Annual report pursuant to Section 13 and 15(d)

Equity-Based Compensation - Summary of RSU Grants (Detail)

v3.10.0.1
Equity-Based Compensation - Summary of RSU Grants (Detail) - Restricted Stock Units - $ / shares
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Beginning Balance, Units 491,786 739,256
Ending Balance, Units 247,316 491,786
Minimum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Fair Value per unit $ 13.19 $ 13.19
Fair Value per unit 13.19 13.19
Maximum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Fair Value per unit 13.23 13.23
Fair Value per unit $ 13.23 $ 13.23
Vested in April 2017    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vested, Units   (1,000)
Fair Value per unit, Vested   $ (13.19)
Vested in May 2017    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vested, Units (2,843) (4,843)
Fair Value per unit, Vested $ (13.19) $ (13.19)
Vested in August 2017    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vested, Units (241,627) (241,627)
Fair Value per unit, Vested $ (13.23) $ (13.23)