Idling event can be detected, and data about this event can be sent to server when using FMB120 feature "Excessive Idling". "Excessive Idling" informs you if your vehicle is stationary but engine is on for selected period of time to help you to save fuel. This feature for FMBxx devices can be configured in the configurator's "Accelerometer Features" section.
FMA120 and FM1100 devices do not have "Excessive Idling" feature in the configurator. You would rather get this information by selecting I/O to get Ignition and Movement parameters in the server and manage this data so you would know when movement is 0, but the ignition is on. Device can be configured to send packet more often while being in states On Stop/Moving. Also you could spectate parameters, trip distance or total distance, when ignition is 1. Trip/Odometer is used to detect and count distance traveled.
Hope this helps if you have any further questions please feel free to ask.