"It's shifted from health care through higher ed institutional to a lot of expansion by the energy companies," Moore adds.

Beyond its business activities, TDI's partners also find time to give back. Despite the economic challenges of the past few years, the firm's 2011-2012 United Way campaign contributions grew by more than $55,000 over the previous year. TDI also supports more than 30 other charities and causes.

Innovation Investment

Part of TDI's success is also tied to its focus on innovation. "Our model is ECOM—engineering, construction, operation and maintenance," MacDowell says. "We've been investing heavily in our engineering capability in order to participate in design-assist and design-build projects."

Over the past several years, TDI has been hard at work developing its "TDWIKI," the company's knowledge management system that enables the sharing of ideas, solutions and best practices across all units.

"The goal of the system is to really try and shave 10 years off the learning curve for new project managers and superintendents coming into our industry," MacDowell says. "So if we can give them access to the knowledge of someone who's been in the business for 20 to 30 years by the time they've been here for five or 10 years, we think it can greatly increase their ability to deliver for the client."

This tool will also help with the labor shortage the construction business is facing, MacDowell adds.

"A lot of our partners are very long term and that's clearly because we work very hard to make it a great place to work, good benefits and good training, good career paths," Richards says. "As we grow, we continue to recruit and hire the best folks that we can find, and again the things that are attractive—training, benefits, fun place to work, family atmosphere—continue to bring that new group along."

These values also support strong vendor and customer relationships.

Bruce Colborne, general manager at Texas Air Systems, says, "The culture of the company is like none other in Houston; most impressive would be the fact that they live servant leadership with their vendors and suppliers."