Details those entering/leaving regularly (3,3,4)
I believe the answer is:
ins and outs
'details' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ins and outs that I've seen before include "signs on doors perhaps" , "parliamentary election result?" , "Details" , "cabinet reshuffle?" .)