Stockholders' Equity And Stock-Based Compensation (Summary Of Stock Option Activity) (Details) - Options outstanding [Member] - $ / shares	6 Months Ended
Jun. 30, 2019
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Beginning Balance, Number of shares	2,956,687
Options granted, Number of shares	487,932
Options exercised, Number of shares	(98,928)
Options canceled, Number of shares	(19,430)
Options expired, Number of shares	(153,958)
Ending Balance, Number of shares	3,172,303
Exercisable, Number of shares	1,670,830
Beginning Balance, Weighted average exercise price per share	$ 17.04
Options granted, Weighted average exercise price per share
Options exercised, Weighted average exercise price per share
Options canceled, Weighted average exercise price per share
Options expired, Weighted average exercise price per share
Ending Balance, Weighted average exercise price per share	16.83
Exercisable, Weighted average exercise price per share	$ 16.11

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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No definition available.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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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.

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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- Definition

Number of share options (or share units) exercised during the current period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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