Stock-Based Compensation (Options Outstanding & Exercisable) (Details) (USD $)	3 Months Ended
Mar. 31, 2014
Number of Shares Subject to Options
Outstanding at January 1	57,094
Expired	7,728
March 31, 2014	49,366
Weighted-Average Exercise Price
Outstanding at January 1	$ 27.96
Expired	$ 28.52
March 31, 2014	$ 27.87
Stock Options
Weighted-average remaining contractual life, outstanding	1 year 5 months 1 day
Aggregate intrinsic value, outstanding	$ 1,000
Number of common shares subject to options, exercisable	49,366
Weighted-average exercise price, exercisable	$ 27.87
Weighted-average remaining contractual life, exercisable	1 year 5 months 1 day
Aggregate intrinsic value, exercisable	$ 1,000
Shares Subject to Options Outstanding & Exercisable	49,366
Weighted-Average Remaining Contractual Life	1 year 5 months 1 day
Weighted-Average Exercise Price	$ 27.87
Range of Exercise Price $23.59 - $25.94
Stock Options
Range of exercise prices, minimum	$ 23.59
Range of exercise prices, maximum	$ 25.94
Shares Subject to Options Outstanding & Exercisable	2,792
Weighted-Average Remaining Contractual Life	0 years 5 months 1 day
Weighted-Average Exercise Price	$ 25.41
Range of Exercise Price $26.01 - $27.74
Stock Options
Range of exercise prices, minimum	$ 26.01
Range of exercise prices, maximum	$ 27.74
Shares Subject to Options Outstanding & Exercisable	20,334
Weighted-Average Remaining Contractual Life	0 years 8 months 1 day
Weighted-Average Exercise Price	$ 27.08
Range of Exercise Price $28.25 - $28.26
Stock Options
Range of exercise prices, minimum	$ 28.25
Range of exercise prices, maximum	$ 28.26
Shares Subject to Options Outstanding & Exercisable	15,040
Weighted-Average Remaining Contractual Life	1 year 11 months 1 day
Weighted-Average Exercise Price	$ 28.25
Range of Exercise Price $28.57 - $30.00
Stock Options
Range of exercise prices, minimum	$ 28.57
Range of exercise prices, maximum	$ 30
Shares Subject to Options Outstanding & Exercisable	11,200
Weighted-Average Remaining Contractual Life	2 years 2 months
Weighted-Average Exercise Price	$ 29.40

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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 by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-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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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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