For almost a decade, Fox Broadcasting ruled television on the back of “American Idol.” But the show that Fox said goodbye to Thursday was a shadow of the one that carried the network to eight straight seasons atop the broadcast ratings. This season, prior to its finale, “Idol” averaged 9 million total viewers and a 2.2 live-plus-same day rating in Nielsen’s key 18-49 demo—down 70% and 82%, respectively, from the show’s peak in 2006. Fox, meanwhile, watches from third place as NBC and CBS tussle for this season’s ratings crown.

The show’s end, nevertheless, presents an opportunity for its chief executives, Gary Newman and Dana Walden, who decided last year to cancel the show ahead of its 15th season. How they guide Fox to a post-“Idol” future — and fill those nearly 40 hours of programming — could define their tenures at the network. As such, they’ve been preparing for this moment for a while.

“In February and March [last year] we began to have conversations with the producers, and everyone came to a consensus that it was time” to end the show, said Newman, chairman and CEO with Walden of Fox Television Group. “As we got into the upfront and started preparing for the farewell season, that’s the point at which we started thinking about what life after ‘Idol’ is going to be like.”

The singing competition took up 38 hours on Fox this season, almost twice as much as any other show. Its departure leaves an enormous hole to fill — especially on a network that programs only 15 primetime hours a week, seven fewer than the other members of broadcast’s Big Four.

In today’s landscape, “Idol’s” 2.2 rating and 9 million viewers are still significant. The network’s highest-rated new continuing series this season, “Lucifer,” has averaged only a 1.5 and 4.8 million viewers.

But Fox does have two things going for it as it leaves “Idol” behind — “Empire” and a plan.

“It’s going to be tough to replace [“Idol”] on a lot of different levels, but we understood the challenge of that and the whole team has embraced it,” Newman said. “We’ve really increased the amount of development this year.”

That development uptick isn’t just about ordering more pilots. “Idol” has been synonymous with the Fox brand for a decade and a half. Now the network no longer has that marketing tool to wield.

But as this season’s “X-Files” miniseries proved, Fox has other franchises it can deploy. Heading toward upfronts, the network has given straight-to-series-order to a “Prison Break” revival and a pilot order to a spin-off of “24.”

“We really focused this year on having a number of projects that were based on existing IP so that we wouldn’t be starting from zero when we’re trying to create awareness about our shows,” Newman said.

No Fox show has more awareness than “Empire.” Developed by Newman and Walden at 20th Century Fox TV, then positioned by them last season as central to the network’s rebuilding strategy, “Empire” is, as “Idol” once was, broadcast’s top-rated entertainment program. With its high-rated return last month from midseason hiatus, it showed a durability that other broadcast dramas such as ABC’s “Scandal” and NBC’s “Blindspot” have not.

But “Empire” has less scheduling utility than “Idol” did. The drama will air only 18 hours this season compared to more than 50 for “Idol” in its prime. And Fox has shown no interest in airing “Empire,” with its very adult themes, at 8 p.m., where it could provide a muscular lead-in to another show but also take a ratings hit broadcasting in the family viewing hour. That scheduling option was discussed last season and ultimately dismissed — though Newman has not ruled it out for next season.

Neither has he ruled out a return for “Idol” at some point. But despite chatter from producers and hosts about continuing the show, no plans are in the works to bring it back on Fox. “We’ve had not a single conversations with the producers about the future of ‘Idol,'” Newman said.

But he and Walden have shown themselves willing to dip into the network’s recent past for new programming. Newman cites Fox’s history of bringing back old series — “The X-Files,” “Prison Break,” “24,” “Family Guy” and “Futurama” — as evidence of an “Idol” return’s feasibility.

“I would not count out in the future the possibility that there will be the comeback season,” he said.