Cut regular trousers short, back in Nashville for American Idol (5,5)

'american idol' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'cut regular trousers short back in nashville' is the wordplay.
'cut regular' becomes 'norma' (I am not sure about this - if you are sure you should believe this answer much more).
'trousers' becomes 'jeans' (denim trousers).
'short' means to remove the last letter.
'back in' indicates one should take the final letters (the 'back' of the word).
The final letter of 'nashville' is 'e'.
'jeans' with its last letter taken away is 'jean'.
'norma'+'jean'+'e'='NORMA JEANE'

'for' acts as a link.

Can you help me to learn more?