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Equity-Based Compensation - Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member] - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unvested, Number of Shares/Units, Beginning balance 484,111 360,909 273,599
Granted, Number of Units 234,408 285,358 219,840
Cancelled, Number of Units (271,162) (89,173)  
Vested, Number of Units   (72,983) (132,530)
Unvested, Number of Shares/Units, Ending balance 447,357 484,111 360,909
Unvested, Weighted Average Grant-Date Fair Value, Beginning balance $ 44.52 $ 50.04 $ 59.68
Granted, Weighted Average Grant-Date Fair Value 34.54 42.26 43.23
Cancelled, Weighted Average Grant-Date Fair Value 45.17 55.44  
Vested, Weighted Average Grant-Date Fair Value   49.64 58.67
Unvested, Weighted Average Grant-Date Fair Value, Ending balance $ 38.89 $ 44.52 $ 50.04