Common Stock	12 Months Ended
Dec. 31, 2017
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common Stock	Common Stock There were no shares of common stock issued from treasury in 2017, 2016 or 2015. In 2017, 2016 and 2015, the Company acquired 677,100 shares, 550,994 shares and 1,352,596 shares, respectively, of the Company’s common stock at a cost of $40,791, $20,520 and $52,103, respectively. These amounts exclude shares reacquired to pay for the related income tax upon issuance of shares in accordance with the terms of the Company’s stockholder-approved equity compensation plans and the equity rights granted under those plans ("Reacquired Shares"). These Reacquired Shares were placed in treasury. In 2017, 2016 and 2015, 341,837 shares, 621,259 shares and 841,164 shares of common stock, respectively, were issued from authorized shares for the exercise of stock options, various other incentive awards and purchases by the Company's Employee Stock Purchase Plan.

Common Stock

There were no shares of common stock issued from treasury in 2017, 2016 or 2015.

In 2017, 2016 and 2015, the Company acquired 677,100 shares, 550,994 shares and 1,352,596 shares, respectively, of the Company’s common stock at a cost of $40,791, $20,520 and $52,103, respectively. These amounts exclude shares reacquired to pay for the related income tax upon issuance of shares in accordance with the terms of the Company’s stockholder-approved equity compensation plans and the equity rights granted under those plans ("Reacquired Shares"). These Reacquired Shares were placed in treasury.

In 2017, 2016 and 2015, 341,837 shares, 621,259 shares and 841,164 shares of common stock, respectively, were issued from authorized shares for the exercise of stock options, various other incentive awards and purchases by the Company's Employee Stock Purchase Plan.