According to the Idaho website:
You are an Idaho resident if you are domiciled in Idaho for the entire year or you keep a home in Idaho and spend more than 270 days in the state. You are also an Idaho resident if you:
- live outside of the state but think of Idaho as your permanent home
- have all of your financial, social and family life centered in Idaho
- intend to return to Idaho when you are away
You are a Nonresident of Idaho is you maintained a permanent home outside of Idaho for the entire year. See the instructions for the a complete list of other conditions.
You are a Part-Year Resident if you moved into or out of Idaho during the tax year. You may also be considered a part-year resident if you moved outside of Idaho temporarily or moved back after a temporary absence.
What if I was a resident but my spouse was not?
If one spouse is a resident and the other is not and a joint federal return was filed, select the status that applies to your spouse's residency.