SIOUX FALLS, S.D. (AP) – The superintendent of South Dakota’s largest school district is resigning. Sioux Falls Superintendent Brian Maher says he’ll step down at the end of June.

Maher says there’s a “shelf life”for superintendents and that he doesn’t want to be the one who stayed too long. Maher has been a superintendent for 21 years, serving the last five years in Sioux Falls.

He says there isn’t one event or destination that contributed to his decision. He says it was simply time to go.

Maher had recently led the charge to address overcrowded campuses by calling on voters to pass a historic $190 million bond to build three new schools by 2024.