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Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Pension Plans, Defined Benefit        
Defined Benefit Plan Disclosure [Line Items]        
Defined benefit plan, employer contributions $ 0.0 $ 0.0    
Supplemental Executive Retirement Plan        
Defined Benefit Plan Disclosure [Line Items]        
Defined benefit plan, employer contributions 0.4      
Obligations under the supplemental plan $ 21.5     $ 21.4
Supplemental Executive Retirement Plan | Scenario, Forecast        
Defined Benefit Plan Disclosure [Line Items]        
Defined benefit plan, employer contributions     $ 1.2