Common stock offering

9 Months Ended

Sep. 30, 2018

Common stock offering

Common stock offering

11.     Common stock offering

On September 7, 2017, we completed a public offering of 4,945,000 shares of our authorized but unissued common stock pursuant to an effective shelf registration statement.  The underwriter had an option for a period of 30 days to purchase a maximum of 741,750 additional shares of our common stock, which expired unexercised.  We sold the shares of common stock to the underwriter at a price of $131.46 per share, resulting in net proceeds, after deducting expenses related to the offering, of approximately $649.4 million.