Moeller says that Rubeling & Associates added a level of expertise in architecture that JMT needed in order to grow, but the firm wasn't "at a size that would overwhelm the rest of our work."

Moeller also notes that JMT had worked often with Rubeling in the past on education and worship projects. "It was one of the easiest acquisitions because we knew each other so well already," he says. "They were a natural fit for us."

Rubeling & Associates was one of four acquisitions JMT made in 2014. Cheng says that before last year, JMT had only acquired three firms in its history. He expects mergers and acquisitions to play a larger role in the firm's future growth. "We do realize that if we want to make that next step, we need to use M&A as a strategy," he says.

Other 2014 acquisitions were aimed at territory beyond the mid-Atlantic. They included Ohio-based transportation engineering firm Barr & Prevost; Florida-based construction engineering and inspection firm GBF Engineering; and Atlantic Engineering, Kinnelon, N.J., which specializes in marine inspections.

As JMT's size increases, Cheng says that he is committed to preserving the firm's culture. JMT, which now employs more than 1,150 people, is 100% employee-owned—a process that began in 1999 and was completed in 2011. "We want the employees to think like owners," he says.

In finding the right fit for its culture, JMT relies heavily on recruiting young talent. Moeller says nearly all of the firm's 130 new hires in 2014 were for entry-level positions.

"We found that we do best by hiring new grads," he says. "Even before that, we hire interns that we hope to bring on later as new grads. It's a long interview process and we get to pick the people we want. We can see if they have initiative or they don't."

The firm also emphasizes to its various offices that they should support, rather than compete against, each other. Moeller says the firms' top managers decided early in its growth plan to formalize this philosophy, which it calls One JMT.

When an office needs additional resources, others are expected to step in and assist. "We saw big firms promoting competition between offices, and we wanted to avoid that," he says.

"We were small enough then that it wasn't an issue yet," Moeller adds, "but we saw it could be a problem down the line. Every chance I get, I preach it."