of Investme

Schedule I. Summary of Investments Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Summary of Investments, Other than Investments in Related Parties	SCHEDULE I RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES (THOUSANDS OF UNITED STATES DOLLARS) December 31, 2018 Amortized Cost or Cost Fair Value Amount at which shown in the Balance Sheet Type of investment: Fixed maturity investments U.S. treasuries $ 3,336,969 $ 3,331,411 $ 3,331,411 Agencies 175,185 174,883 174,883 Municipal 6,070 6,854 6,854 Non-U.S. government 284,965 279,818 279,818 Non-U.S. government-backed corporate 160,286 160,063 160,063 Corporate 2,513,434 2,450,244 2,450,244 Agency mortgage-backed 825,365 817,880 817,880 Non-agency mortgage-backed 266,705 278,680 278,680 Commercial mortgage-backed 284,495 282,294 282,294 Asset-backed 310,488 306,743 306,743 Total fixed maturity investments $ 8,163,962 8,088,870 8,088,870 Short term investments 2,586,520 2,586,520 Equity investments 310,252 310,252 Other investments 784,933 784,933 Investments in other ventures, under equity method 115,172 115,172 Total investments $ 11,885,747 $ 11,885,747

Schedule II. Condensed Financia

Schedule II. Condensed Financial Information Of Registrant	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Registrant	SCHEDULE II RENAISSANCERE HOLDINGS LTD. CONDENSED FINANCIAL INFORMATION OF REGISTRANT RENAISSANCERE HOLDINGS LTD. BALANCE SHEETS AT DECEMBER 31, 2018 AND 2017 (PARENT COMPANY) (THOUSANDS OF UNITED STATES DOLLARS) At December 31, 2018 2017 Assets Fixed maturity investments trading, at fair value - amortized cost $238,989 at December 31, 2018 (2017 - $104,521) $ 240,443 $ 103,638 Short term investments, at fair value 72,917 121,628 Cash and cash equivalents 3,534 14,656 Investments in subsidiaries 4,414,475 4,105,760 Due from subsidiaries 57,039 4,602 Accrued investment income 1,046 405 Receivable for investments sold 203 135 Other assets 458,842 433,468 Goodwill and other intangible assets 120,476 124,960 Total assets $ 5,368,975 $ 4,909,252 Liabilities and Shareholders’ Equity Liabilities Notes and bank loans payable $ 300,000 $ 417,000 Due to subsidiaries 6,453 82,579 Other liabilities 17,442 18,298 Total liabilities 323,895 517,877 Shareholders’ Equity Preference shares: $1.00 par value – 16,010,000 shares issued and outstanding at December 31, 2018 (2017 – 16,000,000) 650,000 400,000 Common shares: $1.00 par value – 42,207,390 shares issued and outstanding at December 31, 2018 (2017 – 40,023,789) 42,207 40,024 Additional paid-in capital 296,099 37,355 Accumulated other comprehensive (loss) income (1,433 ) 224 Retained earnings 4,058,207 3,913,772 Total shareholders’ equity 5,045,080 4,391,375 Total liabilities and shareholders’ equity $ 5,368,975 $ 4,909,252 SCHEDULE II RENAISSANCERE HOLDINGS LTD. CONDENSED FINANCIAL INFORMATION OF REGISTRANT – CONTINUED RENAISSANCERE HOLDINGS LTD. STATEMENTS OF OPERATIONS FOR THE YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 (PARENT COMPANY) (THOUSANDS OF UNITED STATES DOLLARS) Year ended December 31, 2018 2017 2016 Revenues Net investment income $ 24,791 $ 23,109 $ 24,178 Net foreign exchange losses (3 ) (1 ) (2 ) Other loss — — (772 ) Net realized and unrealized gains (losses) on investments 633 (1,357 ) 4,151 Total revenues 25,421 21,751 27,555 Expenses Interest expense 5,683 1,572 562 Operational expenses 7,679 11,314 13,716 Corporate expenses 25,190 18,546 26,848 Total expenses 38,552 31,432 41,126 Loss before equity in net income (loss) of subsidiaries (13,131 ) (9,681 ) (13,571 ) Equity in net income (loss) of subsidiaries 240,495 (212,708 ) 516,533 Net income (loss) 227,364 (222,389 ) 502,962 Dividends on preference shares (30,088 ) (22,381 ) (22,381 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 197,276 $ (244,770 ) $ 480,581 RENAISSANCERE HOLDINGS LTD. STATEMENTS OF COMPREHENSIVE INCOME (LOSS) FOR THE YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 (PARENT COMPANY) (THOUSANDS OF UNITED STATES DOLLARS) Year ended December 31, 2018 2017 2016 Comprehensive income (loss) Net income (loss) $ 227,364 $ (222,389 ) $ 502,962 Comprehensive income (loss) available (attributable) to RenaissanceRe $ 227,364 $ (222,389 ) $ 502,962 SCHEDULE II RENAISSANCERE HOLDINGS LTD. CONDENSED FINANCIAL INFORMATION OF REGISTRANT – CONTINUED RENAISSANCERE HOLDINGS LTD. STATEMENTS OF CASH FLOWS FOR THE YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 (PARENT COMPANY) (THOUSANDS OF UNITED STATES DOLLARS) Year ended December 31, 2018 2017 2016 Cash flows used in operating activities: Net income (loss) $ 227,364 $ (222,389 ) $ 502,962 Less: equity in net (income) loss of subsidiaries (240,495 ) 212,708 (516,533 ) (13,131 ) (9,681 ) (13,571 ) Adjustments to reconcile net income (loss) to net cash used in operating activities Net realized and unrealized (gains) losses on investments (633 ) 1,357 (4,151 ) Other 4,105 4,215 14,213 Net cash used in operating activities (9,659 ) (4,109 ) (3,509 ) Cash flows (used in) provided by investing activities: Proceeds from maturities and sales of fixed maturity investments trading 384,818 261,601 314,568 Purchases of fixed maturity investments trading (520,935 ) (344,463 ) (336,345 ) Net sales (purchases) of short term investments 48,600 243,571 (111,814 ) Dividends and return of capital from subsidiaries 672,098 478,496 617,239 Contributions to subsidiaries (785,785 ) (669,672 ) (108,674 ) Due to (from) subsidiary (200,916 ) 319,646 23,758 Net cash (used in) provided by investing activities (402,120 ) 289,179 398,732 Cash flows provided by (used in) financing activities: Dividends paid – RenaissanceRe common shares (52,841 ) (51,370 ) (51,583 ) Dividends paid – preference shares (30,088 ) (22,381 ) (22,381 ) RenaissanceRe common share repurchases — (188,591 ) (309,434 ) RenaissanceRe common share issuance 250,000 — — Issuance of preference shares, net of expenses 241,448 — — Taxes paid on withholding shares (7,862 ) (15,139 ) (14,943 ) Net cash provided by (used in) financing activities 400,657 (277,481 ) (398,341 ) Net (decrease) increase in cash and cash equivalents (11,122 ) 7,589 (3,118 ) Cash and cash equivalents, beginning of year 14,656 7,067 10,185 Cash and cash equivalents, end of year $ 3,534 $ 14,656 $ 7,067

Schedule III. Supplementary Ins

Schedule III. Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Supplementary Insurance Information	SCHEDULE III RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INSURANCE INFORMATION (THOUSANDS OF UNITED STATES DOLLARS) December 31, 2018 Year ended December 31, 2018 Deferred Policy Acquisition Costs Future Policy Benefits, Losses, Claims and Loss Expenses Unearned Premiums Premium Revenue Net Investment Income Benefits, Claims, Losses and Settlement Expenses Amortization of Deferred Policy Acquisition Costs Other Operating Expenses Net Written Premiums Property $ 66,656 $ 3,086,254 $ 379,943 $ 1,050,831 $ — $ 497,895 $ 177,912 $ 112,954 $ 1,055,188 Casualty and Specialty 410,005 2,985,393 1,336,078 925,298 — 622,320 255,079 64,883 1,076,714 Other — 4,624 — — 261,866 (197 ) (2 ) 430 — Total $ 476,661 $ 6,076,271 $ 1,716,021 $ 1,976,129 $ 261,866 $ 1,120,018 $ 432,989 $ 178,267 $ 2,131,902 December 31, 2017 Year ended December 31, 2017 Deferred Future Policy Unearned Premium Net Benefits, Amortization Other Net Written Property $ 63,583 $ 2,486,390 $ 347,032 $ 931,070 $ — $ 1,297,985 $ 113,816 $ 94,194 $ 978,014 Casualty and Specialty 362,968 2,575,492 1,130,577 786,501 — 565,026 233,077 66,548 893,307 Other — 18,526 — 4 222,209 (1,583 ) (1 ) 36 4 Total $ 426,551 $ 5,080,408 $ 1,477,609 $ 1,717,575 $ 222,209 $ 1,861,428 $ 346,892 $ 160,778 $ 1,871,325 December 31, 2016 Year ended December 31, 2016 Deferred Future Policy Unearned Premium Net Benefits, Amortization Other Net Written Property $ 46,938 $ 627,774 $ 289,080 $ 720,951 $ — $ 151,545 $ 97,594 $ 108,642 $ 725,321 Casualty and Specialty 288,387 2,195,126 942,493 682,337 — 380,396 191,729 88,984 809,848 Other — 25,394 — 142 181,726 (1,110 ) — 123 143 Total $ 335,325 $ 2,848,294 $ 1,231,573 $ 1,403,430 $ 181,726 $ 530,831 $ 289,323 $ 197,749 $ 1,535,312

Schedule IV. Supplemental Sched

Schedule IV. Supplemental Schedule of Reinsurance Premiums	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Supplemental Schedule of Reinsurance Premiums	SCHEDULE IV RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTAL SCHEDULE OF REINSURANCE PREMIUMS (THOUSANDS OF UNITED STATES DOLLARS) Gross Amounts Ceded to Other Companies Assumed From Other Companies Net Amount Percentage of Amount Assumed to Net Year ended December 31, 2018 Property and liability premiums earned $ 292,219 $ 1,095,886 $ 2,779,796 $ 1,976,129 141 % Year ended December 31, 2017 Property and liability premiums earned $ 244,285 $ 833,929 $ 2,307,219 $ 1,717,575 134 % Year ended December 31, 2016 Property and liability premiums earned $ 157,112 $ 628,675 $ 1,874,993 $ 1,403,430 134 %

Schedule VI. Supplementary Insu

Schedule VI. Supplementary Insurance Information Concerning Property-Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]
Supplemental Insurance Information Concerning Property-Casualty Insurance Operations	SCHEDULE VI RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES SUPPLEMENTARY INSURANCE INFORMATION CONCERNING PROPERTY-CASUALTY INSURANCE OPERATIONS (THOUSANDS OF UNITED STATES DOLLARS) Affiliation with Registrant Deferred Policy Acquisition Costs Reserves for Unpaid Claims and Claim Adjustment Expenses Discount, if any, Deducted Unearned Premiums Earned Premiums Net Investment Income Consolidated Subsidiaries Year ended December 31, 2018 $ 476,661 $ 6,076,271 $ — $ 1,716,021 $ 1,976,129 $ 261,866 Year ended December 31, 2017 $ 426,551 $ 5,080,408 $ — $ 1,477,609 $ 1,717,575 $ 222,209 Year ended December 31, 2016 $ 335,325 $ 2,848,294 $ — $ 1,231,573 $ 1,403,430 $ 181,726 Claims and Claim Adjustment Expenses Incurred Related to Amortization of Deferred Policy Acquisition Costs Paid Claims and Claim Adjustment Expenses Net Premiums Written Affiliation with Registrant Current Year Prior Year Consolidated Subsidiaries Year ended December 31, 2018 $ 1,390,767 $ (270,749 ) $ 432,989 $ 894,769 $ 2,131,902 Year ended December 31, 2017 $ 1,902,424 $ (40,996 ) $ 346,892 $ 974,825 $ 1,871,325 Year ended December 31, 2016 $ 694,957 $ (164,126 ) $ 289,323 $ 589,294 $ 1,535,312

Significant Accounting Polici_2

Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION These consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated from these statements. Certain comparative information has been reclassified to conform to the current presentation.
Use of Estimates in Financial Statements	USE OF ESTIMATES IN FINANCIAL STATEMENTS The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. The major estimates reflected in the Company’s consolidated financial statements include, but are not limited to, the reserve for claims and claim expenses; reinsurance recoverables, including allowances for reinsurance recoverables deemed uncollectible; estimates of written and earned premiums; fair value, including the fair value of investments, financial instruments and derivatives; impairment charges; and the Company’s deferred tax valuation allowance.
Premiums and Related Expenses	PREMIUMS AND RELATED EXPENSES Premiums are recognized as income, net of any applicable reinsurance or retrocessional coverage purchased, over the terms of the related contracts and policies. Premiums written are based on contract and policy terms and include estimates based on information received from both insureds and ceding companies. Subsequent differences arising on such estimates are recorded in the period in which they are determined. Unearned premiums represent the portion of premiums written that relate to the unexpired terms of contracts and policies in force. Amounts are computed by pro rata methods based on statistical data or reports received from ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written. Acquisition costs are incurred when a contract or policy is issued and only the costs directly related to the successful acquisition of new and renewal contract or policies are deferred and amortized over the same period in which the related premiums are earned. Acquisition costs are shown net of commissions and profit commissions earned on ceded reinsurance, and consist principally of commissions, brokerage and premium tax expenses incurred at the time a contract or policy is issued. Deferred policy acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated claims and claim expenses, based on historical and current experience, and anticipated investment income related to those premiums are considered in determining the recoverability of deferred acquisition costs.
Claims and Claim Expenses	CLAIMS AND CLAIM EXPENSES The reserve for claims and claim expenses includes estimates for unpaid claims and claim expenses on reported losses as well as an estimate of losses incurred but not reported. The reserve is based on individual claims, case reserves and other reserve estimates reported by insureds and ceding companies as well as management estimates of ultimate losses. Inherent in the estimates of ultimate losses are expected trends in claim severity and frequency and other factors which could vary significantly as claims are settled. Also, during the past few years, the Company has increased its casualty and specialty reinsurance businesses, but does not have the benefit of a significant amount of its own historical experience in certain of these lines of business. Accordingly, the reserving for incurred losses in these lines of business could be subject to greater variability. Ultimate losses may vary materially from the amounts provided in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, are reflected in the consolidated statements of operations in the period in which they become known and are accounted for as changes in estimates.
Reinsurance	REINSURANCE Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. For multi-year retrospectively rated contracts, the Company accrues amounts (either assets or liabilities) that are due to or from assuming companies based on estimated contract experience. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the period in which they are determined. Reinsurance recoverables on dual trigger reinsurance contracts require the Company to estimate its ultimate losses applicable to these contracts as well as estimate the ultimate amount of insured industry losses that will be reported by the applicable statistical reporting agency, as per the contract terms. Amounts recoverable from reinsurers are recorded net of a valuation allowance for estimated uncollectible recoveries. Assumed and ceded reinsurance contracts that lack a significant transfer of risk are treated as deposits. Certain assumed and ceded reinsurance contracts that do not meet all of the criteria to be accounted for as reinsurance in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic Financial Services - Insurance have been accounted for at fair value under the fair value option in accordance with FASB ASC Topic Financial Instruments.
Fixed Maturity Investments, Short Term Investments and Equity Investments, Classified as Trading	INVESTMENTS, CASH AND CASH EQUIVALENTS Fixed Maturity Investments Investments in fixed maturities are classified as trading or available for sale and are reported at fair value. Investment transactions are recorded on the trade date with balances pending settlement reflected in the balance sheet as a receivable for investments sold or a payable for investments purchased. Net investment income includes interest and dividend income together with amortization of market premiums and discounts and is net of investment management and custody fees. The amortization of premium and accretion of discount for fixed maturity securities is computed using the effective yield method. For mortgage-backed securities and other holdings for which there is prepayment risk, prepayment assumptions are evaluated quarterly and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments. Fair values of investments are based on quoted market prices, or when such prices are not available, by reference to broker or underwriter bid indications and/or internal pricing valuation techniques. The net unrealized appreciation or depreciation on fixed maturity investments trading is included in net realized and unrealized gains (losses) on investments in the consolidated statements of operations. The net unrealized appreciation or depreciation on fixed maturity investments available for sale is included in accumulated other comprehensive income. Realized gains or losses on the sale of investments are determined on the basis of the first in first out cost method and, for fixed maturity investments available for sale, include adjustments to the cost basis of investments for declines in value that are considered to be other-than-temporary. Short Term Investments Short term investments, which are managed as part of the Company’s investment portfolio and have a maturity of one year or less when purchased, are carried at fair value. The net unrealized appreciation or depreciation on short term investments is included in net realized and unrealized gains on investments in the consolidated statements of operations. Equity Investments, Classified as Trading Equity investments are accounted for at fair value in accordance with FASB ASC Topic Financial Instruments. Fair values are primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. Net investment income includes dividend income and the net realized and unrealized appreciation or depreciation on equity investments is included in net realized and unrealized gains (losses) on investments in the consolidated statements of operations.
Other Investments	Other Investments The Company accounts for its other investments at fair value in accordance with FASB ASC Topic Financial Instruments with interest, dividend income, income distributions and realized and unrealized gains and losses included in net investment income. The fair value of certain of the Company’s fund investments, which principally include private equity investments, senior secured bank loan funds and hedge funds, is recorded on its balance sheet in other investments, and is generally established on the basis of the net valuation criteria established by the managers of such investments, if applicable. The net valuation criteria established by the managers of such investments is established in accordance with the governing documents of such investments. Certain of the Company’s fund managers, fund administrators, or both, are unable to provide final fund valuations as of the Company’s current reporting date. The typical reporting lag experienced by the Company to receive a final net asset value report is one month for hedge funds and senior secured bank loan funds and three months for private equity investments, although, in the past, in respect of certain of the Company’s private equity investments, the Company has on occasion experienced delays of up to six months at year end, as the private equity investments typically complete their respective year-end audits before releasing their final net asset value statements. In circumstances where there is a reporting lag between the current period end reporting date and the reporting date of the latest fund valuation, the Company estimates the fair value of these funds by starting with the prior month or quarter-end fund valuations, adjusting these valuations for actual capital calls, redemptions or distributions, as well as the impact of changes in foreign currency exchange rates, and then estimating the return for the current period. In circumstances in which the Company estimates the return for the current period, all information available to the Company is utilized. This principally includes preliminary estimates reported to the Company by its fund managers, obtaining the valuation of underlying portfolio investments where such underlying investments are publicly traded and therefore have a readily observable price, using information that is available to the Company with respect to the underlying investments, reviewing various indices for similar investments or asset classes, as well as estimating returns based on the results of similar types of investments for which the Company has obtained reported results, or other valuation methods, where possible. Actual final fund valuations may differ, perhaps materially so, from the Company’s estimates and these differences are recorded in the Company’s statement of operations in the period in which they are reported to the Company as a change in estimate. The Company’s other investments also include investments in catastrophe bonds which are recorded at fair value and the fair value is based on broker or underwriter bid indications.
Investments in Other Ventures, Under Equity Method	Investments in Other Ventures, Under Equity Method Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in other ventures, under equity method, and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period. Any decline in value of investments in other ventures, under equity method considered by management to be other-than-temporary is charged to income in the period in which it is determined.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents include money market instruments with a maturity of ninety days or less when purchased.
Stock Incentive Compensation	STOCK INCENTIVE COMPENSATION The Company is authorized to issue restricted stock awards and units, performance shares, stock options and other equity-based awards to its employees and directors. The fair value of the compensation cost is measured at the grant date and expensed over the period for which the employee is required to provide services in exchange for the award. In addition, the Company is authorized to issue cash settled restricted stock units (“CSRSU”) to its employees. The fair value of CSRSUs is determined using the fair market value of RenaissanceRe common shares at the end of each reporting period and is expensed over the period for which the employee is required to provide service in exchange for the award. The fair value of these awards is recorded on the Company’s consolidated balance sheet as a liability as it is expensed and until the point payment is made to the employee. The Company has elected to recognize forfeitures as they occur rather than estimating service-based forfeitures over the requisite service period.
Derivatives	DERIVATIVES The Company enters into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts in order to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company accounts for its derivatives in accordance with FASB ASC Topic Derivatives and Hedging , which requires all derivatives to be recorded at fair value on the Company’s balance sheet as either assets or liabilities, depending on their rights or obligations, with changes in fair value reflected in current earnings. The Company does not currently apply hedge accounting. The fair value of the Company’s derivatives is estimated by reference to quoted prices or broker quotes, where available, or in the absence of quoted prices or broker quotes, the use of industry or internal valuation models.
Fair Value	FAIR VALUE The Company accounts for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurement s and Disclosures . The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income in shareholders’ equity. The use of fair value to measure certain assets and liabilities with resulting unrealized gains or losses is pervasive within the Company’s consolidated financial statements. Fair value is defined under accounting guidance currently applicable to the Company to be the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between open market participants at the measurement date. The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its consolidated statements of operations. FASB ASC Topic Fair Value Measurements and Disclosures prescribes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to valuation techniques that use at least one significant input that is unobservable (Level 3). The three levels of the fair value hierarchy are described below: • Fair values determined by Level 1 inputs utilize unadjusted quoted prices obtained from active markets for identical assets or liabilities for which the Company has access. The fair value is determined by multiplying the quoted price by the quantity held by the Company; • Fair values determined by Level 2 inputs utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals, broker quotes and certain pricing indices; and • Level 3 inputs are based all or in part on significant unobservable inputs for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In these cases, significant management assumptions can be used to establish management’s best estimate of the assumptions used by other market participants in determining the fair value of the asset or liability. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement of the asset or liability. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and the Company considers factors specific to the asset or liability. In order to determine if a market is active or inactive for a security, the Company considers a number of factors, including, but not limited to, the spread between what a seller is asking for a security and what a buyer is bidding for the same security, the volume of trading activity for the security in question, the price of the security compared to its par value (for fixed maturity investments), and other factors that may be indicative of market activity. There have been no material changes in the Company’s valuation techniques, nor have there been any transfers between Level 1 and Level 2, or Level 2 and Level 3 during the period represented by these consolidated financial statements.
Business Combinations	The Company accounts for business combinations in accordance with FASB ASC Topic Business Combinations , and goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles – Goodwill and Other .
Goodwill and Other Intangible Assets	A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill, and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful life of the asset. Other intangible assets with an indefinite useful life are not amortized. Goodwill and other indefinite life intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable. Finite life intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable, and tested for impairment if appropriate. For purposes of the annual impairment evaluation, goodwill is assigned to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill and other intangible assets recorded in connection with investments accounted for under the equity method, are recorded as “Investments in other ventures, under equity method” on the Company’s consolidated balance sheets. The Company has established the beginning of the fourth quarter as the date for performing its annual impairment tests. The Company has the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative goodwill impairment test. Under this option, the Company would not be required to calculate the fair value of a reporting unit unless the Company determines, based on its qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. If goodwill or other intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense reflected in the Company’s consolidated statements of operations.
Noncontrolling Interests	NONCONTROLLING INTERESTS The Company accounts for redeemable noncontrolling interests in the mezzanine section of the Company’s consolidated balance sheet in accordance with United States Securities and Exchange Commission (“SEC”) guidance which is applicable to SEC registrants. The SEC guidance requires shares, not required to be accounted for in accordance with FASB ASC Topic Distinguishing Liabilities from Equity , and having redemption features that are not solely within the control of the issuer, to be classified outside of permanent equity in the mezzanine section of the balance sheet. Because the share classes related to the redeemable noncontrolling interest portion of the issuer are not considered liabilities in accordance with FASB ASC Topic Distinguishing Liabilities from Equity and have redemption features that are not solely within the control of the issuer, the redeemable noncontrolling interests are presented in the mezzanine section on the Company’s consolidated balance sheet in accordance with the SEC guidance noted above. The SEC guidance does not impact the accounting for redeemable noncontrolling interest on the consolidated statements of operations; therefore, the provisions of FASB ASC Topic Consolidation with respect to the consolidated statements of operations still apply, and net income attributable to redeemable noncontrolling interests is presented separately in the Company’s consolidated statements of operations.
Variable Interest Entities	VARIABLE INTEREST ENTITIES The Company accounts for VIEs in accordance with FASB ASC Topic Consolidation , which requires the consolidation of all VIEs by the primary beneficiary, that being the investor that has the power to direct the activities of the VIE and that will absorb a portion of the VIE’s expected losses or residual returns that could potentially be significant to the VIE. For VIEs the Company determines it has a variable interest in, it determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment.
Earnings Per Share	EARNINGS PER SHARE The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share. Basic earnings per share are based on weighted average common shares and exclude any dilutive effects of options and restricted stock. Diluted earnings per share assumes the exercise of all dilutive stock options and restricted stock grants. The two-class method is used to determine earnings per share based on dividends declared on common shares and participating securities (i.e., distributed earnings) and participation rights of participating securities in any undistributed earnings. Each unvested restricted share granted by the Company to its employees is considered a participating security and the Company uses the two-class method to calculate its net income available to RenaissanceRe common shareholders per common share – basic and diluted.
Foreign Exchange	FOREIGN EXCHANGE The Company’s functional currency is the U.S. dollar. Revenues and expenses denominated in foreign currencies are revalued at the prevailing exchange rate at the transaction date. Monetary assets and liabilities denominated in foreign currencies are remeasured at exchange rates in effect at the balance sheet date, which may result in the recognition of exchange gains or losses which are included in the determination of net income.
Taxation	TAXATION Income taxes have been provided for in accordance with the provisions of FASB ASC Topic Income Taxes . Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the consolidated financial statements and the tax basis of the Company’s assets and liabilities. Such temporary differences are primarily due to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to interest expense, underwriting results, accrued expenses and investments. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to deferred tax assets will not be realized.
Taxation, Uncertainties	Uncertain tax positions are also accounted for in accordance with FASB ASC Topic Income Taxes . Uncertain tax positions must meet a more likely than not recognition threshold to be recognized.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted	RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 was issued to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, treatment of forfeitures, classification of awards as either equity or liabilities, and the classification of taxes paid on the statements of cash flows. ASU 2016-09 became effective for the Company in annual and interim periods beginning after December 15, 2016. The cumulative effect of the adoption of ASU 2016-09 was a $2.2 million increase to opening retained earnings as of January 1, 2017. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also provides guidance on accounting for certain contract costs and had also required new disclosures. ASU 2014-09 was to be effective for public business entities in annual and interim periods beginning after December 15, 2016, however in July 2015, the FASB decided to defer by one year the effective dates of ASU 2014-09, and as a result, ASU 2014-09 is effective for public business entities in annual and interim periods beginning after December 15, 2017. ASU 2014-09 notably excludes the accounting for insurance contracts, leases, financial instruments and guarantees. As a result, the Company’s implementation efforts primarily focused on other income and operational expenses on its consolidated statements of operations. The adoption of ASU 2014-09 did not have a material impact on the Company’s consolidated statements of operations and financial position. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or those that result in the consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option, requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and clarifies that the reporting organization should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the organization’s other deferred tax assets. ASU 2016-01 is effective for public business entities in annual and interim periods beginning after December 15, 2017. The adoption of ASU 2016-01 did not have a material impact on the Company’s consolidated statements of operations and financial position. Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 clarifies the classification of receipts and payments in the statement of cash flows. ASU 2016-15 provides guidance related to (1) settlement and payment of zero coupon debt instruments, (2) contingent consideration, (3) proceeds from settlement of insurance claims, (4) proceeds from settlement of corporate and bank owned life insurance policies, (5) distributions from equity method investees, (6) cash receipts from beneficial interests obtained by a transferor, and (7) general guidelines for cash receipts and payments that have more than one aspect of classification. ASU 2016-15 is effective for public business entities for annual periods beginning after December 15, 2017, and interim periods within those fiscal years. The adoption of ASU 2016-15 resulted in the reclassification of $20.0 million of cash inflows from cash flows provided by operating activities, to cash flows used in investing activities for 2017 . This amount related to a return of investment associated with the Company’s investment in Top Layer Reinsurance Ltd, recorded under the equity method of accounting. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 requires lessees to recognize lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under previous guidance. ASU 2016-02 is effective for public business entities for annual and interim periods beginning after December 15, 2018. Early application is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 modifies the recognition of credit losses by replacing the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 is applicable to financial assets such as loans, debt securities, trade receivables, off-balance sheet credit exposures, reinsurance receivables, and other financial assets that have the contractual right to receive cash. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The Company's invested assets are measured at fair value through net income, and therefore those invested assets would not be impacted by the adoption of ASU 2016-13. The Company has other financial assets, such as reinsurance recoverables, that could be impacted by the adoption of ASU 2016-13. ASU 2016-13 is effective for public business entities that are SEC filers for annual and interim periods beginning after December 15, 2019. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Intra-Entity Transfers of Assets Other Than Inventory In October 2016, the FASB issued ASU No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). ASU 2016-16 requires entities to recognize the income tax consequences of intra-entity transfers of assets other than inventory when the transfers occur; this is a change from current guidance which prohibits the recognition of current and deferred income taxes until the underlying assets have been sold to outside entities. ASU 2016-16 is effective for public business entities for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position. Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). Among other things, ASU 2017-04 requires the following: (1) the elimination of step two of the goodwill impairment test; entities will no longer utilize the implied fair value of their assets and liabilities for purposes of testing goodwill for impairment, (2) the quantitative portion of the goodwill impairment test will be performed by comparing the fair value of a reporting unit with its carrying amount; an impairment charge is to be recognized for the excess of carrying amount over fair value, but only to the extent of the amount of goodwill allocated to that reporting unit, and (3) foreign currency translation adjustments are not to be allocated to a reporting unit from an entity’s accumulated other comprehensive income; the reporting unit’s carrying amount should include only the currently translated balances of the assets and liabilities assigned to the reporting unit. ASU 2017-04 is effective for public business entities that are SEC filers for annual periods, or any interim goodwill impairment tests in annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Goodwill	The following table shows an analysis of goodwill and other intangible assets: Goodwill and other intangible assets Goodwill Other intangible assets Total Balance as of December 31, 2016 Gross amount $ 199,889 $ 96,599 $ 296,488 Accumulated impairment losses and amortization (2,299 ) (43,003 ) (45,302 ) 197,590 53,596 251,186 Amortization — (8,041 ) (8,041 ) Balance as of December 31, 2017 Gross amount 199,889 96,599 296,488 Accumulated impairment losses and amortization (2,299 ) (51,044 ) (53,343 ) 197,590 45,555 243,145 Amortization — (5,727 ) (5,727 ) Balance as of December 31, 2018 Gross amount 199,889 96,599 296,488 Accumulated impairment losses and amortization (2,299 ) (56,771 ) (59,070 ) $ 197,590 $ 39,828 $ 237,418
Schedule of Goodwill and Other Intangible Assets Included In Equity Method Investments	The following table shows an analysis of goodwill and other intangible assets included in investments in other ventures, under equity method: Goodwill and other intangible assets included in investments in other ventures, under equity method Goodwill Other intangible assets Total Balance as of December 31, 2016 Gross amount $ 12,318 $ 51,796 $ 64,114 Accumulated impairment losses and amortization (4,500 ) (39,934 ) (44,434 ) 7,818 11,862 19,680 Amortization — (2,946 ) (2,946 ) Balance as of December 31, 2017 Gross amount 12,318 51,796 64,114 Accumulated impairment losses and amortization (4,500 ) (42,880 ) (47,380 ) 7,818 8,916 16,734 Acquired during the year 2,780 11,108 13,888 Amortization — (2,886 ) (2,886 ) Balance as of December 31, 2018 Gross amount 15,098 62,904 78,002 Accumulated impairment losses and amortization (4,500 ) (45,766 ) (50,266 ) $ 10,598 $ 17,138 $ 27,736
Schedule of Other Intangible Assets By Major Class	The gross carrying value and accumulated amortization by major category of other intangible assets is shown below: Other intangible assets At December 31, 2018 Gross carrying value Accumulated amortization and impairment losses Total Customer relationships and customer lists $ 97,419 $ (60,221 ) $ 37,198 Value of business acquired 20,200 (20,200 ) — Software 12,230 (12,230 ) — Licenses 19,414 — 19,414 Patents and intellectual property 4,500 (4,500 ) — Covenants not-to-compete 4,030 (4,030 ) — Trademarks and trade names 1,710 (1,356 ) 354 $ 159,503 $ (102,537 ) $ 56,966 Other intangible assets At December 31, 2017 Gross carrying value Accumulated amortization and impairment losses Total Customer relationships and customer lists $ 95,458 $ (51,633 ) $ 43,825 Value of business acquired 20,200 (20,200 ) — Software 12,230 (12,230 ) — Licenses 10,267 — 10,267 Patents and intellectual property 4,500 (4,500 ) — Covenants not-to-compete 4,030 (4,030 ) — Trademarks and trade names 1,710 (1,331 ) 379 $ 148,395 $ (93,924 ) $ 54,471
Schedule of Expected Amortization Expense	Expected amortization of the other intangible assets, including other intangible assets recorded in investments in other ventures, under equity method, is shown below: Other intangibles Other intangible assets included in investments in other ventures, under equity method Total 2019 $ 5,446 $ 2,815 $ 8,261 2020 5,237 1,955 7,192 2021 4,910 1,095 6,005 2022 4,522 1,095 5,617 2023 4,093 631 4,724 2024 and thereafter 5,353 400 5,753 Total remaining amortization expense 29,561 7,991 37,552 Indefinite lived 10,267 9,147 19,414 Total $ 39,828 $ 17,138 $ 56,966

