Use an in-place drill down pattern to show a list of items and allow users to select an item to see more of its details.
When an item is selected, the list is replaced with the details view for the item.
Provide a link from the top-left corner of the details view to return to the list of items.
Don't display an item's details below the grid on click. For tall grids, users may not notice the details loading below the fold and may think the UI is broken. Additionally, there's no clear indication that the new section of the UI is showing details of the selected item.