Tidey would be drafted 143rd overall by the Buffalo Sabres. However he was also drafted by the San Diego Mariners of the World Hockey Association. Alex opted to sign with the WHA.
Tidey played only one season in the WHA before crossing back to the NHL. He had an uneventful rookies season with San Diego, scoring 16 goals and 27 points in the high scoring WHA.
Upon his signing with the Sabres it was felt that Alex needed time in the minors to properly develop his game. Aside from 4 regular season games and 2 playoff games, Tidey would spend his entire three years with the Sabres farm team in Hershey. He did develop in his time in the AHL. By his final year he scored 31 goals and 61 points.
Early in the 1979-80 season the Sabres traded Tidey to the Edmonton Oilers in exchange for veteran John Gould. Tidey would rack up the air mile discount points during that 1979-80 season. He ended up playing in 4 different cities - Rochester of the AHL, Cincinnati and Houston of the CHL, as well as Edmonton of the NHL. Tidey participated in 5 games for the Oilers that season - surpassing his entire NHL background by 1 game. He failed to pick up a point, but did pick up 4 minor penalties.
Tidey was released by the Oilers following that season. He signed on with the Los Angeles Kings organization for the 1980-81 season. He spent the entire year in the minor leagues, split between the CHL and AHL. It proved to be Alex's final season in professional hockey.
Tidey played in 9 NHL games, picking up no points, and played in 74 WHA games, collecting 27 points.
Upon his retirement he returned to British Columbia, and although he never skated with the Sabres expansion cousins, he participates with the Vancouver Canucks alumni team in charity games. He established Tidey's, a locksmith business and expanded it to include trophy creation and engraving. He also has been heavily involved with the Queen's Park Pirates/North Delta Flyers (PIJHL), since renamed as the North Delta Devils.