Employee Benefit Plans (Stock Options Outstanding And Exercisable) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
No. of Options Outstanding	290,294
Aggregate Intrinsic Value	$ 679
No. of Options Currently Exercisable	183,584
Aggregate Intrinsic Value of Options Currently Exercisable	366
Ranges Of Exercise Prices 26.62 - 33.90 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
No. of Options Outstanding	165,918
Weighted-Average Exercise Price	$ 31.87
Weighted Average Remaining Contractual Life, Outstanding	43 months
Aggregate Intrinsic Value	659
No. of Options Currently Exercisable	114,584
Weighted-Average Exercise Price of Options Currently Exercisable	$ 32.65
Weighted Average Remaining Contractual Life, Exercisable	26 months
Aggregate Intrinsic Value of Options Currently Exercisable	366
Ranges Of Exercise Prices 26.62 - 33.90 [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges Of Exercise Prices	$ 26.62
Ranges Of Exercise Prices 26.62 - 33.90 [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges Of Exercise Prices	$ 33.90
Ranges Of Exercise Prices 35.09 - 40.88 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
No. of Options Outstanding	124,376
Weighted-Average Exercise Price	$ 37.70
Weighted Average Remaining Contractual Life, Outstanding	65 months
Aggregate Intrinsic Value	$ 20
No. of Options Currently Exercisable	69,000
Weighted-Average Exercise Price of Options Currently Exercisable	$ 38.11
Weighted Average Remaining Contractual Life, Exercisable	46 months
Ranges Of Exercise Prices 35.09 - 40.88 [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges Of Exercise Prices	$ 35.09
Ranges Of Exercise Prices 35.09 - 40.88 [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ranges Of Exercise Prices	$ 40.88

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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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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Weighted average remaining contractual term for fully vested and expected to vest options that are 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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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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