CHICAGO—The Archdiocese of Chicago released thousands of documents Wednesday to attorneys representing sex-abuse victims, and said it plans to eventually release many more detailing the efforts, and mistakes, church hierarchy made in handling abuse allegations and priests who were known offenders.

As part of a court mediation process, the archdiocese turned over roughly 6,000 pages of documents relating to 30 priests with substantiated allegations of sexual offenses against children whose cases have been mediated civilly. Some of those cases stretch back a half century and involve more than a dozen priests who have died. Four of the 30 priests have been prosecuted.

"It's humiliating as a priest to know there were other priests who did something like that," Bishop Francis Kane, the vicar general of the archdiocese, said at a news conference. "I hope it will bring healing and hope."

The document release comes nearly eight years after the church began a mediation process that has paid victims about $100 million in compensation, according to Bishop Kane. The archdiocese said it would make available documents on 35 more priests with substantiated allegations of sexual abuse—those believed to be true after an archdiocesan review—but didn't provide a timeline for the release.