MKS Instruments (MKSI) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares - shares	9 Months Ended
	Sep. 30, 2018	Oct. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	MKSI
Entity Registrant Name	MKS INSTRUMENTS INC
Entity Central Index Key	1,049,502
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		53,986,114

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents, including restricted cash	$ 399,850	$ 333,887
Short-term investments	219,776	209,434
Trade accounts receivable, net of allowance for doubtful accounts of $4,761 and $4,135 at September 30, 2018 and December 31, 2017, respectively	318,470	300,308
Inventories, net	399,077	339,081
Other current assets	75,298	53,543
Total current assets	1,412,471	1,236,253
Property, plant and equipment, net	180,182	171,782
Goodwill	587,861	591,047
Intangible assets, net	331,288	366,398
Long-term investments	10,404	10,655
Other assets	42,390	37,883
Total assets	2,564,596	2,414,018
Current liabilities:
Short-term debt	6,130	2,972
Accounts payable	81,486	82,518
Accrued compensation	74,472	96,147
Income taxes payable	12,942	21,398
Deferred revenue	9,136	12,842
Other current liabilities	78,327	73,945
Total current liabilities	262,493	289,822
Long-term debt, net	342,970	389,993
Non-current deferred taxes	61,540	61,571
Non-current accrued compensation	56,888	51,700
Other liabilities	30,412	32,025
Total liabilities	754,303	825,111
Commitments and contingencies (Note 19)
Stockholders’ equity:
Preferred Stock, $0.01 par value per share, 2,000,000 shares authorized; none issued and outstanding
Common Stock, no par value, 200,000,000 shares authorized; 53,984,623 and 54,355,535 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	113	113
Additional paid-in capital	786,138	789,644
Retained earnings	1,023,959	795,698
Accumulated other comprehensive income	83	3,452
Total stockholders’ equity	1,810,293	1,588,907
Total liabilities and stockholders’ equity	$ 2,564,596	$ 2,414,018

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4,761	$ 4,135
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	53,984,623	54,355,535
Common stock, shares outstanding	53,984,623	54,355,535

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net revenues:
Net revenues		$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Cost of revenues
Cost of revenues		255,292	258,272	844,975	751,052
Gross profit		231,860	227,995	769,592	653,125
Research and development		31,898	32,548	103,259	99,510
Selling, general and administrative		70,822	71,347	229,952	217,546
Acquisition and integration costs		36	2,466	(1,132)	4,698
Restructuring		1,364	10	3,374	2,596
Environmental costs				1,000
Asset impairment					6,719
Fees and expenses related to repricing of term loan			492	378	492
Amortization of intangible assets		10,695	10,977	32,786	34,946
Income from operations		117,045	110,155	399,975	286,618
Interest income		1,516	873	4,077	1,896
Interest expense		3,719	7,172	13,071	23,001
Gain on sale of business					74,856
Other expense, net		326	2,485	1,179	3,741
Income before income taxes		114,516	101,371	389,802	336,628
Provision for income taxes		21,239	25,377	68,542	75,134
Net income		93,277	75,994	321,260	261,494
Other comprehensive income:
Changes in value of financial instruments designated as cash flow hedges, net of tax expense (benefit)	[1]	163	(908)	8,053	(3,578)
Foreign currency translation adjustments, net of tax of $0		(3,576)	8,088	(11,314)	30,352
Unrecognized pension gain (loss), net of tax expense (benefit)	[2]	24	(565)	(13)	(204)
Unrealized gain (loss) on investments, net of tax expense (benefit)	[3]	230	1,301	(95)	1,137
Total comprehensive income		$ 90,118	$ 83,910	$ 317,891	$ 289,201
Net income per share:
Basic		$ 1.71	$ 1.40	$ 5.89	$ 4.84
Diluted		1.70	1.38	5.82	4.75
Cash dividends per common share		$ 0.20	$ 0.175	$ 0.58	$ 0.525
Weighted average common shares outstanding:
Basic		54,476	54,282	54,539	54,076
Diluted		54,954	55,101	55,171	55,020
Products [Member]
Net revenues:
Net revenues		$ 426,255	$ 428,891	$ 1,432,931	$ 1,243,146
Cost of revenues
Cost of revenues		219,311	226,445	747,522	662,985
Services [Member]
Net revenues:
Net revenues		60,897	57,376	181,636	161,031
Cost of revenues
Cost of revenues		$ 35,981	$ 31,827	$ 97,453	$ 88,067
[1]	Tax expense was $49 and $688 for the three months ended September 30, 2018 and 2017, respectively. Tax expense (benefit) was $2,304 and $(884) for the nine months ended September 30, 2018 and 2017, respectively.
[2]	Tax expense (benefit) was $7 and $(312) for the three months ended September 30, 2018 and 2017, respectively. Tax benefit was $(17) and $(315) for the nine months ended September 30, 2018 and 2017, respectively.
[3]	Tax expense (benefit) was $17 and $(467) for the three months ended September 30, 2018 and 2017, respectively. Tax (benefit) expense was $(22) and $274 for the nine months ended September 30, 2018 and 2017, respectively.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Tax expense (benefit) on changes in value of financial instruments designated as cash flow hedges	$ 49	$ 688	$ 2,304	$ (884)
Tax on foreign currency translation adjustments	0	0	0	0
Tax expense (benefit) on unrecognized pension gain (loss)	7	(312)	(17)	(315)
Tax expense (benefit) on unrealized gain (loss) on investments	$ 17	$ (467)	$ (22)	$ 274

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]
Beginning Balance at Dec. 31, 2017	$ 1,588,907	$ 113	$ 789,644	$ 795,698	$ 3,452
Beginning Balance, Shares at Dec. 31, 2017		54,355,535
Net issuance under stock-based plans	(13,641)		(13,641)
Net issuance under stock-based plans, Shares		447,219
Stock-based compensation	22,005		22,005
Stock repurchase	$ (75,000)		(11,870)	(63,130)
Stock repurchase, shares	(818,000)	(818,131)
Cash dividend	$ (31,608)			(31,608)
Accounting Standards Codification Topic 606 adjustment | Accounting Standards Codification Topic 606 Adjustment [Member]	1,739			1,739
Comprehensive income (net of tax):
Net income	321,260			321,260
Other comprehensive loss	(3,369)				(3,369)
Ending Balance at Sep. 30, 2018	1,810,293	$ 113	786,138	1,023,959	83
Ending Balance, Shares at Sep. 30, 2018		53,984,623
Beginning Balance at Jun. 30, 2018	1,801,438	$ 113	793,384	1,004,698	3,243
Beginning Balance, Shares at Jun. 30, 2018		54,787,153
Net issuance under stock-based plans	(589)		(589)
Net issuance under stock-based plans, Shares		15,601
Stock-based compensation	5,213		5,213
Stock repurchase	(75,000)		(11,870)	(63,130)
Stock repurchase, shares		(818,131)
Cash dividend	(10,859)			(10,859)
Accounting Standards Codification Topic 606 adjustment | Accounting Standards Codification Topic 606 Adjustment [Member]	(27)			(27)
Comprehensive income (net of tax):
Net income	93,277			93,277
Other comprehensive loss	(3,160)				(3,160)
Ending Balance at Sep. 30, 2018	$ 1,810,293	$ 113	$ 786,138	$ 1,023,959	$ 83
Ending Balance, Shares at Sep. 30, 2018		53,984,623