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments [Abstract]
Schedule of Fair Value of Fixed Maturity Investments Trading	The following table summarizes the fair value of fixed maturity investments trading: December 31, December 31, U.S. treasuries $ 3,331,411 $ 3,168,763 Agencies 174,883 47,646 Municipal 6,854 509,802 Non-U.S. government 279,818 287,660 Non-U.S. government-backed corporate 160,063 163,651 Corporate 2,450,244 2,063,459 Agency mortgage-backed 817,880 500,456 Non-agency mortgage-backed 278,680 300,331 Commercial mortgage-backed 282,294 202,062 Asset-backed 306,743 182,725 Total fixed maturity investments trading $ 8,088,870 $ 7,426,555 The following table summarizes the fair value of equity investments trading: December 31, December 31, Financials $ 200,357 $ 253,543 Communications and technology 42,333 49,526 Industrial, utilities and energy 24,520 34,325 Consumer 20,639 24,779 Healthcare 18,925 21,364 Basic materials 3,478 4,717 Total $ 310,252 $ 388,254
Schedule of Contractual Maturities of Fixed Maturity Investments	Contractual maturities of fixed maturity investments trading are described in the following table. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. At December 31, 2018 Amortized Cost Fair Value Due in less than one year $ 511,932 $ 507,728 Due after one through five years 4,799,196 4,762,712 Due after five through ten years 1,086,697 1,056,087 Due after ten years 79,084 76,746 Mortgage-backed 1,376,565 1,378,854 Asset-backed 310,488 306,743 Total $ 8,163,962 $ 8,088,870
Schedule of Net Investment Income	The components of net investment income are as follows: Year ended December 31, 2018 2017 2016 Fixed maturity investments $ 211,973 $ 179,624 $ 160,661 Short term investments 33,571 11,082 5,127 Equity investments 4,474 3,628 4,235 Other investments Private equity investments 477 33,999 6,155 Other 22,475 8,067 20,181 Cash and cash equivalents 3,810 1,196 788 276,780 237,596 197,147 Investment expenses (14,914 ) (15,387 ) (15,421 ) Net investment income $ 261,866 $ 222,209 $ 181,726
Schedule of Net Realized and Unrealized Gains (Losses) On Investments and Net Other-Than-Temporary Impairments	Net realized and unrealized (losses) gains on investments are as follows: Year ended December 31, 2018 2017 2016 Gross realized gains $ 21,284 $ 49,121 $ 72,739 Gross realized losses (91,098 ) (38,832 ) (38,315 ) Net realized (losses) gains on fixed maturity investments (69,814 ) 10,289 34,424 Net unrealized (losses) gains on fixed maturity investments trading (57,310 ) 8,479 26,954 Net realized and unrealized losses on investments-related derivatives (8,784 ) (2,490 ) (15,414 ) Net realized gains on equity investments trading sold during the period 27,739 80,027 14,190 Net unrealized (losses) gains on equity investments trading still held at reporting date (66,900 ) 39,517 81,174 Net realized and unrealized (losses) gains on equity investments trading (39,161 ) 119,544 95,364 Net realized and unrealized (losses) gains on investments $ (175,069 ) $ 135,822 $ 141,328
Schedule of Other Investments	The table below shows the fair value of the Company’s portfolio of other investments: At December 31, 2018 2017 Catastrophe bonds $ 516,571 $ 380,475 Private equity investments 242,647 196,220 Senior secured bank loan funds 14,482 17,574 Hedge funds 11,233 524 Total other investments $ 784,933 $ 594,793
Schedule of Equity Method Investments	The table below shows the Company’s portfolio of investments in other ventures, under equity method: 2018 2017 At December 31, Investment Ownership % Carrying Value Investment Ownership % Carrying Value Tower Hill Companies 64,750 24.9 % 38,241 64,750 26.3 % 42,167 Top Layer Re 65,375 50.0 % 46,562 65,375 50.0 % 50,211 Other 35,862 30.6 % 30,369 13,650 40.4 % 9,596 Total investments in other ventures, under equity method $ 165,987 $ 115,172 $ 143,775 $ 101,974
Schedule of Equity In Earnings of Equity Method Investments	The table below shows the Company’s equity in earnings of other ventures, under equity method: Year ended December 31, 2018 2017 2016 Tower Hill Companies $ 9,605 $ (1,647 ) $ 10,379 Top Layer Re 8,852 9,851 (8,576 ) Other 17 (174 ) (840 ) Total equity in earnings of other ventures $ 18,474 $ 8,030 $ 963

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Below is a summary of the assets and liabilities that are measured at fair value on a recurring basis and also represents the carrying amount on the Company’s consolidated balance sheets: At December 31, 2018 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fixed maturity investments U.S. treasuries $ 3,331,411 $ 3,331,411 $ — $ — Agencies 174,883 — 174,883 — Municipal 6,854 — 6,854 — Non-U.S. government 279,818 — 279,818 — Non-U.S. government-backed corporate 160,063 — 160,063 — Corporate 2,450,244 — 2,450,244 — Agency mortgage-backed 817,880 — 817,880 — Non-agency mortgage-backed 278,680 — 278,680 — Commercial mortgage-backed 282,294 — 282,294 — Asset-backed 306,743 — 306,743 — Total fixed maturity investments 8,088,870 3,331,411 4,757,459 — Short term investments 2,586,520 — 2,586,520 — Equity investments trading 310,252 310,252 — — Other investments Catastrophe bonds 516,571 — 516,571 — Private equity investments (1) 242,647 — — 54,545 Senior secured bank loan funds (1) 14,482 — — — Hedge funds (1) 11,233 — — — Total other investments 784,933 — 516,571 54,545 Other assets and (liabilities) Assumed and ceded (re)insurance contracts (2) (8,359 ) — — (8,359 ) Derivatives (3) 12,399 484 11,915 — Total other assets and (liabilities) 4,040 484 11,915 (8,359 ) $ 11,774,615 $ 3,642,147 $ 7,872,465 $ 46,186 (1) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (2) Included in assumed and ceded (re)insurance contracts at December 31, 2018 was $5.0 million and $13.3 million of other assets and other liabilities, respectively. (3) See “Note 18 . Derivative Instruments” for additional information related to the fair value, by type of contract, of derivatives entered into by the Company. At December 31, 2017 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fixed maturity investments U.S. treasuries $ 3,168,763 $ 3,168,763 $ — $ — Agencies 47,646 — 47,646 — Municipal 509,802 — 509,802 — Non-U.S. government 287,660 — 287,660 — Non-U.S. government-backed corporate 163,651 — 163,651 — Corporate 2,063,459 — 2,063,459 — Agency mortgage-backed 500,456 — 500,456 — Non-agency mortgage-backed 300,331 — 300,331 — Commercial mortgage-backed 202,062 — 202,062 — Asset-backed 182,725 — 182,725 — Total fixed maturity investments 7,426,555 3,168,763 4,257,792 — Short term investments 991,863 — 991,863 — Equity investments trading 388,254 388,254 — — Other investments Catastrophe bonds 380,475 — 380,475 — Private equity investments (1) 196,220 — — — Senior secured bank loan fund (1) 17,574 — — — Hedge funds (1) 524 — — — Total other investments 594,793 — 380,475 — Other assets and (liabilities) Assumed and ceded (re)insurance contracts (2) (2,952 ) — — (2,952 ) Derivatives (3) 4,636 (45 ) 4,681 — Total other assets and (liabilities) 1,684 (45 ) 4,681 (2,952 ) $ 9,403,149 $ 3,556,972 $ 5,634,811 $ (2,952 ) (1) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (2) Included in assumed and ceded (re)insurance contracts at December 31, 2017 was $2.5 million and $5.5 million of other assets and other liabilities, respectively. (2) See “Note 18 . Derivative Instruments” for additional information related to the fair value, by type of contract, of derivatives entered into by the Company.
Schedule of Quantitative Information Used as Level 3 Inputs	Below is a summary of quantitative information regarding the significant observable and unobservable inputs (Level 3) used in determining the fair value of assets and liabilities measured at fair value on a recurring basis: December 31, 2018 Fair Value Valuation Technique Unobservable Inputs Low High Weighted Average or Actual Other investments Private equity investments $ 54,545 Internal valuation model Discount rate 16.8 % 29.6 % 23.2 % Total other investments 54,545 Other assets and (liabilities) Assumed and ceded (re)insurance contracts 550 Internal valuation model Bond price $ 100.74 $ 107.82 $ 104.66 Liquidity discount n/a n/a 1.3 % Assumed and ceded (re)insurance contracts (8,909 ) Internal valuation model Net undiscounted cash flows n/a n/a $ (10,528 ) Expected loss ratio n/a n/a 36.1 % Discount rate n/a n/a 2.5 % Total other assets and (liabilities) $ (8,359 ) $ 46,186
Schedule of Assets and Liabilities Measured at Fair Value an a Recurring Basis Using Level 3 Inputs	Below is a reconciliation of the beginning and ending balances, for the periods shown, of assets and liabilities measured at fair value on a recurring basis using Level 3 inputs. Interest and dividend income are included in net investment income and are excluded from the reconciliation. Other investments Other assets and (liabilities) Total Balance - January 1, 2018 $ — $ (2,952 ) $ (2,952 ) Total realized and unrealized gains Included in other income — 2,901 2,901 Purchases 54,545 (9,291 ) 45,254 Settlements — 983 983 Balance - December 31, 2018 $ 54,545 $ (8,359 ) $ 46,186 Other assets and (liabilities) Balance - January 1, 2017 $ (13,004 ) Total realized and unrealized gains Included in other income 3,761 Purchases 354 Settlements 5,937 Balance - December 31, 2017 $ (2,952 )
Schedule of Assets and Liabilities Measured at Fair Value an a Recurring Basis Using Level 3 Inputs	Below is a reconciliation of the beginning and ending balances, for the periods shown, of assets and liabilities measured at fair value on a recurring basis using Level 3 inputs. Interest and dividend income are included in net investment income and are excluded from the reconciliation. Other investments Other assets and (liabilities) Total Balance - January 1, 2018 $ — $ (2,952 ) $ (2,952 ) Total realized and unrealized gains Included in other income — 2,901 2,901 Purchases 54,545 (9,291 ) 45,254 Settlements — 983 983 Balance - December 31, 2018 $ 54,545 $ (8,359 ) $ 46,186 Other assets and (liabilities) Balance - January 1, 2017 $ (13,004 ) Total realized and unrealized gains Included in other income 3,761 Purchases 354 Settlements 5,937 Balance - December 31, 2017 $ (2,952 )
Schedule of the Balances the Company has Elected to Account for at Fair Value	Below is a summary of the balances the Company has elected to account for at fair value: 2018 2017 Other investments $ 784,933 $ 594,793 Other assets $ 4,968 $ 2,542 Other liabilities $ 13,327 $ 5,494
Schedule of Other Investments Measured Using Net Asset Valuations	The table below shows the Company’s portfolio of other investments measured using net asset valuations as a practical expedient: At December 31, 2018 Fair Value Unfunded Redemption Frequency Redemption Redemption Private equity investments $ 188,102 $ 393,700 See below See below See below Senior secured bank loan funds 14,482 20,121 See below See below See below Hedge funds 11,233 — See below See below See below Total other investments measured using net asset valuations $ 213,817 $ 413,821

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Schedule of Effect of Reinsurance and Retrocessional Activity on Premiums Written and Earned and on Net Claims and Claim Expenses Incurred	The following table sets forth the effect of reinsurance and retrocessional activity on premiums written and earned and on net claims and claim expenses incurred: Year ended December 31, 2018 2017 2016 Premiums written Direct $ 337,587 $ 290,730 $ 208,282 Assumed 2,972,840 2,506,810 2,166,294 Ceded (1,178,525 ) (926,215 ) (839,264 ) Net premiums written $ 2,131,902 $ 1,871,325 $ 1,535,312 Premiums earned Direct $ 292,219 $ 244,285 $ 157,112 Assumed 2,779,796 2,307,219 1,874,993 Ceded (1,095,886 ) (833,929 ) (628,675 ) Net premiums earned $ 1,976,129 $ 1,717,575 $ 1,403,430 Claims and claim expenses Gross claims and claim expenses incurred $ 2,578,536 $ 3,420,388 $ 710,651 Claims and claim expenses recovered (1,458,518 ) (1,558,960 ) (179,820 ) Net claims and claim expenses incurred $ 1,120,018 $ 1,861,428 $ 530,831

Reserve for Claims and Claim _2

Reserve for Claims and Claim Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Schedule of Liability for Unpaid Claims and Claim Expenses	The following table details the development of the Company’s liability for unpaid claims and claim expenses for its Casualty and Specialty segment: Year ended December 31, 2018 2017 2016 (Favorable) adverse development (Favorable) adverse development (Favorable) adverse development Actuarial methods - actual reported claims less than expected claims $ (41,476 ) $ (24,836 ) $ (52,601 ) Ogden Rate change — 33,481 — Actuarial assumption changes (7,786 ) (2,462 ) (5,539 ) Total (favorable) adverse development of prior accident years net claims and claim expenses $ (49,262 ) $ 6,183 $ (58,140 ) The following tables and discussion detail the development of the Company’s liability for unpaid claims and claim expenses for its Property segment, allocated between large and small catastrophe net claims and claim expenses and attritional net claims and claim expenses, included in the other line item: Year ended December 31, 2018 (Favorable) adverse development Catastrophe net claims and claim expenses Large catastrophe events 2017 Large Loss Events $ (172,512 ) Other (9,517 ) Total large catastrophe events (182,029 ) Small catastrophe events and attritional loss movements Other small catastrophe events and attritional loss movements (33,579 ) Total small catastrophe events and attritional loss movements (33,579 ) Total catastrophe and attritional net claims and claim expenses (215,608 ) Actuarial assumption changes (5,682 ) Total net favorable development of prior accident years net claims and claim expenses $ (221,290 ) The reconciliation of the net incurred and paid claims development tables to the reserve for claims and claim expenses in the consolidated balance sheet is as follows: At December 31, 2018 Net reserve for claims and claim expenses Property $ 1,373,125 Casualty and Specialty 2,330,557 Other 368 Total net reserve for claims and claim expenses 3,704,050 Reinsurance recoverable Property $ 1,713,129 Casualty and Specialty 654,836 Other 4,256 Total reinsurance recoverable 2,372,221 Total gross reserve for claims and claim expenses $ 6,076,271 Year ended December 31, 2016 (Favorable) adverse development Catastrophe net claims and claim expenses Large catastrophe events Thailand Floods (2011) $ (15,131 ) Storm Sandy (2012) (10,849 ) Tohoku Earthquake and Tsunami (2011) (7,314 ) New Zealand Earthquake (2011) 1,987 New Zealand Earthquake (2010) 6,904 Other (9,523 ) Total large catastrophe events (33,926 ) Small catastrophe events and attritional loss movements Tianjin Explosion (2015) (5,686 ) Other small catastrophe events and attritional loss movements (65,264 ) Total small catastrophe events and attritional loss movements (70,950 ) Total catastrophe and attritional net claims and claim expenses (104,876 ) Total net favorable development of prior accident years net claims and claim expenses $ (104,876 ) Year ended December 31, 2017 (Favorable) adverse development Catastrophe net claims and claim expenses Large catastrophe events Storm Sandy (2012) $ (4,395 ) April and May U.S. Tornadoes (2011) (4,177 ) New Zealand Earthquake (2010) 4,061 New Zealand Earthquake (2011) 5,807 Other (8,936 ) Total large catastrophe events (7,640 ) Small catastrophe events and attritional loss movements Tianjin Explosion (2015) (8,002 ) Fort McMurray Wildfire (2016) (6,364 ) Other small catastrophe events and attritional loss movements (24,432 ) Total small catastrophe events and attritional loss movements (38,798 ) Total catastrophe and attritional net claims and claim expenses (46,438 ) Actuarial assumption changes 842 Total net favorable development of prior accident years net claims and claim expenses $ (45,596 ) The following table details the development of the Company’s liability for unpaid claims and claim expenses for its Other category: Year ended December 31, 2018 2017 2016 (Favorable) adverse development (Favorable) adverse development (Favorable) adverse development Other $ (197 ) $ (1,583 ) $ (1,110 ) The following table details the Company’s prior year development by segment of its liability for unpaid claims and claim expenses: Year ended December 31, 2018 2017 2016 (Favorable) adverse development (Favorable) adverse development (Favorable) adverse development Property $ (221,290 ) $ (45,596 ) $ (104,876 ) Casualty and Specialty (49,262 ) 6,183 (58,140 ) Other (197 ) (1,583 ) (1,110 ) Total favorable development of prior accident years net claims and claim expenses $ (270,749 ) $ (40,996 ) $ (164,126 ) The following table summarizes the Company’s claims and claim expense reserves by segment, allocated between case reserves, additional case reserves and IBNR: At December 31, 2018 Case Reserves Additional Case Reserves IBNR Total Property $ 690,718 $ 1,308,307 $ 1,087,229 $ 3,086,254 Casualty and Specialty 771,537 116,877 2,096,979 2,985,393 Other 1,458 — 3,166 4,624 Total $ 1,463,713 $ 1,425,184 $ 3,187,374 $ 6,076,271 At December 31, 2017 Property $ 696,285 $ 896,522 $ 893,583 $ 2,486,390 Casualty and Specialty 689,962 124,923 1,760,607 2,575,492 Other 6,605 — 11,921 18,526 Total $ 1,392,852 $ 1,021,445 $ 2,666,111 $ 5,080,408 Activity in the liability for unpaid claims and claim expenses is summarized as follows: Year ended December 31, 2018 2017 2016 Net reserves as of January 1 $ 3,493,778 $ 2,568,730 $ 2,632,519 Net incurred related to: Current year 1,390,767 1,902,424 694,957 Prior years (270,749 ) (40,996 ) (164,126 ) Total net incurred 1,120,018 1,861,428 530,831 Net paid related to: Current year 391,061 450,527 83,015 Prior years 503,708 524,298 506,279 Total net paid 894,769 974,825 589,294 Foreign exchange (14,977 ) 38,445 (5,326 ) Net reserves as of December 31 3,704,050 3,493,778 2,568,730 Reinsurance recoverable as of December 31 2,372,221 1,586,630 279,564 Gross reserves as of December 31 $ 6,076,271 $ 5,080,408 $ 2,848,294
Schedule of Short-duration Insurance Contracts, Claims Development	The following table details the Company's cumulative number of reported claims for its excess of loss reinsurance contracts allocated by segment: At December 31, 2018 Cumulative number of reported claims Accident Year Property Casualty and Specialty 2009 743 1,132 2010 787 1,081 2011 1,186 1,411 2012 679 1,448 2013 629 1,557 2014 553 2,040 2015 606 1,992 2016 845 1,650 2017 1,812 1,028 2018 1,014 277 The following table details the Company’s Casualty and Specialty segment incurred claims and claim expenses and cumulative paid claims and claim expenses as of December 31, 2018 , net of reinsurance, as well as IBNR plus ACR included within the net incurred claims amounts. Incurred claims and claim expenses, net of reinsurance For the year ended December 31, At December 31, 2018 Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 IBNR and ACR (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 479,421 $ 470,031 $ 471,808 $ 438,538 $ 417,569 $ 395,631 $ 387,184 $ 382,077 $ 385,230 $ 386,863 $ 17,436 2010 — 382,996 389,460 375,980 340,465 318,979 305,784 304,096 300,054 299,490 19,146 2011 — — 382,194 381,062 351,692 321,471 313,955 307,899 297,405 303,844 29,575 2012 — — — 427,341 425,617 395,823 387,532 377,527 391,350 409,458 36,381 2013 — — — — 392,146 362,017 338,054 319,555 305,114 295,703 44,079 2014 — — — — — 477,587 459,317 454,589 439,609 416,162 112,665 2015 — — — — — — 413,112 432,538 453,052 422,675 116,981 2016 — — — — — — — 427,483 430,606 425,157 177,802 2017 — — — — — — — — 553,215 564,282 374,420 2018 — — — — — — — — — 649,147 587,894 Total $ 4,172,781 $ 1,516,379 Cumulative paid claims and claim expenses, net of reinsurance For the year ended December 31, Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 40,320 $ 168,590 $ 206,047 $ 242,450 $ 269,248 $ 303,482 $ 324,150 $ 329,523 $ 336,950 $ 345,303 2010 — 34,853 98,853 136,319 163,914 182,753 227,403 241,012 257,891 261,215 2011 — — 48,067 113,484 145,642 175,274 206,266 224,112 237,694 251,188 2012 — — — 66,507 121,882 168,622 208,975 242,397 294,897 318,199 2013 — — — — 37,966 86,668 125,902 160,513 193,985 214,392 2014 — — — — — 55,977 104,756 150,103 194,111 230,997 2015 — — — — — — 33,693 85,286 160,013 224,136 2016 — — — — — — — 32,086 98,486 168,307 2017 — — — — — — — — 38,073 105,489 2018 — — — — — — — — — 34,876 Total $ 2,154,102 Outstanding liabilities from accident year 2008 and prior, net of reinsurance 282,641 Adjustment for unallocated claim expenses 24,928 Unamortized fair value adjustments recorded in connection with the acquisition of Platinum 4,309 Liability for claims and claim expenses, net of reinsurance $ 2,330,557 The following table details the Company’s consolidated incurred claims and claim expenses and cumulative paid claims and claim expenses as of December 31, 2018 , net of reinsurance, as well as IBNR plus ACR included within the net incurred claims amounts. Incurred claims and claim expenses, net of reinsurance For the year ended December 31, At December 31, 2018 Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 IBNR and ACR (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 699,400 $ 634,400 $ 617,015 $ 577,285 $ 552,059 $ 530,876 $ 521,723 $ 516,888 $ 519,585 $ 521,739 $ 17,510 2010 — 992,376 950,984 902,908 871,664 869,959 860,517 868,441 866,529 855,132 52,575 2011 — — 1,646,568 1,573,930 1,493,095 1,412,886 1,384,912 1,348,620 1,334,068 1,337,445 76,002 2012 — — — 865,281 770,104 707,471 681,405 653,437 655,882 666,704 52,680 2013 — — — — 619,414 558,746 512,389 472,270 446,311 433,363 46,050 2014 — — — — — 660,836 613,786 601,727 582,473 558,619 117,354 2015 — — — — — — 639,151 627,702 629,211 590,591 136,328 2016 — — — — — — — 680,039 684,757 666,453 241,938 2017 — — — — — — — — 1,895,376 1,731,295 828,815 2018 — — — — — — — — — 1,367,413 923,976 Total $ 8,728,754 $ 2,493,228 Cumulative paid claims and claim expenses, net of reinsurance For the year ended December 31, Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 96,462 $ 269,714 $ 321,506 $ 365,731 $ 398,452 $ 437,232 $ 458,920 $ 465,244 $ 472,679 $ 481,632 2010 — 128,276 315,357 431,562 500,974 555,252 626,094 715,191 741,629 758,762 2011 — — 260,326 540,985 889,387 1,043,763 1,133,013 1,176,892 1,203,998 1,222,512 2012 — — — 166,564 266,980 357,821 417,628 461,035 525,736 551,846 2013 — — — — 86,998 179,709 243,544 289,144 326,807 348,436 2014 — — — — — 111,067 200,830 268,871 317,901 357,894 2015 — — — — — — 95,862 193,965 287,522 362,419 2016 — — — — — — — 79,577 217,746 324,224 2017 — — — — — — — — 450,034 548,619 2018 — — — — — — — — — 389,492 Total $ 5,345,836 Outstanding liabilities from accident year 2008 and prior, net of reinsurance 286,863 Claims and claim expenses, net of reinsurance, from the Company's former Bermuda-based insurance operations 368 Adjustment for unallocated claim expenses 28,956 Unamortized fair value adjustments recorded in connection with the acquisition of Platinum 4,945 Liability for claims and claim expenses, net of reinsurance $ 3,704,050 The following table details the Company’s Property segment incurred claims and claim expenses and cumulative paid claims and claim expenses as of December 31, 2018 , net of reinsurance, as well as IBNR plus ACR included within the net incurred claims amounts. Incurred claims and claim expenses, net of reinsurance For the year ended December 31, At December 31, 2018 Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 IBNR and ACR (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 219,979 $ 164,369 $ 145,207 $ 138,747 $ 134,490 $ 135,245 $ 134,539 $ 134,811 $ 134,355 $ 134,876 $ 74 2010 — 609,380 561,524 526,928 531,199 550,980 554,733 564,345 566,475 555,642 33,429 2011 — — 1,264,374 1,192,868 1,141,403 1,091,415 1,070,957 1,040,721 1,036,663 1,033,601 46,427 2012 — — — 437,940 344,487 311,648 293,873 275,910 264,532 257,246 16,299 2013 — — — — 227,268 196,729 174,335 152,715 141,197 137,660 1,971 2014 — — — — — 183,249 154,469 147,138 142,864 142,457 4,689 2015 — — — — — — 226,039 195,164 176,159 167,916 19,347 2016 — — — — — — — 252,556 254,151 241,296 64,136 2017 — — — — — — — — 1,342,161 1,167,013 454,395 2018 — — — — — — — — — 718,266 336,082 Total $ 4,555,973 $ 976,849 Cumulative paid claims and claim expenses, net of reinsurance For the year ended December 31, Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) (unaudited) 2009 $ 56,142 $ 101,124 $ 115,459 $ 123,281 $ 129,204 $ 133,750 $ 134,770 $ 135,721 $ 135,729 $ 136,329 2010 — 93,423 216,504 295,243 337,060 372,499 398,691 474,179 483,738 497,547 2011 — — 212,259 427,501 743,745 868,489 926,747 952,780 966,304 971,324 2012 — — — 100,057 145,098 189,199 208,653 218,638 230,839 233,647 2013 — — — — 49,032 93,041 117,642 128,631 132,822 134,044 2014 — — — — — 55,090 96,074 118,768 123,790 126,897 2015 — — — — — — 62,169 108,679 127,509 138,283 2016 — — — — — — — 47,491 119,260 155,917 2017 — — — — — — — — 411,961 443,130 2018 — — — — — — — — — 354,616 Total $ 3,191,734 Outstanding liabilities from accident year 2008 and prior, net of reinsurance 4,222 Adjustment for unallocated claim expenses 4,028 Unamortized fair value adjustments recorded in connection with the acquisition of Platinum 636 Liability for claims and claim expenses, net of reinsurance $ 1,373,125
Schedule of Short-duration Insurance Contracts, Schedule of Historical Claims Duration	The following is unaudited supplementary information about average historical claims duration by segment: Average annual percentage payout of incurred claims by age, net of reinsurance (number of years) At December 31, 2018 1 2 3 4 5 6 7 8 9 10 Property 31.7 % 17.3 % 20.8 % 9.1 % 5.2 % 3.3 % 4.7 % 0.9 % 2.0 % 0.4 % Casualty and Specialty 10.1 % 16.9 % 12.9 % 10.9 % 8.5 % 10.0 % 5.1 % 3.6 % 1.6 % 2.2 %

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	A summary of the Company’s debt obligations on its consolidated balance sheets is set forth below: December 31, 2018 December 31, 2017 Fair Value Carrying Value Fair Value Carrying Value 3.450% Senior Notes due 2027 $ 283,680 $ 295,797 $ 294,654 $ 295,303 3.700% Senior Notes due 2025 292,557 297,688 302,781 297,318 5.750% Senior Notes due 2020 255,938 249,602 263,750 249,272 4.750% Senior Notes due 2025 (DaVinciRe) (1) 142,539 148,040 157,050 147,730 $ 974,714 $ 991,127 $ 1,018,235 $ 989,623 (1) RenaissanceRe owns a noncontrolling economic interest in its joint venture DaVinciRe. Because RenaissanceRe controls a majority of DaVinciRe’s outstanding voting rights, the consolidated financial statements of DaVinciRe are included in the consolidated financial statements of RenaissanceRe. However, RenaissanceRe does not guarantee or provide credit support for DaVinciRe and RenaissanceRe’s financial exposure to DaVinciRe is limited to its investment in DaVinciRe’s shares and counterparty credit risk arising from reinsurance transactions.
Schedule of Line of Credit Facilities	The outstanding amounts issued or drawn under each of the Company’s significant credit facilities is set forth below: At December 31, 2018 Issued or Drawn RenaissanceRe Revolving Credit Facility (1) $ — Uncommitted Standby Letter of Credit Facility with Wells Fargo 86,861 Bilateral Letter of Credit Facility with Citibank Europe 243,696 Renaissance Reinsurance FAL Facility 180,000 Total credit facilities in U.S. dollars $ 510,557 Specialty Risks FAL Facility (1) £ — Total credit facilities in pound sterling £ —
Schedule of Aggregate Amount of Maturities Related to the Company's Debt Obligations	The following table sets forth the scheduled maturity of the Company’s aggregate amount of its debt obligation reflected on its consolidated balance sheet at December 31, 2018 : 2019 $ — 2020 250,000 2021 — 2022 — 2023 — After 2023 750,000 Unamortized discount and debt issuance expenses (8,873 ) $ 991,127

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest [Abstract]
Schedule of Redeemable Noncontrolling Interest	The activity in redeemable noncontrolling interest – Vermeer is detailed in the table below: 2018 2017 Balance – January 1 $ — $ — Sale of shares to redeemable noncontrolling interest 600,000 — Net loss attributable to redeemable noncontrolling interest (11 ) — Balance – December 31 $ 599,989 $ — A summary of the Company’s redeemable noncontrolling interests on its consolidated balance sheets is set forth below: December 31, December 31, Redeemable noncontrolling interest - DaVinciRe $ 1,034,946 $ 1,011,659 Redeemable noncontrolling interest - Medici 416,765 284,847 Redeemable noncontrolling interest - Vermeer 599,989 — Redeemable noncontrolling interests $ 2,051,700 $ 1,296,506 A summary of the Company’s redeemable noncontrolling interests on its consolidated statements of operations is set forth below: 2018 2017 2016 Redeemable noncontrolling interest - DaVinciRe $ 27,638 $ (134,860 ) $ 118,748 Redeemable noncontrolling interest - Medici 13,926 2,578 8,338 Redeemable noncontrolling interest - Vermeer (11 ) — — Net income (loss) attributable to redeemable noncontrolling interests $ 41,553 $ (132,282 ) $ 127,086 The activity in redeemable noncontrolling interest – Medici is detailed in the table below: 2018 2017 Balance – January 1 $ 284,847 $ 181,136 Redemption of shares from redeemable noncontrolling interest (90,490 ) (48,049 ) Sale of shares to redeemable noncontrolling interest 208,482 149,182 Net income attributable to redeemable noncontrolling interest 13,926 2,578 Balance – December 31 $ 416,765 $ 284,847 The activity in redeemable noncontrolling interest – DaVinciRe is detailed in the table below: 2018 2017 Balance – January 1 $ 1,011,659 $ 994,458 Redemption of shares from redeemable noncontrolling interest (4,351 ) (80,058 ) Sale of shares to redeemable noncontrolling interest — 232,119 Net income (loss) attributable to redeemable noncontrolling interest 27,638 (134,860 ) Balance – December 31 $ 1,034,946 $ 1,011,659

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Rollforward of Common Stock Issued and Outstanding	The following table is a summary of changes in common shares issued and outstanding: Year ended December 31, 2018 2017 2016 (thousands of shares) Issued and outstanding shares – January 1 40,024 41,187 43,701 Issuance of shares 1,947 — — Repurchase of shares — (1,322 ) (2,741 ) Exercise of options and issuance of restricted stock awards 236 159 227 Issued and outstanding shares – December 31 42,207 40,024 41,187

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share: Year ended December 31, 2018 2017 2016 (common shares in thousands) Numerator: Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 197,276 $ (244,770 ) $ 480,581 Amount allocated to participating common shareholders (1) (2,121 ) (457 ) (5,666 ) Net income (loss) allocated to RenaissanceRe common shareholders $ 195,155 $ (245,227 ) $ 474,915 Denominator: Denominator for basic income (loss) per RenaissanceRe common share - weighted average common shares 39,732 39,854 41,314 Per common share equivalents of employee stock options and performance shares 23 — 245 Denominator for diluted income (loss) per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions 39,755 39,854 41,559 Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic $ 4.91 $ (6.15 ) $ 11.50 Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted $ 4.91 $ (6.15 ) $ 11.43 (1) Represents earnings attributable to holders of unvested restricted shares issued pursuant to the Company’s 2001 Stock Incentive Plan, 2010 Performance-Based Equity Incentive Plan, 2016 Long-Term Incentive Plan and to the Company’s non-employee directors.

