The health insurer Humana will stop providing employer-sponsored commercial coverage as it focuses on bigger parts of its business, like Medicare Advantage.

The insurer said Thursday it would leave the business over the next 18 to 24 months. It includes medical coverage provided through private companies and for federal government employees.

Humana will still provide insurance through its military service business. It covers active duty service members, their families and retirees and a total of nearly 6 million people. It will also still provide employer-sponsored specialty coverage like vision and dental benefits.

Employer-sponsored health insurance is one of the more common ways for Americans to get coverage. But at nearly a million people, it amounts to a small part of Humana’s enrollment of more than 13 million.

Humana’s business largely centers on the military and Medicare Advantage plans. Those are privately run versions of the federal government’s Medicare program for people age 65 and older.

Humana also runs Medicaid coverage in several states.

CEO Bruce Broussard said in a prepared statement that the exit from employer-sponsored coverage lets Humana focus on its “greatest opportunities for growth.”

The company also said its employer-sponsored business “was no longer in a position to sustainably meet the needs of commercial members over the long term or support the company’s long-term strategic plans.”

Employer-sponsored enrollment growth has been partially slowed for insurers, including market leaders like UnitedHealthcare. Companies have turned more to government-backed coverage like Medicare Advantage or Medicaid for growth.

Humana does not expect the change to affect adjusted profit this year, which the company projects to be at least $28 per share.