Thanks for looking into it. following are the my Answer .
1)Can you confirm that the Media Manager dialog looks OK in Firefox and Chrome, but not on IE and Safari Mac? Ans : Yes
2)Do you use any custom skins? Ans :No, use default rad skin
3) Do you have any proxy servers? Ans : No
4) Are there any CSS stylesheet that could break its appearance? Ans: No, As per our Analysis styleshhet not apply on iframe inner element on IE and Safari.
5)Are there any 404 errors in the browser console? Ans: No
Other Information: Actually previously we are using Telerik 10. Version . At Version 10 RadEditor and Dialog working fine on All browser. Now we are upgrated it to Telerik 2016.3.1027.45., while testing we have get the IE/ Safari browser issue.