Taxation (Tables)

Taxation (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The following is a summary of the Company’s income (loss) before taxes allocated between domestic and foreign operations: Year ended December 31, 2018 2017 2016 Domestic Bermuda $ 349,959 $ (262,827 ) $ 652,758 Foreign U.S. (56,261 ) (11,897 ) (1,236 ) U.K. (28,574 ) (41,656 ) (24,278 ) Singapore (3,226 ) (12,421 ) 2,180 Ireland 551 617 964 Switzerland 166 — — Income (loss) before taxes $ 262,615 $ (328,184 ) $ 630,388
Schedule of Components of Income Tax (Expense) Benefit	Income tax benefit (expense) is comprised as follows: Year ended December 31, 2018 Current Deferred Total Total income tax (expense) benefit $ (1,668 ) $ 7,970 $ 6,302 Year ended December 31, 2017 Total income tax expense $ (844 ) $ (25,643 ) $ (26,487 ) Year ended December 31, 2016 Total income tax (expense) benefit $ (2,090 ) $ 1,750 $ (340 )
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows: Year ended December 31, 2018 2017 2016 Expected income tax benefit $ 17,697 $ 14,216 $ 4,856 Tax exempt income 944 3,794 4,487 Non-taxable foreign exchange gains (losses) 586 2,574 (1,126 ) Effect of change in tax rate (708 ) (38,083 ) (1,421 ) U.S. base erosion and anti-abuse tax (1,271 ) — — Withholding tax (1,831 ) (216 ) (2,578 ) Transfer pricing (2,481 ) (11 ) 27 Change in valuation allowance (5,255 ) (11,718 ) (924 ) Other (1,379 ) 2,957 (3,661 ) Income tax benefit (expense) $ 6,302 $ (26,487 ) $ (340 )
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: At December 31, 2018 2017 Deferred tax assets Tax loss and credit carryforwards $ 60,395 $ 62,643 Reserve for claims and claim expenses 17,345 13,992 Deferred finance charges 14,646 11,320 Unearned premiums 10,108 9,436 Investments 4,427 — Accrued expenses 4,292 2,641 Deferred underwriting results 3,514 3,407 114,727 103,439 Deferred tax liabilities Deferred acquisition expenses (11,801 ) (12,343 ) Amortization and depreciation (2,992 ) (3,340 ) Investments — (1,047 ) (14,793 ) (16,730 ) Net deferred tax asset before valuation allowance 99,934 86,709 Valuation allowance (35,271 ) (30,016 ) Net deferred tax asset $ 64,663 $ 56,693

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting, Measurement Disclosures [Abstract]
Schedule of Significant Components of the Company's Revenues and Expenses	A summary of the significant components of the Company’s revenues and expenses by segment is as follows: Year ended December 31, 2018 Property Casualty and Specialty Other Total Gross premiums written $ 1,760,926 $ 1,549,501 $ — $ 3,310,427 Net premiums written $ 1,055,188 $ 1,076,714 $ — $ 2,131,902 Net premiums earned $ 1,050,831 $ 925,298 $ — $ 1,976,129 Net claims and claim expenses incurred 497,895 622,320 (197 ) 1,120,018 Acquisition expenses 177,912 255,079 (2 ) 432,989 Operational expenses 112,954 64,883 430 178,267 Underwriting income (loss) $ 262,070 $ (16,984 ) $ (231 ) 244,855 Net investment income 261,866 261,866 Net foreign exchange losses (12,428 ) (12,428 ) Equity in earnings of other ventures 18,474 18,474 Other income 5,969 5,969 Net realized and unrealized losses on investments (175,069 ) (175,069 ) Corporate expenses (33,983 ) (33,983 ) Interest expense (47,069 ) (47,069 ) Income before taxes and redeemable noncontrolling interests 262,615 Income tax benefit 6,302 6,302 Net income attributable to redeemable noncontrolling interests (41,553 ) (41,553 ) Dividends on preference shares (30,088 ) (30,088 ) Net income available to RenaissanceRe common shareholders $ 197,276 Net claims and claim expenses incurred – current accident year $ 719,185 $ 671,582 $ — $ 1,390,767 Net claims and claim expenses incurred – prior accident years (221,290 ) (49,262 ) (197 ) (270,749 ) Net claims and claim expenses incurred – total $ 497,895 $ 622,320 $ (197 ) $ 1,120,018 Net claims and claim expense ratio – current accident year 68.4 % 72.6 % 70.4 % Net claims and claim expense ratio – prior accident years (21.0 )% (5.3 )% (13.7 )% Net claims and claim expense ratio – calendar year 47.4 % 67.3 % 56.7 % Underwriting expense ratio 27.7 % 34.5 % 30.9 % Combined ratio 75.1 % 101.8 % 87.6 % Year ended December 31, 2017 Property Casualty and Specialty Other Total Gross premiums written $ 1,440,437 $ 1,357,110 $ (7 ) $ 2,797,540 Net premiums written $ 978,014 $ 893,307 $ 4 $ 1,871,325 Net premiums earned $ 931,070 $ 786,501 $ 4 $ 1,717,575 Net claims and claim expenses incurred 1,297,985 565,026 (1,583 ) 1,861,428 Acquisition expenses 113,816 233,077 (1 ) 346,892 Operational expenses 94,194 66,548 36 160,778 Underwriting (loss) income $ (574,925 ) $ (78,150 ) $ 1,552 (651,523 ) Net investment income 222,209 222,209 Net foreign exchange gains 10,628 10,628 Equity in earnings of other ventures 8,030 8,030 Other income 9,415 9,415 Net realized and unrealized gains on investments 135,822 135,822 Corporate expenses (18,572 ) (18,572 ) Interest expense (44,193 ) (44,193 ) Loss before taxes and noncontrolling interests (328,184 ) Income tax expense (26,487 ) (26,487 ) Net loss attributable to noncontrolling interests 132,282 132,282 Dividends on preference shares (22,381 ) (22,381 ) Net loss attributable to RenaissanceRe common shareholders $ (244,770 ) Net claims and claim expenses incurred – current accident year $ 1,343,581 $ 558,843 $ — $ 1,902,424 Net claims and claim expenses incurred – prior accident years (45,596 ) 6,183 (1,583 ) (40,996 ) Net claims and claim expenses incurred – total $ 1,297,985 $ 565,026 $ (1,583 ) $ 1,861,428 Net claims and claim expense ratio – current accident year 144.3 % 71.1 % 110.8 % Net claims and claim expense ratio – prior accident years (4.9 )% 0.7 % (2.4 )% Net claims and claim expense ratio – calendar year 139.4 % 71.8 % 108.4 % Underwriting expense ratio 22.3 % 38.1 % 29.5 % Combined ratio 161.7 % 109.9 % 137.9 % Year ended December 31, 2016 Property Casualty and Specialty Other Total Gross premiums written $ 1,111,263 $ 1,263,313 $ — $ 2,374,576 Net premiums written $ 725,321 $ 809,848 $ 143 $ 1,535,312 Net premiums earned $ 720,951 $ 682,337 $ 142 $ 1,403,430 Net claims and claim expenses incurred 151,545 380,396 (1,110 ) 530,831 Acquisition expenses 97,594 191,729 — 289,323 Operational expenses 108,642 88,984 123 197,749 Underwriting income $ 363,170 $ 21,228 $ 1,129 385,527 Net investment income 181,726 181,726 Net foreign exchange losses (13,788 ) (13,788 ) Equity in earnings of other ventures 963 963 Other income 14,178 14,178 Net realized and unrealized gains on investments 141,328 141,328 Corporate expenses (37,402 ) (37,402 ) Interest expense (42,144 ) (42,144 ) Income before taxes and noncontrolling interests 630,388 Income tax expense (340 ) (340 ) Net income attributable to noncontrolling interests (127,086 ) (127,086 ) Dividends on preference shares (22,381 ) (22,381 ) Net income available to RenaissanceRe common shareholders $ 480,581 Net claims and claim expenses incurred – current accident year $ 256,421 $ 438,536 $ — $ 694,957 Net claims and claim expenses incurred – prior accident years (104,876 ) (58,140 ) (1,110 ) (164,126 ) Net claims and claim expenses incurred – total $ 151,545 $ 380,396 $ (1,110 ) $ 530,831 Net claims and claim expense ratio – current accident year 35.6 % 64.3 % 49.5 % Net claims and claim expense ratio – prior accident years (14.6 )% (8.6 )% (11.7 )% Net claims and claim expense ratio – calendar year 21.0 % 55.7 % 37.8 % Underwriting expense ratio 28.6 % 41.2 % 34.7 % Combined ratio 49.6 % 96.9 % 72.5 %
Schedule of Gross Premiums Written Allocated to the Territory of Coverage Exposure	The following is a summary of the Company’s gross premiums written allocated to the territory of coverage exposure: Year ended December 31, 2018 2017 2016 Property U.S. and Caribbean $ 978,063 $ 954,269 $ 743,226 Worldwide 464,311 305,915 210,168 Europe 144,857 49,486 37,611 Japan 71,601 49,821 44,536 Worldwide (excluding U.S.) (1) 66,872 48,182 55,043 Australia and New Zealand 19,273 14,151 13,729 Other 15,949 18,613 6,950 Total Property 1,760,926 1,440,437 1,111,263 Casualty and Specialty Worldwide 776,976 686,253 581,972 U.S. and Caribbean 667,125 622,757 646,381 Worldwide (excluding U.S.) (1) 31,734 10,104 13,840 Europe 15,296 9,752 5,541 Australia and New Zealand 3,667 4,141 5,073 Other 54,703 24,103 10,506 Total Casualty and Specialty 1,549,501 1,357,110 1,263,313 Other category — (7 ) — Total gross premiums written $ 3,310,427 $ 2,797,540 $ 2,374,576 (1) The category “Worldwide (excluding U.S.)” consists of contracts that cover more than one geographic region (other than the U.S.).

Stock Incentive Compensation _2

Stock Incentive Compensation and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Performance Shares, Valuation Assumptions	The following are the weighted average-assumptions used to estimate the fair value for all performance share awards issued in each respective year. Performance Share Awards Year ended December 31, 2018 2017 Expected volatility (1) 15.8% 14.3% Expected term (in years) n/a n/a Expected dividend yield n/a n/a Risk-free interest rate (1) 1.85% - 2.36% 0.93% - 1.69% (1) The expected volatility and risk-free interest rate applied are specific to each tranche of performance share awards.
Schedule of Share-based Compensation, Options and Premium Option Plan Awards	The following is a summary of activity under the Company’s stock compensation plans. Stock Options Weighted options outstanding Weighted average exercise price Weighted average remaining contractual life Aggregate intrinsic value Range of exercise prices Balance, December 31, 2015 408,212 $ 51.90 1.6 $ 25,020 $42.66 - $59.66 Options granted — — — Options forfeited — — Options expired — — Options exercised (201,417 ) 50.59 $ 14,806 — Balance, December 31, 2016 206,795 $ 53.17 0.9 $ 17,174 $50.71 - $59.66 Options granted — — — Options forfeited — — Options expired — — Options exercised (174,794 ) 53.04 $ 15,945 — Balance, December 31, 2017 32,001 $ 53.86 0.2 $ 2,295 53.86 Options granted — — — Options forfeited — — Options expired — — Options exercised (32,001 ) $ 53.86 $ 2,320 $ — Balance, December 31, 2018 — $ — 0.0 $ — $ — Total options exercisable at December 31, 2018 — $ — 0.0 $ — $ —
Schedule of Share-based Compensation, Cash Settled Restricted Stock Units and Performance Shares	Cash Settled Restricted Stock Units Number of shares Nonvested at December 31, 2015 326,078 Awards granted 135,119 Awards vested (133,278 ) Awards forfeited (19,575 ) Nonvested at December 31, 2016 308,344 Awards granted 98,067 Awards vested (122,088 ) Awards forfeited (21,993 ) Nonvested at December 31, 2017 262,330 Awards granted — Awards vested (108,344 ) Awards forfeited (7,069 ) Nonvested at December 31, 2018 146,917 Performance Share Awards Number of shares (1) Weighted average grant-date fair value Nonvested at December 31, 2015 230,271 $ 41.40 Awards granted 77,045 $ 48.31 Awards vested (58,032 ) $ 38.30 Awards forfeited (37,903 ) Nonvested at December 31, 2016 211,381 $ 44.63 Awards granted 64,947 $ 65.27 Awards vested (62,499 ) $ 43.51 Awards forfeited (46,156 ) Nonvested at December 31, 2017 167,673 $ 53.11 Awards granted 83,475 $ 60.69 Awards vested (16,456 ) $ 53.79 Awards forfeited (82,241 ) Nonvested at December 31, 2018 152,451 $ 57.21 (1) For performance share awards, the number of shares is stated at the maximum number that can be attained if the performance conditions are fully met. Forfeitures represent shares forfeited due to vesting below the maximum attainable as a result of the Company not fully meeting the performance conditions.
Schedule of Share-based Compensation, Restricted Stock Awards	Restricted Stock Awards Employee restricted stock awards Non-employee director restricted stock awards Total restricted stock awards Number of shares Weighted average grant date fair value Number of shares Weighted Number of shares Weighted Nonvested at December 31, 2015 479,040 $ 94.95 26,886 $ 97.61 505,926 $ 95.09 Awards granted 179,003 112.41 14,727 114.71 193,730 112.59 Awards vested (255,873 ) 93.98 (16,068 ) 96.83 (271,941 ) 94.15 Awards forfeited — — — — — — Nonvested at December 31, 2016 402,170 $ 103.34 25,545 $ 107.95 427,715 $ 103.61 Awards granted 116,345 148.66 12,193 150.05 128,538 148.79 Awards vested (185,478 ) 100.17 (17,612 ) 110.66 (203,090 ) 101.08 Awards forfeited — — — — — — Nonvested at December 31, 2017 333,037 $ 120.93 20,126 $ 131.09 353,163 $ 121.51 Awards granted 255,799 132.70 12,169 127.29 267,968 132.79 Awards vested (139,454 ) 112.70 (9,761 ) 123.59 (149,215 ) 113.41 Awards forfeited (1,642 ) 134.38 — — (1,642 ) 134.38 Nonvested at December 31, 2018 447,740 $ 130.37 22,534 $ 132.29 470,274 $ 130.46

Statutory Requirements (Tables)

Statutory Requirements (Tables)	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Schedule of Actual and Required Statutory Capital and Surplus	The statutory economic capital and surplus, required minimum statutory capital and surplus and unrestricted net assets of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below: Bermuda (1) U.S. U.K. (2) (3) At December 31, 2018 2017 2018 2017 2018 2017 Statutory economic capital and surplus $ 4,256,830 $ 4,155,368 $ 502,803 $ 523,384 $ 519,689 $ 527,325 Required statutory capital and surplus 950,915 836,181 306,628 306,375 519,689 527,325 Unrestricted net assets 931,387 790,177 31,228 24,109 — — (1) The Company's Bermuda-domiciled insurance subsidiaries’ capital and surplus is based on the relevant insurer’s statutory financial statements and required statutory capital and surplus is based on the MSM. (2) With respect to statutory capital and surplus and required statutory capital and surplus, and as described below, underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as Funds at Lloyd’s (“FAL”). FAL is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirements as calculated through its internal model. (3) Syndicate 1458 is capitalized by its FAL, with the related assets not held on its balance sheet. As such, unrestricted net assets is not applicable to Syndicate 1458; however, the Company can make an application to obtain approval from Lloyd’s to have funds released to RenaissanceRe from Syndicate 1458, subject to passing a Lloyd’s release test.
Schedule of Statutory Net (Loss) Income	Statutory net income (loss) of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below: Statutory Net Income (Loss) Bermuda U.S. U.K. Year ended December 31, 2018 $ 326,386 $ 25,851 $ (6,692 ) Year ended December 31, 2017 (334,142 ) (3,627 ) (57,050 ) Year ended December 31, 2016 625,371 43,292 28,007

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Derivative Instruments [Abstract]
Schedule of Location on Consolidated Balance Sheets and Fair Value of Principal Derivative Instruments	The tables below show the gross and net amounts of recognized derivative assets and liabilities at fair value, including the location on the consolidated balance sheets of the Company’s principal derivative instruments: Derivative Assets At December 31, 2018 Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet Balance Sheet Location Collateral Net Amount Interest rate futures $ 2,361 1,660 $ 701 Other assets $ — $ 701 Interest rate swaps 860 — 860 Other assets — 860 Foreign currency forward contracts (1) 16,459 2,260 14,199 Other assets — 14,199 Foreign currency forward contracts (2) 3,194 71 3,123 Other assets — 3,123 Total $ 22,874 $ 3,991 $ 18,883 $ — $ 18,883 Derivative Liabilities At December 31, 2018 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet Balance Sheet Location Collateral Pledged Net Amount Interest rate futures $ 1,887 1,670 $ 217 Other liabilities $ 217 $ — Interest rate swaps 506 — 506 Other liabilities 254 252 Foreign currency forward contracts (1) 4,154 — 4,154 Other liabilities — 4,154 Foreign currency forward contracts (2) 72 71 1 Other liabilities — 1 Credit default swaps 1,606 — 1,606 Other liabilities 1,605 1 Total $ 8,225 $ 1,741 $ 6,484 $ 2,076 $ 4,408 (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations. Derivative Assets At December 31, 2017 Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet Balance Sheet Location Collateral Net Amount Interest rate futures $ 684 524 $ 160 Other assets $ — $ 160 Interest rate swaps 424 — 424 Other assets — 424 Foreign currency forward contracts (1) 3,865 358 3,507 Other assets — 3,507 Foreign currency forward contracts (2) 39 11 28 Other assets — 28 Credit default swaps 1,518 — 1,518 Other assets — 1,518 Total $ 6,530 $ 893 $ 5,637 $ — $ 5,637 Derivative Liabilities At December 31, 2017 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet Balance Sheet Location Collateral Pledged Net Amount Interest rate futures $ 729 524 $ 205 Other liabilities $ 205 $ — Foreign currency forward contracts (1) 670 — 670 Other liabilities — 670 Foreign currency forward contracts (2) 115 11 104 Other liabilities — 104 Credit default swaps 22 — 22 Other liabilities 22 — Total $ 1,536 $ 535 $ 1,001 $ 227 $ 774 (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations.
Schedule of Gain (Loss) Recognized in Consolidated Statements of Operations Related to Principal Derivative Instruments	The location and amount of the gain (loss) recognized in the Company’s consolidated statements of operations related to its principal derivative instruments are shown in the following table: Location of gain (loss) recognized on derivatives Amount of gain (loss) recognized on derivatives Year ended December 31, 2018 2017 2016 Interest rate futures Net realized and unrealized (losses) gains on investments $ (5,594 ) $ (3,252 ) $ (17,379 ) Interest rate swaps Net realized and unrealized (losses) gains on investments (84 ) 436 — Foreign currency forward contracts (1) Net foreign exchange (losses) gains 3,840 9,628 (6,937 ) Foreign currency forward contracts (2) Net foreign exchange (losses) gains 5,736 (916 ) (1,591 ) Credit default swaps Net realized and unrealized (losses) gains on investments (3,106 ) 326 1,965 Total $ 792 $ 6,222 $ (23,942 ) (1) Contracts used to manage foreign currency risks in underwriting and non-investment operations. (2) Contracts used to manage foreign currency risks in investment operations.

Commitments, Contingencies an_2

Commitments, Contingencies and Other Items (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments for Operating Leases	Future minimum lease payments under existing operating leases are expected to be as follows: Minimum lease payments 2019 $ 7,137 2020 5,294 2021 4,934 2022 4,225 2023 1,530 After 2023 298 Future minimum lease payments under existing operating leases $ 23,418
Schedule of Future Minimum Lease Payments for Capital Leases	The future minimum lease payments of the Company’s capital leases are detailed below, and relate principally to the transaction noted above, excluding the bargain renewal option. Minimum lease payments 2019 $ 3,331 2020 3,336 2021 3,336 2022 3,336 2023 2,830 After 2023 12,790 Future minimum lease payments under existing capital leases $ 28,959

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data [Abstract]
Quarterly Financial Information (Unaudited)	Quarter Ended March 31, Quarter Ended June 30, Quarter Ended September 30, Quarter Ended December 31, 2018 2017 2018 2017 2018 2017 2018 2017 Revenues Gross premiums written $ 1,159,652 $ 922,090 $ 977,343 $ 827,415 $ 625,677 $ 640,269 $ 547,755 $ 407,766 Net premiums written $ 663,044 $ 544,136 $ 604,509 $ 555,745 $ 453,255 $ 483,221 $ 411,094 $ 288,223 (Increase) decrease in unearned premiums (222,762 ) (178,091 ) (175,124 ) (173,480 ) 78,594 64,571 163,519 133,250 Net premiums earned 440,282 366,045 429,385 382,265 531,849 547,792 574,613 421,473 Net investment income 56,476 54,325 71,356 54,163 80,696 40,257 53,338 73,464 Net foreign exchange gains (losses) 3,757 8,165 (10,687 ) 3,109 (4,566 ) (156 ) (932 ) (490 ) Equity in earnings (losses) of other ventures 857 (1,507 ) 5,826 5,543 7,648 1,794 4,143 2,200 Other (loss) income (1,242 ) 1,665 1,225 2,392 497 2,996 5,489 2,362 Net realized and unrealized (losses) gains on investments (82,144 ) 43,373 (17,901 ) 58,113 13,630 42,052 (88,654 ) (7,716 ) Total revenues 417,986 472,066 479,204 505,585 629,754 634,735 547,997 491,293 Expenses Net claims and claim expenses incurred 171,703 193,081 60,167 142,587 410,510 1,221,696 477,638 304,064 Acquisition costs 97,711 83,282 105,052 88,251 109,761 76,761 120,465 98,598 Operational expenses 41,272 47,283 37,543 41,766 40,593 42,537 58,859 29,192 Corporate expenses 6,733 5,286 8,301 4,636 6,841 4,413 12,108 4,237 Interest expense 11,767 10,526 11,768 10,091 11,769 11,799 11,765 11,777 Total expenses 329,186 339,458 222,831 287,331 579,474 1,357,206 680,835 447,868 Income (loss) before taxes 88,800 132,608 256,373 218,254 50,280 (722,471 ) (132,838 ) 43,425 Income tax benefit (expense) 3,407 (334 ) (4,506 ) (3,904 ) (1,451 ) 18,977 8,852 (41,226 ) Net income (loss) 92,207 132,274 251,867 214,350 48,829 (703,494 ) (123,986 ) 2,199 Net (income) loss attributable to redeemable noncontrolling interests (29,899 ) (34,327 ) (54,483 ) (37,612 ) (6,440 ) 204,277 49,269 (56 ) Net income (loss) available (attributable) to RenaissanceRe 62,308 97,947 197,384 176,738 42,389 (499,217 ) (74,717 ) 2,143 Dividends on preference shares (5,595 ) (5,595 ) (5,596 ) (5,596 ) (9,708 ) (5,595 ) (9,189 ) (5,595 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 56,713 $ 92,352 $ 191,788 $ 171,142 $ 32,681 $ (504,812 ) $ (83,906 ) $ (3,452 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic $ 1.42 $ 2.26 $ 4.78 $ 4.25 $ 0.82 $ (12.75 ) $ (2.10 ) $ (0.09 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted $ 1.42 $ 2.25 $ 4.78 $ 4.24 $ 0.82 $ (12.75 ) $ (2.10 ) $ (0.09 ) Average shares outstanding – basic 39,552 40,408 39,641 39,937 39,624 39,591 40,111 39,478 Average shares outstanding – diluted 39,599 40,623 39,654 40,024 39,637 39,591 40,111 39,478

