Billionaire investor Leon Cooperman says he's concerned about the long-term outlook for the stock market

"I think the near-term outlook is favorable because of Fed policy, because of the apparent election outcome, and I think that we will get, if necessary, we will get a stimulus bill and I think we'll get good news on the vaccine for the virus," Omega Family Office's Leon Cooperman told CNBC's "Squawk Box" Friday. "Longer term, I probably have a dissenting view than Wall Street because I'm of the concern as to who pays the party when the party is over."