The privately held Bloomington-based Holiday Companies has never courted media attention. But the gas station and convenience store operator ranks as the fourth-largest private company in Minnesota, with estimated revenue of $3.9 billion. Under Blackey, the large company continues to findways to grow. Last spring the company acquired severalSuperAmerica locations in Rochester. In a deal announced in August, Holiday added 16 new franchise locations in South Dakota and southwestern Minnesota.