Earnings (Loss) Per Share	6 Months Ended
Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Earnings (loss) per share is based on the weighted average number of outstanding common shares. Basic earnings (loss) per share excludes the impact of dilutive securities and is computed by dividing Net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock. For the three and six months ended June 30, 2018, approximately 835 thousand and 929 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, approximately 445 thousand and 2 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were not included in the calculation of diluted earnings per share, because the effect would have been antidilutive. For the three and six months ended June 30, 2017, approximately 847 thousand and 915 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, less than 1 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were not included in the calculation of diluted earnings per share, because the effect would have been antidilutive.

Earnings (Loss) Per Share

Earnings (loss) per share is based on the weighted average number of outstanding common shares. Basic earnings (loss) per share excludes the impact of dilutive securities and is computed by dividing Net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock.

For the three and six months ended June 30, 2018, approximately 835 thousand and 929 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, approximately 445 thousand and 2 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were not included in the calculation of diluted earnings per share, because the effect would have been antidilutive.

For the three and six months ended June 30, 2017, approximately 847 thousand and 915 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, less than 1 thousand potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were not included in the calculation of diluted earnings per share, because the effect would have been antidilutive.