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Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Defined contribution pension plans	$ 3.2	$ 3.1	$ 2.5
Equity Securities | United States
Compensation And Retirement Disclosure [Abstract]
Long-term return on plan assets	9.00%
Plan asset target allocation	36.00%
Fixed Income | United States
Compensation And Retirement Disclosure [Abstract]
Long-term return on plan assets	4.00%
Plan asset target allocation	49.00%
Funds | United States
Compensation And Retirement Disclosure [Abstract]
Defined benefit plan assets	30.00%
Multi-asset Strategies and CMRT | United States
Compensation And Retirement Disclosure [Abstract]
Long-term return on plan assets	3.00%
Defined Benefit Pension Plans
Compensation And Retirement Disclosure [Abstract]
Expected contributions to Defined Benefit Plans in Next Fiscal Year	$ 2.0
Actuarial losses expected to be recognized as a component of net period cost in next fiscal year	$ 1.5
Weighted-average rate determining the actuarial present value of benefit obligation	2.90%	3.90%
Long-term return on plan assets	4.70%	7.20%	6.90%
Defined Benefit Pension Plans | CMRT
Compensation And Retirement Disclosure [Abstract]
Long-term return on plan assets		7.50%	7.50%

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Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

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Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position.

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Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

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Percentage of investment to total investment within defined benefit plan asset category.

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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Amount of cost for defined contribution plan.

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