C.J.
While I do agree with others that you should not share the informaiton of multiple interviews IF one offers and you are still interviewing simply say.
Wonderful. I'd like to review the terms of employment before I commit. Would you be willing to send over the paperwork/job description/pay grade/benefits, etc. and give me and my family a few days to review it before I make a final commitment?
There is nothing more unprofessional than to accept a position and then decline it because you got "a better offer." If you didn't want it, you should not accept it. Period!
If the company is unwilling to share this information with you, this could be a red flag, btw.
Congratulations and GOOD LUCK!! with both the potential positions.