Nellie Andreeva

UPDATED: The complete revamp of the judging panel with Mariah Carey, Nicki Minaj and Keith Urban could not stop the ratings decline for Fox‘s American Idol. The series’ 12th season last night opened with a 6.0 rating among adults 18-49, down 19% from the 11th Season premiere last January, and 17.9 million total viewers, down also 19%. It was Idol‘s lowest-rated in-season premiere. Still, the singing competition’s debut ranks as one of the highest-rated entertainment telecasts this season and No.1 among fellow unscripted series, including NBC’s The Voice. The two-hour opener gave Fox the highest-rated night with entertainment programming of any network so far this season and outrated the ABC, CBS and NBC combined by 11%.

Idol has been on a downswing ever since the meteoric highs of Season 6, which opened with 15.8 18-49 rating and 37.4 million viewers in 2007. The only time the show was able to stem the ratings erosion since then was in 2009 when Season 9, the final with Simon Cowell as a judge,  premiered with a 11.8 in 18-49, up a smidgen from Season 9′s 11.7, while down slightly in total viewers. The following year, the debut of new judges Jennifer Lopez and Steven Tyler was down 17%, followed by a 24% drop last year. This year’s cast changeover cut the decline back to 19%.

Elsewhere, it was somewhat puzzling that ABC scheduled its big Pritchett baby episode of Modern Family, in which Gloria gives birth, against the Idol season debut. The hit comedy (4.8/11), which had been building toward the birth since last season’s finale, was down 9% from last week. The entire ABC comedy block was pushed down by Idol. The Middle (2.3/7) was down 4% from last week, Neighbors (1.9/5) down 10%, and Suburgatory (2.4/6) down 8%. But at 10 PM, Nashville (2.2/6) perked up, up 5% for its best 18-49 rating since the series premiere.

On CBS, following an NCIS repeat (1.1/3), Criminal Minds (2.8/7) was down 10% from its last original five weeks ago but posted its largest audience of the season (12.5 million). Not facing Idol, CSI (2.3/6) was up 5% from five weeks ago and edged Nashville for the No.1 spot at 10 PM. The CW’s lineup also returned after a long winter break. Arrow held steady in total viewers (3.1 million) and was up a tenth in A18-49 (1.1/3) from its last fresh episode in mid-December. Supernatural also was on par in total viewers (2.1 million) and in A18-49 (0.9/2) and up slightly in 18-34 (0.9/3). NBC stayed out of contention with repeats.

TV Editor Nellie Andreeva - tip her here.