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017
Cash flows provided by operating activities:
Net income		$ 321,260	$ 261,494
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		59,906	62,550
Amortization of debt issuance costs, original issue discount and soft call premium		3,784	6,385
Asset impairment			6,719
Gain on sale of business			(74,856)
Stock-based compensation		22,005	19,834
Provision for excess and obsolete inventory		15,575	15,349
Provision for bad debt		859	650
Deferred income taxes		(3,525)	6,641
Other		531	832
Changes in operating assets and liabilities:
Trade accounts receivable		(23,125)	(26,489)
Inventories		(80,441)	(51,251)
Income taxes		(13,874)	15,646
Other current and non-current assets		(17,652)	(9,714)
Accrued compensation		(15,529)	11,058
Other current and non-current liabilities		8,934	22,517
Accounts payable		(385)	7,071
Net cash provided by operating activities		278,323	274,436
Cash flows (used in) provided by investing activities:
Net proceeds from sale of business			72,509
Purchases of investments		(213,774)	(199,012)
Maturities of investments		135,339	116,779
Sales of investments		67,868	43,571
Purchases of property, plant and equipment		(36,885)	(17,857)
Net cash (used in) provided by investing activities		(47,452)	15,990
Cash flows used in financing activities:
Repurchase of common stock		(75,000)
Proceeds from short and long-term borrowings		60,624	13,158
Payments on short-term borrowings		(57,865)	(13,277)
Payments on long-term borrowings		(50,002)	(178,141)
Net payments related to employee stock awards		(13,641)	(14,719)
Dividend payments to common stockholders		(31,608)	(28,403)
Net cash used in financing activities		(167,492)	(221,382)
Effect of exchange rate changes on cash and cash equivalents		2,584	3,140
Increase in cash and cash equivalents and restricted cash		65,963	72,184
Cash and cash equivalents, including restricted cash, at beginning of period	[1]	333,887	233,910
Cash and cash equivalents, including restricted cash, at end of period	[2]	$ 399,850	$ 306,094
[1]	Restricted cash at the beginning of the period was $119 and $5,287 for the nine months ended September 30, 2018 and 2017, respectively.
[2]	Restricted cash at the end of the period was $114 and $117 for the nine months ended September 30, 2018 and 2017, respectively.

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Statement Of Cash Flows [Abstract]
Restricted cash, beginning balance	$ 119	$ 117	$ 5,287
Restricted cash, ending balance	$ 114	$ 119	$ 117

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1) Basis of Presentation The terms “MKS” and the “Company” refer to MKS Instruments, Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The interim financial data as of September 30, 2018, and for the three and nine months ended September 30, 2018 are unaudited; however, in the opinion of MKS, the interim data includes all adjustments, consisting of normal recurring adjustments, necessary for a fair statement of the results for the interim periods. The condensed consolidated balance sheet presented as of December 31, 2017 has been derived from the consolidated audited financial statements as of that date. The unaudited condensed consolidated financial statements presented herein have been prepared in accordance with the instructions to Form 10-Q and do not include all of the information and note disclosures required by United States generally accepted accounting principles (“U.S. GAAP”). The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the MKS Annual Report on Form 10-K for the year ended December 31, 2017 filed with the Securities and Exchange Commission on February 28, 2018. The preparation of these unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the date of the unaudited condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, management evaluates its estimates and judgments, including those related to revenue recognition, stock-based compensation, inventory, intangible assets, goodwill and other long-lived assets, warranty liabilities, pension liabilities, acquisition expenses, income taxes and investments. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. Reclassification of certain line items in prior period financial statements The Company has historically recorded the revenue and related cost of revenue for the sale of its spare parts within Products in its Statements of Operations for the Vacuum & Analysis segment. The Company has now determined that these items are better presented within revenue and related cost of revenue within Services for the Vacuum & Analysis segment in its Statements of Operations to align with the current manner in which the Company operates its services business, and has elected to reclassify these amounts in previously issued financial statements as shown below. This change in presentation has no impact on total revenue or total cost of revenue. Three Months Ended September 30, 2017 As previously reported Adjustment As reclassified Net revenues: Products $ 434,710 $ (5,819 ) $ 428,891 Services 51,557 5,819 57,376 Total net revenues 486,267 — 486,267 Cost of revenues: Cost of products 225,174 1,271 226,445 Cost of services 33,098 (1,271 ) 31,827 Total cost of revenues $ 258,272 $ — $ 258,272 Nine Months Ended September 30, 2017 As previously reported Adjustment As reclassified Net revenues: Products $ 1,259,582 $ (16,436 ) $ 1,243,146 Services 144,595 16,436 161,031 Total net revenues 1,404,177 — 1,404,177 Cost of revenues: Cost of products 659,538 3,447 662,985 Cost of services 91,514 (3,447 ) 88,067 Total cost of revenues $ 751,052 $ — $ 751,052

