Alaska Airlines will buy 50 Boeing planes at a total value of over $5 billion, the company announced Thursday. The order is the largest in the airline's history.

Boeing will deliver the planes between 2015 and 2022. The order includes 20 737 MAX 8s, 17 737 MAX 9s and 13 Next-Generation 737-900ERs.

Alaska currently operates 120 Boeing 737s, and has existing orders for 25 more planes.