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Share-Based Compensation - Summary of Assumptions (Details) - 2007 Long-Term Incentive Plan
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Director and Officers [Member]      
Expected dividend yield 18.00%   8.00%
Expected volatility 44.14%   47.08%
Risk-free interest rate 1.97%   1.55%
Expected life (in years) 8 years   7 years
Employees      
Expected dividend yield 22.00% 14.00% 8.00%
Expected volatility 42.71% 44.85% 45.92%
Risk-free interest rate 1.41% 2.26% 1.40%
Expected life (in years) 8 years 8 years 8 years