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	2) Recently Issued Accounting Prono uncements In March 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-05, “Income Taxes (Topic 740).” This standard is an amendment that adopts the language of Securities and Exchange Commission Staff Accounting Bulletin No. 118 (“SAB 118”) and aims to address certain circumstances that may arise for registrants in accounting for the income tax effects of the Tax Cuts and Jobs Act (the “Act”) and to address any uncertainty or diversity of views in practice regarding the application of Topic 740 in situations where a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting under Topic 740 for certain income tax effects of the Act for the reporting period in which the Act was enacted. The provisions of this ASU were applied to the Company’s December 31, 2017 financial statements. The Company recorded provisional amounts with respect to the Act under SAB 118 at December 31, 2017 and September 30, 2018 and needs to complete additional analysis and receive additional guidance from the U.S. Internal Revenue Service with respect to provisions of the Act that affect the Company before the provisional determinations become final. Until the Company completes its analysis and receives additional guidance, the Company is not able to determine if the impact of ASU 2018-05 is material to the Company’s consolidated financial statements in any period. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (Topic 815).” This standard better aligns an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The provisions of this ASU are effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The Company does not expect adoption of this ASU to have a material impact on the Company’s consolidated financial statements. In May 2017, the FASB issued ASU 2017-09, “Compensation-Stock Compensation (Topic 718)-Scope of Modification Accounting.” This standard provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The provisions of this ASU are effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, “Compensation-Retirement Benefits (Topic 715)-Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” This standard requires that an employer disaggregate the service cost component from the other components of net benefit cost. This standard also provides explicit guidance on how to present the service cost component and the other components of the net benefit cost in the income statement and allows only the service cost component of net benefit cost to be eligible for capitalization. The provisions of this ASU are effective for annual periods beginning after December 31, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805)-Clarifying the Definition of a Business.” This standard clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This standard also provides a more robust framework to use in determining when a set of assets and activities is a business. Because the current definition of a business is interpreted broadly and can be difficult to apply, stakeholders indicated that analyzing transactions is inefficient and costly and that the definition does not permit the use of reasonable judgment. The provisions of this ASU are effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230)-Restricted Cash,” an amendment to ASU 2016-15. This standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash and restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The provisions of this ASU are effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years and should be applied at the time of adoption of ASU 2016-15. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, “Income Taxes (Topic 740)-Intra-Entity Transfer of Assets Other Than Inventory.” This standard requires that an entity recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs as opposed to when the assets have been sold to an outside party. The provisions of this ASU are effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230)-Classification of Certain Cash Receipts and Cash Payments.” This standard addresses eight specific cash flow issues with the objective of addressing the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230. The provisions of this ASU are effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” This standard requires the recognition of lease assets and liabilities for all leases, with certain exceptions, on the balance sheet. In transition, lessees and lessors have the option to either apply the standard retrospectively through a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption or they can apply the new standard to comparative periods presented. This ASU is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The FASB issued additional updates to the new standard in Topic 842 (Update 2018-01 in January 2018 – Land Easement Practical Expedient for Transition to Topic 842, Update 2018-10 – Codification Improvements to Topic 842 and Update 2018-11 in July 2018 – Targeted Improvements). The Company has reviewed the requirements of this standard and has formulated a plan for implementation. The management team has communicated its approach to the Audit Committee and will provide regular updates as appropriate. The Company is currently accumulating details on the population of leases and entering these details into a selected software database, which will be a repository and accounting solution for reporting and disclosure requirements required by the standard. The Company will continue to assess and disclose the impact that this ASU will have on its consolidated financial statements, disclosures and related controls, when known. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10)-Recognition and Measurement of Financial Assets and Financial Liabilities.” This ASU provides guidance for the recognition, measurement, presentation, and disclosure of financial instruments. The new standard revises accounting related to equity investments and the presentation of certain fair value changes for financial assets and liabilities measured at fair value. Among other things, it amends the presentation and disclosure requirements of equity securities that do not result in consolidation and are not accounted for under the equity method. Changes in the fair value of these equity securities will be recognized directly in net income. This standard is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this ASU during the three month period ended March 31, 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASC 606”). This ASU provides for a single comprehensive model to use in accounting for revenue arising from contracts with customers and has replaced most existing revenue recognition guidance in GAAP. This ASU is effective for fiscal years and interim periods within those years beginning after December 15, 2017. The two permitted transition methods under the new standard are the full retrospective method, in which case the standard would be applied to each prior reporting period presented, or the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company used the modified retrospective method upon adoption in the first quarter of 2018. The FASB issued additional updates to the new revenue standard in Topic 606 relating to reporting revenue on a gross versus net basis (Update 2016-08 in March 2016), identifying performance obligations and licensing arrangements (Update 2016-10 in April 2016), narrow-scope improvements and practical expedients (Update 2016-12 in May 2016), technical corrections and improvements (Update 2016-20 in December 2016), and SEC Updates (Update 2017-13 in September 2017 and Update 2017-14 in November 2017). The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements as described further in Note 3.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	3) Revenue from Contracts with Customers The Company adopted Accounting Standards Codification ASC 606 (“ASC 606”) on January 1, 2018 using the modified retrospective method for all contracts not completed as of the date of adoption. The reported results for the nine months ended September 30, 2018 reflect the application of ASC 606 guidance while the reported results for 2017 were prepared under the guidance of Accounting Standards Codification 605, Revenue Recognition. The Company has recorded a net increase to opening retained earnings of $1,809 as of January 1, 2018 due to the cumulative impact of adopting ASC 606, with the impact primarily related to its service business and certain custom products. The impact to revenue for the quarter ended September 30, 2018 as a result of applying ASC 606 was immaterial. The adoption of ASC 606 represents a change in accounting principle that will more closely align revenue recognition with the delivery of the Company's goods or services and will provide financial statement readers with enhanced disclosures. To achieve this core principle, the Company applies the following five steps: • Identify the contract with a customer • Identify the performance obligations in the contract • Determine the transaction price • Allocate the transaction price to performance obligations in the contract • Recognize revenue when or as the Company satisfies a performance obligation Revenue under ASC 606 is recognized when or as obligations under the terms of a contract with the Company’s customer has been satisfied and control has transferred to the customer. The majority of the Company's performance obligations, and associated revenue, are transferred to customers at a point in time, generally upon shipment of a product to the customer or receipt of the product by the customer and without significant judgments. Installation services are not significant and are usually completed in a short period of time (normally less than two weeks) and therefore, recorded at a point in time when the installation services are completed, rather than over time as they are not material. Extended warranty, service contracts, and repair services, which are transferred to the customer over time, are recorded as revenue as the services are performed. For repair services, the Company makes an accrual at quarter end based upon historical repair times within its product groups to record revenue based upon the estimated number of days completed to date, which is consistent with ratable recognition. Customized products with no alternative future use to the Company, and that have an enforceable right to payment for performance completed to date, are also recorded over time. The Company considers this to be a faithful depiction of the transfer to the customer of revenue over time as the work is performed or service is delivered, ratably over time. Revenue is measured as the amount of consideration the Company expects to receive in exchange for transferring goods or providing services. Performance obligations promised in a contract are identified based on the products or services that will be transferred to the customer that are both capable of being distinct, whereby the customer can benefit from the product or service either on its own or together with other resources that are readily available from third parties or from the Company, and are distinct in the context of the contract, whereby the transfer of the product or service is separately identifiable from other promises in the contract. Sales, value add, and other taxes the Company collects concurrent with revenue-producing activities are excluded from revenue. The Company’s normal payment terms are 30 to 60 days but vary by the type and location of its customers and the products or services offered. The time between invoicing and when payment is due is not significant. For certain products and services and customer types, the Company requires payment before the products or services are delivered to, or performed for, the customer. None of the Company’s contracts as of September 30, 2018 contained a significant financing component. Contract assets as of January 1 and September 30, 2018 were $3,065 and $3,951, respectively, and included in other current assets. Contracts with Multiple Performance Obligations The Company periodically enters into contracts with its customers in which a customer may purchase a combination of goods and or services, such as products with installation services or extended warranty obligations. These contracts include multiple promises that the Company evaluates to determine if the promises are separate performance obligations. Once the Company determines the performance obligations, the Company then determines the transaction price, which includes estimating the amount of variable consideration to be included in the transaction price, if any. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing either the expected value method or the most likely amount method depending on the method the Company expects to better predict the amount of consideration to which it will be entitled. There are no constraints on the variable consideration recorded. The Company then allocates the transaction price to each performance obligation in the contract based on a relative stand-alone selling price charged separately to customers or using an expected cost plus margin method. The corresponding revenues are recognized when or as the related performance obligations are satisfied, which are noted above. The impact of variable consideration was immaterial during the three and nine months ended September 30, 2018. Deferred Revenues The Company’s standard assurance warranty period is normally 12 to 24 months. The Company sells separately-priced service contracts and extended warranty contracts related to certain of its products, especially its laser products. The separately priced contracts generally range from 12 to 60 months. The Company normally receives payment at the inception of the contract and recognizes revenue over the term of the agreement in proportion to the costs expected to be incurred in satisfying the obligations under the contract. The Company has elected to use the practical expedient related to disclosing the remaining performance obligations as of September 30, 2018, as the majority have a duration of less than one year. A rollforward of the Company’s deferred revenue is as follows: Nine Months Ended September 30, 2018 Beginning balance, January 1 (1) $ 14,448 Amount of deferred revenue recognized in income (15,846 ) Additions to deferred revenue 13,869 Ending balance, September 30 (2) $ 12,471 (1) (2) Costs to Obtain and Fulfill a Contract Under ASC 606, the Company expenses sales commissions when incurred because the amortization period would have been one year or less. These costs are recorded within selling, general and administration expenses. The Company has elected to recognize the costs for freight and shipping when control over products has transferred to the customer as an expense in cost of sales. The Company monitors and tracks the amount of product returns and reduces revenue at the time of shipment for the estimated amount of future returns, based on historical experience. The Company makes estimates evaluating its allowance for doubtful accounts. The Company continuously monitors collections and payments from its customers and maintains a provision for estimated credit losses based upon its historical experience and any specific customer collection issues that it has identified. Disaggregation of Revenue The following table summarizes revenue from contracts with customers: Three Months Ended September 30, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 239,924 $ 186,331 $ 426,255 Services 46,114 14,783 60,897 Total net revenues $ 286,038 $ 201,114 $ 487,152 Three Months Ended September 30, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 265,136 $ 163,755 $ 428,891 Services 43,133 14,243 57,376 Total net revenues $ 308,269 $ 177,998 $ 486,267 Nine Months Ended September 30, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 865,714 $ 567,217 $ 1,432,931 Services 136,996 44,640 181,636 Total net revenues $ 1,002,710 $ 611,857 $ 1,614,567 Nine Months Ended September 30, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 776,256 466,890 $ 1,243,146 Services 119,958 41,073 161,031 Total net revenues $ 896,214 $ 507,963 $ 1,404,177 Product revenue, excluding revenue from certain custom products, is recorded at a point in time, while the majority of the service revenue and revenue from certain custom products is recorded over time. Refer to Note 17 in the financial statements for revenue by reportable segment, geography and groupings of similar products.

