Before you go anywhere at all I want you to forget the idea of a "team" or coworkers entirely. You shouldn't even think of asking others to help before you're familiar with the process of making at least a small finished game (making, not looking or reading or hearing about it), or otherwise have lots of development experience or endless pockets
>What are the chances of thieving faggotry happening
Literally zero. There isn't a single person on this earth who doesn't have ideas of their own. Plus other people aren't going to be able to interpret your idea the same way that you are imagining it anyway, at worst they'll get inspired by some specific part of it and do something with some vaguely similar detail.
Most likely you'll realize too late that there was no way you, with no experience making a game, could have actually known all the details that you should or shouldn't have in the game. And more importantly, if you need a "design document", then you're starting too big. From personal experience if you want to start with a big project right away (which I'm not
going to tell you is wrong), it's going to take you so long to learn to do it that in the process you'll change your mind about most/all of the ideas you had at the start.
On the flip side though, if you enjoy doing it and don't feel guilty about doing that instead of working on the game, then there's no harm doing it. Having a plan you feel excited about might also give you motivation to work on it, and even give you a better idea of what the game actually
should be while you work on it (or give you an idea for a better game).
TL;DR the design document itself will probably be ultimately useless, but it's not necessarily useless to make one.
>puts me squarely in the IdeaGuy™ department but how do I get out of that?
>"So you want to make a game" primer I could read to get my head in the right space?
There's so many different ways of making games that it's hard to get someone started without asking some questions first. I also recommend reading this section from the wiki ("What should I use?" and "...so what DO I use?"); http://8agdg.wikidot.com/programming#toc0
It puts pretty nicely the different ways of making a game, and gives a rough idea of what you might want to go with. If you're not particularly enthusiastic about programming, then it's recommended to use an engine like Unity. Unity gets a bad rap but it's popular because of how easy it is to get into, though you'll still need to learn some C# programming. It's still not "easy" to make games with an engine, but the amount of depth you'll have to go with programming is low compared to other options.