Chicago-based Tribune Company announced it’s selling its Long-Island based-paper Newsday to Cablevision Systems Corporation. With a circulation of close to 400,000, Newsday is one of the country’s largest regional newspapers, serving mainly Long Island and parts of New York City.

The cable television provider bought the paper for $650 million. Tribune will retain a 3 percent stake as part of a joint venture, including Newsday.com, some regional magazines and a free New York City daily.

The sale is part of Tribune CEO Sam Zell’s plan to unload certain company assets. Tribune needs to offset $8 billion of debt the company took on when it went private last year. Family-run Cablevision has about three million subscribers. It’s also buying the Sundance Channel and owns Madison Square Garden, the New York Knicks basketball team and the New York Rangers hockey team.