Ratings bellwether “American Idol” held steady Thursday, retaining all but 3% of its audience from its week-earlier outing in leading Fox to a primetime victory.

“Idol” had a 7.6 rating and 21 share in the 18-49 demo and 22.3 million viewers overall, compared with 7.7/21, 22.6 million on Jan. 20, its first Thursday of the season.The ongoing auditions for the singing competish easily outdistanced the second-place network in the 8 p.m. timeslot, ABC with “Wipeout” (2.4/7, 7.6 million).

CBS topped ABC in overall audience at 8 p.m. with a rerun of “The Big Bang Theory” (2.4/7, 9.2 million), followed by an original “Bleep My Dad Says” (2.3/6, 8.9 million).

NBC’s “The Office” (4.0/11, 7.9 million), which featured a surprise, unpromoted appearance from the series’ ancestral star Ricky Gervais, was the night’s top-rated scripted program in the demo, edging Fox’s “Bones” (3.9/10, 12.2 million). Benefiting from “Idol” as a lead-in, “Bones” had its highest-rated telecast since Valentine’s Day 2007.

“Parks and Recreation” (3.0/8, 5.9 million), airing after “The Office,” was the night’s only other series to get at least a 3.0 in the demo. Both NBC sitcoms were No. 1 in their timeslots among adults 18-34 and men 18-49.

As for the rest of NBC’s comedy six-pack, 8:30 p.m. freshman “Perfect Couples” (1.7/4, 3.5 million) shed nearly 25% of its lead-in, “Community” (2.2/6, 4.6 million), which equaled its 18-49 season high. (“Couples” was also down approximately 20% from its official season premiere a week earlier.) At 10 p.m., “30 Rock” (2.4/7, 4.9 million) fell a hair from the previous week. “Outsourced” (1.9/6, 4.1 million), while also losing close to a quarter of its leadin, did deliver NBC’s best performance in the demo at 10:30 p.m. this season and edged out the competition from ABC and CBS.

Those latter networks aired reruns from 9 p.m. on: “Grey’s Anatomy” (1.5/4, 4.5 million) and “Private Practice” (1.0/3, 3.4 million) on ABC, “CSI” (2.1/6, 9.7 million) and “The Mentalist” (1.9/5, 10.1 million) on CBS.

CW offered “The Vampire Diaries” (1.6/4, 3.5 million) and “Nikita” (1.1./3, 2.7 million), each of which had its best numbers since the fall despite preemptions in Chicago and Baltimore.

Preliminary 18-49 averages for the night: Fox 5.8/15, NBC 2.5/7, CBS 2.1/6, ABC 1.6/4, Univision 1.5/4, CW 1.3/4.

In total viewers: Fox 17.2 million, CBS 9.6 million, ABC 5.2 million, NBC 5.2 million, Univision 3.8 million, CW 3.1 million.