Core Media Group, the parent company of American Idol's production company, has filed for bankruptcy.

Core Media Group -- which has nearly 50 subsidiary companies, including 19 Entertainment, the management-production company behind American Idol that was founded by Idol creator Simon Fuller -- filed for bankruptcy protection on Thursday because it owes a total of $420 million to creditors, USA Today reported.

Fuller, who sold 19 Entertainment to one of Core's predecessor companies for $210 million in 2005, is the corporation's top unsecured creditor and owed $3.37 million. Nearly $400 million of Core Media Group's debt is tied to two loans made by secured creditors.

The first is a $209 million senior loan held by lenders including Tennenbaum Capital Partners LLC, Bayside Capital Inc. and Hudson Bay Capital Management LP. The second is $189 million on a second-lien loan, most of which is held by Crestview Media Investors LP, according to Variety.

Numerous other third parties including Sony Music Entertainment and CBS are also owed money.

Crestview Partners and Tennenbaum Capital will reportedly take ownership of Core Media Group from 21st Century Fox and Apollo Global Management -- the media conglomerate's current owners -- once the bankruptcy process is completed.

"Despite its long-running success, however, the company has recently experienced deterioration in its financial performance, primarily attributable to the decline in ratings for American Idol and the corresponding decline in revenues from Idol-related broadcast fees, international tape sales for rebroadcasts, touring fees, sponsorships and Idol-related merchandise sales," Core President Peter Hurwitz said in a media statement.

Unable to replace the American Idol revenue stream as well as reach out-of-court settlements with its lenders, Hurwitz called Core's capital structure "unsustainable," according to USA Today.

As earnings from Idol drastically fell from 2014 to 2015 -- with reduced hours on the air being a factor -- the show also lost valuable sponsors such as Coke and AT&T.

American Idol averaged 11.5 million viewers per broadcast when the franchise's 15th season aired on Fox earlier this year. At its peak in 2006, Idol drew in a whopping 30.3 million people, according to Bloomberg.