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Deferred Compensation Agreements and Stock-Based Compensation (Details) - PICP
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Deferred compensation agreements      
Percentage of participant's annual earned bonus deferred 50.00%    
Period of deferral of annual earned bonus 1 year    
Maximum percentage of participant's earned bonus amount up to which common stock can be purchased in a stock purchase plan 16.67% 16.67%  
Percentage of average market closing prices used in determining number of common stock that could be purchased by participants 75.00% 75.00% 75.00%
Vesting period 3 years