Quarterly report pursuant to Section 13 or 15(d)

Share-based Compensation - Summary of Activity of Restricted Shares (Detail)

v3.21.2
Share-based Compensation - Summary of Activity of Restricted Shares (Detail)
 9 Months Ended
Sep. 30, 2021
$ / shares
shares
Restricted Stock [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of Restricted Shares, Opening balance | shares 1,250,000
Number of Restricted Shares, Granted | shares 1,320,700
Number of Restricted Shares, Vested | shares (5,000)
Number of Restricted Shares, Forfeited | shares (268,400)
Number of Restricted Shares, Ending balance | shares 2,297,300
Weighted Average Grant Date Fair Value, Opening balance | $ / shares $ 15.28
Weighted Average Grant Date Fair Value, Granted | $ / shares 13.48
Weighted Average Grant Date Fair Value, Vested | $ / shares 10.66
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 13.92
Weighted Average Grant Date Fair Value, Ending balance | $ / shares $ 14.37
Performance Condition Awards [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares, Non-vested Opening balance | shares 950,000
Shares, Granted | shares 783,700
Shares, Forfeited | shares (148,400)
Shares, Non-vested Ending balance | shares 1,585,300
Weighted Average Grant Date Fair Value, Non-vested Opening balance | $ / shares $ 15.70
Weighted Average Grant Date Fair Value, Granted | $ / shares 15.49
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 16.15
Weighted Average Grant Date Fair Value, Non-vested Ending balance | $ / shares $ 15.54
Service Condition Shares [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares, Non-vested Opening balance | shares 200,000
Shares, Granted | shares 77,000
Shares, Vested | shares (5,000)
Shares, Non-vested Ending balance | shares 272,000
Weighted Average Grant Date Fair Value, Non-vested Opening balance | $ / shares $ 15.70
Weighted Average Grant Date Fair Value, Granted | $ / shares 14.37
Weighted Average Grant Date Fair Value, Vested | $ / shares 10.66
Weighted Average Grant Date Fair Value, Non-vested Ending balance | $ / shares $ 15.42
Market Condition Awards [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares, Non-vested Opening balance | shares 100,000
Shares, Granted | shares 460,000
Shares, Forfeited | shares (120,000)
Shares, Non-vested Ending balance | shares 440,000
Weighted Average Grant Date Fair Value, Non-vested Opening balance | $ / shares $ 10.45
Weighted Average Grant Date Fair Value, Granted | $ / shares 9.91
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 11.17
Weighted Average Grant Date Fair Value, Non-vested Ending balance | $ / shares $ 9.50