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Net Income Per Common Unit - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Jan. 31, 2008
Unit Repurchase Program [Line Items]      
Amount remaining available for repurchases $ 335,800,000    
Common stock repurchased, units 0 0  
Blackstone      
Unit Repurchase Program [Line Items]      
Amount authorized to repurchase under unit repurchase program     $ 500,000,000