I'm pretty sure that the insurance has to be tied to whatever state you primarily live in. You'll be able to use it in any state but depending on the insurance company, in-network providers might be harder to find when you're outside Virginia. If BCBS is one of your options in Virginia, it has good network coverage in most states, at least in my experience.

The benefits website also has a tool to check whether your providers are in-network, so if you already have providers in Idaho you should be able to put them in and find plans where they're in-network.

Changes in residence are also a qualifying life event to re-enroll immediately without having to wait for open enrollment, so if you were to move to Idaho permanently you'd be able to switch to an Idaho plan.