What is the "Date placed in service" for a newly purchased rental that needed extensive remodeling prior to putting it on the rental market?

The rental property was purchased in 2017 and under renovation the remainder of the year.  It was finished and began being rented in 2018.  Is the "date placed in service" the date it was purchased in 2017 or the date it was available to renters in 2018?  Thank you.