The stitch looks like a brioche
or Fisherman's rib
which if you knit on big needles won't look quite like the picture you posted because it's machine knit, but it'll be close, and it's a very cushy stitch. Just take the yarn and needles and work up a sample of 12 to 16 sts and see how wide that is. You might just get the width you want and can keep on going.