Michigan accounting firm Doeren Mayhew is expanding to Houston by merging with TR Moore and Co.

The Troy, Mich.-based firm is one of the largest in the state, but it wanted to expand to Texas and acquire more clients in the energy industry. “As part of our strategic plan, we were looking to expand outside the Midwest,” said Doeren Mayhew managing director Mark Crawford. “We’ve been here for almost 80 years.”

“[TR Moore managing partner] Tim Moore was somebody I already knew,” he added. “I called Tim and told him I need some staff down in your marketplace. He talked about the fact that they were getting bigger and bigger, and obviously successful. We kept talking. We had the resources they needed to keep growing, and it just became a very good fit.”

Doeren Mayhew already services oil and gas companies in Michigan, but Moore has a much more substantial energy practice in Houston, and that will boost the energy clients for the combined firm. The two firms also share specialties in other industries, such as construction and distribution businesses. They will retain the T.R. Moore name in Houston for about 16 months, until September 2011.

Doeren Mayhew has approximately 200 employees, while T.R. Moore has 45. Doeren Mayhew currently earns nearly $40 million in annual revenue and T.R. Moore nearly $8 million. Crawford anticipates the combined firm will earn about $50 million in revenue next year.