v2.4.0.6

Investments (Schedule of Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	$ 46,555	$ 69,672
Investment expenses	(2,940)	(2,701)
Net investment income (loss)	43,615	66,971
Fixed maturity investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	24,310	26,333
Short term investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	318	500
Equity investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	0	170
Other investments, Hedge funds and private equity investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	14,880	28,473
Other investments, Other [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	6,995	14,170
Cash and cash equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income before investment expenses	$ 52	$ 26

X

- Definition

This item represents the total of all interest and dividend income on fixed maturity investments, short term investments, equity investments trading and other investments (including any amortization/accretion of discounts/premiums), interest income earned on cash and cash equivalents and net gain or loss, both realized and unrealized, on other investments, before investment expenses.

+ References

No definition available.

+ Details

Name:	rnr_InvestmentIncomeBeforeInvestmentExpenses
Namespace Prefix:	rnr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Total expenses related to the generation of investment income in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

Name:	us-gaap_InvestmentIncomeInvestmentExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The income earned from investments in securities and property, equipment and other capital assets. It includes rent from property and equipment, dividends from shares in corporations, and interest from bonds, loans, mortgages, derivatives, commercial paper, bank accounts, certificates of deposits, treasuries, and other financial securities. It does not include realized gains and losses on investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 16

-Article 12



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.2)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 2

-Article 7

+ Details

Name:	us-gaap_NetInvestmentIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration