For the first time in its history, the season finale of Fox's American Idol did not attract 20 million viewers. Far from it. Last night's closer, in which soul singer Candice Glover triumphed over country singer Kree Harrison and judge Randy Jackson bade farewell after 12 seasons, drew 13.61 million viewers, according to overnight Nielsen ratings, down from 21.49 million viewers a year ago. In years past, Idol season enders routinely drew more than 30 million. The number of viewers in the key 18-49 age group was down even more -- a whopping 49 percent. Idol was not even the highest-rated show of the night. That honor went to CBS's The Big Bang Theory (also a season finale) which attracted 14.30 million viewers and clobbered Idol in the 8:00 p.m. half hour. Meanwhile, NBC's series finale of The Office, expanded to an hour and fifteen minutes, went out with a whimper, winding up in fourth place with just 5.41 million viewers.