Annual report pursuant to Section 13 and 15(d)

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

v3.8.0.1
Equity-Based Compensation - Summary of Equity Grants (Detail) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Performance Units    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Beginning Balance, Units 6,386 96,971
Vested, Units (6,386) (90,585)
Ending Balance, Units   6,386
Fair Value per unit $ 3.75 $ 3.75
Vested, Range of Fair Value per unit $ (3.75) (3.75)
Fair Value per unit   $ 3.75
Deferred Compensation Share Based Payments    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Beginning Balance, Units 4,911 52,188
Vested, Units (4,911) (47,277)
Ending Balance, Units   4,911
Deferred Compensation Share Based Payments | Minimum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Fair Value per unit $ 12.00 $ 12.00
Vested, Range of Fair Value per unit (12.00) (12.00)
Fair Value per unit   12.00
Deferred Compensation Share Based Payments | Maximum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Fair Value per unit 11.89 15.65
Vested, Range of Fair Value per unit $ (10.92) (13.97)
Fair Value per unit   $ 11.89