Idrian lace gets it's name from the region of Slovenia which is a country between Italy and Austria. It is a type of bobbin lace with meandering ribbons of clothwork joined with twisted threads. Most often this type of lace is seen on smaller items. To find a full banquet cloth and matching napkins is a very special treat!
For more information be sure to see The Guide to Lace and Linens by Elizabeth M Kurella. Her closeup detail photographs are very educational for lace identification.