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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator:
Net income available to RenaissanceRe common shareholders	$ 136,325	$ 73,233	$ 264,320	$ 241,076
Amount allocated to participating common shareholders	(1,561)	(819)	(3,166)	(2,781)
Net income allocated to RenaissanceRe common shareholders	$ 134,764	$ 72,414	$ 261,154	$ 238,295
Denominator:
Denominator for basic income per RenaissanceRe common share - weighted average common shares	41,693	45,303	42,135	42,467
Per common share equivalents of employee stock options and restricted shares	192	354	263	372
Denominator for diluted income per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions	41,885	45,657	42,398	42,839
Net income available to RenaissanceRe common shareholders per common share – basic (in usd per share)	$ 3.23	$ 1.60	$ 6.20	$ 5.61
Net income available to RenaissanceRe common shareholders per common share – diluted (in usd per share)	$ 3.22	$ 1.59	$ 6.16	$ 5.56