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Share-Based Compensation (Details) - Changes in the stock option plans - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2016
Share-Based Compensation (Details) - Changes in the stock option plans [Line Items]      
Balance, Number of Shares Authorized 800 800 200,800
Balance, Number of Shares Available 800 800 200,800
Balance, Weighted Average Exercise Price (in Dollars per share)    
Number of Shares Authorized, Expired (200,000)    
Number of Shares Available, Expired (200,000)