BOISE, Idaho — Former Idaho Gov. and U.S. Interior Secretary Dirk Kempthorne has died at age 74, his family said in a written statement Saturday. Kempthorne died Friday evening in Boise, the statement said. No cause was given, but he had been diagnosed with colon cancer last year. “Beyond his public service, he was a devoted husband, father, and grandfather whose greatest joy came from time spent with family and the people he met along the way,” his family said. “He had a rare gift for truly