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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net income available to RenaissanceRe common shareholders	$ 146,825	$ 75,529	$ 411,145	$ 316,605
Amount allocated to participating common shareholders	(1,770)	(867)	(4,939)	(3,642)
Net income allocated to RenaissanceRe common shareholders	$ 145,055	$ 74,662	$ 406,206	$ 312,963
Denominator:
Denominator for basic income per RenaissanceRe common share - weighted average common shares (in shares)	40,513	44,564	41,594	43,166
Per common share equivalents of employee stock options and restricted shares (in shares)	220	349	248	365
Denominator for diluted income per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions (in shares)	40,733	44,913	41,842	43,531
Net income available to RenaissanceRe common shareholders per common share – basic (in usd per share)	$ 3.58	$ 1.68	$ 9.77	$ 7.25
Net income available to RenaissanceRe common shareholders per common share – diluted (in usd per share)	$ 3.56	$ 1.66	$ 9.71	$ 7.19