Other, Net - Other Net in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Other Nonoperating Income Expense [Abstract]
Foreign exchange gains (losses)		$ (274)	$ 596		$ 895	$ 97
Investment income		91	69		320	220
Realized and unrealized gains on investments		737	1,101		1,241	3,677
Net periodic benefit cost		(208)	(125)		(466)	(468)
Other, net	[1]	$ 346	$ 1,641	[2]	$ 1,990	$ 3,526	[2]

[1] The 2017 amounts for the noted line items have been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of Accounting Standards Update (ASU) No. 2017-7, Compensation –Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.

[2] The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost