Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Schedule Of Weighted Average Assumptions For Restricted Stock Units) (Details)

v3.8.0.1
Stock-Based Compensation (Schedule Of Weighted Average Assumptions For Restricted Stock Units) (Details) - Restricted Stock Units [Member] - $ / shares
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period, years 4 years 3 years 10 months 27 days
Expected annual dividend yield 1.16% 1.31%
Estimated average grant date fair value per restricted stock unit (in dollars per share) $ 71.99 $ 52.40