Piedmont Healthcare and insurer Blue Cross Blue Shield tentatively reached an agreement over coverage to half a million Georgians.

Their pact, termed a “handshake agreement” by Gov. Nathan Deal, ends a 17-day impasse that left treatment at most of the Piedmont hospitals and clinics covered at the out-of-network rates that added to patients’ health care costs.

“A handshake agreement between Blue Cross Blue Shield of Georgia and Piedmont Healthcare was made in the governor’s office late this afternoon,” Deal’s office said in a statement Tuesday.

Deal had given both parties until the close of business Tuesday to reach an agreement before he took executive action. He could have opened enrollment for state employees months early.

“Announcement of an agreement in the form of a contract will be made by the contracting parties as soon as possible,” the governor’s office said. “This deal ensures no interruption of coverage for Georgians using Piedmont Healthcare as a provider during the contract dispute.”

The rift between the large insurer and the company that owns or operates 11 hospitals was a source of concern for many in the Atlanta area. At Piedmont Newton Hospital, holders of Anthem Blue Cross Blue Shield commercial plans and Anthem Blue Cross Medicare Advantage plans have been affected.

Soon after talks broke down, Deal ordered the parties back to the table for more bargaining and said the state and its two-year college system would make up the difference in costs for affected policyholders.