Thanks for the reply PaulS, that makes sense. So just to be clear, if the Joystick lever is pushed (for example) to the right, then the program interprets that as a value greater than 612, therefore sending the signal to the servo to move one way, and if the Joystick is moved to the left, then the program will interpret that as a value less than 412 and will move the servo in the opposite direction, and if it remains between 412 and 612 it should remain idle, is this right? 
Also, why when idle == 100 it detaches the servo?
if (idle == 100){
myservo*.detach();*
- }*
- } *