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Stock-Based Compensation (PSUs, RSUs and Restricted Stock) - Additional Information (Detail) - USD ($)
shares in Thousands, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
One-time PSU shares grant approved by board of directors   897
Recognition period of unvested compensation expense   3 years
Performance Stock Units (PSUs) [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vesting period   3 years
One-time PSU shares grant approved by board of directors 500  
Performance Stock Units (PSUs) [Member] | Minimum [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Percentage of performance stock units granted   0.00%
Performance Stock Units (PSUs) [Member] | Maximum [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Percentage of performance stock units granted   150.00%
Restricted Stock Units (RSUs) [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vesting period   4 years
Restricted Stock [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Vesting period   1 year
Market-Based PSUs, RSUs and Restricted Stock [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Unrecognized compensation expense related to other than options   $ 17.2
Recognition period of unvested compensation expense   2 years 10 months 24 days
Stock Options, PSUs, RSUs or Restricted Stock [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Options available for issuance under shareholders-approved equity plan   1,000