Can somebody help with this conditional? "If homepage, then this. Else, that."

I'm trying to write a conditional so that the content container can expand depending on whether it is the home page or not. The home page will omit the sidebar.

<div id="{{ if homepage }}home-content {{ else }}content {{ endif }}">
    {{ layout_content }}
</div>

I expected this would work, but the conditional is still outputting "home-content" on other pages.