Investments

Investments	9 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Investments	4) Investments The fair value of investments classified as short-term consists of the following: September 30, 2018 December 31, 2017 Available-for-sale investments: Time deposits and certificates of deposit $ 14,552 $ 9,757 Bankers’ acceptance drafts 2,107 5,330 Asset-backed securities 38,947 36,990 Commercial paper 32,057 13,750 Corporate obligations 71,971 77,821 Municipal bonds 1,288 1,970 U.S. treasury obligations 28,208 28,078 U.S. agency obligations 30,646 35,738 $ 219,776 $ 209,434 Investments classified as long-term consist of the following: September 30, 2018 December 31, 2017 Available-for-sale investments: Group insurance contracts $ 6,004 $ 6,255 Cost method investments: Minority interest in a private company 4,400 4,400 $ 10,404 $ 10,655 The following tables show the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments: As of September 30, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 14,552 $ — $ — $ 14,552 Bankers’ acceptance drafts 2,107 — — 2,107 Asset-backed securities 38,961 11 (25 ) 38,947 Commercial paper 32,238 — (181 ) 32,057 Corporate obligations 71,931 59 (19 ) 71,971 Municipal bonds 1,290 — (2 ) 1,288 U.S. treasury obligations 28,200 10 (2 ) 28,208 U.S. agency obligations 30,649 4 (7 ) 30,646 $ 219,928 $ 84 $ (236 ) $ 219,776 As of September 30, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale investments: Group insurance contracts $ 6,010 $ — $ (6 ) $ 6,004 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 9,756 $ 1 $ — $ 9,757 Bankers acceptance drafts 5,330 — — 5,330 Asset-backed securities 37,017 15 (42 ) 36,990 Commercial paper 13,810 — (60 ) 13,750 Corporate obligations 77,788 58 (25 ) 77,821 Municipal bonds 1,970 — — 1,970 U.S. treasury obligations 28,054 24 — 28,078 U.S. agency obligations 35,728 10 — 35,738 $ 209,453 $ 108 $ (127 ) $ 209,434 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale investments: Group insurance contracts $ 6,006 $ 249 $ — $ 6,255 The tables above, which show the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments as of September 30, 2018 and December 31, 2017, reflect the inclusion within short-term investments of investments with contractual maturities greater than one year from the date of purchase. Management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term on the accompanying balance sheets. The Company reviews and evaluates its investments for any indication of possible impairment. Based on this review, the Company has determined that the unrealized losses related to these investments at September 30, 2018 and December 31, 2017 were temporary. Interest income is accrued as earned. Dividend income is recognized as income on the date the stock trades “ex-dividend.” The cost of marketable securities sold is determined by the specific identification method. Realized gains or losses are reflected in income and were not material for the nine months ended September 30, 2018

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	5) Fair Value Measurements In accordance with the provisions of fair value accounting, a fair value measurement assumes that the transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability and defines fair value based upon an exit price model. The fair value measurement guidance establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The guidance describes three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities assessed as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments or securities or derivative contracts that are valued using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the Company categorizes such assets and liabilities based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. Assets and liabilities of the Company are measured at fair value on a recurring basis as of September 30, 2018 and are summarized as follows: Fair Value Measurements at Reporting Date Using Description September 30, 2018 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 17,584 $ 17,584 $ — $ — Commercial paper 13,283 — 13,283 — Corporate obligations 4,373 — 4,373 — U.S. agency obligations 2,244 — 2,244 — Restricted cash – money market funds 114 114 — — Available-for-sale investments: Time deposits and certificates of deposit 14,552 — 14,552 — Bankers acceptance drafts 2,107 — 2,107 — Asset-backed securities 38,947 — 38,947 — Commercial paper 32,057 — 32,057 — Corporate obligations 71,971 — 71,971 — Municipal bonds 1,288 — 1,288 — U.S. treasury obligations 28,208 — 28,208 — U.S. agency obligations 30,646 — 30,646 — Group insurance contracts 6,004 — 6,004 — Derivatives – foreign exchange contracts 3,434 — 3,434 — Funds in investments and other assets: Israeli pension assets 15,815 — 15,815 — Derivatives – interest rate hedge – non-current 8,539 — 8,539 — Total assets $ 291,166 $ 17,698 $ 273,468 $ — Liabilities: Derivatives – foreign exchange contracts $ 343 $ — $ 343 $ — Reported as follows: Assets: Cash and cash equivalents, including restricted cash ( 1) $ 37,598 $ 17,698 $ 19,900 $ — Short-term investments 219,776 — 219,776 — Other current assets 3,434 — 3,434 — Total current assets $ 260,808 $ 17,698 $ 243,110 $ — Long-term investments ( 2) $ 6,004 $ — $ 6,004 $ — Other assets 24,354 — 24,354 — Total long-term assets $ 30,358 $ — $ 30,358 $ — Liabilities: Other current liabilities $ 343 $ — $ 343 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $362,252 as of September 30, 2018. (2) The long-term investments presented in the table above do not include the Company’s minority interest investment in a private company, which is accounted for under the cost method. Assets and liabilities of the Company are measured at fair value on a recurring basis as of December 31, 2017 and are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2017 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 4,987 $ 4,987 $ — $ — Time deposits and certificates of deposit 2,100 — 2,100 — Commercial paper 30,475 — 30,475 — Restricted cash – money market funds 119 119 — — Available-for-sale investments: Time deposits and certificates of deposit 9,757 — 9,757 — Bankers acceptance drafts 5,330 — 5,330 — Asset-backed securities 36,990 — 36,990 — Commercial paper 13,750 — 13,750 — Corporate obligations 77,821 — 77,821 — Municipal bonds 1,970 — 1,970 — U.S. treasury obligations 28,078 — 28,078 — U.S. agency obligations 35,738 — 35,738 — Group insurance contracts 6,255 — 6,255 — Derivatives – foreign exchange contracts 168 — 168 — Funds in investments and other assets: Israeli pension assets 15,048 — 15,048 — Derivatives – interest rate hedge – non-current 6,179 — 6,179 — Total assets $ 274,765 $ 5,106 $ 269,659 $ — Liabilities: Derivatives – foreign exchange contracts $ 6,198 $ — $ 6,198 $ — Assets: Cash and cash equivalents, including restricted cash ( 1) $ 37,681 $ 5,106 $ 32,575 $ — Short-term investments 209,434 — 209,434 — Other current assets 168 — 168 — Total current assets $ 247,283 $ 5,106 $ 242,177 $ — Long-term investments ( 2) $ 6,255 $ — $ 6,255 $ — Other assets 21,227 — 21,227 — Total long-term assets $ 27,482 $ — $ 27,482 $ — Liabilities: Other current liabilities $ 6,198 $ — $ 6,198 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $292,808 and non-negotiable time deposits of $3,398 as of December 31, 2017. (2) The long-term investments presented in the table above do not include the Company’s minority interest investment in a private company, which is accounted for under the cost method. Money Market Funds Money market funds are cash and cash equivalents and are classified within Level 1 of the fair value hierarchy. Available-For-Sale Investments Available-for-sale investments consisted of time deposits and drafts, certificates of deposit, bankers acceptance drafts, asset-backed securities (which include auto loans, credit card receivables and equipment trust receivables), commercial paper, corporate obligations, municipal bonds, U.S. treasury obligations, U.S. agency obligations and group insurance contracts. The Company measures its debt and equity investments at fair value. The Company’s available-for-sale investments are classified within Level 2 of the fair value hierarchy. Israeli Pension Assets Israeli pension assets represent investments in mutual funds, government securities and other time deposits. These investments are set aside for the retirement benefit of the employees at the Company’s Israeli subsidiaries. These funds are classified within Level 2 of the fair value hierarchy. Derivatives As a result of the Company’s global operating activities, the Company is exposed to market risks from changes in foreign currency exchange rates and variable interest rates, which may adversely affect its operating results and financial position. When deemed appropriate, the Company minimizes its risks from foreign currency exchange rate and interest rate fluctuations through the use of derivative financial instruments. The principal market in which the Company executes its foreign currency contracts and interest rate swaps is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large commercial banks. The forward foreign currency exchange contracts and interest rate hedge are valued using broker quotations or market transactions and are classified within Level 2 of the fair value hierarchy.

