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Stockholder's Equity - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	$ 304,506
Balance at end of year	311,877	$ 304,506
Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	(172,843)	(172,434)	$ (164,467)
Other comprehensive income (loss)	3,268	(409)	(7,967)
Balance at end of year	(169,575)	(172,843)	(172,434)
Accumulated Defined Benefit Plans Adjustment | Defined Benefit Pension Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	(78,257)	(75,286)	(72,951)
Other comprehensive income (loss)	4,330	3,539	(2,335)
Net actuarial gain (loss) arising during year	(6,777)	(6,510)
Balance at end of year	(80,704)	(78,257)	(75,286)
Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year			46,069
Marketable Securities | Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year			(46,069)
Other | OPEB
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	(590)	(550)	(388)
Other comprehensive income (loss)	(320)	(40)	(162)
Balance at end of year	(910)	(590)	(550)
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year	(251,690)	(248,270)	(191,737)
Balance at beginning of year, as adjusted	(251,690)	(248,270)	(237,806)
Other comprehensive income (loss)	501	(3,420)	(10,464)
Balance at end of year	$ (251,189)	$ (251,690)	(248,270)
Accumulated other comprehensive income (loss) | Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of year			$ (46,069)

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Amount, after tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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