Detachment is absolutely a mental process and does not have anything to do with outwardly affairs. Therefore it is not discernible by others surrounding you. Detachment does not again mean keeping away from Karma as you must have heard those great words -"Work is worship."
Our life is consciously or unconsciously revolving continuously around 'Self''. All our efforts are guided to satisfy self as we believe that appeasement of self is our destination. This is why we get enmeshed day in and day out in the quagmire of self-satisfaction but as a matter of fact, demands of self are ever increasing and insatiable.
So try to find pleasure in generalization of your goal. Once one expands "I" into "We" and engage one's efforts for "all" instead of "me", the process of detachment begins. Slowly but steadily, happiness will start percolating into one's "self" in a greatly gratifying way and the process will be liberating one's mind from the grasp of Karma.
Karma with an individual aim only entraps while karma with a universal aim only liberates. The latter is called Detachment and that is in no way passivity. The more we can sacrifice our personal gain in the field of our karma, the more vibrantly we shall be feeling our presence in that arena and in addition to that gradually with the purging of our minds, divine bliss will inundate our existence.