Stock-Based Compensation (Options Outstanding & Exercisable) (Details) (USD $)	3 Months Ended
Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Begining Balance	101,594
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	33,658
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	67,936
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price	$ 26.09
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 22.85
Options Outstanding, Weighted Average Exercise Price	$ 27.69
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	1 year 11 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 2,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	67,936
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 27.69
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	1 year 11 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 2,000
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	67,936.000
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	1 year 11 months 1 day
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 27.69
Range of Exercise Price $21.70 - $21.71
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding & Exercisable, Range of Exercise Prices, Lower Range Limit	$ 21.70
Options Outstanding & Exercisable, Range of Exercise Prices, Upper Range Limit	$ 21.71
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	2,888
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	0 months
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 21.71
Range of Exercise Price $23.59 - $25.94
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding & Exercisable, Range of Exercise Prices, Lower Range Limit	$ 23.59
Options Outstanding & Exercisable, Range of Exercise Prices, Upper Range Limit	$ 25.94
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	2,792
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	1 year 5 months 1 day
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 25.41
Range of Exercise Price $26.01 - $27.74
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding & Exercisable, Range of Exercise Prices, Lower Range Limit	$ 26.01
Options Outstanding & Exercisable, Range of Exercise Prices, Upper Range Limit	$ 27.74
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	23,400
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	1 year 6 months 1 day
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 27.06
Range of Exercise Price $28.25 - $28.26
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding & Exercisable, Range of Exercise Prices, Lower Range Limit	$ 28.25
Options Outstanding & Exercisable, Range of Exercise Prices, Upper Range Limit	$ 28.26
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	18,573
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	2 years 7 months 1 day
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 28.25
Range of Exercise Price $28.57 - $30.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding & Exercisable, Range of Exercise Prices, Lower Range Limit	$ 28.57
Options Outstanding & Exercisable, Range of Exercise Prices, Upper Range Limit	$ 30
Options Outstanding & Exercisable, Common Shares Subject to Options Outstanding	20,283
Options Outstanding & Exercisable, Weighted-Average Remaining Contractual Life	2 years 1 month
Options Outstanding & Exercisable, Weighted-Average Exercise Price (usd per share)	$ 29.09

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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

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For presentations that combine terminations, 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 or that expired.

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Weighted average price of options that were either forfeited or expired.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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- Definition

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

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- Definition

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

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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 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 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.

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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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The ceiling 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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