Padding Is Not Showing Up at Bottom of Div

The padding in my #outerwrapper div is not showing up at the bottom of the div (should be 20px of padding at the bottom of the div). Instead, the 2 divs inside the #outerwrapper div are extending straight to the bottom of the #outerwrapper div… there should be spacing at the bottom. What’s wrong?

And another question - is overflow:hidden on the #outerwrapper div necessary? I don’t plan on extending the content within the Content and #sidebar divs outside the border of the #outerwrapper div.

Here is the page.

Fixed it - removed fixed height on outerwrapper div and just added fixed heights to content & sidebar divs instead.