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivatives	6) Derivatives The Company enters into derivative instruments for risk management purposes only, including derivatives designated as hedging instruments and those utilized as economic hedges. The Company operates internationally and, in the normal course of business, is exposed to fluctuations in interest rates and foreign exchange rates. These fluctuations can increase the costs of financing, investing and operating the business. The Company has used derivative instruments, such as forward foreign currency exchange contracts, to manage certain foreign currency exposure, and interest rate swaps to manage interest rate exposure. By nature, all financial instruments involve market and credit risks. The Company enters into derivative instruments with major investment grade financial institutions, for which no collateral is required. The Company has policies to monitor the credit risk of these counterparties. While there can be no assurance, the Company does not anticipate any material non-performance by any of these counterparties. Interest Rate Swap Agreement On September 30, 2016, the Company entered into an interest rate swap agreement to fix the rate on approximately 50% of its then-outstanding balance under the Credit Agreement, as described further in Note 10. This hedge fixes the interest rate paid on the hedged debt at 1.198% per annum plus the applicable credit spread, which was 1.75% as of September 30, 2018, through September 30, 2020. The interest rate swap is recorded at fair value on the balance sheet and changes in the fair value are recognized in other comprehensive income (loss) (“OCI”). To the extent that this arrangement is no longer an effective hedge, any ineffectiveness measured in the hedging relationship is recorded currently in earnings in the period it occurs. The notional amount of this transaction was $290,000 and had a fair value of $8,539 at September 30, 2018. The notional amount of this transaction was $305,000 and had a fair value of $6,179 at December 31, 2017. Foreign Exchange Contracts The Company hedges a portion of its forecasted foreign currency-denominated intercompany sales of inventory, over a maximum period of eighteen months, using forward foreign exchange contracts accounted for as cash-flow hedges related to Japanese, South Korean, British, Euro and Taiwanese currencies. To the extent these derivatives are effective in off-setting the variability of the hedged cash flows, and otherwise meet the hedge accounting criteria, changes in the derivatives’ fair value are not included in current earnings but are included in OCI in stockholders’ equity. These changes in fair value will subsequently be reclassified into earnings, as applicable, when the forecasted transaction occurs. To the extent that a previously designated hedging transaction is no longer an effective hedge, any ineffectiveness measured in the hedging relationship is recorded currently in earnings in the period it occurs. The cash flows resulting from forward exchange contracts are classified in the consolidated statements of cash flows as part of cash flows from operating activities. The Company does not enter into derivative instruments for trading or speculative purposes. As of September 30, 2018 and December 31, 2017, the Company had outstanding forward foreign exchange contracts with gross notional values of $149,088 and $208,922, respectively. The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of September 30, 2018 and December 31, 2017: September 30, 2018 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value (1) U.S. Dollar/Japanese Yen $ 40,004 $ 1,143 U.S. Dollar/South Korean Won 56,628 759 U.S. Dollar/Euro 23,678 612 U.S. Dollar/U.K. Pound Sterling 10,001 314 U.S. Dollar/Taiwan Dollar 18,777 263 Total $ 149,088 $ 3,091 December 31, 2017 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value (1) U.S. Dollar/Japanese Yen $ 70,175 $ (233 ) U.S. Dollar/South Korean Won 79,672 (3,799 ) U.S. Dollar/Euro 26,140 (1,047 ) U.S. Dollar/U.K. Pound Sterling 12,104 (337 ) U.S. Dollar/Taiwan Dollar 20,831 (614 ) Total $ 208,922 $ (6,030 ) (1) Represents the receivable (payable) amount included in the consolidated balance sheet. The following table provides a summary of the fair value amounts of the Company’s derivative instruments: Derivatives Designated as Hedging Instruments September 30, 2018 December 31, 2017 Derivative assets: Foreign exchange contracts (1) $ 3,434 $ 168 Foreign currency interest rate hedge (2) 8,539 6,179 Derivative liabilities: Foreign exchange contracts (1) (343 ) (6,198 ) Total net derivative asset designated as hedging instruments $ 11,630 $ 149 (1) The derivative asset of $3,434 and $168 as of September 30, 2018 and December 31, 2017, respectively, related to foreign exchange contracts and is classified in other current assets in the consolidated balance sheet. The derivative liability of $(343) and $(6,198) as of September 30, 2018 and December 31, 2017, respectively, is classified in other current liabilities in the consolidated balance sheet. These foreign exchange contracts are subject to a master netting agreement with one financial institution. However, the Company has elected to record these contracts on a gross basis in the balance sheet. (2) The interest rate hedge assets of $8,539 and $6,179 as of September 30, 2018 and December 31, 2017, respectively, are classified in other assets in the consolidated balance sheet. The net amount of existing gains as of September 30, 2018 that the Company expects to reclassify from OCI into earnings within the next twelve months is immaterial. The following table provides a summary of the gains (losses) on derivatives designated as cash flow hedging instruments: Three Months Ended September 30, Nine Months Ended September 30, Derivatives Designated as Cash Flow Hedging Instruments 2018 2017 2018 2017 Forward exchange contracts: Net gain (loss) recognized in OCI (1) $ 212 $ (220 ) $ 10,357 $ (4,462 ) Net gain (loss) reclassified from accumulated OCI into income (2) $ 306 $ (1,360 ) $ (4,882 ) $ (1,842 ) (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified in cost of products for the three and nine months ended September 30, 2018 and 2017. The tax effect of the gains or losses reclassified from accumulated OCI into income is immaterial. The following table provides a summary of the (losses) gains on derivatives not designated as hedging instruments: Three Months Ended September 30, Nine Months Ended September 30, Derivatives Not Designated as Hedging Instruments 2018 2017 2018 2017 Forward exchange contracts: Net (loss) gain recognized in income (1) $ (111 ) $ (877 ) $ 12 $ (2,559 ) (1) The Company enters into foreign exchange contracts to hedge against changes in the balance sheet for certain subsidiaries to mitigate the risk associated with certain foreign currency transactions in the ordinary course of business. These derivatives are not designated as hedging instruments and gains or losses from these derivatives are recorded immediately in other (expense) income.

