As you're developers gollum may work well: it's backed by a git repo so you can edit locally and/or on a shared server.<p>Gollum is what powers GitHub wikis.
What size and what lifetime?<p>If you want something that is about 2-5 pages long and is only actively updated for 3 weeks then archived, Dropbox Paper works well for the 8 months my team has been using it.