Denver's oldest newspaper is up for sale, its owner said today, citing difficult operating conditions in the city and the struggling newspaper market nationwide. "The decision to seek a buyer for the Rocky would have been unthinkable until very recently," Rich Boehne, president and chief executive officer of Scripps, said in a news release, according to the Rocky's report. "Our 50 percent of the cash flow generated by the Denver Newspaper Agency is no longer enough to support the Rocky, leaving us with no choice but to seek an exit." The E.W. Scripps Co. has owned the Rocky for more than 80 years. The newspaper ended its competitive relationship with the Denver Post in 2001, when Scripps and Post parent, MediaNews Group, entered into a joint operating agreement.