Savings Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Savings Plan [Line Items]
Savings plan maximum percentage of employees contribution allowable	20.00%
Percentage of employer contributions vested per year	25.00%
Maximum employment period considered for vesting of employers' contribution, in years	4 years
Liability, Retirement and Postemployment Benefits	$ 32.7	$ 24.4
U.S. Qualified Pension Plan
Savings Plan [Line Items]
Maximum percentage of matching contributions made by the employer	100.00%	100.00%	100.00%
Percentage of employer match on employee contribution	4.00%	4.00%	4.00%
Savings Plan
Savings Plan [Line Items]
Amounts charged to statements of operations	$ 20.9	$ 19.4	$ 16.8

Maximum employment period considered for vesting of employers' contribution

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- Definition

Savings Plan [Line Items]

+ References

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- Definition

Savings plan maximum percentage of employees contribution allowable

+ References

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- Definition

Amount of cost for defined contribution plan.

+ References

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

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Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

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- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

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- Definition

Amount of liability, recognized in statement of financial position, for pension, other postretirement and postemployment benefits.

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