Hi Emily–sorry to hear you’re running into this, it is a known issue.
If you get a document stuck under there again, another option besides Cascade is to use the Tab key to temporarily hide your panels/bars. That should enable you to select your document and move it to a more accessible spot; hit the Tab key again and your panels will return.
Another approach you could take to keep your documents & panels tidy is to gather them in one window, by using Window > Application Frame. This has some handy behaviors for managing multiple documents, and you can still float documents as needed (say, for putting one on a second monitor). Some Mac users swear by it, others swear at it; you can decide if it’s right for you. 🙂