I have two geldings. One is three and one is four. I bought the three year old about a month ago. They are turned out together and it like watching Dumb and Dumber on loop. They rear, paw, nip, kick, spin, bolt, run, jump... You get the picture. Will they outgrow this? It would be a pain but I'm thinking about putting those two in their own pasture so they won't accidentally hurt someone else. 

It will get less as they get older, but my boys are in their mid to late teens and they still play. A little rearing, a little nipping and some loping and bucking. But this is a GOOD sign. This kind of movement actually builds movement resilience, stability and strength. Look up movement science. They have done a lot of research on this in human athletics which is applicable to equine athletes. 

It's healthy for them to play and be active.

In a small addition going to town every day or so I pass a house that has a very small pen in the back yard (don't know how they get away with this) with a horse that doesn't have room to run or play.  He's been there for years.  He gets attention obviously from his owners as far as feed and shelter but that's it.  No horse buddies, no room to roam..............

Your horses are lucky.

my geldings play a bunch. they are not young (24 + 16) either so they didnt outgrow it. Its fun to watch though and they have a blast. im happy they both feel good enough to play and arent in pain just standing there. When my mare is out there with them (coming 2 year old who has her own pen at night and with the boys during the day) she loves getting into their play fests