Employee Benefit Plans - Information Concerning Defined Benefit Pension Plans (Including Certain Plans for Which ABO Exceeds Fair Value of Plan Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
PBO	$ 49,249	$ 53,978	$ 54,261
Fair value of plan assets	40,626	44,222	$ 42,268
U.S.
Defined Benefit Plan Disclosure [Line Items]
PBO for plans for which ABO exceeds plan assets	40,643	44,709
ABO for plans for which ABO exceeds plan assets	40,643	44,709
Fair value of plan assets for plans for which ABO exceeds plan assets	30,122	32,360
U.S. \| Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
PBO	40,643	44,709
Fair value of plan assets	30,122	32,360
U.K. \| Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
PBO	8,606	9,269
Fair value of plan assets	$ 10,504	$ 11,862

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

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