To the average fan, perhaps not, but to the Big Sky Conference, this would be huge.
Idaho is also a flagship school, not a directional school or commuter college.
One of the reasons that North Dakota was added to the Big Sky was UND added to the academic side of the conference affiliation. Idaho was ranked a little bit better in the recent USNews Tier I rankings, so academically they would be nice for the Big Sky.
Would love to see it happen, but it is a low probability.