Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation and Other Benefit Plans (Detail)

v3.20.4
Share-Based Compensation and Other Benefit Plans (Detail) - USD ($)
4 Months Ended 12 Months Ended
Dec. 31, 2016
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Severance Costs   $ 200,000    
Share-based Payment Arrangement, Accelerated Cost   700,000 $ 200,000 $ 600,000
Defined Contribution Plan, Cost   900,000 900,000 600,000
Pension and Other Postretirement Benefits Cost (Reversal of Cost)   100,000 100,000 100,000
Share-based compensation $ 4,600,000 3,284,000 $ 4,082,000 4,618,000
Separation Agreement, Consulting Fees       300,000
Restricted Stock Units (RSUs)        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount   $ 3,000,000.0    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   281,382    
Stock Options        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition   1 year    
Performance Restricted Stock Units [Domain]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount   $ 1,500,000    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   145,399    
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition   1 year 3 months 18 days    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   145,399 15,066  
Other Pension, Postretirement and Supplemental Plans [Member]        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Liability, Defined Benefit Plan, Noncurrent   $ 1,300,000 $ 1,300,000 1,300,000
Pension and Other Postretirement Benefits Cost (Reversal of Cost)   $ 100,000 $ 100,000 $ 100,000