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Equity-Based Compensation - Summary of Status of Stock Options (Details 5) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Options    
Additional Disclosure Status of Stock Options    
Weighted average remaining contractual life 0 years  
Share Based Compensation Arrangement By Share Based Payment Award Options Maximum Contractual Term 10 years  
Employee Service Share Based Compensation Awards Stock Options Outstanding 0 0
Performance Option [Member]    
Summary of Status of Stock Options    
Outstanding, Options at end of period, shares 295,000  
Weighted- Average Exercise Price    
Exercisable, Weighted - Average Exercise Price at end of period $ 18.37  
Additional Disclosure Status of Stock Options    
Share Based Compensation Arrangement By Share Based Payment Award Options Maximum Contractual Term 5 years