Stock-Based Compensation Plans (Schedule of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Number of Shares
Options outstanding, beginning	111,950
Granted	4,500
Exercised	(19,000)
Forfeited and expired	(3,200)
Options outstanding, ending	94,250
Options exercisable	73,150
Weighted Average Exercise Price Per Share
Options outstanding, beginning	$ 33.36
Granted	$ 35.22
Exercised	$ 32.58
Forfeited and expired	$ 38.32
Options outstanding, ending	$ 33.44
Options exercisable	$ 33.21
Weighted- Average Remaining Contractual Term
Options outstanding	4 years 6 months
Options exercisable	3 years 9 months 18 days
Aggregate Intrinsic Value
Options outstanding	$ 664
Options exercisable	$ 545

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

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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 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 price at which option holders acquired shares when converting their stock options into shares.

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Number of share options (or share units) exercised during the current period.

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