Share Based Compensation (Share Based Compensation Plans) (Details) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Director stock awards granted	3,000
Employee Stock Purchase Plan shares issued	39,980
Restricted stock awards granted	117,600
Restricted stock awards forfeited	650
Shares released from Deferred Compensation Plan	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options, Outstanding as of December 31, 2011	1,272,192
Stock Option, Granted	136,315
Stock Option, Exercised	(81,465)
Stock Option, Forfeited	0
Stock Option, Expired	(14,090)
Stock Options, Outstanding as of March 31, 2012	1,312,952
Shares available for future grants and ESPP purchases as of March 31, 2012	1,254,132
Restricted Stock Units (RSUs) [Member]
Restricted Stock Unit Activities:
Restricted Stock Units, Outstanding as of December 31, 2011	1,130
Restricted Stock Units, Granted	0
Restricted Stock Units, Converted to shares and issued to Deferred Compensation Plan	(370)
Restricted Stock Units, Outstanding as of March 31, 2012	760

Number of restricted stock units released from a non-qualified deferred compensation plan.

No definition available.

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Stock issued to company directors during the period.

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The number of shares issued pursuant to the terms of the deferred compensation plan as of the balance sheet date.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The decrease in the number of shares that could be issued attributable to the lapse of rights to exercise previously issued stock options under the terms of the option agreements under the plan during the reporting period.

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

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Number of shares related to Restricted Stock Award forfeited during the period.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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