717 in dtw has recently had a significant increase in 1 and 2 day trips. Prior to the last few months they were harder to find. Things change, but I wouldn't expect 1-2 day trips to stay a large portion of any fleets flying at Delta if history is any sort of guide. A good number of those 1 day trips are 4 legs, which is generally seen as undesirable so they tend to go relatively junior. You may find that your relative seniority as 717b will increase faster than the other fleets, but the seniority movement is pretty strong for all the domestic fleets in dtw anyway.