v2.4.0.6
Segment Reporting (Schedule Of Significant Components Of The Company's Revenues And Expenses) (Details) (USD $)
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Segment Reporting Information [Line Items]    
Gross premiums written $ 635,418,000 $ 664,151,000
Net premiums written 436,813,000 492,575,000
Net premiums earned 271,255,000 278,665,000
Net claims and claim expenses incurred 27,251,000 15,552,000
Acquisition expenses 25,009,000 24,111,000
Operational expenses 46,014,000 42,383,000
Underwriting income 172,981,000 196,619,000
Net investment income 43,615,000 66,971,000
Net foreign exchange gains (losses) 1,756,000 (1,460,000)
Equity in earnings of other ventures 5,835,000 5,470,000
Other income (loss) 7,004,000 (39,094,000)
Net realized and unrealized gains on investments 13,850,000 46,113,000
Net other-than-temporary impairments 0 (134,000)
Corporate expenses (4,529,000) (4,811,000)
Interest expense (5,034,000) (5,718,000)
Income from continuing operations before taxes 235,478,000 263,956,000
Income tax (expense) benefit (122,000) 37,000
Loss from discontinued operations 0 (173,000)
Net income attributable to noncontrolling interests (38,607,000) (53,641,000)
Dividends on preference shares (6,275,000) (8,750,000)
Net income available to RenaissanceRe common shareholders 190,474,000 201,429,000
Net claims and claim expenses incurred - current accident year 64,900,000 71,424,000
Net claims and claim expenses incurred – prior accident years (37,649,000) (55,872,000)
Net claims and claim expenses incurred 27,251,000 15,552,000
Net claims and claim expense ratio - current accident year 23.90% 25.60%
Net claims and claim expense ratio - prior accident years (13.90%) (20.00%)
Net claims and claim expense ratio - calendar year 10.00% 5.60%
Underwriting expense ratio 26.20% 23.80%
Combined ratio 36.20% 29.40%
Reinsurance [Member]
    
Segment Reporting Information [Line Items]    
Gross premiums written 561,126,000 609,762,000
Net premiums written 380,872,000 458,638,000
Net premiums earned 233,460,000 253,818,000
Net claims and claim expenses incurred 13,400,000 8,324,000
Acquisition expenses 18,059,000 19,386,000
Operational expenses 33,675,000 32,044,000
Underwriting income 168,326,000 194,064,000
Net claims and claim expenses incurred - current accident year 47,029,000 55,144,000
Net claims and claim expenses incurred – prior accident years (33,629,000) (46,820,000)
Net claims and claim expenses incurred 13,400,000 8,324,000
Net claims and claim expense ratio - current accident year 20.10% 21.70%
Net claims and claim expense ratio - prior accident years (14.40%) (18.40%)
Net claims and claim expense ratio - calendar year 5.70% 3.30%
Underwriting expense ratio 22.20% 20.20%
Combined ratio 27.90% 23.50%
Lloyd's [Member]
    
Segment Reporting Information [Line Items]    
Gross premiums written 74,292,000 54,817,000
Net premiums written 55,924,000 33,937,000
Net premiums earned 37,779,000 24,822,000
Net claims and claim expenses incurred 14,528,000 9,001,000
Acquisition expenses 6,916,000 4,668,000
Operational expenses 12,178,000 10,057,000
Underwriting income 4,157,000 1,096,000
Net claims and claim expenses incurred - current accident year 17,871,000 16,280,000
Net claims and claim expenses incurred – prior accident years (3,343,000) (7,279,000)
Net claims and claim expenses incurred 14,528,000 9,001,000
Net claims and claim expense ratio - current accident year 47.30% 65.60%
Net claims and claim expense ratio - prior accident years (8.80%) (29.30%)
Net claims and claim expense ratio - calendar year 38.50% 36.30%
Underwriting expense ratio 50.50% 59.30%
Combined ratio 89.00% 95.60%
Other [Member]
    
Segment Reporting Information [Line Items]    
Gross premiums written 0 0
Net premiums written 17,000 0
Net premiums earned 16,000 25,000
Net claims and claim expenses incurred (677,000) (1,773,000)
Acquisition expenses 34,000 57,000
Operational expenses 161,000 282,000
Underwriting income 498,000 1,459,000
Net investment income 43,615,000 66,971,000
Net foreign exchange gains (losses) 1,756,000 (1,460,000)
Equity in earnings of other ventures 5,835,000 5,470,000
Other income (loss) 7,004,000 (39,094,000)
Net realized and unrealized gains on investments 13,850,000 46,113,000
Net other-than-temporary impairments   (134,000)
Corporate expenses (4,529,000) (4,811,000)
Interest expense (5,034,000) (5,718,000)
Income tax (expense) benefit (122,000) 37,000
Loss from discontinued operations   (173,000)
Net income attributable to noncontrolling interests (38,607,000) (53,641,000)
Dividends on preference shares (6,275,000) (8,750,000)
Net claims and claim expenses incurred - current accident year 0 0
Net claims and claim expenses incurred – prior accident years (677,000) (1,773,000)
Net claims and claim expenses incurred (677,000) (1,773,000)
Net claims and claim expense ratio - current accident year 0.00% 0.00%
Net claims and claim expense ratio - prior accident years (4231.30%) (7092.00%)
Net claims and claim expense ratio - calendar year (4231.30%) (7092.00%)
Underwriting expense ratio 1218.80% 1356.00%
Combined ratio (3012.50%) (5736.00%)
Eliminations [Member]
    
Segment Reporting Information [Line Items]    
Gross premiums written   (428,000) [1]
Intersegment Elimination, Reinsurance Segment To Lloyds Segment Member
    
Segment Reporting Information [Line Items]    
Gross premiums ceded from segment to segment   $ 400,000
[1] Represents $0.4 million of gross premiums ceded from the Reinsurance segment to the Lloyd’s segment.