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet at December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Assets Total investments $ 313,360 $ 77,842 $ 28,885 $ 11,465,660 $ — $ 11,885,747 Cash and cash equivalents 3,534 3,350 9,604 1,091,434 — 1,107,922 Investments in subsidiaries 4,414,475 58,458 1,215,663 — (5,688,596 ) — Due from subsidiaries and affiliates 57,039 101,579 — — (158,618 ) — Premiums receivable — — — 1,537,188 — 1,537,188 Prepaid reinsurance premiums — — — 616,185 — 616,185 Reinsurance recoverable — — — 2,372,221 — 2,372,221 Accrued investment income 1,046 310 127 49,828 — 51,311 Deferred acquisition costs — — — 476,661 — 476,661 Receivable for investments sold 203 23,885 — 232,328 — 256,416 Other assets 458,842 22,571 313,636 (1,403,636 ) 743,714 135,127 Goodwill and other intangible assets 120,476 — — 116,942 — 237,418 Total assets $ 5,368,975 $ 287,995 $ 1,567,915 $ 16,554,811 $ (5,103,500 ) $ 18,676,196 Liabilities, Noncontrolling Interests and Shareholders’ Equity Liabilities Reserve for claims and claim expenses $ — $ — $ — $ 6,076,271 $ — $ 6,076,271 Unearned premiums — — — 1,716,021 — 1,716,021 Debt 300,000 — 843,086 148,041 (300,000 ) 991,127 Amounts due to subsidiaries and affiliates 6,453 217 102,243 — (108,913 ) — Reinsurance balances payable — — — 1,902,056 — 1,902,056 Payable for investments purchased — 24 — 380,308 — 380,332 Other liabilities 17,442 5,362 13,918 482,422 (5,535 ) 513,609 Total liabilities 323,895 5,603 959,247 10,705,119 (414,448 ) 11,579,416 Redeemable noncontrolling interests — — — 2,051,700 — 2,051,700 Shareholders’ Equity Total shareholders’ equity 5,045,080 282,392 608,668 3,797,992 (4,689,052 ) 5,045,080 Total liabilities, noncontrolling interests and shareholders’ equity $ 5,368,975 $ 287,995 $ 1,567,915 $ 16,554,811 $ (5,103,500 ) $ 18,676,196 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Balance Sheet at December 31, 2017 RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Assets Total investments $ 225,266 $ 129,732 $ 31,255 $ 9,117,186 $ — $ 9,503,439 Cash and cash equivalents 14,656 139 1,469 1,345,328 — 1,361,592 Investments in subsidiaries 4,105,760 36,140 1,141,733 — (5,283,633 ) — Due from subsidiaries and affiliates 4,602 91,891 — — (96,493 ) — Premiums receivable — — — 1,304,622 — 1,304,622 Prepaid reinsurance premiums — — — 533,546 — 533,546 Reinsurance recoverable — — — 1,586,630 — 1,586,630 Accrued investment income 405 428 82 41,320 — 42,235 Deferred acquisition costs — — — 426,551 — 426,551 Receivable for investments sold 135 51 8 102,951 — 103,145 Other assets 433,468 21,342 430,481 76,703 (840,768 ) 121,226 Goodwill and other intangible assets 124,960 — — 118,185 — 243,145 Total assets $ 4,909,252 $ 279,723 $ 1,605,028 $ 14,653,022 $ (6,220,894 ) $ 15,226,131 Liabilities, Redeemable Noncontrolling Interest and Shareholders’ Equity Liabilities Reserve for claims and claim expenses $ — $ — $ — $ 5,080,408 $ — $ 5,080,408 Unearned premiums — — — 1,477,609 — 1,477,609 Debt 417,000 — 841,892 147,731 (417,000 ) 989,623 Amounts due to subsidiaries and affiliates 82,579 54 92,794 — (175,427 ) — Reinsurance balances payable — — — 989,090 — 989,090 Payable for investments purchased — — — 208,749 — 208,749 Other liabilities 18,298 1,053 14,117 764,432 (5,129 ) 792,771 Total liabilities 517,877 1,107 948,803 8,668,019 (597,556 ) 9,538,250 Redeemable noncontrolling interests — — — 1,296,506 — 1,296,506 Shareholders’ Equity Total shareholders’ equity 4,391,375 278,616 656,225 4,688,497 (5,623,338 ) 4,391,375 Total liabilities, redeemable noncontrolling interest and shareholders’ equity $ 4,909,252 $ 279,723 $ 1,605,028 $ 14,653,022 $ (6,220,894 ) $ 15,226,131 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations	Condensed Consolidating Statement of Operations RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North America Holdings Inc. (Subsidiary Issuer) Platinum RenaissanceRe Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Revenues Net premiums earned $ — $ — $ — $ — $ 1,403,430 $ — $ 1,403,430 Net investment income 24,178 1,852 3,989 569 175,407 (24,269 ) 181,726 Net foreign exchange losses (2 ) — — — (13,786 ) — (13,788 ) Equity in earnings of other ventures — — — — 963 — 963 Other (loss) income (772 ) — — — 14,950 — 14,178 Net realized and unrealized gains on investments 4,151 4,659 8,193 46 124,279 — 141,328 Total revenues 27,555 6,511 12,182 615 1,705,243 (24,269 ) 1,727,837 Expenses Net claims and claim expenses incurred — — — — 530,831 — 530,831 Acquisition expenses — — — — 289,323 — 289,323 Operational expenses 13,716 (112 ) 296 22,152 176,041 (14,344 ) 197,749 Corporate expenses 26,848 203 — 7 10,344 — 37,402 Interest expense 562 — 5,906 26,176 10,062 (562 ) 42,144 Total expenses 41,126 91 6,202 48,335 1,016,601 (14,906 ) 1,097,449 (Loss) income before equity in net income of subsidiaries and taxes (13,571 ) 6,420 5,980 (47,720 ) 688,642 (9,363 ) 630,388 Equity in net income of subsidiaries 516,533 3,857 25,073 38,628 — (584,091 ) — Income (loss) before taxes 502,962 10,277 31,053 (9,092 ) 688,642 (593,454 ) 630,388 Income tax (expense) benefit — (2,275 ) (1,462 ) 11,014 (7,617 ) — (340 ) Net income 502,962 8,002 29,591 1,922 681,025 (593,454 ) 630,048 Net income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Net income attributable to RenaissanceRe 502,962 8,002 29,591 1,922 553,939 (593,454 ) 502,962 Dividends on preference shares (22,381 ) — — — — — (22,381 ) Net income available to RenaissanceRe common shareholders $ 480,581 $ 8,002 $ 29,591 $ 1,922 $ 553,939 $ (593,454 ) $ 480,581 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income for the year ended December 31, 2016 RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North America Holdings Inc. (Subsidiary Issuer) Platinum RenaissanceRe Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Comprehensive income Net income $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 681,025 $ (593,454 ) $ 630,048 Change in net unrealized gains on investments — — — — (975 ) — (975 ) Comprehensive income 502,962 8,002 29,591 1,922 680,050 (593,454 ) 629,073 Net income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to RenaissanceRe $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 552,964 $ (593,454 ) $ 501,987 Condensed Consolidating Statement of Operations for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Revenues Net premiums earned $ — $ — $ — $ — $ 1,717,575 $ — $ 1,717,575 Net investment income 23,109 1,947 1,373 3,090 219,490 (26,800 ) 222,209 Net foreign exchange (losses) gains (1 ) — — — 10,629 — 10,628 Equity in (losses) earnings of other ventures — — — (223 ) 8,253 — 8,030 Other income — — — — 9,415 — 9,415 Net realized and unrealized (losses) gains on investments (1,357 ) 9,621 4,916 (479 ) 123,121 — 135,822 Total revenues 21,751 11,568 6,289 2,388 2,088,483 (26,800 ) 2,103,679 Expenses Net claims and claim expenses incurred — — — — 1,861,428 — 1,861,428 Acquisition expenses — — — — 346,892 — 346,892 Operational expenses 11,314 103 85 26,063 141,572 (18,359 ) 160,778 Corporate expenses 18,546 — — — 26 — 18,572 Interest expense 1,572 — 2,461 31,657 10,075 (1,572 ) 44,193 Total expenses 31,432 103 2,546 57,720 2,359,993 (19,931 ) 2,431,863 (Loss) income before equity in net (loss) income of subsidiaries and taxes (9,681 ) 11,465 3,743 (55,332 ) (271,510 ) (6,869 ) (328,184 ) Equity in net (loss) income of subsidiaries (212,708 ) 756 28,028 9,298 — 174,626 — (Loss) income before taxes (222,389 ) 12,221 31,771 (46,034 ) (271,510 ) 167,757 (328,184 ) Income tax (expense) benefit — (18,147 ) (1,175 ) 7,163 (14,328 ) — (26,487 ) Net (loss) income (222,389 ) (5,926 ) 30,596 (38,871 ) (285,838 ) 167,757 (354,671 ) Net loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Net (loss) income attributable to RenaissanceRe (222,389 ) (5,926 ) 30,596 (38,871 ) (153,556 ) 167,757 (222,389 ) Dividends on preference shares (22,381 ) — — — — — (22,381 ) Net (loss) income (attributable) available to RenaissanceRe common shareholders $ (244,770 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (153,556 ) $ 167,757 $ (244,770 ) (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Operations for RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Revenues Net premiums earned $ — $ — $ — $ 1,976,129 $ — $ 1,976,129 Net investment income 24,791 2,193 6,219 261,192 (32,529 ) 261,866 Net foreign exchange losses (3 ) — — (12,425 ) — (12,428 ) Equity in earnings of other ventures — — 3,065 15,409 — 18,474 Other income — — — 5,969 — 5,969 Net realized and unrealized gains (losses) on investments 633 (4,360 ) (329 ) (171,013 ) — (175,069 ) Total revenues 25,421 (2,167 ) 8,955 2,075,261 (32,529 ) 2,074,941 Expenses Net claims and claim expenses incurred — — — 1,120,018 — 1,120,018 Acquisition expenses — — — 432,989 — 432,989 Operational expenses 7,679 110 34,534 164,605 (28,661 ) 178,267 Corporate expenses 25,190 — 7 3,103 5,683 33,983 Interest expense 5,683 — 37,019 4,367 — 47,069 Total expenses 38,552 110 71,560 1,725,082 (22,978 ) 1,812,326 (Loss) income before equity in net income of subsidiaries and taxes (13,131 ) (2,277 ) (62,605 ) 350,179 (9,551 ) 262,615 Equity in net income of subsidiaries 240,495 5,631 9,091 — (255,217 ) — Income (loss) before taxes 227,364 3,354 (53,514 ) 350,179 (264,768 ) 262,615 Income tax benefit (expense) — 582 6,119 (399 ) — 6,302 Net income (loss) 227,364 3,936 (47,395 ) 349,780 (264,768 ) 268,917 Net income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Net income (loss) attributable to RenaissanceRe 227,364 3,936 (47,395 ) 308,227 (264,768 ) 227,364 Dividends on preference shares (30,088 ) — — — — (30,088 ) Net income (loss) available (attributable) to RenaissanceRe common shareholders $ 197,276 $ 3,936 $ (47,395 ) $ 308,227 $ (264,768 ) $ 197,276 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor, Subsidiary Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Comprehensive income (loss) Net income (loss) $ 227,364 $ 3,936 $ (47,395 ) $ 349,780 $ (264,768 ) $ 268,917 Change in net unrealized gains on investments — — — (1,657 ) — (1,657 ) Comprehensive income (loss) 227,364 3,936 (47,395 ) 348,123 (264,768 ) 267,260 Net income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income (loss) available (attributable) to RenaissanceRe $ 227,364 $ 3,936 $ (47,395 ) $ 306,570 $ (264,768 ) $ 225,707
Condensed Consolidating Statement of Comprehensive Income	Condensed Consolidating Statement of Comprehensive (Loss) Income for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Comprehensive (loss) income Net (loss) income $ (222,389 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (285,838 ) $ 167,757 $ (354,671 ) Change in net unrealized gains on investments — — — — (909 ) — (909 ) Comprehensive (loss) income (222,389 ) (5,926 ) 30,596 (38,871 ) (286,747 ) 167,757 (355,580 ) Net loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Comprehensive loss attributable to redeemable noncontrolling interests — — — — 132,282 — 132,282 Comprehensive (loss) income (attributable) available to RenaissanceRe $ (222,389 ) $ (5,926 ) $ 30,596 $ (38,871 ) $ (154,465 ) $ 167,757 $ (223,298 ) (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other Consolidating RenaissanceRe Comprehensive income (loss) Net income (loss) $ 227,364 $ 3,936 $ (47,395 ) $ 349,780 $ (264,768 ) $ 268,917 Change in net unrealized gains on investments — — — (1,657 ) — (1,657 ) Comprehensive income (loss) 227,364 3,936 (47,395 ) 348,123 (264,768 ) 267,260 Net income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income attributable to redeemable noncontrolling interests — — — (41,553 ) — (41,553 ) Comprehensive income (loss) available (attributable) to RenaissanceRe $ 227,364 $ 3,936 $ (47,395 ) $ 306,570 $ (264,768 ) $ 225,707 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor, Subsidiary Guarantor and Subsidiary Issuer consolidating adjustments. Condensed Consolidating Statement of Comprehensive Income for the year ended December 31, 2016 RenaissanceRe Holdings Ltd. (Parent Guarantor) RenRe North America Holdings Inc. (Subsidiary Issuer) Platinum RenaissanceRe Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) Consolidating Adjustments (2) RenaissanceRe Consolidated Comprehensive income Net income $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 681,025 $ (593,454 ) $ 630,048 Change in net unrealized gains on investments — — — — (975 ) — (975 ) Comprehensive income 502,962 8,002 29,591 1,922 680,050 (593,454 ) 629,073 Net income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to redeemable noncontrolling interests — — — — (127,086 ) — (127,086 ) Comprehensive income attributable to RenaissanceRe $ 502,962 $ 8,002 $ 29,591 $ 1,922 $ 552,964 $ (593,454 ) $ 501,987 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. (2) Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2018 RenaissanceRe RenRe North RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Consolidated Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (9,659 ) $ 6,315 $ 62,645 $ 1,162,400 $ 1,221,701 Cash flows used in investing activities Proceeds from sales and maturities of fixed maturity investments trading 384,818 97,272 56,518 11,046,968 11,585,576 Purchases of fixed maturity investments trading (520,935 ) (72,292 ) (55,932 ) (11,840,813 ) (12,489,972 ) Net (purchases) sales of equity investments trading — (1,308 ) — 15,464 14,156 Net sales (purchases) of short term investments 48,600 (404 ) 455 (1,485,040 ) (1,436,389 ) Net purchases of other investments — — — (199,475 ) (199,475 ) Net purchases of investments in other ventures — — — (21,473 ) (21,473 ) Return of investment from investment in other ventures — — — 8,464 8,464 Net sales of other assets — — — 2,500 2,500 Dividends and return of capital from subsidiaries 672,098 — — (672,098 ) — Contributions to subsidiaries (785,785 ) (16,847 ) (65,000 ) 867,632 — Due (from) to subsidiary (200,916 ) (9,525 ) 9,449 200,992 — Net cash used in investing activities (402,120 ) (3,104 ) (54,510 ) (2,076,879 ) (2,536,613 ) Cash flows provided by financing activities Dividends paid – RenaissanceRe common shares (52,841 ) — — — (52,841 ) Dividends paid – preference shares (30,088 ) — — — (30,088 ) RenaissanceRe common share issuance 250,000 — — — 250,000 Issuance of preference shares, net of expenses 241,448 — — — 241,448 Net third party redeemable noncontrolling interest share transactions — — — 665,683 665,683 Taxes paid on withholding shares (7,862 ) — — — (7,862 ) Net cash provided by financing activities 400,657 — — 665,683 1,066,340 Effect of exchange rate changes on foreign currency cash — — — (5,098 ) (5,098 ) Net (decrease) increase in cash and cash equivalents (11,122 ) 3,211 8,135 (253,894 ) (253,670 ) Cash and cash equivalents, beginning of period 14,656 139 1,469 1,345,328 1,361,592 Cash and cash equivalents, end of period $ 3,534 $ 3,350 $ 9,604 $ 1,091,434 $ 1,107,922 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2017 RenaissanceRe RenRe North Inc. Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-guarantor Subsidiaries) (1) RenaissanceRe Consolidated Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (4,109 ) $ (8,253 ) $ (2,272 ) $ (347,890 ) $ 1,388,311 $ 1,025,787 Cash flows provided by (used in) investing activities Proceeds from sales and maturities of fixed maturity investments trading 261,601 100,248 289,741 288,900 8,550,179 9,490,669 Purchases of fixed maturity investments trading (344,463 ) (99,568 ) (143,991 ) (275,778 ) (9,229,732 ) (10,093,532 ) Net (purchases) sales of equity investments trading — (1,752 ) 85,324 — 32,265 115,837 Net sales (purchases) of short term investments 243,571 114 41,299 (493 ) 79,520 364,011 Net purchases of other investments — — — — (19,419 ) (19,419 ) Return of investment from investment in other ventures — — — — 20,000 20,000 Dividends and return of capital from subsidiaries 478,496 9,175 — 41,866 (529,537 ) — Contributions to subsidiaries (669,672 ) — (26,649 ) (9,890 ) 706,211 — Due to (from) subsidiaries 319,646 13 (123 ) (509 ) (319,027 ) — Net cash provided by (used in) investing activities 289,179 8,230 245,601 44,096 (709,540 ) (122,434 ) Cash flows (used in) provided by financing activities Dividends paid – RenaissanceRe common shares (51,370 ) — — — — (51,370 ) Dividends paid – preference shares (22,381 ) — — — — (22,381 ) RenaissanceRe common share repurchases (188,591 ) — — — — (188,591 ) Issuance of debt, net of expenses — — — 295,866 — 295,866 Repayment of debt — — (250,000 ) — — (250,000 ) Net third party redeemable noncontrolling interest share transactions — — — — 260,475 260,475 Taxes paid on withholding shares (15,139 ) — — — — (15,139 ) Net cash (used in) provided by financing activities (277,481 ) — (250,000 ) 295,866 260,475 28,860 Effect of exchange rate changes on foreign currency cash — — — — 8,222 8,222 Net increase (decrease) in cash and cash equivalents 7,589 (23 ) (6,671 ) (7,928 ) 947,468 940,435 Cash and cash equivalents, beginning of period 7,067 162 6,671 9,397 397,860 421,157 Cash and cash equivalents, end of period $ 14,656 $ 139 $ — $ 1,469 $ 1,345,328 $ 1,361,592 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations. Condensed Consolidating Statement of Cash Flows for the year ended December 31, 2016 RenaissanceRe RenRe North Platinum Underwriters Finance, Inc. (Subsidiary Issuer) RenaissanceRe Finance, Inc. (Subsidiary Issuer) Other RenaissanceRe Cash flows (used in) provided by operating activities Net cash (used in) provided by operating activities $ (3,509 ) $ 1,477 $ (14,501 ) $ (34,607 ) $ 535,912 $ 484,772 Cash flows provided by (used in) investing activities Proceeds from sales and maturities of fixed maturity investments trading 314,568 69,941 145,082 — 7,572,923 8,102,514 Purchases of fixed maturity investments trading (336,345 ) (123,046 ) (291,053 ) — (7,532,276 ) (8,282,720 ) Proceeds from sales and maturities of fixed maturity investments available for sale — — — — 17,692 17,692 Net (purchases) sales of equity investments trading — (2,389 ) 193,022 — (5,845 ) 184,788 Net (purchases) sales of short term investments (111,814 ) 67,684 (32,901 ) — (41,586 ) (118,617 ) Net purchases of other investments — — — — (68,589 ) (68,589 ) Net sales of other assets — — — — 400 400 Dividends and return of capital from subsidiaries 617,239 2,900 — 13,125 (633,264 ) — Contributions to subsidiaries (108,674 ) — — — 108,674 — Due to (from) subsidiary 23,758 (22,313 ) (81 ) 30,202 (31,566 ) — Net cash provided by (used in) investing activities 398,732 (7,223 ) 14,069 43,327 (613,437 ) (164,532 ) Cash flows used in financing activities Dividends paid – RenaissanceRe common shares (51,583 ) — — — — (51,583 ) Dividends paid – preference shares (22,381 ) — — — — (22,381 ) RenaissanceRe common share repurchases (309,434 ) — — — — (309,434 ) Net third party redeemable noncontrolling interest share transactions — — — — (2,990 ) (2,990 ) Taxes paid on withholding shares (14,943 ) — — — — (14,943 ) Net cash used in financing activities (398,341 ) — — — (2,990 ) (401,331 ) Effect of exchange rate changes on foreign currency cash — — — — (4,637 ) (4,637 ) Net (decrease) increase in cash and cash equivalents (3,118 ) (5,746 ) (432 ) 8,720 (85,152 ) (85,728 ) Cash and cash equivalents, beginning of year 10,185 5,908 7,103 677 483,012 506,885 Cash and cash equivalents, end of year $ 7,067 $ 162 $ 6,671 $ 9,397 $ 397,860 $ 421,157 (1) Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.

Organization (Details)

Organization (Details)	12 Months Ended
	Dec. 31, 2018
RenaissanceRe Upsilon Fund Ltd | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Percent of segregated funds owned by third party investors	100.00%

Significant Accounting Polici_3

Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in cash inflows from cash flows provided by operating activities	$ (1,221,701)	$ (1,025,787)	$ (484,772)
Increase in cash flows used in investing activities	$ (2,536,613)	(122,434)	$ (164,532)
Accounting Standards Update 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in cash inflows from cash flows provided by operating activities		20,000
Increase in cash flows used in investing activities		$ 20,000
Retained earnings | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of new accounting principle in period of adoption				$ 2,200

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Schedule of Intangible Assets and Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other intangible assets
Gross amount	$ 159,503	$ 148,395
Accumulated impairment losses and amortization	(102,537)	(93,924)
Intangible Assets, Net, Excluding Goodwill [Roll Forward]
Other intangible assets, net, beginning balance	54,471
Other intangible assets, net, ending balance	56,966	54,471
Intangible Assets, Net, Including Goodwill [Roll Forward]
Goodwill and Other intangible assets, net, beginning balance	243,145
Goodwill and Other intangible assets, net, ending balance	237,418	243,145
Excluding Equity Method Investments
Goodwill
Gross amount	199,889	199,889	$ 199,889
Accumulated impairment losses and amortization	(2,299)	(2,299)	(2,299)
Goodwill	197,590	197,590	197,590
Other intangible assets
Gross amount	96,599	96,599	96,599
Accumulated impairment losses and amortization	(56,771)	(51,044)	(43,003)
Intangible Assets, Net, Excluding Goodwill [Roll Forward]
Other intangible assets, net, beginning balance	45,555	53,596
Amortization	(5,727)	(8,041)
Other intangible assets, net, ending balance	39,828	45,555
Goodwill and Other intangible assets, Total
Gross amount	296,488	296,488	296,488
Accumulated impairment losses and amortization	(59,070)	(53,343)	$ (45,302)
Intangible Assets, Net, Including Goodwill [Roll Forward]
Goodwill and Other intangible assets, net, beginning balance	243,145	251,186
Amortization	(5,727)	(8,041)
Goodwill and Other intangible assets, net, ending balance	$ 237,418	$ 243,145

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Mar. 23, 2018	Dec. 31, 2017	Dec. 31, 2016
Minimum
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	2 years
Maximum
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	15 years
Weighted Average
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	6 years 7 months 6 days
Equity Method Investments
Goodwill and Intangible Assets [Line Items]
Goodwill	$ 10,598		$ 7,818	$ 7,818
Equity Method Investments | TWFG Holding Company LLC
Goodwill and Intangible Assets [Line Items]
Finite-lived intangible assets		$ 2,000
Indefinite-lived intangible assets		9,100
Goodwill		$ 2,800

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets (Schedule of Goodwill and Other Intangible Assets Included in Equity Method Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other intangible assets
Gross amount	$ 159,503	$ 148,395
Accumulated impairment losses and amortization	(102,537)	(93,924)
Intangible Assets, Net, Excluding Goodwill [Roll Forward]
Other intangible assets, net, beginning balance	54,471
Other intangible assets, net, ending balance	56,966	54,471
Intangible Assets, Net, Including Goodwill [Roll Forward]
Goodwill and Other intangible assets, net, beginning balance	243,145
Goodwill and Other intangible assets, net, ending balance	237,418	243,145
Investments in other ventures, under equity method
Goodwill
Gross amount	15,098	12,318	$ 12,318
Accumulated impairment losses and amortization	(4,500)	(4,500)	(4,500)
Goodwill	10,598	7,818	7,818
Acquired during the year	2,780
Other intangible assets
Gross amount	62,904	51,796	51,796
Accumulated impairment losses and amortization	(45,766)	(42,880)	(39,934)
Intangible Assets, Net, Excluding Goodwill [Roll Forward]
Other intangible assets, net, beginning balance	8,916	11,862
Acquired during the year	11,108
Amortization	(2,886)	(2,946)
Other intangible assets, net, ending balance	17,138	8,916
Goodwill and Other intangible assets, Total
Gross amount	78,002	64,114	64,114
Accumulated impairment losses and amortization	(50,266)	(47,380)	$ (44,434)
Intangible Assets, Net, Including Goodwill [Roll Forward]
Goodwill and Other intangible assets, net, beginning balance	16,734	19,680
Acquired during the year	13,888
Amortization	(2,886)	(2,946)
Goodwill and Other intangible assets, net, ending balance	$ 27,736	$ 16,734

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	$ 159,503	$ 148,395
Accumulated amortization and impairment losses	(102,537)	(93,924)
Other intangible assets, net	56,966	54,471
Licenses
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	19,414	10,267
Accumulated amortization and impairment losses	0	0
Other intangible assets, net	19,414	10,267
Customer relationships and customer lists
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	97,419	95,458
Accumulated amortization and impairment losses	(60,221)	(51,633)
Other intangible assets, net	37,198	43,825
Value of business acquired
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	20,200	20,200
Accumulated amortization and impairment losses	(20,200)	(20,200)
Other intangible assets, net	0	0
Software
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	12,230	12,230
Accumulated amortization and impairment losses	(12,230)	(12,230)
Other intangible assets, net	0	0
Patents and intellectual property
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	4,500	4,500
Accumulated amortization and impairment losses	(4,500)	(4,500)
Other intangible assets, net	0	0
Covenants not-to-compete
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	4,030	4,030
Accumulated amortization and impairment losses	(4,030)	(4,030)
Other intangible assets, net	0	0
Trademarks and trade names
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	1,710	1,710
Accumulated amortization and impairment losses	(1,356)	(1,331)
Other intangible assets, net	$ 354	$ 379

Goodwill and Other Intangible_7

Goodwill and Other Intangible Assets (Schedule of Expected Impairment Charges and Amortization Expense) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Total	$ 56,966
Other intangible assets | Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Total	39,828
Other intangible assets | Investments in other ventures, under equity method
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Total	17,138
Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Indefinite lived	19,414
Other intangible assets | Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Indefinite lived	10,267
Other intangible assets | Investments in other ventures, under equity method
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Indefinite lived	9,147
Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2,019	8,261
2,020	7,192
2,021	6,005
2,022	5,617
2,023	4,724
2024 and thereafter	5,753
Total remaining amortization expense	37,552
Other intangible assets | Other intangible assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2,019	5,446
2,020	5,237
2,021	4,910
2,022	4,522
2,023	4,093
2024 and thereafter	5,353
Total remaining amortization expense	29,561
Other intangible assets | Investments in other ventures, under equity method
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2,019	2,815
2,020	1,955
2,021	1,095
2,022	1,095
2,023	631
2024 and thereafter	400
Total remaining amortization expense	$ 7,991

Investments (Schedule of Fair V

Investments (Schedule of Fair Value of Fixed Maturity Investments Trading) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Fixed maturity investments trading	$ 8,088,870	$ 7,426,555
U.S. treasuries
Investment [Line Items]
Fixed maturity investments trading	3,331,411	3,168,763
Agencies
Investment [Line Items]
Fixed maturity investments trading	174,883	47,646
Municipal
Investment [Line Items]
Fixed maturity investments trading	6,854	509,802
Non-U.S. government
Investment [Line Items]
Fixed maturity investments trading	279,818	287,660
Non-U.S. government-backed corporate
Investment [Line Items]
Fixed maturity investments trading	160,063	163,651
Corporate
Investment [Line Items]
Fixed maturity investments trading	2,450,244	2,063,459
Agency mortgage-backed
Investment [Line Items]
Fixed maturity investments trading	817,880	500,456
Non-agency mortgage-backed
Investment [Line Items]
Fixed maturity investments trading	278,680	300,331
Commercial mortgage-backed
Investment [Line Items]
Fixed maturity investments trading	282,294	202,062
Asset-backed
Investment [Line Items]
Fixed maturity investments trading	$ 306,743	$ 182,725

Investments (Schedule of Contra

Investments (Schedule of Contractual Maturities of Fixed Maturity Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost
Due in less than one year	$ 511,932
Due after one through five years	4,799,196
Due after five through ten years	1,086,697
Due after ten years	79,084
Fixed maturity investments trading	8,163,962	$ 7,434,870
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Due in less than one year	507,728
Due after one through five years	4,762,712
Due after five through ten years	1,056,087
Due after ten years	76,746
Fixed maturity investments trading	8,088,870	7,426,555
Mortgage-backed
Amortized Cost
Fixed maturity investments trading	1,376,565
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Fixed maturity investments trading	1,378,854
Asset-backed
Amortized Cost
Fixed maturity investments trading	310,488
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Fixed maturity investments trading	$ 306,743	$ 182,725

Investments (Schedule of Fair_2

Investments (Schedule of Fair Value of Equity Investments Trading) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Equity investments, trading	$ 310,252	$ 388,254
Financials
Investment [Line Items]
Equity investments, trading	200,357	253,543
Communications and technology
Investment [Line Items]
Equity investments, trading	42,333	49,526
Industrial, utilities and energy
Investment [Line Items]
Equity investments, trading	24,520	34,325
Consumer
Investment [Line Items]
Equity investments, trading	20,639	24,779
Healthcare
Investment [Line Items]
Equity investments, trading	18,925	21,364
Basic materials
Investment [Line Items]
Equity investments, trading	$ 3,478	$ 4,717

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Investments [Abstract]
Cash and investments at fair value on deposit with, or in trust accounts for the benefit of, various counterparties	$ 5,700	$ 4,400
Cash and investments at fair value on deposit with, or in trust accounts for the benefit of, U.S. state regulatory authorities	2,000	1,700
Reverse repurchase agreements	$ 3.7	$ 30
Minimum percentage of collateral required	102.00%

Investments (Schedule of Net In

Investments (Schedule of Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Investment Income [Line Items]
Gross investment income									$ 276,780	$ 237,596	$ 197,147
Investment expenses									(14,914)	(15,387)	(15,421)
Net investment income	$ 53,338	$ 80,696	$ 71,356	$ 56,476	$ 73,464	$ 40,257	$ 54,163	$ 54,325	261,866	222,209	181,726
Fixed maturity investments
Net Investment Income [Line Items]
Gross investment income									211,973	179,624	160,661
Short term investments
Net Investment Income [Line Items]
Gross investment income									33,571	11,082	5,127
Equity investments
Net Investment Income [Line Items]
Gross investment income									4,474	3,628	4,235
Private equity investments
Net Investment Income [Line Items]
Gross investment income									477	33,999	6,155
Other
Net Investment Income [Line Items]
Gross investment income									22,475	8,067	20,181
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income									$ 3,810	$ 1,196	$ 788

Investments (Schedule of Net Re

Investments (Schedule of Net Realized and Unrealized Gains on Investments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gain (Loss) on Securities [Line Items]
Net realized and unrealized (losses) gains on equity investments trading									$ (39,161)	$ 119,544	$ 95,364
Net realized and unrealized (losses) gains on investments	$ (88,654)	$ 13,630	$ (17,901)	$ (82,144)	$ (7,716)	$ 42,052	$ 58,113	$ 43,373	(175,069)	135,822	141,328
Fixed maturity investments
Gain (Loss) on Securities [Line Items]
Gross realized gains									21,284	49,121	72,739
Gross realized losses									(91,098)	(38,832)	(38,315)
Net realized (losses) gains on fixed maturity investments									(69,814)	10,289	34,424
Net unrealized (losses) gains on fixed maturity investments trading									(57,310)	8,479	26,954
Investments-related derivatives
Gain (Loss) on Securities [Line Items]
Net realized and unrealized losses on investments-related derivatives									(8,784)	(2,490)	(15,414)
Equity investments
Gain (Loss) on Securities [Line Items]
Net realized gains on equity investments trading sold during the period									27,739	80,027	14,190
Net unrealized (losses) gains on equity investments trading still held at reporting date									$ (66,900)	$ 39,517	$ 81,174

Investments (Schedule of Other

Investments (Schedule of Other Investments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Other investments	$ 784,933				$ 594,793				$ 784,933	$ 594,793
Net investment income	53,338	$ 80,696	$ 71,356	$ 56,476	73,464	$ 40,257	$ 54,163	$ 54,325	261,866	222,209	$ 181,726
Net unrealized gains recognized in earnings									(8,309)	24,737	11,542
Initial commitments	1,200,000								1,200,000
Fulfilled commitments	686,400								686,400
Unfunded commitments	470,800								470,800
Other investments
Schedule of Investments [Line Items]
Net investment income									23,000	42,100	26,300
Net unrealized gains recognized in earnings due to change in estimate									300	1,900	(3,400)
Other investments | Net investment income
Schedule of Investments [Line Items]
Net unrealized gains recognized in earnings									(8,300)	24,700	$ 11,500
Catastrophe bonds
Schedule of Investments [Line Items]
Other investments	516,571				380,475				516,571	380,475
Private equity investments
Schedule of Investments [Line Items]
Other investments	242,647				196,220				242,647	196,220
Senior secured bank loan funds
Schedule of Investments [Line Items]
Other investments	14,482				17,574				14,482	17,574
Hedge funds
Schedule of Investments [Line Items]
Other investments	$ 11,233				$ 524				$ 11,233	$ 524

Investments (Schedule of Invest

Investments (Schedule of Investments in Other Ventures, under Equity Method) (Details) - USD ($) $ in Thousands	Jul. 01, 2008	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 06, 1999
Schedule of Equity Method Investments [Line Items]
Investment					$ 165,987	$ 143,775
Carrying Value					115,172	101,974
Equity method investee, additional contribution					21,473	0	$ 0
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Investment					$ 64,750	$ 64,750
Ownership %					24.90%	26.30%
Carrying Value					$ 38,241	$ 42,167
THIG
Schedule of Equity Method Investments [Line Items]
Investment	$ 50,000
Ownership %	25.00%
Intangible assets, net	$ 40,000
Goodwill	$ 7,800
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Investment					$ 65,375	$ 65,375		$ 13,100
Ownership %					50.00%	50.00%		50.00%
Carrying Value					$ 46,562	$ 50,211
Equity method investee, additional contribution		$ 18,000	$ 20,500	$ 13,800
Other
Schedule of Equity Method Investments [Line Items]
Investment					$ 35,862	$ 13,650
Ownership %					30.60%	40.40%
Carrying Value					$ 30,369	$ 9,596

Investments (Schedule of Equity

Investments (Schedule of Equity in (Losses) Earnings of Other Ventures, Under Equity Method) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investment, dividends or distributions									$ (26,100)	$ 29,700	$ 9,400
Equity in earnings (losses) of other ventures	$ 4,143	$ 7,648	$ 5,826	$ 857	$ 2,200	$ 1,794	$ 5,543	$ (1,507)	18,474	8,030	963
Undistributed earnings (losses) from equity method investments	$ (3,800)				$ (6,300)				(3,800)	(6,300)
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures									8,852	9,851	(8,576)
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures									9,605	(1,647)	10,379
Other
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of other ventures									$ 17	$ (174)	$ (840)

