| Stock-Based Compensation (Summary Of Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
| Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018 | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Stock-based compensation expense | $ 4,378 | $ 3,648 | $ 13,159 | $ 10,247 | 
| Employee Stock Options [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based Payment Arrangement, Expense | 1,509 | 1,277 | 4,600 | 3,571 | 
| Restricted Stock Units [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based Payment Arrangement, Expense | $ 2,869 | $ 2,371 | $ 8,559 | $ 6,676 | 
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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of noncash expense for share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- 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. 
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