v3.3.0.814
Equity-Based Compensation Plan - Summary of Performance Unit Award Activity (Detail) - Performance Shares [Member]
9 Months Ended
Sep. 30, 2015
shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Outstanding at December 31, 2014 924,143
Granted 597,249
Outstanding at September 30, 2015 1,521,392