CSS vertical height adjust based on content, not window

I have a contentcontainer in my CSS Stylesheet that is set to 100% height that I need to work properly. It works and sets up the heigt as 100%, but if the window is shrunk, then the page scrolled down, it only fills 100% of the window, not my content. Any ideas? This is making my content overflow outside of the div, but I want the div to strecth vertically with the content.

Here is the container:

 #bodycontainer {
      position:relative;
                    margin: 0 auto; /* This centers the container */
                    width: 760px;
                    font: Arial, Helvetica, sans-serif;
                    cursor:default;
                    background-image:url(../images/back.gif);
                    padding: 10px 15px 0 15px;
      overflow:visible;
      height:100%;
}