"I usually have 15 idols once I have enough money and that's too many contracts for me to keep track of without it being displayed. "It's not displayed (per se) but the information can be pulled up by right clicking on the girl's portrait.
Ahh my bad my bad, I didn't realize you could right click on them in the contracts pop-up. That's helpful! But I still feel there could be a more convenient/obvious way to display it in future updates :)