Deltek [PROJ] yesterday said that the private equity firm Thoma Bravo, LLC, has agreed to acquire it for $1.1 billion in cash in a deal that will take the enterprise software and information technology services firm private.

Deltek’s board of directors and its majority shareholder, New Mountain Capital, have approved the sale. Thoma Bravo is paying $13 per share for Deltek, representing a 7 percent discount to the closing price of the company’s stock last Friday and a 24 percent premium above Deltek’s stock price on June 11, the day before the company disclosed privately to interested parties that it was for sale.

Deltek provides a range of solutions for government contractors and professional services firms in the aerospace and defense, energy and environment, engineering, accounting, advertising, and architecture, engineering and construction markets. The company had $341 million in sales last year, up 22 percent from 2011.

“Deltek’s powerful brand presence in the government contractor, professional services, and project-oriented markets makes it well poised for continued global industry leadership,” Holden Spaht, partner with Thoma Bravo, said in a statement. “Thoma Bravo is excited to work with Deltek’s leadership team to accelerate growth of the company through the firm’s proven buy and build strategy.”

Credit Suisse Group acted as financial adviser to Deltek on the deal. Jefferies & Co. served as Thoma Bravo’s financial adviser.

The transaction is expected to close in the fourth quarter of 2012. Deltek will remain headquartered in Northern Virginia.