Stockholders' Equity - Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax by Component (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 443,547	$ 475,736	$ 446,279	$ 497,911
Other comprehensive income (loss) before reclassifications	713	(3,506)	(216)	(2,921)
Amounts reclassified from accumulated other comprehensive income (loss)	77	191	152	318
Amounts reclassified to retained earnings			385	(3,220)
Net current period other comprehensive income (loss)	790	(3,315)	321	(5,823)
Ending Balance	445,975	459,627	445,975	459,627
ASU 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	385
Amounts reclassified to retained earnings			385
Net current period other comprehensive income (loss)			385
Ending Balance	385		385
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(378)	(845)	(563)	2,567
Other comprehensive income (loss) before reclassifications	180	(82)	411	(339)
Amounts reclassified from accumulated other comprehensive income (loss)	(73)	186	(119)	251
Amounts reclassified to retained earnings				(3,220)
Net current period other comprehensive income (loss)	107	104	292	(3,308)
Ending Balance	(271)	(741)	(271)	(741)
Defined Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(7,920)	(4,224)	(8,041)	(4,286)
Amounts reclassified from accumulated other comprehensive income (loss)	150	5	271	67
Net current period other comprehensive income (loss)	150	5	271	67
Ending Balance	(7,770)	(4,219)	(7,770)	(4,219)
Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(6,972)	(734)	(5,812)	(1,576)
Other comprehensive income (loss) before reclassifications	533	(3,424)	(627)	(2,582)
Net current period other comprehensive income (loss)	533	(3,424)	(627)	(2,582)
Ending Balance	(6,439)	(4,158)	(6,439)	(4,158)
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(14,885)	(5,803)	(14,416)	(3,295)
Ending Balance	$ (14,095)	$ (9,118)	$ (14,095)	$ (9,118)

Cumulative effect on reclassification from AOCI to retained earnings due to changes in accounting standard.

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Other comprehensive income loss net of tax due to changes in accounting standard.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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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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