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 cannot tell whether it can be defined by this definition.

'cut regular trousers short back in nashville' is the wordplay.
'cut regular' becomes 'norma' (I can't justify this - if you can you should give a lot more credence to this answer).
'trousers' becomes 'jeans' (denim trousers).
'short' means to remove the last letter.
'back in' says to take the final letters (the 'back' of the word).
The last letter of 'nashville' is 'e'.
'jeans' with its final letter taken away is 'jean'.
'norma'+'jean'+'e'='NORMA JEANE'

'for' is the link.

Can you help me to learn more?