Idaho is an awful cold place for even the most hardy palms. I do tip my hat to those that are willing to protect palms in areas like this though: Washingtonia filifera in Idaho

No where near zone 7 way up there. More like zone 4 or 5 at most. Without a hut with lights and insulation it's very very unlikely.

Idaho Plant Hardiness Zone Map

There are a few spots in Idaho that are 7a or 7b but yes a lot of the state is zone 4 and 5.

This map is a bit easier to read but less detailed and doesn't include zone 7b.

For some reason there is/was a restaurant in Idaho Falls on Hitt Rd that had a large palm in a raised bed. I never looked at it up close but from the road it looked real. Of course, it didn't survive the winter some years ago. I think it has since then been removed.

This map includes the zones 7a and 7b. Either way, it would be tough to grow even Sabal minor or Rhapidophyllum hystrix unprotected.