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	$ 8,088,870	$ 7,426,555
Equity investments trading, at fair value (Notes 4 and 5)	310,252	388,254
Other investments	784,933	594,793
Other assets	4,968	2,542
Other liabilities	13,327	5,494
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	8,088,870	7,426,555
Short term investments	2,586,520	991,863
Equity investments trading, at fair value (Notes 4 and 5)	310,252	388,254
Other investments	784,933	594,793
Other assets	4,040	1,684
Assets (liabilities), at fair value	11,774,615	9,403,149
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	3,331,411	3,168,763
Short term investments	0	0
Equity investments trading, at fair value (Notes 4 and 5)	310,252	388,254
Other investments	0	0
Other assets	484
Other liabilities		45
Assets (liabilities), at fair value	3,642,147	3,556,972
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	4,757,459	4,257,792
Short term investments	2,586,520	991,863
Equity investments trading, at fair value (Notes 4 and 5)	0	0
Other investments	516,571	380,475
Other assets	11,915	4,681
Assets (liabilities), at fair value	7,872,465	5,634,811
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Short term investments	0	0
Equity investments trading, at fair value (Notes 4 and 5)	0	0
Other investments	54,545	0
Other liabilities	8,359	2,952
Assets (liabilities), at fair value	46,186	(2,952)
Fair Value, Measurements, Recurring | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	3,331,411	3,168,763
Fair Value, Measurements, Recurring | U.S. treasuries | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	3,331,411	3,168,763
Fair Value, Measurements, Recurring | U.S. treasuries | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | U.S. treasuries | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	174,883	47,646
Fair Value, Measurements, Recurring | Agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Agencies | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	174,883	47,646
Fair Value, Measurements, Recurring | Agencies | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	6,854	509,802
Fair Value, Measurements, Recurring | Municipal | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Municipal | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	6,854	509,802
Fair Value, Measurements, Recurring | Municipal | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-U.S. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	279,818	287,660
Fair Value, Measurements, Recurring | Non-U.S. government | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-U.S. government | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	279,818	287,660
Fair Value, Measurements, Recurring | Non-U.S. government | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	160,063	163,651
Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	160,063	163,651
Fair Value, Measurements, Recurring | Non-U.S. government-backed corporate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	2,450,244	2,063,459
Fair Value, Measurements, Recurring | Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Corporate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	2,450,244	2,063,459
Fair Value, Measurements, Recurring | Corporate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	817,880	500,456
Fair Value, Measurements, Recurring | Agency mortgage-backed | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Agency mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	817,880	500,456
Fair Value, Measurements, Recurring | Agency mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	278,680	300,331
Fair Value, Measurements, Recurring | Non-agency mortgage-backed | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Non-agency mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	278,680	300,331
Fair Value, Measurements, Recurring | Non-agency mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	282,294	202,062
Fair Value, Measurements, Recurring | Commercial mortgage-backed | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Commercial mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	282,294	202,062
Fair Value, Measurements, Recurring | Commercial mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	306,743	182,725
Fair Value, Measurements, Recurring | Asset-backed | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Asset-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	306,743	182,725
Fair Value, Measurements, Recurring | Asset-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments trading	0	0
Fair Value, Measurements, Recurring | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	516,571	380,475
Fair Value, Measurements, Recurring | Catastrophe bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Catastrophe bonds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	516,571	380,475
Fair Value, Measurements, Recurring | Catastrophe bonds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	242,647	196,220
Fair Value, Measurements, Recurring | Private equity investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Private equity investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Private equity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	54,545	0
Fair Value, Measurements, Recurring | Senior secured bank loan funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	14,482	17,574
Fair Value, Measurements, Recurring | Senior secured bank loan funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Senior secured bank loan funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Senior secured bank loan funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	11,233	524
Fair Value, Measurements, Recurring | Hedge funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Hedge funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Hedge funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	8,359	2,952
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0
Other liabilities		0
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0
Other liabilities		0
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	8,359	2,952
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Significant Unobservable Inputs (Level 3) | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	5,000	2,500
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Significant Unobservable Inputs (Level 3) | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	13,300	5,500
Fair Value, Measurements, Recurring | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	12,399	4,636
Fair Value, Measurements, Recurring | Derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	484
Other liabilities		45
Fair Value, Measurements, Recurring | Derivatives | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	11,915	4,681
Fair Value, Measurements, Recurring | Derivatives | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	$ 0
Other liabilities		$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	$ 784,933,000	$ 594,793,000
Other assets	4,968,000	2,542,000
Other liabilities	(13,327,000)	(5,494,000)
Long-term debt	991,127,000	989,623,000
Senior notes, fair value	974,700,000	1,000,000,000
Net unrealized gains (losses) included in net investment income	(8,309,000)	24,737,000	$ 11,542,000
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	784,933,000	594,793,000
Other assets	4,040,000	1,684,000
Other investments | Net investment income
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized gains (losses) included in net investment income	(8,300,000)	24,700,000	11,500,000
Other assets and (liabilities) | Other income (loss)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized gains (losses) included in net investment income	0	0	$ 0
Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	991,127,000	989,623,000
Senior notes, fair value	974,714,000	1,018,235,000
Private equity investments | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	242,647,000	196,220,000
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	516,571,000	380,475,000
Other assets	11,915,000	4,681,000
Significant Other Observable Inputs (Level 2) | Private equity investments | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	54,545,000	0
Other liabilities	(8,359,000)	(2,952,000)
Significant Unobservable Inputs (Level 3) | Internal Valuation Model Valuation Technique | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments				$ 54,545,000
Other assets	46,186,000
Significant Unobservable Inputs (Level 3) | Private equity investments | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	54,545,000	$ 0
Significant Unobservable Inputs (Level 3) | Private equity investments | Internal Valuation Model Valuation Technique | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments				$ 54,545,000
Significant Unobservable Inputs (Level 3) | Assumed reinsurance contract | Internal Valuation Model Valuation Technique | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	550,000
Significant Unobservable Inputs (Level 3) | Assumed and ceded (re)insurance contracts | Internal Valuation Model Valuation Technique | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities	(8,909,000)
Fair Value Measured at Net Asset Value Per Share
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments fair value	$ 213,817,000
U.S. treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	2.50%
Weighted average credit quality		1.90%
Agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	3.00%
Weighted average credit quality		2.10%
Municipal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	4.80%
Weighted average credit quality		2.20%
Non-U.S. government
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	2.70%
Weighted average credit quality		2.00%
Non-U.S. government-backed corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	2.80%
Weighted average credit quality		2.30%
Corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	4.90%
Weighted average credit quality		3.80%
Agency mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	3.50%
Weighted average credit quality		3.00%
Weighted average life	7 years 1 month 6 days	6 years 4 months 24 days
Non-agency prime residential mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	4.40%
Weighted average credit quality		3.70%
Weighted average life	4 years 8 months 12 days	5 years 1 month 6 days
Alt-A non-agency mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	4.70%
Weighted average credit quality		3.70%
Weighted average life	6 years 3 months 18 days	6 years 2 months 12 days
Commercial mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	3.60%
Weighted average credit quality		2.90%
Weighted average life	5 years	4 years 6 months
Asset-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	4.30%
Weighted average credit quality		2.80%
Weighted average life	3 years 2 months 12 days	3 years
Short term investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average yield to maturity	2.10%
Weighted average credit quality		1.40%
Private equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	$ 242,647,000	$ 196,220,000
Private equity investments | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	7 years
Private equity investments | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	10 years
Private equity investments | Fair Value Measured at Net Asset Value Per Share
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments fair value	$ 188,102,000
Senior secured bank loan funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	14,482,000	17,574,000
Investment in closed end fund	$ 14,500,000
Senior secured bank loan funds | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	4 years
Senior secured bank loan funds | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	5 years
Senior secured bank loan funds | Fair Value Measured at Net Asset Value Per Share
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments fair value	$ 14,482,000
Hedge funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	11,233,000	$ 524,000
Hedge funds | Fair Value Measured at Net Asset Value Per Share
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments fair value	11,233,000
Hedge Funds Redeemable at Option of Shareholder | Fair Value Measured at Net Asset Value Per Share
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments fair value	$ 11,000,000

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Information Used As Level 3 Inputs) (Details) $ in Thousands	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)	Jun. 30, 2016USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments	$ 784,933	$ 594,793
Other assets and (liabilities)	4,968	2,542
Total other assets and (liabilities)	13,327	5,494
Fair Value, Measurements, Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments	784,933	594,793
Other assets and (liabilities)	4,040	1,684
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments	54,545	0
Total other assets and (liabilities)	8,359	2,952
Fair Value, Measurements, Recurring | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments			$ 54,545
Other assets and (liabilities)	46,186
Fair Value, Measurements, Recurring | Private equity investments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments	242,647	196,220
Fair Value, Measurements, Recurring | Private equity investments | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments	54,545	0
Fair Value, Measurements, Recurring | Private equity investments | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other investments			$ 54,545
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other assets and (liabilities)	8,359	2,952
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other assets and (liabilities)	8,359	$ 2,952
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other assets and (liabilities)	8,359
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group one | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other assets and (liabilities)	550
Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group two | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other assets and (liabilities)	$ 8,909
Discount rate | Fair Value, Measurements, Recurring | Private equity investments | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	0.168
Discount rate | Fair Value, Measurements, Recurring | Private equity investments | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	0.296
Discount rate | Fair Value, Measurements, Recurring | Private equity investments | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	0.232
Discount rate | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group two | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs	0.025
Bond price | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group one | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	100.74
Bond price | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group one | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	107.82
Bond price | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group one | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs | $ / shares	104.66
Liquidity discount | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group one | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs	0.013
Net undiscounted cash flows | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group two | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs	10,528,000
Expected loss ratio | Fair Value, Measurements, Recurring | Assumed and ceded (re)insurance contracts, group two | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Significant observable and unobservable inputs	0.361

Fair Value Measurements (Asse_2

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Level 3 Inputs) (Details) - Significant Unobservable Inputs (Level 3) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (2,952)
Total realized and unrealized gains
Purchases	45,254
Settlements	983
Ending balance	46,186	$ (2,952)
Other income (loss)
Total realized and unrealized gains
Included in other income	2,901
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0
Total realized and unrealized gains
Purchases	54,545
Settlements	0
Ending balance	54,545	0
Other investments | Other income (loss)
Total realized and unrealized gains
Included in other income	0
Other assets and (liabilities)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(2,952)	(13,004)
Total realized and unrealized gains
Purchases	(9,291)	354
Settlements	983	5,937
Ending balance	(8,359)	(2,952)
Other assets and (liabilities) | Other income (loss)
Total realized and unrealized gains
Included in other income	$ 2,901	$ 3,761

Fair Value Measurements (Summar

Fair Value Measurements (Summary of the Balances Company Has Elected to Account For at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Other investments	$ 784,933	$ 594,793
Other assets and (liabilities)	4,968	2,542
Other liabilities	$ 13,327	$ 5,494

Fair Value Measurements (Compan

Fair Value Measurements (Company's Portfolio of Other Investments Measured Using Net Asset Valuations) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 413,821
Fair Value Measured at Net Asset Value Per Share
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	213,817
Fair Value Measured at Net Asset Value Per Share | Private equity investments
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	188,102
Unfunded Commitments	393,700
Fair Value Measured at Net Asset Value Per Share | Senior secured bank loan funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	14,482
Unfunded Commitments	20,121
Fair Value Measured at Net Asset Value Per Share | Hedge funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	11,233
Unfunded Commitments	$ 0

Reinsurance (Effect of Reinsura

Reinsurance (Effect of Reinsurance and Retrocessional Activity on Premiums Written and Earned and on Net Claims and Claim Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Premiums written
Direct									$ 337,587	$ 290,730	$ 208,282
Assumed									2,972,840	2,506,810	2,166,294
Ceded									(1,178,525)	(926,215)	(839,264)
Net premiums written	$ 411,094	$ 453,255	$ 604,509	$ 663,044	$ 288,223	$ 483,221	$ 555,745	$ 544,136	2,131,902	1,871,325	1,535,312
Premiums earned
Direct									292,219	244,285	157,112
Assumed									2,779,796	2,307,219	1,874,993
Ceded									(1,095,886)	(833,929)	(628,675)
Net premiums earned (Note 6)	574,613	531,849	429,385	440,282	421,473	547,792	382,265	366,045	1,976,129	1,717,575	1,403,430
Claims and claim expenses
Gross claims and claim expenses incurred									2,578,536	3,420,388	710,651
Claims and claim expenses recovered									(1,458,518)	(1,558,960)	(179,820)
Net claims and claim expenses incurred	$ 477,638	$ 410,510	$ 60,167	$ 171,703	$ 304,064	$ 1,221,696	$ 142,587	$ 193,081	$ 1,120,018	$ 1,861,428	$ 530,831

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Reinsurance recoverable	$ 2,372,221	$ 1,586,630	$ 279,564
Allowance for Reinsurance Recoverable
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation allowance recorded against reinsurance recoverable	$ 9,000	$ 7,000
Reinsurance Recoverable | Largest reinsurance recoverable, Customer One
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	15.50%	10.40%
Reinsurance Recoverable | Largest reinsurance recoverable, Customer Two
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	6.70%	7.50%
Reinsurance Recoverable | Largest reinsurance recoverable, Customer Three
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	6.50%	7.30%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer One
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	16.20%	11.10%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer Two
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	14.80%	9.20%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer Three
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	12.30%	8.40%
Ceded Credit Risk, Secured | Reinsurance Recoverable | Reinsurer Concentration Risk
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	60.80%	54.50%
Rated A- or higher | Ceded Credit Risk, Unsecured | Reinsurance Recoverable | Reinsurer Concentration Risk
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	38.00%	44.50%
Rated lower than A- | Ceded Credit Risk, Unsecured | Reinsurance Recoverable | Reinsurer Concentration Risk
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Concentration risk percentage	1.20%	1.00%

Reserve for Claims and Claim _3

Reserve for Claims and Claim Expenses (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 02, 2015
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	$ 3,704,050	$ 3,493,778	$ 2,568,730	$ 2,632,519
Claims and claim expenses recovered	(1,458,518)	(1,558,960)	(179,820)
Reinsurance balances payable
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Aggregate deposit liabilities	10,300	21,700
Aggregate deposit assets
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Aggregate deposit assets	0	0
Deposit Contracts, Underwriting Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Claims and claim expenses recovered	200	200	200
Deposit Contracts, Timing Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase in other income related to assumed reinsurance contracts	11,200	$ 3,700	$ 6,200
Property
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	1,373,125
Casualty and Specialty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	$ 2,330,557
Platinum Underwriters Holdings, Ltd.
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses					$ 1,400,000
Platinum Underwriters Holdings, Ltd. | Property
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses					179,700
Platinum Underwriters Holdings, Ltd. | Casualty and Specialty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses					$ 1,200,000

Reserve for Claims and Claim _4

Reserve for Claims and Claim Expenses (Claims and Claim Expense Reserves by Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Case Reserves	$ 1,463,713	$ 1,392,852
Additional Case Reserves	1,425,184	1,021,445
IBNR	3,187,374	2,666,111
Net reserve for claims and claim expenses	6,076,271	5,080,408	$ 2,848,294
Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Case Reserves	1,458	6,605
Additional Case Reserves	0	0
IBNR	3,166	11,921
Net reserve for claims and claim expenses	4,624	18,526
Property | Operating Segments
Liability for Claims and Claims Adjustment Expense [Line Items]
Case Reserves	690,718	696,285
Additional Case Reserves	1,308,307	896,522
IBNR	1,087,229	893,583
Net reserve for claims and claim expenses	3,086,254	2,486,390
Casualty and Specialty | Operating Segments
Liability for Claims and Claims Adjustment Expense [Line Items]
Case Reserves	771,537	689,962
Additional Case Reserves	116,877	124,923
IBNR	2,096,979	1,760,607
Net reserve for claims and claim expenses	$ 2,985,393	$ 2,575,492

Reserve for Claims and Claim _5

Reserve for Claims and Claim Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Net reserves as of January 1	$ 3,493,778	$ 2,568,730	$ 2,632,519
Net incurred related to:
Current year	1,390,767	1,902,424	694,957
Prior years	(270,749)	(40,996)	(164,126)
Total net incurred	1,120,018	1,861,428	530,831
Net paid related to:
Current year	391,061	450,527	83,015
Prior years	503,708	524,298	506,279
Total net paid	894,769	974,825	589,294
Foreign exchange	(14,977)	38,445	(5,326)
Net reserves as of December 31	3,704,050	3,493,778	2,568,730
Reinsurance recoverable as of December 31	2,372,221	1,586,630	279,564
Gross reserves as of December 31	$ 6,076,271	$ 5,080,408	$ 2,848,294

Reserve for Claims and Claim _6

Reserve for Claims and Claim Expenses (Incurred and Paid Claims Development) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	$ 8,728,754
IBNR and ACR	2,493,228
Cumulative paid claims and claim expenses, net of reinsurance	5,345,836
Outstanding liabilities from accident year 2008 and prior, net of reinsurance	286,863
Claims and claim expenses, net of reinsurance, from the Company's former Bermuda-based insurance operations	368
Adjustment for unallocated claim expenses	28,956
Unamortized fair value adjustments recorded in connection with the acquisition of Platinum	4,945
Liability for claims and claim expenses, net of reinsurance	3,704,050
Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	4,555,973
IBNR and ACR	976,849
Cumulative paid claims and claim expenses, net of reinsurance	3,191,734
Outstanding liabilities from accident year 2008 and prior, net of reinsurance	4,222
Adjustment for unallocated claim expenses	4,028
Unamortized fair value adjustments recorded in connection with the acquisition of Platinum	636
Liability for claims and claim expenses, net of reinsurance	1,373,125
Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	4,172,781
IBNR and ACR	1,516,379
Cumulative paid claims and claim expenses, net of reinsurance	2,154,102
Outstanding liabilities from accident year 2008 and prior, net of reinsurance	282,641
Adjustment for unallocated claim expenses	24,928
Unamortized fair value adjustments recorded in connection with the acquisition of Platinum	4,309
Liability for claims and claim expenses, net of reinsurance	2,330,557
Accident Year 2009
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	521,739	$ 519,585	$ 516,888	$ 521,723	$ 530,876	$ 552,059	$ 577,285	$ 617,015	$ 634,400	$ 699,400
IBNR and ACR	17,510
Cumulative paid claims and claim expenses, net of reinsurance	481,632	472,679	465,244	458,920	437,232	398,452	365,731	321,506	269,714	96,462
Accident Year 2009 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	134,876	134,355	134,811	134,539	135,245	134,490	138,747	145,207	164,369	219,979
IBNR and ACR	74
Cumulative paid claims and claim expenses, net of reinsurance	136,329	135,729	135,721	134,770	133,750	129,204	123,281	115,459	101,124	56,142
Accident Year 2009 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	386,863	385,230	382,077	387,184	395,631	417,569	438,538	471,808	470,031	479,421
IBNR and ACR	17,436
Cumulative paid claims and claim expenses, net of reinsurance	345,303	336,950	329,523	324,150	303,482	269,248	242,450	206,047	168,590	$ 40,320
Accident Year 2010
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	855,132	866,529	868,441	860,517	869,959	871,664	902,908	950,984	992,376
IBNR and ACR	52,575
Cumulative paid claims and claim expenses, net of reinsurance	758,762	741,629	715,191	626,094	555,252	500,974	431,562	315,357	128,276
Accident Year 2010 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	555,642	566,475	564,345	554,733	550,980	531,199	526,928	561,524	609,380
IBNR and ACR	33,429
Cumulative paid claims and claim expenses, net of reinsurance	497,547	483,738	474,179	398,691	372,499	337,060	295,243	216,504	93,423
Accident Year 2010 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	299,490	300,054	304,096	305,784	318,979	340,465	375,980	389,460	382,996
IBNR and ACR	19,146
Cumulative paid claims and claim expenses, net of reinsurance	261,215	257,891	241,012	227,403	182,753	163,914	136,319	98,853	$ 34,853
Accident Year 2011
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	1,337,445	1,334,068	1,348,620	1,384,912	1,412,886	1,493,095	1,573,930	1,646,568
IBNR and ACR	76,002
Cumulative paid claims and claim expenses, net of reinsurance	1,222,512	1,203,998	1,176,892	1,133,013	1,043,763	889,387	540,985	260,326
Accident Year 2011 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	1,033,601	1,036,663	1,040,721	1,070,957	1,091,415	1,141,403	1,192,868	1,264,374
IBNR and ACR	46,427
Cumulative paid claims and claim expenses, net of reinsurance	971,324	966,304	952,780	926,747	868,489	743,745	427,501	212,259
Accident Year 2011 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	303,844	297,405	307,899	313,955	321,471	351,692	381,062	382,194
IBNR and ACR	29,575
Cumulative paid claims and claim expenses, net of reinsurance	251,188	237,694	224,112	206,266	175,274	145,642	113,484	$ 48,067
Accident Year 2012
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	666,704	655,882	653,437	681,405	707,471	770,104	865,281
IBNR and ACR	52,680
Cumulative paid claims and claim expenses, net of reinsurance	551,846	525,736	461,035	417,628	357,821	266,980	166,564
Accident Year 2012 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	257,246	264,532	275,910	293,873	311,648	344,487	437,940
IBNR and ACR	16,299
Cumulative paid claims and claim expenses, net of reinsurance	233,647	230,839	218,638	208,653	189,199	145,098	100,057
Accident Year 2012 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	409,458	391,350	377,527	387,532	395,823	425,617	427,341
IBNR and ACR	36,381
Cumulative paid claims and claim expenses, net of reinsurance	318,199	294,897	242,397	208,975	168,622	121,882	$ 66,507
Accident Year 2013
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	433,363	446,311	472,270	512,389	558,746	619,414
IBNR and ACR	46,050
Cumulative paid claims and claim expenses, net of reinsurance	348,436	326,807	289,144	243,544	179,709	86,998
Accident Year 2013 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	137,660	141,197	152,715	174,335	196,729	227,268
IBNR and ACR	1,971
Cumulative paid claims and claim expenses, net of reinsurance	134,044	132,822	128,631	117,642	93,041	49,032
Accident Year 2013 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	295,703	305,114	319,555	338,054	362,017	392,146
IBNR and ACR	44,079
Cumulative paid claims and claim expenses, net of reinsurance	214,392	193,985	160,513	125,902	86,668	$ 37,966
Accident Year 2014
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	558,619	582,473	601,727	613,786	660,836
IBNR and ACR	117,354
Cumulative paid claims and claim expenses, net of reinsurance	357,894	317,901	268,871	200,830	111,067
Accident Year 2014 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	142,457	142,864	147,138	154,469	183,249
IBNR and ACR	4,689
Cumulative paid claims and claim expenses, net of reinsurance	126,897	123,790	118,768	96,074	55,090
Accident Year 2014 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	416,162	439,609	454,589	459,317	477,587
IBNR and ACR	112,665
Cumulative paid claims and claim expenses, net of reinsurance	230,997	194,111	150,103	104,756	$ 55,977
Accident Year 2015
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	590,591	629,211	627,702	639,151
IBNR and ACR	136,328
Cumulative paid claims and claim expenses, net of reinsurance	362,419	287,522	193,965	95,862
Accident Year 2015 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	167,916	176,159	195,164	226,039
IBNR and ACR	19,347
Cumulative paid claims and claim expenses, net of reinsurance	138,283	127,509	108,679	62,169
Accident Year 2015 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	422,675	453,052	432,538	413,112
IBNR and ACR	116,981
Cumulative paid claims and claim expenses, net of reinsurance	224,136	160,013	85,286	$ 33,693
Accident Year 2016
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	666,453	684,757	680,039
IBNR and ACR	241,938
Cumulative paid claims and claim expenses, net of reinsurance	324,224	217,746	79,577
Accident Year 2016 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	241,296	254,151	252,556
IBNR and ACR	64,136
Cumulative paid claims and claim expenses, net of reinsurance	155,917	119,260	47,491
Accident Year 2016 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	425,157	430,606	427,483
IBNR and ACR	177,802
Cumulative paid claims and claim expenses, net of reinsurance	168,307	98,486	$ 32,086
Accident Year 2017
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	1,731,295	1,895,376
IBNR and ACR	828,815
Cumulative paid claims and claim expenses, net of reinsurance	548,619	450,034
Accident Year 2017 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	1,167,013	1,342,161
IBNR and ACR	454,395
Cumulative paid claims and claim expenses, net of reinsurance	443,130	411,961
Accident Year 2017 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	564,282	553,215
IBNR and ACR	374,420
Cumulative paid claims and claim expenses, net of reinsurance	105,489	$ 38,073
Accident Year 2018
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	1,367,413
IBNR and ACR	923,976
Cumulative paid claims and claim expenses, net of reinsurance	389,492
Accident Year 2018 | Property
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	718,266
IBNR and ACR	336,082
Cumulative paid claims and claim expenses, net of reinsurance	354,616
Accident Year 2018 | Casualty and Specialty
Claims Development [Line Items]
Incurred claims and claim expenses, net of reinsurance	649,147
IBNR and ACR	587,894
Cumulative paid claims and claim expenses, net of reinsurance	$ 34,876

Reserve for Claims and Claim _7

Reserve for Claims and Claim Expenses (Prior Year Development of the Reserve for Net Claims and Claim Expenses) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	$ (270,749)	$ (40,996)	$ (164,126)
Discount rate | Ogden Rate
Liability for Catastrophe Claims [Line Items]
Cash surrender value, measurement input		(0.0075)	0.025
Other
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(197)	$ (1,583)	$ (1,110)
Property
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(221,290)	(45,596)	(104,876)
Property | Actuarial assumption changes
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(5,682)	842
Property | Large and small catastrophe events and attritional loss movements
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(215,608)	(46,438)	(104,876)
Property | Large catastrophe events
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(182,029)	(7,640)	(33,926)
Property | Storm Sandy (2012)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		(4,395)	(10,849)
Property | April and May U.S. Tornadoes (2011)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		(4,177)
Property | Thailand Floods (2011)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years			(15,131)
Property | Tohoku Earthquake and Tsunami (2011)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years			(7,314)
Property | New Zealand Earthquake (2010)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		4,061	6,904
Property | New Zealand Earthquake (2011)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		5,807	1,987
Property | Other
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(9,517)	(8,936)	(9,523)
Property | Small catastrophe events and attritional loss movements
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(33,579)	(38,798)	(70,950)
Property | 2017 Large Loss Events
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(172,512)
Property | Tianjin Explosion (2015)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		(8,002)	(5,686)
Property | Fort McMurray Wildfire (2016)
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years		(6,364)
Property | Other small catastrophe events and attritional loss movements
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(33,579)	(24,432)	(65,264)
Casualty and Specialty
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(49,262)	6,183	(58,140)
Casualty and Specialty | Actuarial methods - actual reported claims less than expected claims
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	(41,476)	(24,836)	(52,601)
Casualty and Specialty | Ogden Rate change
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	0	33,481	0
Casualty and Specialty | Actuarial assumption changes
Liability for Catastrophe Claims [Line Items]
Net claims and claim expenses incurred – prior accident years	$ (7,786)	$ (2,462)	$ (5,539)

Reserve for Claims and Claim _8

Reserve for Claims and Claim Expenses (Reconciliation of the Disclosure of Incurred and Paid Claims Development to the Reserve for Claims and Claim Expenses) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	$ 3,704,050	$ 3,493,778	$ 2,568,730	$ 2,632,519
Reinsurance recoverable	2,372,221
Total gross reserve for claims and claim expenses	6,076,271	5,080,408	$ 2,848,294
Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	368
Reinsurance recoverable	4,256
Total gross reserve for claims and claim expenses	4,624	$ 18,526
Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	1,373,125
Reinsurance recoverable	1,713,129
Casualty and Specialty
Liability for Claims and Claims Adjustment Expense [Line Items]
Net reserve for claims and claim expenses	2,330,557
Reinsurance recoverable	$ 654,836

Reserve for Claims and Claim _9

Reserve for Claims and Claim Expenses (Historical Claims Duration) (Details)	Dec. 31, 2018
Property
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average annual percentage payout, year one	31.70%
Average annual percentage payout, year two	17.30%
Average annual percentage payout, year three	20.80%
Average annual percentage payout, year four	9.10%
Average annual percentage payout, year five	5.20%
Average annual percentage payout, year six	3.30%
Average annual percentage payout, year seven	4.70%
Average annual percentage payout, year eight	0.90%
Average annual percentage payout, year nine	2.00%
Average annual percentage payout, year ten	0.40%
Casualty and Specialty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average annual percentage payout, year one	10.10%
Average annual percentage payout, year two	16.90%
Average annual percentage payout, year three	12.90%
Average annual percentage payout, year four	10.90%
Average annual percentage payout, year five	8.50%
Average annual percentage payout, year six	10.00%
Average annual percentage payout, year seven	5.10%
Average annual percentage payout, year eight	3.60%
Average annual percentage payout, year nine	1.60%
Average annual percentage payout, year ten	2.20%

Reserve for Claims and Claim_10

Reserve for Claims and Claim Expenses (Cumulative Number of Claims Reported) (Details) - Excess of Loss Reinsurance Contracts	Dec. 31, 2018claim
Accident Year 2009 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	743
Accident Year 2009 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,132
Accident Year 2010 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	787
Accident Year 2010 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,081
Accident Year 2011 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,186
Accident Year 2011 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,411
Accident Year 2012 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	679
Accident Year 2012 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,448
Accident Year 2013 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	629
Accident Year 2013 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,557
Accident Year 2014 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	553
Accident Year 2014 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	2,040
Accident Year 2015 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	606
Accident Year 2015 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,992
Accident Year 2016 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	845
Accident Year 2016 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,650
Accident Year 2017 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,812
Accident Year 2017 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,028
Accident Year 2018 | Property
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	1,014
Accident Year 2018 | Casualty and Specialty
Claims Development [Line Items]
Cumulative number of reported claims (in claims)	277

Debt and Credit Facilities (Sum

Debt and Credit Facilities (Summary of Debt Obligations) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jun. 29, 2017	May 04, 2015	Mar. 24, 2015
Debt Instrument [Line Items]
Senior notes, fair value	$ 974,700	$ 1,000,000
Long-term debt	$ 991,127	989,623
3.450% Senior Notes due 2027
Debt Instrument [Line Items]
Interest rate	3.45%
3.700% Senior Notes due 2025
Debt Instrument [Line Items]
Interest rate	3.70%
5.750% Senior Notes due 2020
Debt Instrument [Line Items]
Interest rate	5.75%
4.750% Senior Notes due 2025 (DaVinciRe)
Debt Instrument [Line Items]
Interest rate	4.75%
RenaissanceRe Finance, Inc. | 3.700% Senior Notes due 2025
Debt Instrument [Line Items]
Interest rate					3.70%
DaVinciRe Holdings Ltd. | 4.750% Senior Notes due 2025 (DaVinciRe)
Debt Instrument [Line Items]
Interest rate				4.75%
Senior Notes
Debt Instrument [Line Items]
Senior notes, fair value	$ 974,714	1,018,235
Long-term debt	991,127	989,623
Senior Notes | RenaissanceRe Finance, Inc. | 3.450% Senior Notes due 2027
Debt Instrument [Line Items]
Interest rate			3.45%
Senior notes, fair value	283,680	294,654
Long-term debt	295,797	295,303
Senior Notes | RenaissanceRe Finance, Inc. | 3.700% Senior Notes due 2025
Debt Instrument [Line Items]
Senior notes, fair value	292,557	302,781
Long-term debt	297,688	297,318
Senior Notes | RenaissanceRe Finance, Inc. | 5.750% Senior Notes due 2020
Debt Instrument [Line Items]
Senior notes, fair value	255,938	263,750
Long-term debt	249,602	249,272
Senior Notes | DaVinciRe Holdings Ltd. | 4.750% Senior Notes due 2025 (DaVinciRe)
Debt Instrument [Line Items]
Senior notes, fair value	142,539	157,050
Long-term debt	$ 148,040	$ 147,730

Debt and Credit Facilities (Nar

Debt and Credit Facilities (Narrative) (Details)

Dec. 31, 2018USD ($)

Dec. 31, 2018GBP (£)

Nov. 09, 2018USD ($)

Jun. 29, 2017USD ($)

May 25, 2017USD ($)

May 31, 2016USD ($)

May 31, 2016GBP (£)

Nov. 23, 2015USD ($)

Nov. 23, 2015GBP (£)

May 04, 2015USD ($)

Mar. 24, 2015USD ($)

Sep. 17, 2010USD ($)

Mar. 17, 2010USD ($)

Nov. 02, 2005USD ($)

Debt Instrument [Line Items]

Margin facility amount outstanding

$ 510,557,000

£ 0

Bridge Loan | Platinum Underwriters Holdings, Ltd.

