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EMPLOYEE STOCK COMPENSATION - SARs Weighted Average Fair Value Assumptions (Details) - Stock appreciation rights - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 0.00% 0.00% 0.00%
Expected volatility 23.79% 27.28% 30.54%
Expected term 2 years 7 days 2 years 8 months 7 days 2 years 6 months 25 days
Risk-free interest rate 0.64% 0.70% 0.36%
Fair value per share (in dollars per share) $ 1.72 $ 1.93 $ 2.33