(14)  401(k) Plan and Profit Sharing Plan

We maintain a defined contribution plan under Section 401(k) of the Internal Revenue Code of 1986, as amended, that covers substantially all of our employees. Under the provisions of our 401(k) plan, employees' eligible contributions are matched at rates specified in the plan documents. Our expense associated with this plan was approximately $4.8 million, $4 million and $3.7 million for the years ended December 31, 2015, 2014, and 2013, respectively.

Energetics maintains a profit sharing plan for its employees.  All employees who have completed at least two years of service are members of the profit sharing plan. At our discretion, we may make contributions to the Energetics plan. Total expense for the years ended December 31, 2015, 2014, and 2013 was $0, $190 thousand, and $175 thousand, respectively.