I'll post a very broad answer that might apply to many; I hope to edit it to more specific advice if you can add a recording of yourself.
Pay attention to the moment that the bow changes direction. (Well, okay, that mantra will be part of any work on bowing, including work on proper form and motion.) It's very easy to instinctively slow the bow speed down or even stop entirely before changing bow. For your plain-vanilla detaché, though, you want the speed and weight to be constant; all that changes is direction. Think of the bow as "bouncing off of" something, like the ball in the video game Pong. (Though, by the way, you want to have the control to be able to do anything with the bow, including tapering off the speed or stopping early before a bow change.)
Now, one big reason you might stop before changing direction is that you're focusing on the left hand, changing your finger. Simplify your bow work by practicing on an open string. Simplify even further: put the violin down and just move the bow in the air (or rest it on your shoulder, inside a cardboard tube, or other ways to support it in the right position without worrying about the violin). Think about the fact that the bow doesn't move itself; observe and reflect on the way your right arm is moving and what effect it has on the bow. Think about the movement of your upper arm, your elbow, your forearm, your wrist, and each knuckle in your fingers.
Once you have the seamless motion you're looking for, "de-simplify" in stages. Put the violin back under the bow and bow open strings. Get the left hand involved again by playing something very simple like a scale.