Stock-Based Compensation (Schedule of Activity and Changes Under the Principal Option Plan) (Details) (USD $)	6 Months Ended
Jun. 30, 2012
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Outstanding Begninng Balance- shares	171,378
Outstanding Beginning Balance- weighted average exercise price	$ 10.01
Granted- shares	27,784
Granted- weighted average exercise price	$ 9.64
Exercised- shares	14,761
Exercised- Weighted Average Exercise Price	$ 8.89
Outstaning Ending Balance- shares	184,401
Outstanding Ending Balance- weighted average exercise price	$ 10.04
Outstanding Ending Balance- weighted average remaining contractual term (years)	6 years 5 months 23 days
Outstanding Ending Balance- aggregate intrinsic value	$ 282,988
Exercisable- shares	115,813
Exercisable- weighted average exercise price	$ 10.61
Exercisable- weighed average remaining contractual term (years)	5 years 1 month 28 days
Exercisable- aggregate intrinsic value	$ 134,131

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options outstanding.

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

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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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