Inventories, net

Inventories, net	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventories, net	7) Inventories, net Inventories consist of the following: September 30, 2018 December 31, 2017 Raw materials $ 237,547 $ 191,351 Work-in-process 66,635 54,050 Finished goods 94,895 93,680 $ 399,077 $ 339,081

Dispositions

Dispositions	9 Months Ended
	Sep. 30, 2018
Discontinued Operations And Disposal Groups [Abstract]
Dispositions	8) Dispositions Sale of Data Analytics Solutions In April 2017, the Company completed the sale of its Data Analytics Solutions business for total proceeds of $72,509, net of cash sold and recorded a gain of $74,856. This business, which had revenues in 2016 of $12,700 and was included in the Vacuum & Analysis segment, was no longer a part of the Company’s long-term strategic objectives. The business did not qualify as a discontinued operation as this sale did not represent a strategic shift in the Company’s business, nor did the sale have a major effect on the Company’s operations. Therefore, the results of operations for all periods are included in the Company’s income from operations. The assets and liabilities of this business have not been reclassified or segregated in the consolidated balance sheet or consolidated statements of cash flows as the amounts were immaterial.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	9) Goodwill and Intangible Assets Goodwill The Company’s methodology for allocating the purchase price relating to purchase acquisitions is determined through established and generally accepted valuation techniques. Goodwill is measured as the excess of the cost of the acquisition over the sum of the amounts assigned to tangible and identifiable intangible assets acquired less liabilities assumed. The Company assigns assets acquired (including goodwill) and liabilities assumed to one or more reporting units as of the date of acquisition. Typically acquisitions relate to a single reporting unit and thus do not require the allocation of goodwill to multiple reporting units. If the products obtained in an acquisition are assigned to multiple reporting units, the goodwill is distributed to the respective reporting units as part of the purchase price allocation process. Goodwill and purchased intangible assets with indefinite useful lives are not amortized, but are reviewed for impairment annually during the fourth quarter of each fiscal year and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. The process of evaluating the potential impairment of goodwill and intangible assets requires significant judgment. The Company regularly monitors current business conditions and other factors including, but not limited to, adverse industry or economic trends, restructuring actions and lower projections of profitability that may impact future operating results. Effective July 1, 2018, the Company reassigned goodwill to certain reporting units within the Light & Motion reportable segment resulting from a reorganization of the composition of goodwill reporting units. The goodwill was reassigned to the reporting units affected using the relative fair value approach. In conjunction with this goodwill reassignment, the Company performed an interim quantitative impairment test as of July 1, 2018 for all of its reporting units and concluded that the fair values of each reporting unit exceeded their respective carrying values. The changes in the carrying amount of goodwill and accumulated impairment loss during the nine months ended September 30, 2018 and year ended December 31, 2017 were as follows: Nine Months Ended September 30, 2018 Twelve Months Ended December 31, 2017 Gross Carrying Amount Accumulated Impairment Loss Net Gross Carrying Amount Accumulated Impairment Loss Net Beginning balance at January 1 $ 735,323 $ (144,276 ) $ 591,047 $ 727,999 $ (139,414 ) $ 588,585 Sale of business ( 1) — — — (3,115 ) — (3,115 ) Impairment loss ( 2) — — — — (4,862 ) (4,862 ) Foreign currency translation (3,186 ) — (3,186 ) 10,439 — 10,439 Ending balance at September 30, 2018 and December 31, 2017 $ 732,137 $ (144,276 ) $ 587,861 $ 735,323 $ (144,276 ) $ 591,047 (1) (2) Intangible Assets Components of the Company’s intangible assets are comprised of the following: As of September 30, 2018: Gross Impairment Charges ( 1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (131,840 ) $ — $ 40,486 Customer relationships 282,744 (1,406 ) (59,260 ) 174 222,252 Patents, trademarks, trade names and other 110,523 — (41,970 ) (3 ) 68,550 $ 565,698 $ (1,511 ) $ (233,070 ) $ 171 $ 331,288 As of December 31, 2017: Gross Impairment Charges ( 1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (115,371 ) $ 333 $ 57,288 Customer relationships 282,744 (1,406 ) (45,518 ) 1,571 237,391 Patents, trademarks, trade names and other 110,523 — (38,730 ) (74 ) 71,719 $ 565,698 $ (1,511 ) $ (199,619 ) $ 1,830 $ 366,398 (1) In 2017, the Company recorded impairment charges of $1,511 related to the write-off of intangible assets as a result of the discontinuation of a product line and consolidation of two manufacturing plants. Aggregate amortization expense related to acquired intangibles for the nine months ended September 30, 2018 and 2017 was $32,786 and $34,946, respectively. The amortization expense for the nine months ended September 30, 2018 and 2017 is net of $665 and $588, respectively, of amortization income from unfavorable lease commitments. Aggregate net amortization expense related to acquired intangible assets and unfavorable lease commitments for future years is as follows: Year Amount 2018 (remaining) $ 10,760 2019 $ 40,144 2020 $ 28,125 2021 $ 20,248 2022 $ 17,619 2023 $ 17,253 Thereafter $ 138,955

