iPad over capacity
Ever since I bought my iPad Air, I have only used about 1/3 of its total capacity, consisting mostly of apps and a few small iTunes playlists. Now, it's 14GB over capacity, taken up by a nebulous "documents and data" category. I can't figure out what this is. I checked, and all the other syncing categories are deselected.
How do I fix this? It's not syncing anymore and if I restore the iPad, will I lose a lot of data?
iPad Air Wi-Fi, iOS 10.0.2