Fox dominated its two hours of primetime on Thursday, as “Amercian Idol” crushed everything in its path and “Bones” beat out its crime drama rival “CSI” in key demos on a night when ABC and NBC mailed it in with repeats.

According to preliminary nationals from Nielsen, “American Idol” averaged an impressive 6.5 rating/19 share in adults 18-49 and 21.7 million viewers overall during the 8 o’clock hour. Though down from last week’s big two-hour results-show premiere, it was off just 4% in the demo and actually up 6% in total viewers vs. the comparable night a year ago (a Wednesday). “Idol” beat its combined ABC-CBS-NBC competition during the 8 o’clock hour by 10% in adults 18-49 (6.5 vs. 5.9) and by 17% in total viewers (21.7 million vs. 18.6 million). And from 9 to 10, “Bones” (3.4/10 in 18-49, 10.9 million viewers overall) was up slightly from its most recent airing to win its timeslot in adults 18-49.

At CBS, “The Big Bang Theory” kicked off the night as Thursday’s No. 1 scripted program in demos (3.8/11 in 18-49, 12.1 million viewers overall), in line with its most recent original, and was followed by “Rules of Engagement” (2.8/8 in 18-49, 9.5 million viewers overall), which was up from last week when it followed a “Big Bang” repeat. And from 9 to 11, both “CSI” (3.1/9 in 18-49, 13.6 million viewers overall) and “The Mentalist” (3.0/9 in 18-49, 14.4 million viewers overall) were up from their most recent first-run episodes, with the latter dominating its repeat broadcast rivals in the 10 o’clock hour and standing as Thursday’s most-watched scripted program.

ABC aired a two-hour “Wipeout” repeat (1.8/5 in 18-49, 5.5 million viewers overall) followed by a “Grey’s Anatomy” repeat at a special time (1.2/3 in 18-49, 3.5 million viewers overall). And NBC settled for a measly 3 share with encores of its comedies “Community” (1.0/3 in 18-49, 2.7 million viewers overall), “Perfect Couples” (0.8/2 in 18-49, 1.9 million viewers overall), “The Office” (1.4/4 in 18-49, 3.0 million viewers overall), “Parks and Recreation” (1.1/3 in 18-49, 2.5 million viewers overall), “30 Rock” (1.1/3 in 18-49, 2.4 million viewers overall) and “Outsourced” (0.9/3 in 18-49, 2.2 million viewers overall).

Univision moved up to third place on the night in 18-49 (tied with ABC) behind “Eva Luna” (1.7/5 in 18-49, 4.6 million viewers overall) and a two-hour “Triunfo del Amor” (1.5/4 in 18-49, 3.9 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 5.0/14; CBS, 3.1/9; ABC and Univision, 1.6/5; NBC, 1.1/3; CW, 0.4/1.

In total viewers: Fox, 16.3 million; CBS, 12.9 million; ABC, 4.8 million; Univision, 4.1 million; NBC, 2.4 million; CW, 1.2 million.