Excessive idling alerts are triggered whenever a vehicle - one that has a running engine - stays stationary for too long.
The idling state starts whenever the vehicle has been stationary for more than 5 minutes. Once the vehicle has entered the idling state, it has to move for more than 5 seconds to exit this state.

See how to set up alerts about such events in the below article.
Set vehicle event alerts (geofence, maintenance, crash,...)
Set up rules to get alerts about vehicle events