The calculated distance (air line) between Idlib and Jisr ash Shughūr is approximately 19 miles respectively 31 kilometers.
By car or train, the actual journey to Jisr ash Shughūr is certainly longer, as only the direct route (as the crow flies) between Idlib and Jisr ash Shughūr has been calculated here.
Air line (approximately)
31 kilometers
17 nautical miles