Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Equity-Based Compensation - Summary of Equity Grants (Detail) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Performance Units        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Beginning Balance, Units 6,386 96,971 238,371  
Vested, Units (6,386) (90,585) (140,549)  
Forfeited, Units     (851)  
Ending Balance, Units   6,386 96,971  
Fair Value per unit   $ 3.75 $ 3.75 $ 3.75
Vested, Range of Fair Value per unit $ (3.75) $ (3.75) $ (3.75)  
Deferred Compensation Share Based Payments        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Beginning Balance, Units 4,911 52,188 175,298  
Vested, Units (4,911) (47,277) (123,110)  
Ending Balance, Units   4,911 52,188  
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)    
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 $ 17.05
Vested, Range of Fair Value per unit $ (10.92) $ (13.97) $ (16.81)