It pivots on the mounting bolt. The idler arm should not turn on the bushing itself.
This is a great piece, it was a noticeable difference in the amount of drag in the steering on my Duster. Especially when changing directions.
Just a note, you will likely need to adjust the idler arm mounting flanges in order to install this successfully. The pivot bolt torque is pretty high, the mounting flanges tend to get pinched in. I had to expand the flanges on my K to get the proper fit for the bearings. I'm sure this isn't an issue with all K's, but given how the original parts work I wouldn't be surprised if quite few of the mounts needed some tweaking.