'Big Bang' sets viewer record

CBS' "The Big Bang Theory" continued its assault of "American Idol" Thursday, defeating Fox's reality giant for the third straight week in the 18-49 demo and second consecutive week in total viewers.According to early estimates from Nielsen, "Big Bang" was seen by a series-record 16.3 million viewers (assuming the number doesn't decrease when final numbers are received Friday afternoon). In the demo, the laffer earned a 5.4 rating/16 share at 8 o'clock.For the half-hour, "American Idol" drew 15.8 million viewers and a 5.0/15.Fox won an all-originals Thursday night as over the hourlong telecast "Idol" averaged a 5.4/15 and 17.1m, down slightly from a week ago. "Idol" lead-out "The Finder" (2.4/6) took a bigger hit from last week, off 14%.Following "Big Bang," "Rob" (3.4/9, 11.2m) was down a notch from a week ago and was best in the 8:30 timeslot after "Idol." From 9-11 p.m., CBS offered its procedural doubleheader of "Person of Interest" (3.3/9, 14.9m) and "The Mentalist" (2.8/8, 13.5m).In the 9 p.m. post-"Wipeout" (1.8/5, 5.9m) timeslot for ABC, "Grey's Anatomy" was best for the night for the Alphabet. Longtime Shonda Rhimes drama drew a 3.5/9, 5.9m, an improvement over its most recent original episode, and was tops against all competition. "Private Practice" (2.3/6, 6.6m) was slightly below "The Mentalist" at 10 o'clock.After being off the schedule last week, "The Office" returned to the Peacock's lineup and drew a 2.7/7, 5.2m. That was the high-water mark for the net, where "30 Rock" (1.3/4, 3.2m) started the night down and "Park and Recreation" (1.8/5, 3.6m) slightly up. Airing at 9:30, "Up All Night" (1.8/5, 3.7m) has been a consistent freshman comedy performer this season and could likely be back next season.The same can't be said for "The Firm (0.8/2, 2.9m), which continues to flounder at 10 p.m. Despite lower production costs because of having Canadian-based E1 as an outside producer, the series has been a major disappointment.Both "The Vampire Diaries" (1.2/3, 2.7m) and "The Secret Circle" (0.7/2, 1.7m) were up for the CW from their last original airings. Net, however, can't be happy with the million-viewer drop-off from one show to the next.Preliminary 18-49 averages for the night: Fox, 3.9/11; CBS, 3.5/9; ABC, 2.5/7; Univision, 1.5/4; NBC, 1.5/4; CW, 0.9/2.In total viewers: CBS, 14 million; Fox, 12 million; ABC, 7.4 million; Univision, 3.6 million; NBC, 3.6 million; CW, 2.2 million. Contact Stuart Levine at stuart.levine@variety.com