Wicked range is made up of opaque colours, Wicked detail range is made up of transparent colours and has a finer pigment grind. As fr as i know that is. Someone else may have better info but thats how i understand it.
According to the store where I buy colors you have 3 different wicked colors + few others:
1) Opague - black and white(Wicked Opaque)
2) Semi opague - Full range of colors(Wicked Semi-opaque)
3)Transparent: - Wicked detail colors(Wicked Detail White)
4)other colors:Fluorescent,Pearl,Metallic
So if I understand correctly detail are transparent.
When wicked first came out their was no detail wicked. Detail Wicked came out and was marketed as just that. A paint that had much finer ground pigment and could be used in the super detail brushes.