of course you need to pull back the thrust levers to idle...that's the standard since that DC-8 accidentally deployed the reversers and crashed many years ago. ::)
See the DC8's were not equipped with speedbrakes so the only way to reduce speed was to reverse the thrust. An accident sooner or later was inevitable...
The boeings have an interlock mechanism which prevents you from moving the reverse levers upwards (=deploy) unless the thrust levers are fully retarded
Airbus has a more basic design. They lack reverse thrust levers. instead, the newer models have the MREV gate located on the far back, so you need to pass the IDLE gate before deploying reversers.
Airbus thrust levers moves through distinct detents, more commonly refered to as 'gates'
