Fox’s “American Idol” continues to produce lower ratings, sinking to an all-time low in the key 18-49 demo Wednesday night, based on Nielsen overnights.

TVbytheNumbers.com reports that the two-hour “Idol” slipped to a 3.1 average in adults 18-49, losing a half-point from a week earlier for the show’s lowest-ever Wednesday rating. That made “Idol” the second-highest-rated show of the night behind ABC’s “Modern Family.” Still, Fox scored an easy win for prime time overall.

Fox’s 3.1 average rating for prime time in viewers 18-49 placed the network well ahead of ABC (1.9 average), CBS (1.7) and NBC (1.5). Fox also won by a wide margin in total viewers, averaging 12.0 million to 7.3 million for CBS, 6.2 million for ABC and 5.5 million for NBC.

On ABC, “Modern Family’s” broadcast-best 3.2 average in 18-49 was a season low, and a drop of seven-tenths from its previous original. “The Neighbors” bounced back slightly from last week’s series low, ticking up one-tenth to a 1.5. “Suburgatory” rebounded four-tenths from last week’s series low to a 1.9, while “Nashville” dipped to a 1.5 for its return, down one-tenth from its previous original.

CBS ran mostly repeat programming, along with a fresh episode of “Survivor: Caramoan,” which pulled a 2.4 in the 18-49 demo, off two-tenths from last week.

NBC’s best number was for “Chicago Fire,” which won the 10 p.m. hour with a 1.8 in the 18-49 demo, inching up one-tenth from a week ago. “Law & Order: SVU” was also up one-tenth, to a 1.7, while back-to-back installments of “Whitney” settled for a 1.0 and a 1.1.