Debt Instrument [Line Items]

Short-term debt

$ 300,000,000

3.450% Senior Notes due 2027

Debt Instrument [Line Items]

Interest rate

3.45%

3.45%

3.700% Senior Notes due 2025

Debt Instrument [Line Items]

Interest rate

3.70%

3.70%

5.75% Senior Notes Due March 15, 2020

Debt Instrument [Line Items]

Interest rate

5.75%

5.75%

4.750% Senior Notes Due May 1, 2025

Debt Instrument [Line Items]

Interest rate

4.75%

4.75%

Revolving Credit Facility

Debt Instrument [Line Items]

Letter of credit aggregate commitment

$ 500,000,000

Line of credit facility, maximum borrowing capacity

750,000,000

Debt to capital ratio

0.35

0.35

Minimum net worth requirements

$ 2,900,000,000

Bridge Loan | Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 50,000,000

Line of Credit | Revolving Credit Facility

Debt Instrument [Line Items]

Margin facility amount outstanding

0

Line of Credit | Renaissance Reinsurance FAL Facility

Debt Instrument [Line Items]

Margin facility amount outstanding

180,000,000

Line of Credit | Specialty Risks FAL Facility

Debt Instrument [Line Items]

Margin facility amount outstanding | £

£ 0

Letter of Credit | Standby Letter of Credit Facility | Wells Fargo

Debt Instrument [Line Items]

Margin facility amount outstanding

86,861,000

Letter of Credit | Bilateral Facility | Citibank Europe PLC

Debt Instrument [Line Items]

Margin facility amount outstanding

243,696,000

RenaissanceRe Finance, Inc. | 3.700% Senior Notes due 2025

Debt Instrument [Line Items]

Interest rate

3.70%

Debt instrument, face amount

$ 300,000,000

RenaissanceRe Finance, Inc. | Senior Notes | 3.450% Senior Notes due 2027

Debt Instrument [Line Items]

Interest rate

3.45%

Debt instrument, face amount

$ 300,000,000

RenRe North America Holdings Inc | 5.75% Senior Notes Due March 15, 2020

Debt Instrument [Line Items]

Interest rate

5.75%

Debt instrument, face amount

$ 250,000,000

Platinum Underwriters Finance, Inc | Senior Notes | Series B 7.50% Notes Due June 1, 2017

Debt Instrument [Line Items]

Interest rate

7.50%

Debt instrument, face amount

$ 250,000,000

DaVinciRe Holdings Ltd.

Debt Instrument [Line Items]

Loan agreement with related party

$ 100,000,000

DaVinciRe Holdings Ltd. | 4.750% Senior Notes Due May 1, 2025

Debt Instrument [Line Items]

Interest rate

4.75%

Debt instrument, face amount

$ 150,000,000

Bilateral Facility Participants | Letter of Credit | Bilateral Facility

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 300,000,000

Bilateral Facility Participants | Letter of Credit | Bilateral Facility | Citibank Europe PLC

Debt Instrument [Line Items]

Loan agreement, remaining borrowing capacity

$ 56,300,000

Renaissance Reinsurance U.S. Inc. | Letter of Credit | Bilateral Facility

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 25,000,000

Syndicate 1458 | Line of Credit | Renaissance Reinsurance FAL Facility | Bank of Montreal, Citibank Europe and ING Bank

Debt Instrument [Line Items]

Aggregate amount of issuances

$ 150,000,000

Syndicate 1458 | Line of Credit | Renaissance Reinsurance FAL Facility | Line of Credit | Bank of Montreal, Citibank Europe and ING Bank

Debt Instrument [Line Items]

Letter of credit aggregate commitment

$ 360,000,000

£ 85,000,000

Line of credit facility, maximum borrowing capacity

$ 180,000,000

$ 380,000,000

Syndicate 1458 | Line of Credit | Renaissance Reinsurance FAL Facility | Line of Credit Two | Bank of Montreal, Citibank Europe and ING Bank

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity | £

£ 90,000,000

Syndicate 1458 | Letter of Credit | Renaissance Reinsurance FAL Facility | Bank of Montreal, Citibank Europe and ING Bank

Debt Instrument [Line Items]

Collateral amount, percent of aggregate outstanding letters of credit in option 1

100.00%

100.00%

Collateral amount, percent of aggregate outstanding letters of credit in case of Full Collateralization Event

100.00%

100.00%

100.00%

100.00%

Syndicate 1458 | Letter of Credit | Renaissance Reinsurance FAL Facility | Bank of Montreal, Citibank Europe and ING Bank | Greater than or equal to

Debt Instrument [Line Items]

Collateral amount, percent of aggregate outstanding letters of credit in option 2

60.00%

60.00%

Syndicate 1458 | Letter of Credit | Renaissance Reinsurance FAL Facility | Bank of Montreal, Citibank Europe and ING Bank | Less than

Debt Instrument [Line Items]

Collateral amount, percent of aggregate outstanding letters of credit in option 2

100.00%

100.00%

Top Layer Reinsurance Ltd. | Letter of Credit

Debt Instrument [Line Items]

Collateralized letter of credit and reimbursement agreement

$ 37,500,000

Top Layer Reinsurance Ltd. | Letter of Credit | Capital Support Agreement

Debt Instrument [Line Items]

Mandatory capital contribution in the event of capital and surplus reduction below a specified level

$ 50,000,000

Debt and Credit Facilities (Sch

Debt and Credit Facilities (Schedule of Credit Facilities) (Details) - Dec. 31, 2018 £ in Thousands, $ in Thousands	USD ($)	GBP (£)
Line of Credit Facility [Line Items]
Credit facilities outstanding	$ 510,557	£ 0
Renaissance Reinsurance FAL Facility | Line of Credit
Line of Credit Facility [Line Items]
Credit facilities outstanding	180,000
Specialty Risks FAL Facility | Line of Credit
Line of Credit Facility [Line Items]
Credit facilities outstanding | £		£ 0
Wells Fargo | Standby Letter of Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Credit facilities outstanding	86,861
Citibank Europe PLC | Bilateral Facility | Letter of Credit
Line of Credit Facility [Line Items]
Credit facilities outstanding	243,696
Revolving Credit Facility | Line of Credit
Line of Credit Facility [Line Items]
Credit facilities outstanding	$ 0

Debt and Credit Facilities (S_2

Debt and Credit Facilities (Schedule of Maturities of Long-term Debt) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt Disclosure [Abstract]
2,019	$ 0
2,020	250,000
2,021	0
2,022	0
2,023	0
After 2,023	750,000
Unamortized discount and debt issuance expenses	(8,873)
Total	$ 991,127

Noncontrolling Interests (Summa

Noncontrolling Interests (Summary of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	$ 2,051,700	$ 1,296,506
Net income (loss) attributable to redeemable noncontrolling interest	41,553	(132,282)	$ 127,086
DaVinciRe Holdings Ltd.
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	1,034,946	1,011,659	994,458
Net income (loss) attributable to redeemable noncontrolling interest	27,638	(134,860)	118,748
RenaissanceRe Medici Fund Ltd.
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	416,765	284,847	181,136
Net income (loss) attributable to redeemable noncontrolling interest	13,926	2,578	8,338
Vermeer Reinsurance Ltd.
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	599,989	0	0
Net income (loss) attributable to redeemable noncontrolling interest	$ (11)	$ 0	$ 0

Noncontrolling Interests (Narra

Noncontrolling Interests (Narrative) (Details) - USD ($) $ in Thousands	Oct. 01, 2017	Jul. 31, 2017	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jul. 01, 2017	Jan. 01, 2017
Noncontrolling Interest [Line Items]
Noncontrolling interest, value subscribed				$ 1
DaVinci Reinsurance Ltd.
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, ownership percentage	22.10%			22.10%	22.10%	23.50%	22.60%
RenaissanceRe Medici Fund Ltd.
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, ownership percentage				16.60%	26.80%
DaVinciRe Holdings Ltd.
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, net redemptions			$ 75,000
Redeemable noncontrolling interest, reserve holdback			7,500
Redeemable noncontrolling interest, sale of interest	$ 49,700	$ 12,000	$ 24,000
Non-voting preference shares issued to third parties	$ 248,600
Noncontrolling interest, value subscribed				$ 0	$ 232,119
Redemption of shares from redeemable noncontrolling interests				$ 4,351	80,058
DaVinciRe Holdings Ltd. | Maximum
Noncontrolling Interest [Line Items]
Share repurchase requests, limit				25.00%
DaVinciRe Holdings Ltd. | Redeemable Noncontrolling Interest
Noncontrolling Interest [Line Items]
Share repurchase requests, percent of aggregate shares, limit				50.00%
RenaissanceRe Medici Fund Ltd.
Noncontrolling Interest [Line Items]
Written notice period for redemption				30 days
Noncontrolling interest, value subscribed				$ 208,482	149,182
Redemption of shares from redeemable noncontrolling interests				90,490	48,049
Vermeer Reinsurance Ltd.
Noncontrolling Interest [Line Items]
Noncontrolling interest, value subscribed				$ 600,000	$ 0

Noncontrolling Interests (Sched

Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Activity in redeemable noncontrolling interest
Beginning balance	$ 1,296,506
Sale of shares to redeemable noncontrolling interest	1
Comprehensive income:
Net income (loss) attributable to redeemable noncontrolling interest	41,553	$ (132,282)	$ 127,086
Ending balance	2,051,700	1,296,506
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	1,011,659	994,458
Redemption of shares from redeemable noncontrolling interest	(4,351)	(80,058)
Sale of shares to redeemable noncontrolling interest	0	232,119
Comprehensive income:
Net income (loss) attributable to redeemable noncontrolling interest	27,638	(134,860)	118,748
Ending balance	1,034,946	1,011,659	994,458
RenaissanceRe Medici Fund Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	284,847	181,136
Redemption of shares from redeemable noncontrolling interest	(90,490)	(48,049)
Sale of shares to redeemable noncontrolling interest	208,482	149,182
Comprehensive income:
Net income (loss) attributable to redeemable noncontrolling interest	13,926	2,578	8,338
Ending balance	416,765	284,847	181,136
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	0	0
Sale of shares to redeemable noncontrolling interest	600,000	0
Comprehensive income:
Net income (loss) attributable to redeemable noncontrolling interest	(11)	0	0
Ending balance	$ 599,989	$ 0	$ 0

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Total assets	$ 18,676,196,000		$ 15,226,131,000
Total liabilities	11,579,416,000		9,538,250,000
Ceded premiums written	1,178,525,000		926,215,000	$ 839,264,000
Ceded premiums earned	1,095,886,000		833,929,000	628,675,000
Investments in other ventures, under equity method (Note 4)	115,172,000		101,974,000
Redeemable noncontrolling interests	2,051,700,000		1,296,506,000
Upsilon RFO Re Ltd. | Primary Beneficiary
Variable Interest Entity [Line Items]
Return of capital			84,300,000
Total assets	2,200,000,000		1,200,000,000
Total liabilities	2,200,000,000		1,200,000,000
Upsilon RFO Re Ltd. | Primary Beneficiary | Non-voting preference shares
Variable Interest Entity [Line Items]
Non-voting preference shares issued to third parties			180,600,000
Investment in variable interest entity	$ 109,800,000		27,200,000
Upsilon RFO Re Ltd. | Primary Beneficiary | RenaissanceRe Holdings Ltd.
Variable Interest Entity [Line Items]
Return of capital			$ 33,000,000
Variable interest entity, ownership percentage	14.00%		20.80%
Upsilon RFO Re Ltd. | Primary Beneficiary | Investor | Non-voting preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity	$ 856,700,000	$ 400,000,000	$ 7,500,000
Mona Lisa Re Ltd. | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	41,000		25,900,000
Total liabilities	41,000		25,900,000
Mona Lisa Re Ltd. | Not Primary Beneficiary | Renaissance Reinsurance Ltd.
Variable Interest Entity [Line Items]
Ceded premiums written	200,000		400,000
Ceded premiums earned	200,000		4,100,000
Mona Lisa Re Ltd. | Not Primary Beneficiary | DaVinci Reinsurance Ltd.
Variable Interest Entity [Line Items]
Ceded premiums written	200,000		400,000
Ceded premiums earned	200,000		2,900,000
Fibonacci Reinsurance Ltd. | Not Primary Beneficiary | Other investments
Variable Interest Entity [Line Items]
Fair value of investment	6,000,000		14,100,000
Renaissance Reinsurance Ltd. | Not Primary Beneficiary | Fibonacci Reinsurance Ltd.
Variable Interest Entity [Line Items]
Ceded premiums written	9,100,000		9,000,000
Ceded premiums earned	10,000,000		8,200,000
Langhorne Holdings LLC | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method (Note 4)	1,300,000		600,000
Langhorne Partners | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method (Note 4)	100,000		0
Vermeer Reinsurance Ltd.
Variable Interest Entity [Line Items]
Redeemable noncontrolling interests	599,989,000		$ 0	$ 0
Vermeer Reinsurance Ltd. | Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	600,400,000
Total liabilities	$ 400,000

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details)	Dec. 31, 2018USD ($)directorperiod$ / sharesshares	Dec. 20, 2018shares	Dec. 14, 2018$ / shares	Oct. 30, 2018USD ($)	Sep. 28, 2018$ / shares	Sep. 14, 2018$ / shares	Jun. 29, 2018$ / shares	Jun. 15, 2018$ / shares	Mar. 29, 2018$ / shares	Mar. 15, 2018$ / shares	Jun. 27, 2013USD ($)shares	Jun. 30, 2018USD ($)$ / sharesshares	May 31, 2013USD ($)$ / sharesshares	Mar. 31, 2004USD ($)$ / sharesshares	Dec. 31, 2018USD ($)directorperiod$ / sharesshares	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)$ / sharesshares	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)$ / sharesshares	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)directorperiod$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2013USD ($)	Nov. 10, 2017USD ($)
Class of Stock [Line Items]
Aggregate authorized shares (in shares) | shares	325,000,000														325,000,000								325,000,000
Authorized common shares (in shares) | shares	225,000,000														225,000,000								225,000,000
Authorized preference shares (in shares) | shares	100,000,000														100,000,000								100,000,000
Dividends on preference shares | $															$ 9,189,000	$ 9,708,000	$ 5,596,000	$ 5,595,000	$ 5,595,000	$ 5,595,000	$ 5,596,000	$ 5,595,000	$ 30,088,000	$ 22,381,000	$ 22,381,000
Preference shares, issued, value | $																							$ 241,448,000	$ 0
Par value (in usd per share)	$ 1														$ 1				$ 1				$ 1	$ 1
Preference shares, shares outstanding (in shares) | shares	16,010,000														16,010,000				16,000,000				16,010,000	16,000,000
Shares issued (in shares) | shares	16,010,000														16,010,000				16,000,000				16,010,000	16,000,000
Common shares
Class of Stock [Line Items]
Preference shares, shares issued (in shares) | shares																							1,947,000	0	0
Common shares | Private Placement | State Farm
Class of Stock [Line Items]
Investment Agreement, shares issued in transaction (in shares) | shares		1,947,496
Investment Agreement, consideration received per transaction | $				$ 250,000,000
Retained earnings
Class of Stock [Line Items]
Dividends on preference shares | $																							$ 30,088,000	$ 22,381,000	$ 22,381,000
Dividends on common shares | $																							(52,841,000)	$ (51,370,000)	$ (51,583,000)
Common shares
Class of Stock [Line Items]
Dividends declared per common share (in usd per share)			$ 0.33			$ 0.33		$ 0.33		$ 0.33
Dividends paid per common share (in usd per share)	$ 0.33				$ 0.33		$ 0.33		$ 0.33
Share repurchase program, authorized aggregate amount | $																											$ 500,000,000
Share repurchase program, remaining authorized shares (in shares) | $	$ 500,000,000														$ 500,000,000								$ 500,000,000
Series C Preferred Stock
Class of Stock [Line Items]
Dividend rate, percentage																							6.08%
Liquidation preference per annum (in usd per share)	$ 1.52														$ 1.52								$ 1.52
Quarterly liquidation preference (in usd per share)	$ 0.38														$ 0.38								$ 0.38
Preference shares, issued, value | $														$ 250,000,000
Preference shares, shares issued (in shares) | shares														10,000,000
Par value (in usd per share)														$ 25
Preference shares, shares redeemed (in shares) | shares											5,000,000
Preference shares, redemption amount | $											$ 125,000,000
Preference shares, shares outstanding (in shares) | shares											5,000,000
Proceeds from Issuance of Convertible Preferred Stock | $												$ 250,000,000
Right to elect directors, required number of dividend periods in arrears | period	6														6								6
Right to elect directors, number of directors | director	2														2								2
Series E Preferred Stock
Class of Stock [Line Items]
Dividend rate, percentage																							5.375%
Liquidation preference per annum (in usd per share)	$ 1.34375														$ 1.34375								$ 1.34375
Quarterly liquidation preference (in usd per share)	0.3359375														0.3359375								0.3359375
Preference shares, issued, value | $													$ 275,000,000													$ 0
Preference shares, shares issued (in shares) | shares													11,000,000
Par value (in usd per share)													$ 25
Redemption price per share (in usd per share)	$ 25														$ 25								$ 25
Series F Preferred Stock
Class of Stock [Line Items]
Dividend rate, percentage												5.75%
Liquidation preference per annum (in usd per share)												$ 1,437.50					$ 1,437.50
Quarterly liquidation preference (in usd per share)												$ 359.375					$ 359.375
Shares issued (in shares) | shares												10,000					10,000
Liquidation preference (in usd per share)												$ 25,000					$ 25,000
Redemption price per share (in usd per share)												25,000					25,000
Depositary Shares
Class of Stock [Line Items]
Liquidation preference per annum (in usd per share)												1.4375					1.4375
Quarterly liquidation preference (in usd per share)												$ 0.359375					$ 0.359375
Shares issued (in shares) | shares												10,000,000					10,000,000
Percentage interest in underlying shares												0.10%					0.10%
Redemption price per share (in usd per share)												$ 25					$ 25

Shareholders' Equity (Shares Is

Shareholders' Equity (Shares Issued and Outstanding) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued - January 1 (in shares)	40,023,789
Shares outstanding - January 1 (in shares)	40,023,789
Shares issued - December 31 (in shares)	42,207,390	40,023,789
Shares outstanding - December 31 (in shares)	42,207,390	40,023,789
Common shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued - January 1 (in shares)	40,024,000	41,187,000	43,701,000
Shares outstanding - January 1 (in shares)	40,024,000	41,187,000	43,701,000
Issuance of shares (in shares)	1,947,000	0	0
Repurchase of shares (in shares)	0	(1,322,000)	(2,741,000)
Exercise of options and issuance of restricted stock awards (in shares)	236,000	159,000	227,000
Shares issued - December 31 (in shares)	42,207,000	40,024,000	41,187,000
Shares outstanding - December 31 (in shares)	42,207,000	40,024,000	41,187,000

Earnings Per Share (Computation

Earnings Per Share (Computation of Basic and Diluted Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	$ 197,276	$ (244,770)	$ 480,581
Amount allocated to participating common shareholders									(2,121)	(457)	(5,666)
Net income (loss) allocated to RenaissanceRe common shareholders									$ 195,155	$ (245,227)	$ 474,915
Denominator:
Denominator for basic income (loss) per RenaissanceRe common share - weighted average common shares (in shares)	40,111	39,624	39,641	39,552	39,478	39,591	39,937	40,408	39,732	39,854	41,314
Per common share equivalents of employee stock options and performance shares (in shares)									23	0	245
Denominator for diluted income (loss) per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions (in shares)	40,111	39,637	39,654	39,599	39,478	39,591	40,024	40,623	39,755	39,854	41,559
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.25	$ 2.26	$ 4.91	$ (6.15)	$ 11.50
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.24	$ 2.25	$ 4.91	$ (6.15)	$ 11.43

Related Party Transactions an_2

Related Party Transactions and Major Customers (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Gross premiums written	$ 547,755	$ 625,677	$ 977,343	$ 1,159,652	$ 407,766	$ 640,269	$ 827,415	$ 922,090	$ 3,310,427	$ 2,797,540	$ 2,374,576
Gross premiums earned									2,779,796	2,307,219	1,874,993
Acquisition expenses	120,465	$ 109,761	$ 105,052	$ 97,711	98,598	$ 76,761	$ 88,251	$ 83,282	432,989	346,892	289,323
Net reinsurance costs and recoveries									(1,458,518)	(1,558,960)	(179,820)
Total gross reserve for claims and claim expenses	6,076,271				5,080,408				$ 6,076,271	$ 5,080,408	$ 2,848,294
Gross premiums written | Three Brokers
Related Party Transaction [Line Items]
Percent of gross premiums received									75.20%	76.40%	80.80%
Gross premiums written | AON
Related Party Transaction [Line Items]
Percent of gross premiums received									40.70%	42.80%	46.40%
Gross premiums written | Marsh
Related Party Transaction [Line Items]
Percent of gross premiums received									24.60%	23.80%	23.60%
Gross premiums written | Willis Towers Watson
Related Party Transaction [Line Items]
Percent of gross premiums received									9.90%	9.80%	10.80%
Tower Hill Companies
Related Party Transaction [Line Items]
Gross premiums written									$ 45,500	$ 39,100	$ 32,800
Gross premiums earned									43,800	35,700	32,300
Acquisition expenses									7,100	5,100	3,800
Related party receivables	19,300				14,100				19,300	14,100
Net reinsurance costs and recoveries									111,200	94,400	1,500
Total gross reserve for claims and claim expenses	$ 98,800				$ 65,300				98,800	65,300
Distributions received									12,100	8,300	9,000
Top Layer Reinsurance Ltd.
Related Party Transaction [Line Items]
Distributions received									4,000	20,000	0
Top Layer Reinsurance Ltd. | Management Fee
Related Party Transaction [Line Items]
Revenue recorded									$ 2,700	$ 2,700	$ 2,600

Taxation (Narrative) (Details)

Taxation (Narrative) (Details) - USD ($)	Dec. 22, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Partial write-down of U.S. deferred tax asset pursuant to the Tax Cuts and Jobs Act of 2017	$ 36,700,000
Increase (decrease) in valuation allowance		$ 5,300,000	$ (11,200,000)	$ (900,000)
Valuation allowance		35,271,000	30,016,000
Income taxes paid (refunded)		341,000	343,000	$ (1,118,000)
Unrecognized tax benefits		0	0
Interest and penalties accrued on unrecognized tax benefits		$ 0	$ 0
Bermuda
Operating Loss Carryforwards [Line Items]
Statutory income tax rate		0.00%
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Expected tax rate		5.00%
Foreign statutory income tax rate		21.00%
Operating loss carryforwards		$ 164,200,000
Ireland
Operating Loss Carryforwards [Line Items]
Foreign statutory income tax rate		12.50%
Operating loss carryforwards		$ 4,800,000
U.K.
Operating Loss Carryforwards [Line Items]
Foreign statutory income tax rate		19.00%
Increase (decrease) in valuation allowance		$ 4,000,000
Operating loss carryforwards		$ 114,400,000
Singapore
Operating Loss Carryforwards [Line Items]
Foreign statutory income tax rate		17.00%
Operating loss carryforwards		$ 21,700,000
Switzerland
Operating Loss Carryforwards [Line Items]
Foreign statutory income tax rate		21.20%

Taxation (Income Before Income

Taxation (Income Before Income Taxes, Foreign and Domestic) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit)
Income (loss) before taxes	$ (132,838)	$ 50,280	$ 256,373	$ 88,800	$ 43,425	$ (722,471)	$ 218,254	$ 132,608	$ 262,615	$ (328,184)	$ 630,388
Bermuda
Income Tax Expense (Benefit)
Domestic									349,959	(262,827)	652,758
U.S.
Income Tax Expense (Benefit)
Foreign									(56,261)	(11,897)	(1,236)
U.K.
Income Tax Expense (Benefit)
Foreign									(28,574)	(41,656)	(24,278)
Singapore
Income Tax Expense (Benefit)
Foreign									(3,226)	(12,421)	2,180
Ireland
Income Tax Expense (Benefit)
Foreign									551	617	964
Switzerland
Income Tax Expense (Benefit)
Foreign									$ 166	$ 0	$ 0

Taxation (Components of Income

Taxation (Components of Income Tax Benefit (Expense)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit)
Current									$ (1,668)	$ (844)	$ (2,090)
Deferred									7,970	(25,643)	1,750
Income tax benefit (expense)	$ 8,852	$ (1,451)	$ (4,506)	$ 3,407	$ (41,226)	$ 18,977	$ (3,904)	$ (334)	$ 6,302	$ (26,487)	$ (340)

Taxation (Income Tax Reconcilia

Taxation (Income Tax Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Expected income tax benefit									$ 17,697	$ 14,216	$ 4,856
Tax exempt income									944	3,794	4,487
Non-taxable foreign exchange gains (losses)									586	2,574	(1,126)
Effect of change in tax rate									(708)	(38,083)	(1,421)
U.S. base erosion and anti-abuse tax									(1,271)	0	0
Withholding tax									(1,831)	(216)	(2,578)
Transfer pricing									(2,481)	(11)	27
Change in valuation allowance									(5,255)	(11,718)	(924)
Other									(1,379)	2,957	(3,661)
Income tax benefit (expense)	$ 8,852	$ (1,451)	$ (4,506)	$ 3,407	$ (41,226)	$ 18,977	$ (3,904)	$ (334)	$ 6,302	$ (26,487)	$ (340)

Taxation (Deferred Tax Assets a

Taxation (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Tax loss and credit carryforwards	$ 60,395	$ 62,643
Reserve for claims and claim expenses	17,345	13,992
Deferred finance charges	14,646	11,320
Unearned premiums	10,108	9,436
Investments	4,427	0
Accrued expenses	4,292	2,641
Deferred underwriting results	3,514	3,407
Deferred tax assets	114,727	103,439
Deferred tax liabilities
Deferred acquisition expenses	(11,801)	(12,343)
Amortization and depreciation	(2,992)	(3,340)
Investments	0	(1,047)
Deferred tax liabilities	(14,793)	(16,730)
Net deferred tax asset before valuation allowance	99,934	86,709
Valuation allowance	(35,271)	(30,016)
Net deferred tax asset	$ 64,663	$ 56,693

Segment Reporting (Schedule of

Segment Reporting (Schedule of Significant Components of the Company's Revenues and Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Gross premiums written	$ 547,755	$ 625,677	$ 977,343	$ 1,159,652	$ 407,766	$ 640,269	$ 827,415	$ 922,090	$ 3,310,427	$ 2,797,540	$ 2,374,576
Net premiums written	411,094	453,255	604,509	663,044	288,223	483,221	555,745	544,136	2,131,902	1,871,325	1,535,312
Net premiums earned	574,613	531,849	429,385	440,282	421,473	547,792	382,265	366,045	1,976,129	1,717,575	1,403,430
Net claims and claim expenses incurred	477,638	410,510	60,167	171,703	304,064	1,221,696	142,587	193,081	1,120,018	1,861,428	530,831
Acquisition expenses	120,465	109,761	105,052	97,711	98,598	76,761	88,251	83,282	432,989	346,892	289,323
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Underwriting income (loss)									244,855	(651,523)	385,527
Net investment income	53,338	80,696	71,356	56,476	73,464	40,257	54,163	54,325	261,866	222,209	181,726
Net foreign exchange (losses) gains	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Equity in earnings (losses) of other ventures	4,143	7,648	5,826	857	2,200	1,794	5,543	(1,507)	18,474	8,030	963
Other income	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Corporate expenses	(12,108)	(6,841)	(8,301)	(6,733)	(4,237)	(4,413)	(4,636)	(5,286)	(33,983)	(18,572)	(37,402)
Interest expense	(11,765)	(11,769)	(11,768)	(11,767)	(11,777)	(11,799)	(10,091)	(10,526)	(47,069)	(44,193)	(42,144)
Income (loss) before taxes	(132,838)	50,280	256,373	88,800	43,425	(722,471)	218,254	132,608	262,615	(328,184)	630,388
Income tax benefit (expense)	8,852	(1,451)	(4,506)	3,407	(41,226)	18,977	(3,904)	(334)	6,302	(26,487)	(340)
Net (income) loss attributable to redeemable noncontrolling interests	49,269	(6,440)	(54,483)	(29,899)	(56)	204,277	(37,612)	(34,327)	(41,553)	132,282	(127,086)
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	197,276	(244,770)	480,581
Net claims and claim expenses incurred – current accident year									1,390,767	1,902,424	694,957
Net claims and claim expenses incurred – prior accident years									(270,749)	(40,996)	(164,126)
Total net incurred									$ 1,120,018	$ 1,861,428	$ 530,831
Net claims and claim expense ratio – current accident year									70.40%	110.80%	49.50%
Net claims and claim expense ratio – prior accident years									(13.70%)	(2.40%)	(11.70%)
Net claims and claim expense ratio – calendar year									56.70%	108.40%	37.80%
Underwriting expense ratio									30.90%	29.50%	34.70%
Combined ratio									87.60%	137.90%	72.50%
Other
Segment Reporting Information [Line Items]
Gross premiums written									$ 0	$ (7)	$ 0
Net premiums written									0	4	143
Net premiums earned									0	4	142
Net claims and claim expenses incurred									(197)	(1,583)	(1,110)
Acquisition expenses									(2)	(1)	0
Operational expenses									430	36	123
Underwriting income (loss)									(231)	1,552	1,129
Net investment income									261,866	222,209	181,726
Net foreign exchange (losses) gains									(12,428)	10,628	(13,788)
Equity in earnings (losses) of other ventures									18,474	8,030	963
Other income									5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments									(175,069)	135,822	141,328
Corporate expenses									(33,983)	(18,572)	(37,402)
Interest expense									(47,069)	(44,193)	(42,144)
Income tax benefit (expense)									6,302	(26,487)	(340)
Net (income) loss attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net claims and claim expenses incurred – current accident year									0	0	0
Net claims and claim expenses incurred – prior accident years									(197)	(1,583)	(1,110)
Total net incurred									(197)	(1,583)	(1,110)
Property
Segment Reporting Information [Line Items]
Gross premiums written									1,760,926	1,440,437	1,111,263
Net claims and claim expenses incurred – prior accident years									(221,290)	(45,596)	(104,876)
Property | Operating Segments
Segment Reporting Information [Line Items]
Gross premiums written									1,760,926	1,440,437	1,111,263
Net premiums written									1,055,188	978,014	725,321
Net premiums earned									1,050,831	931,070	720,951
Net claims and claim expenses incurred									497,895	1,297,985	151,545
Acquisition expenses									177,912	113,816	97,594
Operational expenses									112,954	94,194	108,642
Underwriting income (loss)									262,070	(574,925)	363,170
Net claims and claim expenses incurred – current accident year									719,185	1,343,581	256,421
Net claims and claim expenses incurred – prior accident years									(221,290)	(45,596)	(104,876)
Total net incurred									$ 497,895	$ 1,297,985	$ 151,545
Net claims and claim expense ratio – current accident year									68.40%	144.30%	35.60%
Net claims and claim expense ratio – prior accident years									(21.00%)	(4.90%)	(14.60%)
Net claims and claim expense ratio – calendar year									47.40%	139.40%	21.00%
Underwriting expense ratio									27.70%	22.30%	28.60%
Combined ratio									75.10%	161.70%	49.60%
Casualty and Specialty
Segment Reporting Information [Line Items]
Gross premiums written									$ 1,549,501	$ 1,357,110	$ 1,263,313
Net claims and claim expenses incurred – prior accident years									(49,262)	6,183	(58,140)
Casualty and Specialty | Operating Segments
Segment Reporting Information [Line Items]
Gross premiums written									1,549,501	1,357,110	1,263,313
Net premiums written									1,076,714	893,307	809,848
Net premiums earned									925,298	786,501	682,337
Net claims and claim expenses incurred									622,320	565,026	380,396
Acquisition expenses									255,079	233,077	191,729
Operational expenses									64,883	66,548	88,984
Underwriting income (loss)									(16,984)	(78,150)	21,228
Net claims and claim expenses incurred – current accident year									671,582	558,843	438,536
Net claims and claim expenses incurred – prior accident years									(49,262)	6,183	(58,140)
Total net incurred									$ 622,320	$ 565,026	$ 380,396
Net claims and claim expense ratio – current accident year									72.60%	71.10%	64.30%
Net claims and claim expense ratio – prior accident years									(5.30%)	0.70%	(8.60%)
Net claims and claim expense ratio – calendar year									67.30%	71.80%	55.70%
Underwriting expense ratio									34.50%	38.10%	41.20%
Combined ratio									101.80%	109.90%	96.90%

