Fox’s American Idol reigned supreme last night while the other networks turned off the lights following the end of the February sweep on Wednesday. The two-hour Idol broadcast, which revealed the Top 13 finalists, drew a 8.1/23 in adults 18-49 and 25 million viewers. With no original competition besides a new Rules of Engagement on CBS, Idol was up 13% in the demo from last Thursday (15% in viewers) to hit its highest marks on the night this season in 18-49 and total viewers. Versus the comparable episode last year, which was less dramatic as cuts had been made gradually and not in one fell swoop as they were this year, Idol was up 29% in 18-49 and viewers. Fox logged the highest-rated Thursday night for any network in four years. With a Big Bang Theory repeat as a lead-in, Rules of Engagement (2.3/7) was down 18% from last week when it followed an original Big Bang to hit a series low with a regularly scheduled telecast.