Copy detailed response by art institute (7)
I believe the answer is:
replica
'copy' is the definition.
(replica is a kind of copy)
'detailed response by art institute' is the wordplay.
'detailed' means to remove the last letter (the word must be end-less or 'de-tailed').
'response' becomes 'reply' (synonyms).
'by art institute' becomes 'ica' (I am not sure about this - if you are sure you should believe this answer much more).
'reply' with its final letter taken away is 'repl'.
'repl'+'ica'='REPLICA'
Can you help me to learn more?
(Other definitions for replica that I've seen before include "Parcel I used to contain exact copy" , "Perfect copy" , "Parcel I made into an exact copy" , "knock-off" , "Copy original" .)