Document banks called crazy (8)
I believe the answer is:
deranged
'crazy' is the definition.
(I've seen this before)
'document banks called' is the wordplay.
'document' becomes 'deed' (deed is a kind of document).
'banks' is an insertion indicator (bank can mean to surround or border).
'called' becomes 'rang' ('ring' can be a synonym of 'call').
'deed' placed around 'rang' is 'DERANGED'.
(Other definitions for deranged that I've seen before include "irrational" , "Mentally unbalanced" , "Disordered; insane" , "Crazy" , "Upset" .)