Quarterly report pursuant to Section 13 or 15(d)

Equity-Based Compensation - Performance Units to be Settled in Common Stock (Detail)

v3.10.0.1
Equity-Based Compensation - Performance Units to be Settled in Common Stock (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Non-cash stock compensation expense $ 13,485 $ 11,557 $ 28,172 $ 23,423
Performance Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Required performance period     3 years  
Performance units granted (in shares)     300,000 300,000
Granted, weighted average grant date fair value, per share (in usd per share)     $ 12.24 $ 17.63
Non-cash stock compensation expense $ 2,700 $ 1,400 $ 6,200 $ 2,100
Performance units vested (in shares) 0 0 100,000 100,000
Number of common shares issued in connection with performance units (in shares) 0 0 100,000 100,000
Performance Units | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Performance units performance percentage     0.00%  
Performance Units | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Performance units performance percentage     200.00%