Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Stock-Based Compensation (Schedule Of Weighted Average Assumptions) (Details) - Stock Option [Member] - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected term, years 4 years 4 months 7 days 4 years 4 months 12 days 4 years 6 months 14 days 4 years 7 months 17 days
Expected stock price volatility 28.79% 29.34% 28.91% 29.80%
Risk-free interest rate 1.68% 0.94% 1.72% 1.17%
Expected annual dividend yield 1.23% 1.17% 1.30% 1.20%
Weighted average grant date fair value (in dollars per share) $ 13.47 $ 13.12 $ 13.03 $ 13.38