Tenuto marking too close to note

[Erika Pirnes]

Hi,

I would like to have the tenuto mark a bit farther away from the note. I had a 
similar issue with tuplet numbers and then "\override TupletNumber.Y-offset = 
#-2.5" fixed the issue. I don't know what I should replace "TupletNumber" by in 
the case of tenuto lines.

Minimal example here:

\version "2.18.2"

\new Staff {
  \relative c'' {\time 3/4 a g e--}
}

Thank you!
Erika