Text box when "Other" option is selected in an Idea Form

Idea forms allow for the user to choose which option. I have also added a choice of "Other." I would like the user to explain the "Other" selection when this is selected.  As a workaround I have added a notes field after the selection options and a help text that says:  Use the Notes to explain Other.  Ideally it would be helpful to allow for an option of Other that includes a text box to explain.