Other, Net - Other Net in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Other Nonoperating Income Expense [Abstract]
Foreign exchange gains (losses)		$ 1,053	$ (484)
Investment income		139	102
Realized and unrealized gains on investments		97	1,645
Net periodic benefit cost		(129)	(171)
Other, net	[1],[2]	$ 1,160	$ 1,092

[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.