Segment Reporting (Schedule o_2

Segment Reporting (Schedule of Gross Premiums Written Allocated to the Territory of Coverage Exposure) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$ 547,755	$ 625,677	$ 977,343	$ 1,159,652	$ 407,766	$ 640,269	$ 827,415	$ 922,090	$ 3,310,427	$ 2,797,540	$ 2,374,576
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									0	(7)	0
Property
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									1,760,926	1,440,437	1,111,263
Property | U.S. and Caribbean
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									978,063	954,269	743,226
Property | Worldwide
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									464,311	305,915	210,168
Property | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									144,857	49,486	37,611
Property | Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									71,601	49,821	44,536
Property | Worldwide (excluding U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									66,872	48,182	55,043
Property | Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									19,273	14,151	13,729
Property | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									15,949	18,613	6,950
Casualty and Specialty
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									1,549,501	1,357,110	1,263,313
Casualty and Specialty | U.S. and Caribbean
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									667,125	622,757	646,381
Casualty and Specialty | Worldwide
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									776,976	686,253	581,972
Casualty and Specialty | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									15,296	9,752	5,541
Casualty and Specialty | Worldwide (excluding U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									31,734	10,104	13,840
Casualty and Specialty | Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									3,667	4,141	5,073
Casualty and Specialty | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									$ 54,703	$ 24,103	$ 10,506

Stock Incentive Compensation _3

Stock Incentive Compensation and Employee Benefit Plans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018USD ($)dshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	May 16, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of shares and share units vested	$ 37,200,000	$ 56,900,000	$ 54,500,000
Cash received from exercises of stock options during the period	0	0	0
Excess windfall tax benefit realized by the Company due to its net operating loss position in the taxable jurisdictions in which it operates	0
Total stock compensation expense recognized	35,700,000	37,200,000	47,400,000
Contributions to defined contribution pension plans	4,100,000	$ 4,400,000	$ 4,000,000
Total restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to restricted stock awards	$ 43,200,000
Periods for recognition of compensation costs not yet recognized	1 year 9 months 18 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	3 years
Vesting maximum as a percentage of target if performance goal are achieved	250.00%
Period for average closing share price to determine total shareholder return | d	20
Unrecognized compensation costs related to restricted stock awards	$ 4,800,000
Periods for recognition of compensation costs not yet recognized	1 year 8 months 12 days
Cash Settled Restricted Stock Unit (CSRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	4 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to restricted stock awards	$ 11,200,000
Periods for recognition of compensation costs not yet recognized	1 year 3 months 18 days
2016 Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance (in shares) | shares				1,625,000
Number of shares available for grant (in shares) | shares	1,553,000
2001 Stock Incentive Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	4 years
Share-based payment award, expiration period	10 years
2001 Stock Incentive Plan and 2016 Long-Term Incentive Plan | Total restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	4 years
Non-Employee Director Stock Incentive Plan | Total restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	3 years
2001 Stock Incentive Plan and 2010 Performance Share Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares) | shares	0

Stock Incentive Compensation _4

Stock Incentive Compensation and Employee Benefit Plans (Schedule of Valuation Assumptions) (Details) - Performance Shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	15.80%	14.30%
Risk free interest rate, minimum	1.85%	0.93%
Risk free interest rate, maximum	2.36%	1.69%
Expected term	1 year

Stock Incentive Compensation _5

Stock Incentive Compensation and Employee Benefit Plans (Schedule of Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted options outstanding
Beginning balance (in shares)	32,001	206,795	408,212
Options granted (in shares)	0	0	0
Options forfeited (in shares)	0	0	0
Options expired (in shares)	0	0	0
Options exercised (in shares)	(32,001)	(174,794)	(201,417)
Ending balance (in shares)	0	32,001	206,795	408,212
Weighted options outstanding, Total options exercisable (in shares)	0
Weighted average exercise price
Beginning balance (in usd per share)	$ 53.86	$ 53.17	$ 51.90
Options granted, Weighted average exercise price (in usd per share)	0	0	0
Options forfeited, Weighted average exercise price (in usd per share)	0	0	0
Options expired, Weighted average exercise price (in usd per share)	0	0	0
Options exercised, Weighted average exercise price (in usd per share)	53.86	53.04	50.59
Ending balance (in usd per share)	0	$ 53.86	$ 53.17	$ 51.90
Weighted average exercise price, Total options exercisable (in usd per share)	$ 0
Weighted average remaining contractual life	1 day	2 months 12 days	10 months 24 days	1 year 7 months 6 days
Weighted average remaining contractual life, Total options exercisable	1 day
Aggregate intrinsic value, Options outstanding	$ 0	$ 2,295	$ 17,174	$ 25,020
Aggregate intrinsic value, Options exercised	2,320	$ 15,945	$ 14,806
Aggregate intrinsic value, Total options exercisable	$ 0
Range of exercise prices, lower range limit (in usd per share)			$ 50.71	$ 42.66
Range of exercise prices, upper range limit (in usd per share)			$ 59.66	$ 59.66
Range of exercise prices, Total options outstanding (in usd per share)	$ 0	$ 53.86
Range of exercise prices, Total options exercisable (in usd per share)	$ 0

Stock Incentive Compensation _6

Stock Incentive Compensation and Employee Benefit Plans (Equity Compensation Other than Options) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Settled Restricted Stock Unit (CSRSUs)
Number of shares
Nonvested, beginning balance (in shares)	262,330	308,344	326,078
Awards granted (in shares)	0	98,067	135,119
Awards vested (in shares)	(108,344)	(122,088)	(133,278)
Awards forfeited (in shares)	(7,069)	(21,993)	(19,575)
Nonvested, Ending balance (in shares)	146,917	262,330	308,344
Performance Shares
Number of shares
Nonvested, beginning balance (in shares)	167,673	211,381	230,271
Awards granted (in shares)	83,475	64,947	77,045
Awards vested (in shares)	(16,456)	(62,499)	(58,032)
Awards forfeited (in shares)	(82,241)	(46,156)	(37,903)
Nonvested, Ending balance (in shares)	152,451	167,673	211,381
Weighted average grant-date fair value
Nonvested, beginning balance (in usd per share)	$ 53.11	$ 44.63	$ 41.40
Awards granted (in usd per share)	60.69	65.27	48.31
Awards vested (in usd per share)	53.79	43.51	38.30
Nonvested, ending balance (in usd per share)	$ 57.21	$ 53.11	$ 44.63
Employee restricted stock awards
Number of shares
Nonvested, beginning balance (in shares)	333,037	402,170	479,040
Awards granted (in shares)	255,799	116,345	179,003
Awards vested (in shares)	(139,454)	(185,478)	(255,873)
Awards forfeited (in shares)	(1,642)	0	0
Nonvested, Ending balance (in shares)	447,740	333,037	402,170
Weighted average grant-date fair value
Nonvested, beginning balance (in usd per share)	$ 120.93	$ 103.34	$ 94.95
Awards granted (in usd per share)	132.70	148.66	112.41
Awards vested (in usd per share)	112.70	100.17	93.98
Awards forfeited (in usd per share)	134.38	0	0
Nonvested, ending balance (in usd per share)	$ 130.37	$ 120.93	$ 103.34
Non-employee director restricted stock awards
Number of shares
Nonvested, beginning balance (in shares)	20,126	25,545	26,886
Awards granted (in shares)	12,169	12,193	14,727
Awards vested (in shares)	(9,761)	(17,612)	(16,068)
Awards forfeited (in shares)	0	0	0
Nonvested, Ending balance (in shares)	22,534	20,126	25,545
Weighted average grant-date fair value
Nonvested, beginning balance (in usd per share)	$ 131.09	$ 107.95	$ 97.61
Awards granted (in usd per share)	127.29	150.05	114.71
Awards vested (in usd per share)	123.59	110.66	96.83
Awards forfeited (in usd per share)	0	0	0
Nonvested, ending balance (in usd per share)	$ 132.29	$ 131.09	$ 107.95
Total restricted stock awards
Number of shares
Nonvested, beginning balance (in shares)	353,163	427,715	505,926
Awards granted (in shares)	267,968	128,538	193,730
Awards vested (in shares)	(149,215)	(203,090)	(271,941)
Awards forfeited (in shares)	(1,642)	0	0
Nonvested, Ending balance (in shares)	470,274	353,163	427,715
Weighted average grant-date fair value
Nonvested, beginning balance (in usd per share)	$ 121.51	$ 103.61	$ 95.09
Awards granted (in usd per share)	132.79	148.79	112.59
Awards vested (in usd per share)	113.41	101.08	94.15
Awards forfeited (in usd per share)	134.38	0	0
Nonvested, ending balance (in usd per share)	$ 130.46	$ 121.51	$ 103.61

Statutory Requirements (Narrati

Statutory Requirements (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Statutory Accounting Practices [Line Items]
Assets held in trust	$ 5,700,000		$ 4,400,000
U.S.
Statutory Accounting Practices [Line Items]
Unrestricted net assets	31,228		24,109
U.S. | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Unrestricted net assets		$ 31,200
New York | Multi-Beneficiary Reinsurance Trust | Renaissance Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Assets held in trust	1,200,000		1,200,000
New York | Multi-Beneficiary Reinsurance Trust | Renaissance Reinsurance Ltd. | Minimum
Statutory Accounting Practices [Line Items]
Assets held in trust	1,100,000		1,100,000
New York | Multi-Beneficiary Reinsurance Trust | DaVinci Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Assets held in trust	385,800		377,000
New York | Multi-Beneficiary Reinsurance Trust | DaVinci Reinsurance Ltd. | Minimum
Statutory Accounting Practices [Line Items]
Assets held in trust	356,900		326,900
New York | Multi-Beneficiary Reduced Collateral Reinsurance Trust | Renaissance Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Assets held in trust	50,300		49,400
New York | Multi-Beneficiary Reduced Collateral Reinsurance Trust | Renaissance Reinsurance Ltd. | Minimum
Statutory Accounting Practices [Line Items]
Assets held in trust	36,800		39,700
New York | Multi-Beneficiary Reduced Collateral Reinsurance Trust | DaVinci Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Assets held in trust	63,200		62,000
New York | Multi-Beneficiary Reduced Collateral Reinsurance Trust | DaVinci Reinsurance Ltd. | Minimum
Statutory Accounting Practices [Line Items]
Assets held in trust	$ 26,900		$ 46,000
Florida | Multi-Beneficiary Reduced Collateral Reinsurance Trust | Renaissance Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Multi-beneficiary reduced collateral reinsurance trust collateral reduction	20.00%
Florida | Multi-Beneficiary Reduced Collateral Reinsurance Trust | DaVinci Reinsurance Ltd.
Statutory Accounting Practices [Line Items]
Multi-beneficiary reduced collateral reinsurance trust collateral reduction	50.00%

Statutory Requirements (Statuto

Statutory Requirements (Statutory Capital and Surplus) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Bermuda
Statutory Accounting Practices [Line Items]
Statutory economic capital and surplus	$ 4,256,830	$ 4,155,368
Required statutory capital and surplus	950,915	836,181
Unrestricted net assets	931,387	790,177
U.S.
Statutory Accounting Practices [Line Items]
Statutory economic capital and surplus	502,803	523,384
Required statutory capital and surplus	306,628	306,375
Unrestricted net assets	31,228	24,109
U.K.
Statutory Accounting Practices [Line Items]
Statutory economic capital and surplus	519,689	527,325
Required statutory capital and surplus	519,689	527,325
Unrestricted net assets	$ 0	$ 0

Statutory Requirements (Statu_2

Statutory Requirements (Statutory Net Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Bermuda
Statutory Accounting Practices [Line Items]
Statutory Net Income (Loss)	$ 326,386	$ (334,142)	$ 625,371
U.S.
Statutory Accounting Practices [Line Items]
Statutory Net Income (Loss)	25,851	(3,627)	43,292
U.K.
Statutory Accounting Practices [Line Items]
Statutory Net Income (Loss)	$ (6,692)	$ (57,050)	$ 28,007

Derivative Instruments (Consoli

Derivative Instruments (Consolidated Balance Sheets and Fair Value of the Principal Derivative Instruments) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other assets
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	$ 22,874	$ 6,530
Gross Amounts Offset in the Balance Sheet	3,991	893
Net Amounts of Assets Presented in the Balance Sheet	18,883	5,637
Collateral	0	0
Net Amount	18,883	5,637
Other assets | Interest rate futures
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	2,361	684
Gross Amounts Offset in the Balance Sheet	1,660	524
Net Amounts of Assets Presented in the Balance Sheet	701	160
Collateral	0	0
Net Amount	701	160
Other assets | Interest rate swaps
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	860	424
Gross Amounts Offset in the Balance Sheet	0	0
Net Amounts of Assets Presented in the Balance Sheet	860	424
Collateral	0	0
Net Amount	860	424
Other assets | Foreign currency forward contracts
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	16,459	3,865
Gross Amounts Offset in the Balance Sheet	2,260	358
Net Amounts of Assets Presented in the Balance Sheet	14,199	3,507
Collateral	0	0
Net Amount	14,199	3,507
Other assets | Foreign currency forward contracts
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	3,194	39
Gross Amounts Offset in the Balance Sheet	71	11
Net Amounts of Assets Presented in the Balance Sheet	3,123	28
Collateral	0	0
Net Amount	3,123	28
Other assets | Credit default swaps
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets		1,518
Gross Amounts Offset in the Balance Sheet		0
Net Amounts of Assets Presented in the Balance Sheet		1,518
Collateral		0
Net Amount		1,518
Other liabilities
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	8,225	1,536
Gross Amounts Offset in the Balance Sheet	1,741	535
Net Amounts of Liabilities Presented in the Balance Sheet	6,484	1,001
Collateral Pledged	2,076	227
Net Amount	4,408	774
Other liabilities | Interest rate futures
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	1,887	729
Gross Amounts Offset in the Balance Sheet	1,670	524
Net Amounts of Liabilities Presented in the Balance Sheet	217	205
Collateral Pledged	217	205
Net Amount	0	0
Other liabilities | Interest rate swaps
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	506
Gross Amounts Offset in the Balance Sheet	0
Net Amounts of Liabilities Presented in the Balance Sheet	506
Collateral Pledged	254
Net Amount	252
Other liabilities | Foreign currency forward contracts
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	4,154	670
Gross Amounts Offset in the Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Balance Sheet	4,154	670
Collateral Pledged	0	0
Net Amount	4,154	670
Other liabilities | Foreign currency forward contracts
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	72	115
Gross Amounts Offset in the Balance Sheet	71	11
Net Amounts of Liabilities Presented in the Balance Sheet	1	104
Collateral Pledged	0	0
Net Amount	1	104
Other liabilities | Credit default swaps
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	1,606	22
Gross Amounts Offset in the Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Balance Sheet	1,606	22
Collateral Pledged	1,605	22
Net Amount	$ 1	$ 0

Derivative Instruments (Gain (L

Derivative Instruments (Gain (Loss) Recognized in the Consolidated Statements of Operations Related to Its Derivative Instruments) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	$ 792	$ 6,222	$ (23,942)
Net realized and unrealized (losses) gains on investments | Interest rate futures
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	(5,594)	(3,252)	(17,379)
Net realized and unrealized (losses) gains on investments | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	(84)	436	0
Net realized and unrealized (losses) gains on investments | Credit default swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	(3,106)	326	1,965
Net foreign exchange (losses) gains | Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	3,840	9,628	(6,937)
Net foreign exchange (losses) gains | Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	$ 5,736	$ (916)	$ (1,591)

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - Not Designated as Hedging Instrument - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Interest rate swaps | Paying a Fixed Rate | United States of America, Dollars
Derivative [Line Items]
Derivative notional amount	$ 78,400,000	$ 40,300,000
Interest rate swaps | Receiving a Fixed Rate | United States of America, Dollars
Derivative [Line Items]
Derivative notional amount	32,100,000	0
Long | Interest rate futures
Derivative [Line Items]
Derivative notional amount	1,900,000,000	1,500,000,000
Long | Foreign currency forward contracts
Derivative [Line Items]
Derivative notional amount	354,100,000	215,400,000
Long | Foreign currency forward contracts
Derivative [Line Items]
Derivative notional amount	121,300,000	16,600,000
Long | Credit default swaps
Derivative [Line Items]
Derivative notional amount	1,000,000	1,000,000
Short | Interest rate futures
Derivative [Line Items]
Derivative notional amount	545,800,000	801,100,000
Short | Foreign currency forward contracts
Derivative [Line Items]
Derivative notional amount	601,200,000	44,200,000
Short | Foreign currency forward contracts
Derivative [Line Items]
Derivative notional amount	42,900,000	5,100,000
Short | Credit default swaps
Derivative [Line Items]
Derivative notional amount	$ 126,200,000	$ 18,800,000

Commitments, Contingencies an_3

Commitments, Contingencies and Other Items (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018USD ($)
Commitments and Contingencies [Line Items]
Initial commitments	$ 1,200,000,000
Fulfilled commitments	686,400,000
Unfunded commitments	$ 470,800,000
Initial capital lease term	20 years
Bargain renewal option term	30 years
Letter of Credit
Commitments and Contingencies [Line Items]
Letters of credit outstanding	$ 510,600,000
Letter of Credit | Top Layer Reinsurance Ltd.
Commitments and Contingencies [Line Items]
Collateral pledged to support letter of credit	37,500,000
Letter of Credit | Capital Support Agreement | Top Layer Reinsurance Ltd.
Commitments and Contingencies [Line Items]
Maximum mandatory capital contribution in the event of loss that reduced capital and surplus below specified level	$ 50,000,000
Investments as a Percentage of Shareholders' Equity
Commitments and Contingencies [Line Items]
Concentration risk percentage	10.00%

Commitments, Contingencies an_4

Commitments, Contingencies and Other Items (Future Minimum Payments, Operating Leases) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,019	$ 7,137
2,020	5,294
2,021	4,934
2,022	4,225
2,023	1,530
After 2,023	298
Future minimum lease payments under existing operating leases	$ 23,418

Commitments, Contingencies an_5

Commitments, Contingencies and Other Items (Future Minimum Payments, Capital Leases) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,019	$ 3,331
2,020	3,336
2,021	3,336
2,022	3,336
2,023	2,830
After 2,023	12,790
Future minimum lease payments under existing capital leases	$ 28,959

Acquisition of Tokio Millenni_2

Acquisition of Tokio Millennium RE (Details) - Tokio Millennium Re $ / shares in Units, $ in Millions	Oct. 30, 2018USD ($)$ / shares
Business Acquisition [Line Items]
Stock Purchase Agreement, multiple applied to determine aggregate consideration	1.02
Stock Purchase Agreement, volume-weighted average closing price, term	30 days
Stock Purchase Agreement, minimum volume-weighted average closing price (in dollars per share) | $ / shares	$ 128.37
Stock Purchase Agreement, amount used to determine additional consideration	$ 250
Minimum
Business Acquisition [Line Items]
Stock Purchase Agreement, expected dividend payments	275
Maximum
Business Acquisition [Line Items]
Stock Purchase Agreement, expected dividend payments	$ 500

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Gross premiums written	$ 547,755	$ 625,677	$ 977,343	$ 1,159,652	$ 407,766	$ 640,269	$ 827,415	$ 922,090	$ 3,310,427	$ 2,797,540	$ 2,374,576
Net premiums written	411,094	453,255	604,509	663,044	288,223	483,221	555,745	544,136	2,131,902	1,871,325	1,535,312
(Increase) decrease in unearned premiums	163,519	78,594	(175,124)	(222,762)	133,250	64,571	(173,480)	(178,091)	(155,773)	(153,750)	(131,882)
Net premiums earned (Note 6)	574,613	531,849	429,385	440,282	421,473	547,792	382,265	366,045	1,976,129	1,717,575	1,403,430
Net investment income	53,338	80,696	71,356	56,476	73,464	40,257	54,163	54,325	261,866	222,209	181,726
Net foreign exchange (losses) gains	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Equity in earnings (losses) of other ventures	4,143	7,648	5,826	857	2,200	1,794	5,543	(1,507)	18,474	8,030	963
Other income	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Total revenues	547,997	629,754	479,204	417,986	491,293	634,735	505,585	472,066	2,074,941	2,103,679	1,727,837
Expenses
Net claims and claim expenses incurred	477,638	410,510	60,167	171,703	304,064	1,221,696	142,587	193,081	1,120,018	1,861,428	530,831
Acquisition costs	120,465	109,761	105,052	97,711	98,598	76,761	88,251	83,282	432,989	346,892	289,323
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Corporate expenses	12,108	6,841	8,301	6,733	4,237	4,413	4,636	5,286	33,983	18,572	37,402
Interest expense	11,765	11,769	11,768	11,767	11,777	11,799	10,091	10,526	47,069	44,193	42,144
Total expenses	680,835	579,474	222,831	329,186	447,868	1,357,206	287,331	339,458	1,812,326	2,431,863	1,097,449
Income (loss) before taxes	(132,838)	50,280	256,373	88,800	43,425	(722,471)	218,254	132,608	262,615	(328,184)	630,388
Income tax benefit (expense)	8,852	(1,451)	(4,506)	3,407	(41,226)	18,977	(3,904)	(334)	6,302	(26,487)	(340)
Net income (loss)	(123,986)	48,829	251,867	92,207	2,199	(703,494)	214,350	132,274	268,917	(354,671)	630,048
Net (income) loss attributable to redeemable noncontrolling interests	49,269	(6,440)	(54,483)	(29,899)	(56)	204,277	(37,612)	(34,327)	(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe	(74,717)	42,389	197,384	62,308	2,143	(499,217)	176,738	97,947	227,364	(222,389)	502,962
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	$ 197,276	$ (244,770)	$ 480,581
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.25	$ 2.26	$ 4.91	$ (6.15)	$ 11.50
Net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – diluted (in usd per share)	$ (2.10)	$ 0.82	$ 4.78	$ 1.42	$ (0.09)	$ (12.75)	$ 4.24	$ 2.25	$ 4.91	$ (6.15)	$ 11.43
Average shares outstanding - basic	40,111	39,624	39,641	39,552	39,478	39,591	39,937	40,408	39,732	39,854	41,314
Average shares outstanding - diluted	40,111	39,637	39,654	39,599	39,478	39,591	40,024	40,623	39,755	39,854	41,559

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Total investments	$ 11,885,747	$ 9,503,439
Cash and cash equivalents	1,107,922	1,361,592	$ 421,157	$ 506,885
Investments in subsidiaries	0	0
Due from subsidiaries and affiliates	0	0
Premiums receivable	1,537,188	1,304,622
Prepaid reinsurance premiums	616,185	533,546
Reinsurance recoverable	2,372,221	1,586,630	279,564
Accrued investment income	51,311	42,235
Deferred acquisition costs	476,661	426,551
Receivable for investments sold	256,416	103,145
Other assets	135,127	121,226
Goodwill and other intangible assets	237,418	243,145
Total assets	18,676,196	15,226,131
Liabilities
Reserve for claims and claim expenses (Note 7)	6,076,271	5,080,408	2,848,294
Unearned premiums	1,716,021	1,477,609
Debt (Note 8)	991,127	989,623
Amounts due to subsidiaries and affiliates	0	0
Reinsurance balances payable	1,902,056	989,090
Payable for investments purchased	380,332	208,749
Other liabilities	513,609	792,771
Total liabilities	11,579,416	9,538,250
Redeemable noncontrolling interests	2,051,700	1,296,506
Shareholders’ Equity
Total shareholders’ equity	5,045,080	4,391,375	4,866,577
Total liabilities, noncontrolling interests and shareholders’ equity	18,676,196	15,226,131
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Assets
Cash and cash equivalents	3,534	14,656	7,067	10,185
Investments in subsidiaries	4,414,475	4,105,760
Accrued investment income	1,046	405
Receivable for investments sold	203	135
Other assets	458,842	433,468
Goodwill and other intangible assets	120,476	124,960
Total assets	5,368,975	4,909,252
Liabilities
Amounts due to subsidiaries and affiliates	6,453	82,579
Other liabilities	17,442	18,298
Total liabilities	323,895	517,877
Shareholders’ Equity
Total shareholders’ equity	5,045,080	4,391,375
Total liabilities, noncontrolling interests and shareholders’ equity	5,368,975	4,909,252
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Assets
Total investments	313,360	225,266
Cash and cash equivalents	3,534	14,656	7,067	10,185
Investments in subsidiaries	4,414,475	4,105,760
Due from subsidiaries and affiliates	57,039	4,602
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	1,046	405
Deferred acquisition costs	0	0
Receivable for investments sold	203	135
Other assets	458,842	433,468
Goodwill and other intangible assets	120,476	124,960
Total assets	5,368,975	4,909,252
Liabilities
Reserve for claims and claim expenses (Note 7)	0	0
Unearned premiums	0	0
Debt (Note 8)	300,000	417,000
Amounts due to subsidiaries and affiliates	6,453	82,579
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	17,442	18,298
Total liabilities	323,895	517,877
Redeemable noncontrolling interests	0	0
Shareholders’ Equity
Total shareholders’ equity	5,045,080	4,391,375
Total liabilities, noncontrolling interests and shareholders’ equity	5,368,975	4,909,252
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Assets
Total investments	11,465,660	9,117,186
Cash and cash equivalents	1,091,434	1,345,328	397,860	483,012
Investments in subsidiaries	0	0
Due from subsidiaries and affiliates	0	0
Premiums receivable	1,537,188	1,304,622
Prepaid reinsurance premiums	616,185	533,546
Reinsurance recoverable	2,372,221	1,586,630
Accrued investment income	49,828	41,320
Deferred acquisition costs	476,661	426,551
Receivable for investments sold	232,328	102,951
Other assets	(1,403,636)	76,703
Goodwill and other intangible assets	116,942	118,185
Total assets	16,554,811	14,653,022
Liabilities
Reserve for claims and claim expenses (Note 7)	6,076,271	5,080,408
Unearned premiums	1,716,021	1,477,609
Debt (Note 8)	148,041	147,731
Amounts due to subsidiaries and affiliates	0	0
Reinsurance balances payable	1,902,056	989,090
Payable for investments purchased	380,308	208,749
Other liabilities	482,422	764,432
Total liabilities	10,705,119	8,668,019
Redeemable noncontrolling interests	2,051,700	1,296,506
Shareholders’ Equity
Total shareholders’ equity	3,797,992	4,688,497
Total liabilities, noncontrolling interests and shareholders’ equity	16,554,811	14,653,022
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Assets
Total investments	77,842	129,732
Cash and cash equivalents	3,350	139	162	5,908
Investments in subsidiaries	58,458	36,140
Due from subsidiaries and affiliates	101,579	91,891
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	310	428
Deferred acquisition costs	0	0
Receivable for investments sold	23,885	51
Other assets	22,571	21,342
Goodwill and other intangible assets	0	0
Total assets	287,995	279,723
Liabilities
Reserve for claims and claim expenses (Note 7)	0	0
Unearned premiums	0	0
Debt (Note 8)	0	0
Amounts due to subsidiaries and affiliates	217	54
Reinsurance balances payable	0	0
Payable for investments purchased	24	0
Other liabilities	5,362	1,053
Total liabilities	5,603	1,107
Redeemable noncontrolling interests	0	0
Shareholders’ Equity
Total shareholders’ equity	282,392	278,616
Total liabilities, noncontrolling interests and shareholders’ equity	287,995	279,723
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Assets
Total investments	28,885	31,255
Cash and cash equivalents	9,604	1,469	$ 9,397	$ 677
Investments in subsidiaries	1,215,663	1,141,733
Due from subsidiaries and affiliates	0	0
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	127	82
Deferred acquisition costs	0	0
Receivable for investments sold	0	8
Other assets	313,636	430,481
Goodwill and other intangible assets	0	0
Total assets	1,567,915	1,605,028
Liabilities
Reserve for claims and claim expenses (Note 7)	0	0
Unearned premiums	0	0
Debt (Note 8)	843,086	841,892
Amounts due to subsidiaries and affiliates	102,243	92,794
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	13,918	14,117
Total liabilities	959,247	948,803
Redeemable noncontrolling interests	0	0
Shareholders’ Equity
Total shareholders’ equity	608,668	656,225
Total liabilities, noncontrolling interests and shareholders’ equity	1,567,915	1,605,028
Consolidating Adjustments
Assets
Total investments	0	0
Cash and cash equivalents	0	0
Investments in subsidiaries	(5,688,596)	(5,283,633)
Due from subsidiaries and affiliates	(158,618)	(96,493)
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	0	0
Deferred acquisition costs	0	0
Receivable for investments sold	0	0
Other assets	743,714	(840,768)
Goodwill and other intangible assets	0	0
Total assets	(5,103,500)	(6,220,894)
Liabilities
Reserve for claims and claim expenses (Note 7)	0	0
Unearned premiums	0	0
Debt (Note 8)	(300,000)	(417,000)
Amounts due to subsidiaries and affiliates	(108,913)	(175,427)
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	(5,535)	(5,129)
Total liabilities	(414,448)	(597,556)
Redeemable noncontrolling interests	0	0
Shareholders’ Equity
Total shareholders’ equity	(4,689,052)	(5,623,338)
Total liabilities, noncontrolling interests and shareholders’ equity	$ (5,103,500)	$ (6,220,894)

