Can't keep terrain detail

While I'm actively working with the terrain editor brushes (on the right), my terrain has the level of detail that I'd like. At every other time, it changes to this blurry low res thing (on the left). I can tell the editor is keeping this detail, because it reappears when I activate the brush. But I can't get it to keep this level of detail when I view the scene in the editor or start the game and view it through a camera.

I've raised the resolution. I've unchecked Compress Holes, I've reduced Pixel Error to 1 (as low as it can go). Reducing the pixel error helped to some extent, but not enough. How do I get the terrain editor to simply give me the sandswept terrain that I've drawn, and not some rough downscaling that looks like clumps of mud.

 

Bumping this in hopes of a reply. Even if you don't know the answer, maybe you know of a resource where I could learn to understand the terrain editor better? Or a better way to achieve the same result?