If you already know chevron stitch, this stitch is quite self explained and easy. Detached chevron stitch is just a segment of the chevron stitch, that looks like a ‘pi’ sign.  🙂 

detached_chevron_stitch_1      detached_chevron_stitch_2
Fig 1: Bring the needle out through A. Go diagonally in through B and out through C, as shown.    Fig 2: Now, take the needle in through D. B should lie midway between C-D. Come back out through B. 
detached_chevron_stitch_3   Fig 3: Finish it off as shown to get a pattern like this.