Stock-based Compensation (Details 2) (USD $)	6 Months Ended
Jun. 30, 2012
Contractual weighted-average lives of outstanding options
Total outstanding, options	185,500
Total exercisable Option	35,500
Weighted-average, Total outstanding	$ 16.01
Weighted-average, Total exercisable	$ 32.05
Weighted-average, Total outstanding life	8 years 7 months 6 days
Weighted-average, Total exercisable life	4 years 2 months 12 days
$10.79 - $12.44 [Member]
Contractual weighted-average lives of outstanding options
From	$ 10.79
To	$ 12.44
Outstanding stock options	90,000
Weighted-average remaining life	9 years 8 months 12 days
Weighted-average exercise price	$ 11.47
Exercisable stock options
Weighted-average remaining life
Weighted-average exercise price
$13.13 - $13.44 [Member]
Contractual weighted-average lives of outstanding options
From	$ 13.13
To	$ 13.44
Outstanding stock options	60,000
Weighted-average remaining life	9 years 8 months 12 days
Weighted-average exercise price	$ 13.34
Exercisable stock options
Weighted-average remaining life
Weighted-average exercise price
$28.30 - $31.83 [Member]
Contractual weighted-average lives of outstanding options
From	$ 28.30
To	$ 31.83
Outstanding stock options	19,000
Weighted-average remaining life	4 years 7 months 6 days
Weighted-average exercise price	$ 30.36
Exercisable stock options	19,000
Weighted-average remaining life	4 years 7 months 6 days
Weighted-average exercise price	$ 30.36
$32.90 - $34.95 [Member]
Contractual weighted-average lives of outstanding options
From	$ 32.90
To	$ 34.95
Outstanding stock options	16,500
Weighted-average remaining life	3 years 8 months 12 days
Weighted-average exercise price	$ 34.00
Exercisable stock options	16,500
Weighted-average remaining life	3 years 8 months 12 days
Weighted-average exercise price	$ 34.00

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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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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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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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Weighted average remaining contractual term of exercisable 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 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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