I was trying to do a similar task to get a dropdown arrow always on the right side of the table header and came up with this which seemed to work in Chrome and Firefox, but safari was telling me it was an invalid property.
background: url(http://goo.gl/P93P5Q) center right 10px no-repeat;
After doing a bit of messing around in the inspector, I came up with this cross-browser solution that works in IE8+, Chrome, Firefox, and Safari, as well as responsive designs.
background: url(http://goo.gl/P93P5Q) no-repeat 95% center;
Here is a codepen of how it looks and works. Codepen is written with SCSS - http://cdpn.io/xqGbk