Debt

Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	10 ) Debt Term Loan Credit Agreement In connection with the completion of the Company’s acquisition of Newport Corporation (“Newport”) in April 2016 (the “Newport Merger”), the Company entered into a term loan credit agreement (the “Credit Agreement”) with Barclays Bank PLC, as administrative agent and collateral agent, and the lenders from time to time party thereto (the “Lenders”), that provided senior secured financing of $780,000, subject to increase at the Company’s option in accordance with the Credit Agreement (the “Term Loan Facility”). Borrowings under the Term Loan Facility bear interest per annum at one of the following rates selected by the Company: (a) a base rate determined by reference to the highest of (1) the federal funds effective rate plus 0.50%, (2) the “prime rate” quoted in The Wall Street Journal, (3) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month adjusted for certain additional costs, plus 1.00%, and (4) a floor of 1.75%, plus, in each case, an applicable margin; or (b) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing adjusted for certain additional costs, subject to a LIBOR rate floor of 0.75%, plus an applicable margin. The Company has elected the interest rate as described in clause (b). The Credit Agreement provides that all loans will be determined by reference to the Base Rate if the LIBOR rate cannot be ascertained, if regulators impose material restrictions on the authority of a lender to make LIBOR rate loans, or for other reasons. The Term Loan Facility was issued with original issue discount of 1.00% of the principal amount thereof. On June 9, 2016, the Company entered into Amendment No. 1 (the “Repricing Amendment 1”) to the Credit Agreement by and among the Company, the Lenders and Barclays Bank PLC, as administrative agent and collateral agent for the Lenders. The Repricing Amendment 1 decreased the applicable margin for borrowings under the Company’s Term Loan Facility to 2.50% for base rate borrowings and 3.50% for LIBOR borrowings and extended the period during which a prepayment premium may be required for a “Repricing Transaction” (as defined in the Credit Agreement) until six months after the effective date of the Repricing Amendment 1. In connection with the execution of the Repricing Amendment 1, the Company paid a prepayment premium of 1.00%, or $7,300, as well as certain fees and expenses of the administrative agent and the Lenders, in accordance with the terms of the Credit Agreement. Immediately prior to the effectiveness of the Repricing Amendment 1, the Company prepaid $50,000 of principal under the Credit Agreement. In September 2016, the Company prepaid an additional $60,000 under the Credit Agreement. On September 30, 2016, the Company entered into an interest rate swap agreement, which has a maturity date of September 30, 2020, to fix the rate on $335,000 of the then-outstanding balance of the Credit Agreement. The rate is fixed at 1.198% per annum plus the applicable credit spread, which was 1.75% at September 30, 2018. The notional amount of this transaction was $290,000 and had a fair value of $8,539 at September 30, 2018. On December 14, 2016, the Company entered into Amendment No. 2 (the "Repricing Amendment 2") to the Credit Agreement by and among the Company, the Lenders and Barclays Bank PLC, as administrative agent and collateral agent for the Lenders. The Repricing Amendment 2 decreased the applicable margin for the Company’s term loan under the Credit Agreement to 2.75% for LIBOR borrowings and 1.75% for base rate borrowings and reset the period during which a prepayment premium may be required for a Repricing Transaction until six months after the effective date of the Repricing Amendment 2. In November 2016, prior to the effectiveness of the Repricing Amendment 2, the Company prepaid an additional $40,000 of principal under the Credit Agreement. In March 2017, the Company prepaid an additional $50,000 of principal under the Credit Agreement. On July 6, 2017, the Company entered into Amendment No. 3 (the “Repricing Amendment 3”) to the Credit Agreement by and among the Company, the Lenders and Barclays Bank PLC, as administrative agent and collateral agent for the Lenders. The Repricing Amendment 3 decreased the applicable margin for the Company’s term loan under the Credit Agreement to 2.25% for LIBOR rate loans when the Total Leverage Ratio (as defined in the Credit Agreement) was at or above 1.25:1 and decreased to 2.00% when the Total Leverage Ratio was below 1.25:1, both with a LIBOR floor of 0.75%. The margin for base rate borrowings decreased to 1.25% when the Total Leverage Ratio is at or above 1.25:1 and to 1.00% when the Total Leverage Ratio is below 1.25:1. The period during which a prepayment premium may be required for a Repricing Transaction was reset to six months after the effective date of the Repricing Amendment 3. On April 11, 2018, the Company entered into Amendment No. 4 (the “Repricing Amendment 4”) to the Credit Agreement by and among the Company, the Lenders and Barclays Bank PLC, as administrative agent and collateral agent for the Lenders. The Repricing Amendment 4 decreased the applicable margin for the Company’s LIBOR rate term loan under the Credit Agreement to 1.75%, with a LIBOR rate floor of 0.75%. The margin for base rate borrowings decreased to 0.75% with a base rate floor of 1.75%. The period during which a prepayment premium may be required for a Repricing Transaction was reset to six months after the effective date of the Repricing Amendment 4. In July 2017, August 2017, November 2017 and March 2018, the Company voluntarily prepaid $50,000, $75,000, $50,000 and $50,000, respectively, of principal under the Credit Agreement. As of September 30, 2018, after total prepayments of $425,000 and regularly scheduled principal payments of $6,536, the total outstanding principal balance was $348,464. The interest rate as of September 30, 2018 was 3.8%. The Company incurred $28,747 of deferred finance fees, original issue discount and repricing fees related to the term loans under the Term Loan Facility, which are included in long-term debt in the accompanying consolidated balance sheets and are being amortized to interest expense over the estimated life of the term loans using the effective interest method. A portion of these fees has been accelerated in connection with the various debt prepayments during 2016, 2017 and 2018. As of September 30, 2018, the remaining balance of the deferred finance fees, original issue discount and repricing fee related to the Term Loan Facility was $5,581. Under the Credit Agreement, the Company is required to prepay outstanding term loans, subject to certain exceptions, with portions of its annual excess cash flow as well as with the net cash proceeds of certain asset sales, certain casualty and condemnation events and the incurrence or issuance of certain debt. The Company is also required to make scheduled quarterly payments each equal to 0.25% of the principal amount of the term loans outstanding, less the amount of certain voluntary and mandatory repayments after such date, with the balance due on the seventh anniversary of the closing date. As a result of making total prepayments of $425,000 through September 30, 2018 and based on the Company’s Total Leverage Ratio, the Company is no longer required to make any scheduled principal payments until maturity date of the loan. All obligations under the Term Loan Facility are guaranteed by certain of the Company’s domestic subsidiaries, and are collateralized by substantially all of the Company’s assets and the assets of such subsidiaries, subject to certain exceptions and exclusions. The Credit Agreement contains customary representations and warranties, affirmative and negative covenants and provisions relating to events of default. If an event of default occurs, the Lenders under the Term Loan Facility will be entitled to take various actions, including the acceleration of amounts due under the Term Loan Facility and all actions generally permitted to be taken by a secured creditor. At September 30, 2018, the Company was in compliance with all covenants under the Credit Agreement. Senior Secured Asset-Based Revolving Credit Facility In connection with the completion of the Newport Merger, the Company also entered into an asset-based credit agreement with Deutsche Bank AG New York Branch, as administrative agent and collateral agent, the other borrowers from time to time party thereto, and the lenders and letters of credit issuers from time to time party thereto (the “ABL Facility”), that provides senior secured financing of up to $50,000, subject to a borrowing base limitation. The borrowing base for the ABL Facility at any time equals the sum of: (a) 85% of certain eligible accounts; plus (b) subject to certain notice and field examination and appraisal requirements, the lesser of (i) the lesser of (A) 65% of the lower of cost or market value of certain eligible inventory and (B) 85% of the net orderly liquidation value of certain eligible inventory and (ii) 30% of the borrowing base; minus (c) reserves established by the administrative agent; provided that until the administrative agent’s receipt of a field examination of accounts receivable the borrowing base shall be equal to 70% of the book value of certain eligible accounts. The ABL Facility includes borrowing capacity in the form of letters of credit up to $15,000. The Company has not drawn against the ABL Facility as of September 30, 2018. Borrowings under the ABL Facility bear interest per annum at one of the following rates selected by the Company: (a) a base rate determined by reference to the highest of (1) the federal funds effective rate plus 0.50%, (2) the “prime rate” quoted in The Wall Street Journal, and (3) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month adjusted for certain additional costs, plus 1.00%, plus, in each case, an initial applicable margin of 0.75%; and (b) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing adjusted for certain additional costs, plus an initial applicable margin of 1.75%. Commencing with the completion of the first fiscal quarter ending after the closing of the ABL Facility, the applicable margin for borrowings thereunder is subject to upward or downward adjustment each fiscal quarter, based on the average historical excess availability during the preceding quarter. The Company incurred $1,201 of costs in connection with the ABL Facility, which were capitalized and included in other assets in the accompanying consolidated balance sheets and are being amortized to interest expense using the straight-line method over the contractual term of five years of the ABL Facility. In addition to paying interest on outstanding principal under the ABL Facility, the Company is required to pay a commitment fee in respect of the unutilized commitments thereunder. The initial commitment fee is 0.375% per annum. The total commitment fees recognized in interest expense for the three and nine months ended September 30, 2018 were immaterial. Commencing Lines of Credit and Short-Term Borrowing Arrangements One of the Company’s Japanese subsidiaries has lines of credit and short-term borrowing arrangements with two financial institutions, which arrangements generally expire and are renewed at three month intervals. The lines of credit provided for aggregate borrowings as of September 30, 2018 of up to an equivalent of $35,623 U.S. dollars. One of the borrowing arrangements has an interest rate based on the Tokyo Interbank Offer Rate at the time of borrowing and the other has an interest rate based on the Japanese Short-Term Prime Lending Rate. Total borrowings outstanding under these arrangements were $484 at September 30, 2018. There were no borrowings outstanding under these arrangements at December 31, 2017. The Company assumed various revolving lines of credit and a financing facility with the completion of the Newport Merger. These revolving lines of credit and financing facility have no expiration date and provided for aggregate borrowings as of September 30, 2018 of up to an equivalent of $10,995 U.S. dollars. These lines of credit have a base interest rate of 1.25% plus a Japanese Yen overnight LIBOR rate. Total borrowings outstanding under these arrangements were $5,040 and $2,965 at September 30, 2018 and December 31, 2017. One of the Company’s Austrian subsidiaries has various outstanding loans from the Austrian government to fund research and development. These loans are unsecured and do not require principal repayment as long as certain conditions are met. Interest on these loans is payable semi-annually. The interest rates associated with these loans range from 0.75% to 2.00%. September 30, 2018 December 31, 2017 Short-term debt: Japanese lines of credit $ 5,524 $ 2,750 Japanese receivables financing facility — 215 Austrian loans due through March 2020 606 — Other debt — 7 $ 6,130 $ 2,972 September 30, 2018 December 31, 2017 Long-term debt: Austrian loans due through March 2020 and other debt $ 87 $ 714 Term Loan Facility, net ( 1) 342,883 389,279 $ 342,970 $ 389,993 (1) Net of deferred financing fees, original issuance discount and repricing fee of The Company recognized interest expense of $13,071 and $23,001 for the nine months ended September 30, 2018 and 2017, respectively. Contractual maturities of the Company’s debt obligations as of September 30, 2018 are as follows: Year Amount 2018 (remaining) $ 5,524 2019 $ 606 2020 $ 73 2021 $ 14 2022 $ — 2023 $ — Thereafter $ 348,464

