Other, Net - Other Net in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Nonoperating Income Expense [Abstract]
Foreign exchange gains	$ 1,367	$ 123	$ 1,902
Investment income	1,681	968	1,554
Realized and unrealized gains (losses) on investments	3,143	3,955	(2,966)
Net periodic benefit cost	(874)	(351)	(1,215)
Gain on sale of asset		570
Other retirement obligation	(363)	(694)
Other, net	$ 4,954	$ 4,571	$ (725)

Other retirement obligation.

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Amount of net periodic benefit cost (credit) for defined benefit plan.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Amount of realized and unrealized gain (loss) on investment.

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Amount of income (expense) related to nonoperating activities, classified as other.

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