Annual report pursuant to Section 13 and 15(d)

Employee Retirement Savings Plan And Other Employee Matters (Details)

v3.20.1
Employee Retirement Savings Plan And Other Employee Matters (Details)
$ in Millions
12 Months Ended
Dec. 31, 2019
USD ($)
item
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Defined Contribution Plan Disclosure [Line Items]      
Minimum age to participate in plan, in years | item 21    
Term of service to become eligible for retirement plan 3 months    
Percentage of employer discretionary contribution 4.00%    
Contribution expense recorded | $ $ 5.7 $ 5.0 $ 5.1
401(k), Participant’s Contributions Not Exceeding 3% [Member]      
Defined Contribution Plan Disclosure [Line Items]      
Percentage employer matches of the employee's percentage contribution matched 100.00%    
401(k), Participant’s Contributions Not Exceeding 3% [Member] | Maximum [Member]      
Defined Contribution Plan Disclosure [Line Items]      
Percentage of employees' pay for which the employer contributes a matching contribution 3.00%    
401(k), Participant’s Contributions In Excess 3% But Not In Excess Of 5% [Member]      
Defined Contribution Plan Disclosure [Line Items]      
Percentage employer matches of the employee's percentage contribution matched 50.00%    
401(k), Participant’s Contributions In Excess 3% But Not In Excess Of 5% [Member] | Maximum [Member]      
Defined Contribution Plan Disclosure [Line Items]      
Percentage of employees' pay for which the employer contributes a matching contribution 5.00%    
401(k), Participant’s Contributions In Excess 3% But Not In Excess Of 5% [Member] | Minimum [Member]      
Defined Contribution Plan Disclosure [Line Items]      
Percentage of employees' pay for which the employer contributes a matching contribution 3.00%