Stock Options And Employee Stock Purchase Plan (Outstanding And Exercisable Options) (Details)	12 Months Ended
Dec. 31, 2018 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	707,777
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 9 months 26 days
Options Outstanding, Weighted Average Exercise Price	$ 56.84
Exercisable Options, Number Exercisable \| shares	298,577
Exercisable Options, Weighted Average Exercise Price	$ 32.15
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	20,000
Options Outstanding, Weighted Average Remaining Contractual Life	2 months 5 days
Options Outstanding, Weighted Average Exercise Price	$ 17.19
Exercisable Options, Number Exercisable \| shares	20,000
Exercisable Options, Weighted Average Exercise Price	$ 17.19
Exercise price range (in dollars per share)	$ 17.19
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	50,040
Options Outstanding, Weighted Average Remaining Contractual Life	4 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 21.67
Exercisable Options, Number Exercisable \| shares	50,040
Exercisable Options, Weighted Average Exercise Price	$ 21.67
Exercise price range (in dollars per share)	$ 21.67
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	84,092
Options Outstanding, Weighted Average Remaining Contractual Life	1 year 4 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 22.92
Exercisable Options, Number Exercisable \| shares	84,092
Exercisable Options, Weighted Average Exercise Price	$ 22.92
Exercise price range (in dollars per share)	$ 22.92
Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	2,600
Options Outstanding, Weighted Average Remaining Contractual Life	3 years 4 months 10 days
Options Outstanding, Weighted Average Exercise Price	$ 25.09
Exercisable Options, Number Exercisable \| shares	2,600
Exercisable Options, Weighted Average Exercise Price	$ 25.09
Exercise price range (in dollars per share)	$ 25.09
Range Five [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	75,585
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 4 months 10 days
Options Outstanding, Weighted Average Exercise Price	$ 29.34
Exercisable Options, Number Exercisable \| shares	75,585
Exercisable Options, Weighted Average Exercise Price	$ 29.34
Exercise price range (in dollars per share)	$ 29.34
Range Six [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	9,710
Options Outstanding, Weighted Average Remaining Contractual Life	3 years 2 months 1 day
Options Outstanding, Weighted Average Exercise Price	$ 29.53
Exercisable Options, Number Exercisable \| shares	9,710
Exercisable Options, Weighted Average Exercise Price	$ 29.53
Exercise price range (in dollars per share)	$ 29.53
Range Seven [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	3,750
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 9 months 26 days
Options Outstanding, Weighted Average Exercise Price	$ 31.07
Exercisable Options, Number Exercisable \| shares	3,750
Exercisable Options, Weighted Average Exercise Price	$ 31.07
Exercise price range (in dollars per share)	$ 31.07
Range Eight [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	62,000
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 6 months 4 days
Options Outstanding, Weighted Average Exercise Price	$ 67.35
Exercisable Options, Number Exercisable \| shares	52,800
Exercisable Options, Weighted Average Exercise Price	$ 67.35
Exercise price range (in dollars per share)	$ 67.35
Range Nine [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding \| shares	400,000
Options Outstanding, Weighted Average Remaining Contractual Life	9 years
Options Outstanding, Weighted Average Exercise Price	$ 75.03
Exercisable Options, Number Exercisable \| shares	0
Exercisable Options, Weighted Average Exercise Price	$ 0.00
Exercise price range (in dollars per share)	$ 75.03

Share based compensation shares authorized under stock option plans exercise price range.

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ 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
-Subparagraph (c)(iii)
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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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