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Stock Option And Stock Award Plans (Summary Of Additional Information On Stock Options Outstanding And Exercisable) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options Outstanding, Shares	1,628,903
Options Outstanding, Weighted Average, Remaining Contractual Life (Years)	5 years
Options Outstanding, Weighted Average, Exercise Price	$ 19.13
Options Outstanding, Aggregate Intrinsic Value	$ 5,520,800
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	360,218	275,392
Options Exercisable, Weighted Average Exercise Price	$ 20.81
Options Exercisable, Aggregate Intrinsic Value	$ 835,569
- To 15.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 0
Range of Exercise Prices, Maximum	$ 15
Options Outstanding, Shares	0
Options Outstanding, Weighted Average, Remaining Contractual Life (Years)	0 years
Options Outstanding, Weighted Average, Exercise Price	$ 0.00
Options Outstanding, Aggregate Intrinsic Value	$ 0
Options Exercisable, Shares	0
Options Exercisable, Weighted Average Exercise Price	$ 0.00
Options Exercisable, Aggregate Intrinsic Value	$ 0
15.01 To 17.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 15.01
Range of Exercise Prices, Maximum	$ 17.5
Options Outstanding, Shares	163,641
Options Outstanding, Weighted Average, Remaining Contractual Life (Years)	4 years 4 months 21 days
Options Outstanding, Weighted Average, Exercise Price	$ 15.65
Options Outstanding, Aggregate Intrinsic Value	$ 1,096,395
Options Exercisable, Shares	104,326
Options Exercisable, Weighted Average Exercise Price	$ 15.65
Options Exercisable, Aggregate Intrinsic Value	$ 698,984
17.51 To 20.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 17.51
Range of Exercise Prices, Maximum	$ 20
Options Outstanding, Shares	1,255,670
Options Outstanding, Weighted Average, Remaining Contractual Life (Years)	5 years 3 months 29 days
Options Outstanding, Weighted Average, Exercise Price	$ 18.83
Options Outstanding, Aggregate Intrinsic Value	$ 4,424,405
Options Exercisable, Shares	46,300
Options Exercisable, Weighted Average Exercise Price	$ 19.40
Options Exercisable, Aggregate Intrinsic Value	$ 136,585
20.01 To 25.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 20.01
Range of Exercise Prices, Maximum	$ 25
Options Outstanding, Shares	209,592
Options Outstanding, Weighted Average, Remaining Contractual Life (Years)	3 years 6 months 7 days
Options Outstanding, Weighted Average, Exercise Price	$ 23.69
Options Outstanding, Aggregate Intrinsic Value	$ 0
Options Exercisable, Shares	209,592
Options Exercisable, Weighted Average Exercise Price	$ 23.69
Options Exercisable, Aggregate Intrinsic Value	$ 0

X

- Definition

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
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- Definition

Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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

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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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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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