Looks like a scheduled sale, from the SEC form 4 filing:
Explanation of Responses: ( 1) These are additional shares issued due to the vesting of 134% of the performance shares initially awarded under the 2005/2007 Performance Share Plan, as amended and restated (the ?Plan?). The Compensation Committee determined that the Plan?s total shareholder return and corporate objectives performance criteria for the 2005-2007 measurement period were achieved at 134% (of a possible maximum of 175%). The awards were originally reported at target (or 100%) at the time of grant.