LOS ANGELES (AP) - It's one-and-done for two "American Idol" judges. Both Mariah Carey and Nicki Minaj say they won't be back for a second season. Minaj says on Twitter that it is time to focus on music. Carey says she's not coming back to "Idol" so she can concentrate on her upcoming tour. Idol ratings took a dive this season -- with three new judges. Randy Jackson announced before the season finale that he won't be back. Keith Urban says he's in the dark on what's going on, and he'll be on tour beginning in July. Auditions for the next season of Idol begin July 10 in Salt Lake City.