I believe it to be a Dieffenbachia plant - sometimes commonly called "Dumb Cane". Let dry out a little between waterings, bright light If they grow too tall, you can "lop" the top with a bit of trunk and strike a new plant, and the "old" stump will probably send out a couple of new nodes as well

It's one of the Aglaonema cultivars.

Aglaonema.

Looks a lot like the one from Costa farms' "plants of steel" collection.

Though it's an Aglaonema, the care should be about the same as stated above for a Dieffenbachia.