David,
I heard they had 4,500ish a number of years ago, around when they bought Torresdale Frankford. Not sure if they consider this ongoing expansion as an opportunity to grow, or to simply better serve their current members...think the latter.
FWIW, I heard the purchase price was in the $70M neighborhood. Not necessarily an informed source, but that's a number bouncing around. I have no idea what the hotel and conference center infrastructure is...