Going off the SMA and eccentricity, part of its orbit is "relatively" close to the sun, ~ 45 AU, about 1.5x the distance to Neptune (~ 30 AU), and the other half of its orbit is very, very far away, ~ 1700 AU, over 50 times the distance to Neptune, but still less than 1% of the distance to the next star.
When it's in the faraway part of its orbit, it is moving very slowly, probably only tens of meters per second, but it's still close enough to the sun to eventually fall back in for another loop.
However, if something else dense enough got close enough out there, it would be easily perturbed and have its whole orbit altered, or even be ejected.
But interstellar space is pretty void of wandering solid bodies, so it keeps falling back towards the sun.
After I posted that, I did some more research to see how typical it is, over longer time periods, that our nearest star is about 4 ly away. That seems to be about average spacing for our part of the galaxy, but it turns out in a little over a million years, a star about half the size of the sun will pass around 0.15 ly away or 10,000 AU, which is far outside the kuiper belt, but solidly though the middle of the inner oort cloud, and will leave a wake of scattered comets and asteroids, some of which will rain down on Earth.
