Is there a word for a person who gives out too many extraneous details?

I'm looking for a single-word term that describes a personality that wants to give out too many unnecessary details in a conversation.

[EDIT] Let me give you guys an example. Suppose you ask your friend, at what time will he reach your place? Instead of saying it directly, he wanders off track by regurgitating unnecessary details like "I'd be catching the bus at 10, then I'll reach place X by this time, then I'll take another bus to your place, and maybe I'll arrive by 12". Is it circumlocution?

I once knew a fellow who was prone to this specific fault. He wasn't a "circumlocutor," as that would mean a person who "talks around" a topic without coming to the point. Rather, this person would trail off into arabesques of detail that were unneeded (and unwanted). Let me give you an example:

"I had a teacher who wore shoes like that - he was from Amherst, you know, the school in Massachusetts, and I got a speeding ticket there from a cop who had a radar gun that looked like the things you'd see in an RKO serial, like Flash Gordon, and y'know I think we ought to have those again in theaters except that theaters today just show trailers, and do you know why those things are called "trailers" anyway? They don't "trail" anything, they lead it off so maybe they should be called "headers" except that a header is maybe something you'd see in soccer, which is called "football" in most countries where it's played and isn't that weird?"

And in this, I believe that English suffers from a fault in that we do not have a precise word for a person who talks this way. We could coin "digressor," perhaps.

There's always the classic loudmouth or blabbermouth. You might describe such a blowhard as having loose lips, because he's always yapping. Chatterboxes and gossip mongers never know when to keep things discreet. And, if such a person goes a million miles a second while he's regurgitating all the sensitive information you've ever told him, he probably deserves to be called a motormouth. If you want the emphasis to be on the unnecessary aspect, instead of all the details he's giving out, one might say that gasbag is prattling on and on, instead of getting straight to the point.

Overparticular is an apt term for this.

Loquacious is a nice way of saying that someone talks perhaps a bit too much. Blabbermouth is an insulting way of saying the same thing.

Such a person might be called garrulous or prolix, or said to be suffering from logorrhea (a personal favorite), though these are more about verbal profusity in general than excessive detail in specific. One of the meanings of "to niggle" is "to spend too much time and effort on inconsequential details", but you're taking your life in your hands calling anyone a niggler.

If these unnecessary details tend to shade into the inappropriately personal, then the fairly recent coinage oversharer may be called for.