Stock-Based Compensation (Schedule Of Weighted Average Assumptions For Restricted Stock Units) (Details)  | 
9 Months Ended | 
|---|---|
| 
 Sep. 30, 2019  
$ / shares 
 | |
| Restricted Stock Units [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 95.47 | 
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
  | 
| X | ||||||||||
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Details 
  |