A lot of outfitters run lions in Idaho.I am aware of a few in the Clearwater region of Idaho,I hunt in that area every year for whitetails.Unfortunately I can't vouch for any of their results or credibility.I hunt unguided and have not used any of them.Ones that I am aware of are Travis Reggears,Shattuck Creek outfitters,the owner's last name is Molsee,Duncan Outfitters the owner is George Duncan,Idaho Whitetail adventures,the owners name is Mike Stockton.
If you are going to any of the big outdoor shows you would be able to talk to outfitters there.Shed33 lives in Idaho and would be an excellent one to PM to ask about the outfitters he knows of in Northern Idaho.I would be extremenly cautious in my selection of an outfitter,thoroughly check them out and insist on speaking with their successful and unsuccessful clients.
You would likely be better off using a booking service like one of the reputable ones (Garth Carters Huntin fool) is very highly regarded.
Idaho has an association of outfitters,Idaho Outfitters and Guides association,that site will provide you with names and addresses of most if not all the licensed guides in Idaho.You can also contact the association office to inquire as to whether the guide you are considering has any complaints filed against them.
If you know the region that you want to hunt in call Idaho Fish and Game asking to speak with a biologist and ask the biologist who the most reputable guides are in the region,who would they hunt with.
I hope some of these things help,if you think there is any thing else I may be able to help with just let me know!