As the competition wraps up its 20th season overall (and its fifth on ABC), it's been marked by some aspects of years past, such as contestants leaving early. However, one judge is enjoying a year that proves the worth of sticking with a music career, since Lionel Richie has The Library of Congress Gershwin Prize for Popular Song and (soon) induction into the Rock & Roll Hall of Fame. Luke Bryan and Katy Perry also cast their final votes on the remaining contenders, and per "Idol" finale tradition, expect other big-name stars to appear. Ryan Seacrest is, of course, the host.