"details behind" is grammatically correct and can be used in written English.
For example, "We were curious to learn more about the details behind the new policy."
There are a lot of details behind it.
Few knew the details behind the new clintonemail.com address.
Welcome to the finer details behind "more research is needed".
There's more talk and hope than firm details behind the new TechShop operation at this point.
Cathy Horyn shares more details behind the split, in the On the Runway blog.
New Yorkers, and all Americans, want to know the details behind this near disaster.
This exploration of famous foods sheds some light on the details behind the dishes.
Where can I see the details behind my monthly AWS bill?
Sunlight touches the white walls and the opulent golden details behind the altar.
Brendan Barber, the TUC general secretary, seized on the details behind the headline fall in unemployment.
But when you watch it now, the details behind its production fade away.
