Akerman LLP is more than doubling the size of its Loop office space in a move that will allow it to house 90 lawyers by 2018, just four years after the Miami-based firm established a Windy City outpost.The firm announced today that it would add 41,000 square feet to its lease at 71 S. Wacker Drive, formerly the Hyatt Center, where it currently takes up roughly 33,000 square feet. The new space on the top two floors of the building will be ready to move into by early 2018.The expansion highlights the rapid growth the firm …