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums earned	$ 574,613	$ 531,849	$ 429,385	$ 440,282	$ 421,473	$ 547,792	$ 382,265	$ 366,045	$ 1,976,129	$ 1,717,575	$ 1,403,430
Net investment income	53,338	80,696	71,356	56,476	73,464	40,257	54,163	54,325	261,866	222,209	181,726
Net foreign exchange (losses) gains	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Equity in earnings (losses) of other ventures	4,143	7,648	5,826	857	2,200	1,794	5,543	(1,507)	18,474	8,030	963
Other loss	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Total revenues	547,997	629,754	479,204	417,986	491,293	634,735	505,585	472,066	2,074,941	2,103,679	1,727,837
Expenses
Net claims and claim expenses incurred	477,638	410,510	60,167	171,703	304,064	1,221,696	142,587	193,081	1,120,018	1,861,428	530,831
Acquisition expenses	120,465	109,761	105,052	97,711	98,598	76,761	88,251	83,282	432,989	346,892	289,323
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Corporate expenses	12,108	6,841	8,301	6,733	4,237	4,413	4,636	5,286	33,983	18,572	37,402
Interest expense	11,765	11,769	11,768	11,767	11,777	11,799	10,091	10,526	47,069	44,193	42,144
Total expenses	680,835	579,474	222,831	329,186	447,868	1,357,206	287,331	339,458	1,812,326	2,431,863	1,097,449
(Loss) income before equity in net income of subsidiaries and taxes									262,615	(328,184)	630,388
Equity in net income of subsidiaries									0	0	0
Income (loss) before taxes	(132,838)	50,280	256,373	88,800	43,425	(722,471)	218,254	132,608	262,615	(328,184)	630,388
Income tax benefit (expense)	8,852	(1,451)	(4,506)	3,407	(41,226)	18,977	(3,904)	(334)	6,302	(26,487)	(340)
Net income (loss)	(123,986)	48,829	251,867	92,207	2,199	(703,494)	214,350	132,274	268,917	(354,671)	630,048
Net (income) loss attributable to redeemable noncontrolling interests	49,269	(6,440)	(54,483)	(29,899)	(56)	204,277	(37,612)	(34,327)	(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe	(74,717)	42,389	197,384	62,308	2,143	(499,217)	176,738	97,947	227,364	(222,389)	502,962
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	197,276	(244,770)	480,581
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net investment income									24,791	23,109	24,178
Net foreign exchange (losses) gains									(3)	(1)	(2)
Other loss									0	0	(772)
Net realized and unrealized (losses) gains on investments									633	(1,357)	4,151
Total revenues									25,421	21,751	27,555
Expenses
Operational expenses									7,679	11,314	13,716
Corporate expenses									25,190	18,546	26,848
Interest expense									5,683	1,572	562
Total expenses									38,552	31,432	41,126
(Loss) income before equity in net income of subsidiaries and taxes									(13,131)	(9,681)	(13,571)
Equity in net income of subsidiaries									240,495	(212,708)	516,533
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders									197,276	(244,770)	480,581
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned									0	0	0
Net investment income									24,791	23,109	24,178
Net foreign exchange (losses) gains									(3)	(1)	(2)
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	(772)
Net realized and unrealized (losses) gains on investments									633	(1,357)	4,151
Total revenues									25,421	21,751	27,555
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									7,679	11,314	13,716
Corporate expenses									25,190	18,546	26,848
Interest expense									5,683	1,572	562
Total expenses									38,552	31,432	41,126
(Loss) income before equity in net income of subsidiaries and taxes									(13,131)	(9,681)	(13,571)
Equity in net income of subsidiaries									240,495	(212,708)	516,533
Income (loss) before taxes									227,364	(222,389)	502,962
Income tax benefit (expense)									0	0	0
Net income (loss)									227,364	(222,389)	502,962
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders									197,276	(244,770)	480,581
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned									1,976,129	1,717,575	1,403,430
Net investment income									261,192	219,490	175,407
Net foreign exchange (losses) gains									(12,425)	10,629	(13,786)
Equity in earnings (losses) of other ventures									15,409	8,253	963
Other loss									5,969	9,415	14,950
Net realized and unrealized (losses) gains on investments									(171,013)	123,121	124,279
Total revenues									2,075,261	2,088,483	1,705,243
Expenses
Net claims and claim expenses incurred									1,120,018	1,861,428	530,831
Acquisition expenses									432,989	346,892	289,323
Operational expenses									164,605	141,572	176,041
Corporate expenses									3,103	26	10,344
Interest expense									4,367	10,075	10,062
Total expenses									1,725,082	2,359,993	1,016,601
(Loss) income before equity in net income of subsidiaries and taxes									350,179	(271,510)	688,642
Equity in net income of subsidiaries									0	0	0
Income (loss) before taxes									350,179	(271,510)	688,642
Income tax benefit (expense)									(399)	(14,328)	(7,617)
Net income (loss)									349,780	(285,838)	681,025
Net (income) loss attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe									308,227	(153,556)	553,939
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									308,227	(153,556)	553,939
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Revenues
Net premiums earned									0	0	0
Net investment income									2,193	1,947	1,852
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									(4,360)	9,621	4,659
Total revenues									(2,167)	11,568	6,511
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									110	103	(112)
Corporate expenses									0	0	203
Interest expense									0	0	0
Total expenses									110	103	91
(Loss) income before equity in net income of subsidiaries and taxes									(2,277)	11,465	6,420
Equity in net income of subsidiaries									5,631	756	3,857
Income (loss) before taxes									3,354	12,221	10,277
Income tax benefit (expense)									582	(18,147)	(2,275)
Net income (loss)									3,936	(5,926)	8,002
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									3,936	(5,926)	8,002
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									3,936	(5,926)	8,002
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned										0	0
Net investment income										1,373	3,989
Net foreign exchange (losses) gains										0	0
Equity in earnings (losses) of other ventures										0	0
Other loss										0	0
Net realized and unrealized (losses) gains on investments										4,916	8,193
Total revenues										6,289	12,182
Expenses
Net claims and claim expenses incurred										0	0
Acquisition expenses										0	0
Operational expenses										85	296
Corporate expenses										0	0
Interest expense										2,461	5,906
Total expenses										2,546	6,202
(Loss) income before equity in net income of subsidiaries and taxes										3,743	5,980
Equity in net income of subsidiaries										28,028	25,073
Income (loss) before taxes										31,771	31,053
Income tax benefit (expense)										(1,175)	(1,462)
Net income (loss)										30,596	29,591
Net (income) loss attributable to redeemable noncontrolling interests										0	0
Net income (loss) attributable to RenaissanceRe										30,596	29,591
Dividends on preference shares										0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders										30,596	29,591
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned									0	0	0
Net investment income									6,219	3,090	569
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									3,065	(223)	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									(329)	(479)	46
Total revenues									8,955	2,388	615
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									34,534	26,063	22,152
Corporate expenses									7	0	7
Interest expense									37,019	31,657	26,176
Total expenses									71,560	57,720	48,335
(Loss) income before equity in net income of subsidiaries and taxes									(62,605)	(55,332)	(47,720)
Equity in net income of subsidiaries									9,091	9,298	38,628
Income (loss) before taxes									(53,514)	(46,034)	(9,092)
Income tax benefit (expense)									6,119	7,163	11,014
Net income (loss)									(47,395)	(38,871)	1,922
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									(47,395)	(38,871)	1,922
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									(47,395)	(38,871)	1,922
Consolidating Adjustments
Revenues
Net premiums earned									0	0	0
Net investment income									(32,529)	(26,800)	(24,269)
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									0	0	0
Total revenues									(32,529)	(26,800)	(24,269)
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									(28,661)	(18,359)	(14,344)
Corporate expenses									5,683	0	0
Interest expense									0	(1,572)	(562)
Total expenses									(22,978)	(19,931)	(14,906)
(Loss) income before equity in net income of subsidiaries and taxes									(9,551)	(6,869)	(9,363)
Equity in net income of subsidiaries									(255,217)	174,626	(584,091)
Income (loss) before taxes									(264,768)	167,757	(593,454)
Income tax benefit (expense)									0	0	0
Net income (loss)									(264,768)	167,757	(593,454)
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									(264,768)	167,757	(593,454)
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									$ (264,768)	$ 167,757	$ (593,454)

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ (123,986)	$ 48,829	$ 251,867	$ 92,207	$ 2,199	$ (703,494)	$ 214,350	$ 132,274	$ 268,917	$ (354,671)	$ 630,048
Change in net unrealized (losses) gains on investments									(1,657)	(909)	(975)
Comprehensive income (loss)									267,260	(355,580)	629,073
Net (income) loss attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Comprehensive income attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Comprehensive income (loss) attributable to RenaissanceRe									225,707	(223,298)	501,987
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Comprehensive income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									227,364	(222,389)	502,962
Change in net unrealized (losses) gains on investments									0	0	0
Comprehensive income (loss)									227,364	(222,389)	502,962
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									349,780	(285,838)	681,025
Change in net unrealized (losses) gains on investments									(1,657)	(909)	(975)
Comprehensive income (loss)									348,123	(286,747)	680,050
Net (income) loss attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Comprehensive income attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Comprehensive income (loss) attributable to RenaissanceRe									306,570	(154,465)	552,964
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									3,936	(5,926)	8,002
Change in net unrealized (losses) gains on investments									0	0	0
Comprehensive income (loss)									3,936	(5,926)	8,002
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income (loss) attributable to RenaissanceRe									3,936	(5,926)	8,002
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)										30,596	29,591
Change in net unrealized (losses) gains on investments										0	0
Comprehensive income (loss)										30,596	29,591
Net (income) loss attributable to redeemable noncontrolling interests										0	0
Comprehensive income attributable to redeemable noncontrolling interests										0	0
Comprehensive income (loss) attributable to RenaissanceRe										30,596	29,591
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									(47,395)	(38,871)	1,922
Change in net unrealized (losses) gains on investments									0	0	0
Comprehensive income (loss)									(47,395)	(38,871)	1,922
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income (loss) attributable to RenaissanceRe									(47,395)	(38,871)	1,922
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									(264,768)	167,757	(593,454)
Change in net unrealized (losses) gains on investments									0	0	0
Comprehensive income (loss)									(264,768)	167,757	(593,454)
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income attributable to redeemable noncontrolling interests									0	0	0
Comprehensive income (loss) attributable to RenaissanceRe									$ (264,768)	$ 167,757	$ (593,454)

Condensed Consolidating Finan_6

Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	$ 1,221,701	$ 1,025,787	$ 484,772
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	11,585,576	9,490,669	8,102,514
Purchases of fixed maturity investments trading	(12,489,972)	(10,093,532)	(8,282,720)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	17,692
Net (purchases) sales of equity investments trading	14,156	115,837	184,788
Net sales (purchases) of short term investments	(1,436,389)	364,011	(118,617)
Net purchases of other investments	(199,475)	(19,419)	(68,589)
Net purchases of investments in other ventures	(21,473)	0	0
Return of investment from investment in other ventures	8,464	20,000	0
Net sales of other assets	2,500	0	400
Dividends and return of capital from subsidiaries	0	0	0
Contributions to subsidiaries	0	0	0
Due to (from) subsidiaries	0	0	0
Net cash used in investing activities	(2,536,613)	(122,434)	(164,532)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases	0	(188,591)	(309,434)
RenaissanceRe common share issuance	250,000	0	0
Issuance of preference shares, net of expenses	241,448	0
Issuance of debt, net of expenses	0	295,866	0
Repayment of debt	0	(250,000)	0
Net third party redeemable noncontrolling interest share transactions	665,683	260,475	(2,990)
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	1,066,340	28,860	(401,331)
Effect of exchange rate changes on foreign currency cash	(5,098)	8,222	(4,637)
Net (decrease) increase in cash and cash equivalents	(253,670)	940,435	(85,728)
Cash and cash equivalents, beginning of period	1,361,592	421,157	506,885
Cash and cash equivalents, end of period	1,107,922	1,361,592	421,157
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	(9,659)	(4,109)	(3,509)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	384,818	261,601	314,568
Purchases of fixed maturity investments trading	(520,935)	(344,463)	(336,345)
Net sales (purchases) of short term investments	48,600	243,571	(111,814)
Dividends and return of capital from subsidiaries	672,098	478,496	617,239
Net cash used in investing activities	(402,120)	289,179	398,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases	0	(188,591)	(309,434)
RenaissanceRe common share issuance	250,000	0	0
Issuance of preference shares, net of expenses	241,448	0	0
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	400,657	(277,481)	(398,341)
Net (decrease) increase in cash and cash equivalents	(11,122)	7,589	(3,118)
Cash and cash equivalents, beginning of period	14,656	7,067	10,185
Cash and cash equivalents, end of period	3,534	14,656	7,067
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	(9,659)	(4,109)	(3,509)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	384,818	261,601	314,568
Purchases of fixed maturity investments trading	(520,935)	(344,463)	(336,345)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	0	0	0
Net sales (purchases) of short term investments	48,600	243,571	(111,814)
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	672,098	478,496	617,239
Contributions to subsidiaries	(785,785)	(669,672)	(108,674)
Due to (from) subsidiaries	(200,916)	319,646	23,758
Net cash used in investing activities	(402,120)	289,179	398,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases		(188,591)	(309,434)
RenaissanceRe common share issuance	250,000
Issuance of preference shares, net of expenses	241,448
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	400,657	(277,481)	(398,341)
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	(11,122)	7,589	(3,118)
Cash and cash equivalents, beginning of period	14,656	7,067	10,185
Cash and cash equivalents, end of period	3,534	14,656	7,067
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	1,162,400	1,388,311	535,912
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	11,046,968	8,550,179	7,572,923
Purchases of fixed maturity investments trading	(11,840,813)	(9,229,732)	(7,532,276)
Proceeds from sales and maturities of fixed maturity investments available for sale			17,692
Net (purchases) sales of equity investments trading	15,464	32,265	(5,845)
Net sales (purchases) of short term investments	(1,485,040)	79,520	(41,586)
Net purchases of other investments	(199,475)	(19,419)	(68,589)
Net purchases of investments in other ventures	(21,473)
Return of investment from investment in other ventures	8,464	20,000
Net sales of other assets	2,500		400
Dividends and return of capital from subsidiaries	(672,098)	(529,537)	(633,264)
Contributions to subsidiaries	867,632	706,211	108,674
Due to (from) subsidiaries	200,992	(319,027)	(31,566)
Net cash used in investing activities	(2,076,879)	(709,540)	(613,437)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases		0	0
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	665,683	260,475	(2,990)
Taxes paid on withholding shares	0	0	0
Net cash provided by (used in) financing activities	665,683	260,475	(2,990)
Effect of exchange rate changes on foreign currency cash	(5,098)	8,222	(4,637)
Net (decrease) increase in cash and cash equivalents	(253,894)	947,468	(85,152)
Cash and cash equivalents, beginning of period	1,345,328	397,860	483,012
Cash and cash equivalents, end of period	1,091,434	1,345,328	397,860
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	6,315	(8,253)	1,477
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	97,272	100,248	69,941
Purchases of fixed maturity investments trading	(72,292)	(99,568)	(123,046)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	(1,308)	(1,752)	(2,389)
Net sales (purchases) of short term investments	(404)	114	67,684
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	0	9,175	2,900
Contributions to subsidiaries	(16,847)	0	0
Due to (from) subsidiaries	(9,525)	13	(22,313)
Net cash used in investing activities	(3,104)	8,230	(7,223)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases		0	0
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	3,211	(23)	(5,746)
Cash and cash equivalents, beginning of period	139	162	5,908
Cash and cash equivalents, end of period	3,350	139	162
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities		(2,272)	(14,501)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading		289,741	145,082
Purchases of fixed maturity investments trading		(143,991)	(291,053)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading		85,324	193,022
Net sales (purchases) of short term investments		41,299	(32,901)
Net purchases of other investments		0	0
Return of investment from investment in other ventures		0
Net sales of other assets			0
Dividends and return of capital from subsidiaries		0	0
Contributions to subsidiaries		(26,649)	0
Due to (from) subsidiaries		(123)	(81)
Net cash used in investing activities		245,601	14,069
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares		0	0
Dividends paid – preference shares		0	0
RenaissanceRe common share repurchases		0	0
Issuance of debt, net of expenses		0
Repayment of debt		(250,000)
Net third party redeemable noncontrolling interest share transactions		0	0
Taxes paid on withholding shares		0	0
Net cash provided by (used in) financing activities		(250,000)	0
Effect of exchange rate changes on foreign currency cash		0	0
Net (decrease) increase in cash and cash equivalents		(6,671)	(432)
Cash and cash equivalents, beginning of period	0	6,671	7,103
Cash and cash equivalents, end of period		0	6,671
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	62,645	(347,890)	(34,607)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	56,518	288,900	0
Purchases of fixed maturity investments trading	(55,932)	(275,778)	0
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	0	0	0
Net sales (purchases) of short term investments	455	(493)	0
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	0	41,866	13,125
Contributions to subsidiaries	(65,000)	(9,890)	0
Due to (from) subsidiaries	9,449	(509)	30,202
Net cash used in investing activities	(54,510)	44,096	43,327
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases		0	0
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		295,866
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	0	0	0
Net cash provided by (used in) financing activities	0	295,866	0
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	8,135	(7,928)	8,720
Cash and cash equivalents, beginning of period	1,469	9,397	677
Cash and cash equivalents, end of period	$ 9,604	$ 1,469	$ 9,397

Subsequent Events (Details)

Subsequent Events (Details) - Upsilon RFO Re Ltd. - Primary Beneficiary - USD ($) $ in Millions	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2018	Dec. 30, 2018	Dec. 31, 2017
Non-voting preference shares
Subsequent Event [Line Items]
Investment in variable interest entity			$ 109.8		$ 27.2
Investor | Non-voting preference shares
Subsequent Event [Line Items]
Investment in variable interest entity			$ 856.7	$ 400	$ 7.5
RenaissanceRe Holdings Ltd.
Subsequent Event [Line Items]
Variable interest entity, ownership percentage			14.00%		20.80%
Subsequent Event | Non-voting preference shares
Subsequent Event [Line Items]
Investment in variable interest entity	$ 100
Subsequent Event | Investor | Non-voting preference shares
Subsequent Event [Line Items]
Investment in variable interest entity	$ 456.8
Subsequent Event | RenaissanceRe Holdings Ltd.
Subsequent Event [Line Items]
Variable interest entity, ownership percentage	16.90%
Other liabilities | Investor | Non-voting preference shares
Subsequent Event [Line Items]
Investment in variable interest entity		$ 300

Schedule I. Summary of Invest_2

Schedule I. Summary of Investments Other Than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2018USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	$ 11,885,747
Amount at which shown in the Balance Sheet	11,885,747
U.S. treasuries
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	3,336,969
Fair Value	3,331,411
Amount at which shown in the Balance Sheet	3,331,411
Agencies
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	175,185
Fair Value	174,883
Amount at which shown in the Balance Sheet	174,883
Municipal
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	6,070
Fair Value	6,854
Amount at which shown in the Balance Sheet	6,854
Non-U.S. government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	284,965
Fair Value	279,818
Amount at which shown in the Balance Sheet	279,818
Non-U.S. government-backed corporate
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	160,286
Fair Value	160,063
Amount at which shown in the Balance Sheet	160,063
Corporate
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	2,513,434
Fair Value	2,450,244
Amount at which shown in the Balance Sheet	2,450,244
Agency mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	825,365
Fair Value	817,880
Amount at which shown in the Balance Sheet	817,880
Non-agency mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	266,705
Fair Value	278,680
Amount at which shown in the Balance Sheet	278,680
Commercial mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	284,495
Fair Value	282,294
Amount at which shown in the Balance Sheet	282,294
Asset-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	310,488
Fair Value	306,743
Amount at which shown in the Balance Sheet	306,743
Fixed maturity investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized Cost or Cost	8,163,962
Fair Value	8,088,870
Amount at which shown in the Balance Sheet	8,088,870
Short term investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	2,586,520
Amount at which shown in the Balance Sheet	2,586,520
Equity investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	310,252
Amount at which shown in the Balance Sheet	310,252
Other investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	784,933
Amount at which shown in the Balance Sheet	784,933
Investments in other ventures, under equity method
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	115,172
Amount at which shown in the Balance Sheet	$ 115,172

Schedule II. Condensed Financ_2

Schedule II. Condensed Financial Information Of Registrant (Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Fixed maturity investments trading	$ 8,088,870	$ 7,426,555
Short term investments, at fair value (Notes 4 and 5)	2,586,520	991,863
Cash and cash equivalents	1,107,922	1,361,592	$ 421,157	$ 506,885
Investments in subsidiaries	0	0
Accrued investment income	51,311	42,235
Receivable for investments sold	256,416	103,145
Other assets	135,127	121,226
Goodwill and other intangible assets	237,418	243,145
Total assets	18,676,196	15,226,131
Liabilities
Due to subsidiaries	0	0
Other liabilities	513,609	792,771
Total liabilities	11,579,416	9,538,250
Shareholders’ Equity
Preference shares: $1.00 par value – 16,010,000 shares issued and outstanding at December 31, 2018 (2017 – 16,000,000)	650,000	400,000
Common shares: $1.00 par value – 42,207,390 shares issued and outstanding at December 31, 2018 (2017 – 40,023,789)	42,207	40,024
Additional paid-in capital	296,099	37,355
Accumulated other comprehensive (loss) income	(1,433)	224
Retained earnings	4,058,207	3,913,772
Total shareholders’ equity attributable to RenaissanceRe	5,045,080	4,391,375	4,866,577
Total liabilities, noncontrolling interests and shareholders’ equity	18,676,196	15,226,131
Parent Company
Assets
Fixed maturity investments trading	240,443	103,638
Short term investments, at fair value (Notes 4 and 5)	72,917	121,628
Cash and cash equivalents	3,534	14,656	$ 7,067	$ 10,185
Investments in subsidiaries	4,414,475	4,105,760
Due from subsidiaries	57,039	4,602
Accrued investment income	1,046	405
Receivable for investments sold	203	135
Other assets	458,842	433,468
Goodwill and other intangible assets	120,476	124,960
Total assets	5,368,975	4,909,252
Liabilities
Notes and bank loans payable	300,000	417,000
Due to subsidiaries	6,453	82,579
Other liabilities	17,442	18,298
Total liabilities	323,895	517,877
Shareholders’ Equity
Preference shares: $1.00 par value – 16,010,000 shares issued and outstanding at December 31, 2018 (2017 – 16,000,000)	650,000	400,000
Common shares: $1.00 par value – 42,207,390 shares issued and outstanding at December 31, 2018 (2017 – 40,023,789)	42,207	40,024
Additional paid-in capital	296,099	37,355
Accumulated other comprehensive (loss) income	(1,433)	224
Retained earnings	4,058,207	3,913,772
Total shareholders’ equity attributable to RenaissanceRe	5,045,080	4,391,375
Total liabilities, noncontrolling interests and shareholders’ equity	$ 5,368,975	$ 4,909,252

Schedule II. Condensed Financ_3

Schedule II. Condensed Financial Information Of Registrant (Balance Sheets Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Fixed maturity investments trading, amortized cost	$ 8,163,962	$ 7,434,870
Preference shares, par value (in usd per share)	$ 1	$ 1
Preference shares, shares issued (in shares)	16,010,000	16,000,000
Preference shares, shares outstanding (in shares)	16,010,000	16,000,000
Common shares, par value (in usd per share)	$ 1	$ 1
Common shares, shares issued (in shares)	42,207,390	40,023,789
Common shares, shares outstanding (in shares)	42,207,390	40,023,789
Parent Company
Condensed Financial Statements, Captions [Line Items]
Fixed maturity investments trading, amortized cost	$ 238,989	$ 104,521
Preference shares, par value (in usd per share)	$ 1	$ 1
Preference shares, shares issued (in shares)	16,010,000	16,000,000
Preference shares, shares outstanding (in shares)	16,010,000	16,000,000
Common shares, par value (in usd per share)	$ 1	$ 1
Common shares, shares issued (in shares)	42,207,390	40,023,789
Common shares, shares outstanding (in shares)	42,207,390	40,023,789

Schedule II. Condensed Financ_4

Schedule II. Condensed Financial Information Of Registrant (Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net investment income	$ 53,338	$ 80,696	$ 71,356	$ 56,476	$ 73,464	$ 40,257	$ 54,163	$ 54,325	$ 261,866	$ 222,209	$ 181,726
Net foreign exchange losses	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Other loss	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Total revenues	547,997	629,754	479,204	417,986	491,293	634,735	505,585	472,066	2,074,941	2,103,679	1,727,837
Expenses
Interest expense	11,765	11,769	11,768	11,767	11,777	11,799	10,091	10,526	47,069	44,193	42,144
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Corporate expenses	12,108	6,841	8,301	6,733	4,237	4,413	4,636	5,286	33,983	18,572	37,402
Total expenses	680,835	579,474	222,831	329,186	447,868	1,357,206	287,331	339,458	1,812,326	2,431,863	1,097,449
Loss before equity in net income (loss) of subsidiaries									262,615	(328,184)	630,388
Equity in net income (loss) of subsidiaries									0	0	0
Net income (loss) attributable to RenaissanceRe	(74,717)	42,389	197,384	62,308	2,143	(499,217)	176,738	97,947	227,364	(222,389)	502,962
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	197,276	(244,770)	480,581
Parent Company
Revenues
Net investment income									24,791	23,109	24,178
Net foreign exchange losses									(3)	(1)	(2)
Other loss									0	0	(772)
Net realized and unrealized (losses) gains on investments									633	(1,357)	4,151
Total revenues									25,421	21,751	27,555
Expenses
Interest expense									5,683	1,572	562
Operational expenses									7,679	11,314	13,716
Corporate expenses									25,190	18,546	26,848
Total expenses									38,552	31,432	41,126
Loss before equity in net income (loss) of subsidiaries									(13,131)	(9,681)	(13,571)
Equity in net income (loss) of subsidiaries									240,495	(212,708)	516,533
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders									$ 197,276	$ (244,770)	$ 480,581

Schedule II. Condensed Financ_5

Schedule II. Condensed Financial Information Of Registrant (Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ (74,717)	$ 42,389	$ 197,384	$ 62,308	$ 2,143	$ (499,217)	$ 176,738	$ 97,947	$ 227,364	$ (222,389)	$ 502,962
Comprehensive income (loss) attributable to RenaissanceRe									225,707	(223,298)	501,987
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									227,364	(222,389)	502,962
Comprehensive income (loss) attributable to RenaissanceRe									$ 227,364	$ (222,389)	$ 502,962

Schedule II. Condensed Financ_6

Schedule II. Condensed Financial Information Of Registrant (Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows (used in) provided by operating activities
Net income (loss) attributable to RenaissanceRe	$ (74,717)	$ 42,389	$ 197,384	$ 62,308	$ 2,143	$ (499,217)	$ 176,738	$ 97,947	$ 227,364	$ (222,389)	$ 502,962
Less: equity in net (income) loss of subsidiaries									0	0	0
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Net realized and unrealized losses (gains) on investments	88,654	$ (13,630)	$ 17,901	82,144	7,716	$ (42,052)	$ (58,113)	(43,373)	175,069	(135,822)	(141,328)
Other									(223,280)	518,100	99,943
Net cash provided by operating activities									1,221,701	1,025,787	484,772
Cash flows provided by (used in) investing activities
Proceeds from maturities and sales of fixed maturity investments trading									11,585,576	9,490,669	8,102,514
Purchases of fixed maturity investments trading									(12,489,972)	(10,093,532)	(8,282,720)
Net sales (purchases) of short term investments									(1,436,389)	364,011	(118,617)
Dividends and return of capital from subsidiaries									0	0	0
Net cash used in investing activities									(2,536,613)	(122,434)	(164,532)
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares									(52,841)	(51,370)	(51,583)
Dividends paid – preference shares									(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases									0	(188,591)	(309,434)
RenaissanceRe common share issuance									250,000	0	0
Issuance of preference shares, net of expenses									241,448	0
Taxes paid on withholding shares									(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities									1,066,340	28,860	(401,331)
Net (decrease) increase in cash and cash equivalents									(253,670)	940,435	(85,728)
Cash and cash equivalents, beginning of period				1,361,592				421,157	1,361,592	421,157	506,885
Cash and cash equivalents, end of period	1,107,922				1,361,592				1,107,922	1,361,592	421,157
Parent Company
Cash flows (used in) provided by operating activities
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Less: equity in net (income) loss of subsidiaries									(240,495)	212,708	(516,533)
Loss before equity in net income of subsidiaries									(13,131)	(9,681)	(13,571)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Net realized and unrealized losses (gains) on investments									(633)	1,357	(4,151)
Other									4,105	4,215	14,213
Net cash provided by operating activities									(9,659)	(4,109)	(3,509)
Cash flows provided by (used in) investing activities
Proceeds from maturities and sales of fixed maturity investments trading									384,818	261,601	314,568
Purchases of fixed maturity investments trading									(520,935)	(344,463)	(336,345)
Net sales (purchases) of short term investments									48,600	243,571	(111,814)
Dividends and return of capital from subsidiaries									672,098	478,496	617,239
Contributions to subsidiaries									(785,785)	(669,672)	(108,674)
Due to (from) subsidiary									(200,916)	319,646	23,758
Net cash used in investing activities									(402,120)	289,179	398,732
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares									(52,841)	(51,370)	(51,583)
Dividends paid – preference shares									(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases									0	(188,591)	(309,434)
RenaissanceRe common share issuance									250,000	0	0
Issuance of preference shares, net of expenses									241,448	0	0
Taxes paid on withholding shares									(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities									400,657	(277,481)	(398,341)
Net (decrease) increase in cash and cash equivalents									(11,122)	7,589	(3,118)
Cash and cash equivalents, beginning of period				$ 14,656				$ 7,067	14,656	7,067	10,185
Cash and cash equivalents, end of period	$ 3,534				$ 14,656				$ 3,534	$ 14,656	$ 7,067

Schedule III. Supplementary I_2

Schedule III. Supplementary Insurance Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Policy Acquisition Costs	$ 476,661	$ 426,551	$ 335,325
Future Policy Benefits, Losses, Claims and Loss Expenses	6,076,271	5,080,408	2,848,294
Unearned Premiums	1,716,021	1,477,609	1,231,573
Premium Revenue	1,976,129	1,717,575	1,403,430
Net Investment Income	261,866	222,209	181,726
Benefits, Claims, Losses and Settlement Expenses	1,120,018	1,861,428	530,831
Amortization of Deferred Policy Acquisition Costs	432,989	346,892	289,323
Other Operating Expenses	178,267	160,778	197,749
Net Written Premiums	2,131,902	1,871,325	1,535,312
Property
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Policy Acquisition Costs	66,656	63,583	46,938
Future Policy Benefits, Losses, Claims and Loss Expenses	3,086,254	2,486,390	627,774
Unearned Premiums	379,943	347,032	289,080
Premium Revenue	1,050,831	931,070	720,951
Net Investment Income	0	0	0
Benefits, Claims, Losses and Settlement Expenses	497,895	1,297,985	151,545
Amortization of Deferred Policy Acquisition Costs	177,912	113,816	97,594
Other Operating Expenses	112,954	94,194	108,642
Net Written Premiums	1,055,188	978,014	725,321
Casualty and Specialty
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Policy Acquisition Costs	410,005	362,968	288,387
Future Policy Benefits, Losses, Claims and Loss Expenses	2,985,393	2,575,492	2,195,126
Unearned Premiums	1,336,078	1,130,577	942,493
Premium Revenue	925,298	786,501	682,337
Net Investment Income	0	0	0
Benefits, Claims, Losses and Settlement Expenses	622,320	565,026	380,396
Amortization of Deferred Policy Acquisition Costs	255,079	233,077	191,729
Other Operating Expenses	64,883	66,548	88,984
Net Written Premiums	1,076,714	893,307	809,848
Other
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Policy Acquisition Costs	0	0	0
Future Policy Benefits, Losses, Claims and Loss Expenses	4,624	18,526	25,394
Unearned Premiums	0	0	0
Premium Revenue	0	4	142
Net Investment Income	261,866	222,209	181,726
Benefits, Claims, Losses and Settlement Expenses	(197)	(1,583)	(1,110)
Amortization of Deferred Policy Acquisition Costs	(2)	(1)	0
Other Operating Expenses	430	36	123
Net Written Premiums	$ 0	$ 4	$ 143

Schedule IV. Supplemental Sch_2

Schedule IV. Supplemental Schedule of Reinsurance Premiums (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Gross Amounts									$ 292,219	$ 244,285	$ 157,112
Ceded to Other Companies									1,095,886	833,929	628,675
Assumed									2,779,796	2,307,219	1,874,993
Net premiums earned (Note 6)	$ 574,613	$ 531,849	$ 429,385	$ 440,282	$ 421,473	$ 547,792	$ 382,265	$ 366,045	$ 1,976,129	$ 1,717,575	$ 1,403,430
Percentage of Amount Assumed to Net									141.00%	134.00%	134.00%

Schedule VI. Supplementary In_2

Schedule VI. Supplementary Insurance Information Concerning Property-Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Line Items]
Current year	$ 1,390,767	$ 1,902,424	$ 694,957
Prior years	(270,749)	(40,996)	(164,126)
Consolidated Subsidiaries
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Line Items]
Deferred Policy Acquisition Costs	476,661	426,551	335,325
Reserves for Unpaid Claims and Claim Adjustment Expenses	6,076,271	5,080,408	2,848,294
Discount, if any, Deducted	0	0	0
Unearned Premiums	1,716,021	1,477,609	1,231,573
Earned Premiums	1,976,129	1,717,575	1,403,430
Net Investment Income	261,866	222,209	181,726
Current year	1,390,767	1,902,424	694,957
Prior years	(270,749)	(40,996)	(164,126)
Amortization of Deferred Policy Acquisition Costs	432,989	346,892	289,323
Paid Claims and Claim Adjustment Expenses	894,769	974,825	589,294
Net Premiums Written	$ 2,131,902	$ 1,871,325	$ 1,535,312

Uncategorized Items - rnr-20181

Label	Element	Value
Additional Paid-in Capital [Member]
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	$ 0