Stock Based Compensation (Restricted Stock Activity) (Details) (Restricted Stock [Member], USD $)	12 Months Ended
Dec. 31, 2012
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Shares, Outstanding at January 1, 2012	70,300
Shares, Vested	1,500
Shares, Outstanding at December 31, 2012	68,800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Shares, Outstanding at January 1, 2012, Weighted Average Grant Date Fair Value	$ 32.83
Shares, Vested, Weighted Average Grant Date Fair Value	$ 44.44
Shares, Outstanding at December 31, 2012, Weighted Average Grant Date Fair Value	$ 32.57
Shares, Outstanding at December 31, 2012, Weighted Average Remaining Years Contractual Term	2 months
Shares, Outstanding at December 31, 2012, Aggregate Intrinsic Value	$ 2,105,280

The intrinsic value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units, as calculated by applying the disclosed pricing methodology.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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