NEW YORK (CNN/Money) - Shares of Adelphia Communications Corp. tumbled nearly 30 percent Tuesday after the troubled cable operator disclosed details Friday of its off-balance sheet transactions with the Rigas family.

Shares in Coudersport, Pennsylvania-based Adelphia fell 77 cents, or about 28 percent, to close at $2 on Nasdaq. The shares, among the 10 most active on the exchange Tuesday, have tumbled almost 94 percent since the start of the year.

In addition, the company said Tuesday it offered board seats to Leonard Tow, who is chairman and chief executive of Citizens Communications, and Scott Schneider, who is vice chairman of Citizens.

Tow owns 12 percent of Adelphia's shares and said in a statement he is the largest unaffiliated investor in Adelphia.

Late Friday, Adelphia gave federal regulators the most detailed accounting yet of its tangled dealings with the founding Rigas family, including $2.45 billion in company-backed loans, rent-free New York apartments and a $26 million timber deal.

The Rigas family and Adelphia also had jointly managed their cash holdings, an arrangement the company's board had not approved, the nation's sixth biggest cable operator said in a 32-page filing with the Securities and Exchange Commission.

Under pressure from creditors and independent directors, the Rigas family agreed to relinquish control of Adelphia on Thursday. It was the end of the family's 50-year reign over the business that founder John Rigas built up in the tiny west Pennsylvania town of Coudersport.

Adelphia said it had agreed to pay Rigas $1.4 million per year for three years and provide him with an office and a secretary. He also received emergency access to company jets, all his vested stock options and medical coverage for life.

But Adelphia said that severance package would be immediately terminated "upon the conviction of John Rigas of any felony."

--from staff and wire reports