Ask HN: Best tools for large code base documentation?

We are grappling with code documentation at work (large Django application). We use Python's docstrings and JIRA's confluence but they are not enough. Confluence is not very easy to maintain and as somewhat distant from developers' daily workflow -- rarely gazed upon. Docstrings are all right -- but we don't do much with them. I know of Sphinx and that is a tool we are thinking about, but we want to do a proper research first, so here is my question for you today: what documentation tools do you use? What's your favourite and why?