Star Trek IV: The Voyage Home was released on the 26th of November 1986. I had started my post-secondary education at the University of Waterloo in September of '86, so if memory serves I saw this one with a few university buddies at a theater in Waterloo. I don't recall if we went opening night, but we may have.
This fourth film was received very well at the tim, with most reviewers and much of the general public enjoying the lighter approach used in the film.
The fourth movie also received a lot of press at the time, due in large part to its success but also due to the fact that its was Star Trek's 20th anniversary and due to the recent announcement of a new TV series, The Next Generation, that would feature a new crew.