Ryan Cos. is building one more office building in the Downtown East district of Minneapolis — this time, for itself.

The developer unveiled images Monday of a four-story office building at the corner of 3rd Street and Portland Avenue. It will adjoin one of the two new Wells Fargo towers that Ryan is nearly finished building.

The company will occupy about 55,000 square feet on the lower floors and hopes to find tenants for the remaining space in the 172,000-square-foot building.

Ryan, now headquartered on Nicollet Mall, has led the five-block redevelopment project near U.S. Bank Stadium on land formerly owned by Star Tribune Media Co. About 250 to 300 employees will move from the company's home at Target Plaza to the new headquarters, dubbed the Millwright Building.

Since its inception, the Downtown East master plan has called for development of the two liner parcels behind the two 17-story Wells Fargo towers. On one of the parcels, Carlson Cos. will manage one of its new Radisson Red hotels. The Millwright Building will occupy the second.

Apartments and retail space fill the front side of the two towers and they look out on the Commons park that is now under construction.

All components have been developed by Ryan, but the Millwright Building will have an architectural style distinct from the neighboring Wells Fargo towers and Radisson Red.

Construction will begin next spring and is expected to finish in 2017.

Ryan has been shopping for new office space for awhile and Ryan executives have been hinting throughout the fall that they were considering constructing their own new headquarters on the Downtown East site.

"When it came to choosing a location for our new home, downtown Minneapolis was the only option. It's where we've been for the last 30 years and we love the energy and richness of the culture, recreation, transit, and the relationships it enables," Pat Ryan, the company's chief executive, said in a statement.

Its new office building will connect to the skyway system, which is being extended from the central business district to the new stadium by passing through the Wells Fargo towers and a new parking ramp.

The office space will have exposed steel beams, a brick exterior and curve-topped windows, similar to older warehouses and factories and resembling some buildings in the North Loop and Mill District neighborhoods. As for the name, millwrights are specialized carpenters that build machinery. In Minneapolis' history, skilled millwrights helped build the mills used by the city's flour-making industry.

Ryan is handling all aspects of the project from development, construction, architecture, engineering, capital markets and real estate management. It hired CBRE to market the additional space to other office users.