Boeing ( BA) and its striking machinists union have agreed to return to the bargaining table, according to reports. Both sides said Wednesday night that a federal mediator will help work out details of the resumed talks, the Associated Press reports. About 27,000 union members walked out Sept. 6 in a contract dispute. The Wall Street Journal reports the parties may return to the bargaining table in the next few days. The International Association of Machinists walked out after rejecting a contract offer over concerns about job security, pay, health care and retirement benefits. On Monday, an analyst said the strike is expected to cost Boeing about 21 aircraft deliveries and up to 15 cents a share in earnings for every two weeks the strike continues, AP reports. Boeing, the world's largest maker of commercial aircraft, reported last week that deliveries were down largely because of the strike.