CHICAGO (AP) — The Chicago Teachers Union is delaying a vote by its membership on a four-year contract proposal.

The vote on the tentative contract agreement was set for Thursday and Friday, however Vice President Jesse Sharkey says the union’s more than 20,000 members instead will begin casting votes Monday.

According to Sharkey, the CTU is sharing contract details with members, but couldn’t get a shop to distribute printed copies in time for a vote this week.

The proposed contract averted a strike that would have affected about 390,000 students. It includes cost-of-living increases in the third and fourth years. It doesn’t require current teachers to pay more toward their pensions — a change Chicago Public Schools was seeking and the union rejected.

Future CPS hires would pick up that additional pension cost.