Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation and Other Benefit Plans - Activity of Awarded Restricted Stock Units (Detail)

v3.10.0.1
Share-Based Compensation and Other Benefit Plans - Activity of Awarded Restricted Stock Units (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Restricted Stock Units (RSUs)    
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value $ 3.3 $ 0.8
Number of shares    
Vested (in shares) (79,828)  
Forfeited (in shares) (14,581)  
Weighted-Average Grant Date Fair Value    
Vested (in dollars per share) $ 38.90  
Forfeited (in dollars per share) $ 43.64  
Performance Restricted Stock Units [Domain]    
Number of shares    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 0  
Vested (in shares) (1,968)  
Forfeited (in shares) (7,487)  
Weighted-Average Grant Date Fair Value    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 0.00  
Vested (in dollars per share) 49.56  
Forfeited (in dollars per share) $ 49.56  
Minimum | Performance Restricted Stock Units [Domain]    
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage 0.00%  
Maximum | Performance Restricted Stock Units [Domain]    
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage 200.00%  
Successor [Member] | Restricted Stock Units (RSUs)    
Number of shares    
Balance at beginning of year (in shares) 259,990  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 42,459  
Balance at end of year (in shares) 208,040 259,990
Weighted-Average Grant Date Fair Value    
Balance at beginning of year (in dollars per share) $ 41.32  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value 65.96  
Balance at end of year (in dollars per share) $ 47.35 $ 41.32
Successor [Member] | Performance Restricted Stock Units [Domain]    
Number of shares    
Balance at beginning of year (in shares) 98,526  
Balance at end of year (in shares) 89,071 98,526
Weighted-Average Grant Date Fair Value    
Balance at beginning of year (in dollars per share) $ 57.81  
Balance at end of year (in dollars per share) $ 58.69 $ 57.81