Stock Incentive Plan (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Stock Incentive Plan 1994 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price	$ 19.5
Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Rights	could be exercised in increments of 25% on each anniversary of the date of the grant
Equity Incentive Plan 2005 [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Shares Authorized	1

Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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