Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Gross Profit to Consolidated Net Income (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Gross profit	$ 262,855	$ 205,547
Research and development	34,857	33,282
Selling, general and administrative	82,949	74,220
Acquisition and integration costs		1,442
Restructuring	1,220	522
Environmental costs	1,000
Amortization of intangible assets	11,190	12,501
Income from operations	131,639	83,580
Interest and other expense, net	(4,897)	(6,295)
Income before income taxes	126,742	77,285
Provision for income taxes	21,621	12,225
Net income	105,121	65,060
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Gross profit	158,500	128,924
Light & Motion [Member]
Segment Reporting Information [Line Items]
Gross profit	$ 104,355	$ 76,623

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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