Product Warranties

Product Warranties	9 Months Ended
	Sep. 30, 2018
Guarantees And Product Warranties [Abstract]
Product Warranties	11 ) Product Warranties The Company records the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. While the Company engages in extensive product quality programs and processes, including actively monitoring and evaluating the quality of its component suppliers, the Company’s warranty obligation is affected by shipment volume, product failure rates, utilization levels, material usage, and supplier warranties on parts delivered to the Company. Should actual product failure rates, utilization levels, material usage, or supplier warranties on parts differ from the Company’s estimates, revisions to the estimated warranty liability would be required. Product warranty activities were as follows: Nine Months Ended September 30, 2018 2017 Beginning of period $ 10,104 $ 8,261 Provision for product warranties 11,448 11,941 Direct and other charges to warranty liability (11,072 ) (10,080 ) End of period ( 1) $ 10,480 $ 10,122 (1) Short-term product warranty of $10,067 and long-term product warranty of $413 as of September 30, 2018, are included within other current liabilities and other liabilities, respectively, within the accompanying condensed consolidated balance sheet. Short-term product warranty of $9,725 and long-term product warranty of $397 as of September 30, 2017, are included within other current liabilities and other liabilities, respectively, within the accompanying condensed consolidated balance sheet.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	12 ) Income Taxes The Act was enacted on December 22, 2017. The Act reduces the U.S. federal corporate income tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. The Company is applying SAB 118 when accounting for the enactment effects of the Act. As of September 30, 2018, the Company has not completed the accounting for all of the tax effects of the Act; however, provisional estimates have been recorded. For the quarter ended September 30, 2018, the Company recognized a tax expense of $863 from an adjustment of the provisional estimates recorded for the Act and included these adjustments as a component of income tax expense from continuing operations. The calculations will continue to be refined and adjusted as additional analysis is completed. Future adjustments are not expected to be material. The global intangible low-taxed income (“GILTI”) provision from the Act subjects a U.S. shareholder to current tax on GILTI earned by certain foreign subsidiaries. Under FASB Staff Q&A, Topic 740 No. 5, the Company has elected to recognize the resulting tax on GILTI as a period expense in the period the tax is incurred. The Company expects to incur GILTI tax for the year ended December 31, 2018. The estimate for this GILTI tax, net of foreign tax credits, increased the Company’s effective tax rate for 2018 by approximately 0.3%. The Company’s effective tax rate for the three and nine months ended September 30, 2018 was 18.5% and 17.6%, respectively. The effective tax rate for the three and nine months ended September 30, 2018, and related income tax expense, was lower than the U.S. statutory tax rate mainly due to the geographic mix of income earned by the Company’s international subsidiaries being taxed at rates lower than the U.S. statutory tax rate, windfall tax benefits of stock compensation, and the new deduction for foreign derived intangible income from the Act, offset by state taxes. The Company’s effective tax rate for the three and nine months ended September 30, 2017 was 25.0% and 22.3%, respectively. The effective tax rate for the three and nine months ended September 30, 2017 was lower than the U.S. statutory tax rate of 35.0% mainly due to the impact of lower tax rates on foreign income, and the deductions for domestic production activities and windfall tax benefits of stock compensation. As of September 30, 2018 and December 31, 2017, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was approximately $32,535 and $27,345, respectively. As of September 30, 2018, if these benefits were recognized in a future period, the timing of which is not estimable, the net unrecognized tax benefit of $25,008, excluding interest and penalties, would impact the Company’s effective tax rate. The Company accrues interest expense, and if applicable, penalties, for any uncertain tax positions. Interest and penalties are classified as a component of income tax expense. As of September 30, 2018 and December 31, 2017, the Company had accrued interest on unrecognized tax benefits of approximately $511 and $327, respectively. Over the next 12 months it is reasonably possible that the Company may recognize approximately $1,521 of previously net unrecognized tax benefits, excluding interest and penalties, related to various U.S. federal, state and foreign tax positions primarily as a result of the expiration of certain statutes of limitations. The Company and its subsidiaries are subject to examination by U.S. federal, state and foreign tax authorities. The U.S. Internal Revenue Service commenced an examination of our U.S. federal income tax filings for tax years 2015 and 2016 during the quarter ended September 30, 2017. This audit was effectively settled during the quarter ended March 31, 2018, and the impact was not material. During the quarter ended March 31, 2018, the Company received notification from the U.S. Internal Revenue Service of its intent to audit the Company’s U.S. subsidiary, Newport Corporation, for tax year 2015. This audit commenced during the quarter ended June 30, 2018 and there have been no issues identified at this time. The U.S. statute of limitations remains open for tax years 2015 through present. The statute of limitations for the Company’s tax filings in other jurisdictions varies between fiscal years 2012 through present. The Company has certain federal credit carry-forwards and state tax loss and credit carry-forwards that are open to examination for tax years 2000 through the present.

Pension Plans

Pension Plans	9 Months Ended
	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Pension Plans	13 ) Pension Plans As a result of the acquisition of Newport, the Company has assumed all assets and liabilities of Newport’s defined benefit pension plans, which cover substantially all of its full-time employees in France, Germany, Israel and Japan. In addition, there are certain pension liabilities relating to former employees in the United Kingdom. The German plan is unfunded, as permitted under the plan and applicable laws. The net periodic benefit costs were immaterial for both the three and nine month periods ended September 30, 2018 and 2017. The Company’s contributions to these plans for both the three and nine month periods ended September 30, 2018 and 2017, as required by local pension accounting laws, were immaterial.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income Per Share	14 ) Net Income Per Share The following table sets forth the computation of basic and diluted net income per share: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net income $ 93,277 $ 75,994 $ 321,260 $ 261,494 Denominator: Shares used in net income per common share – basic 54,476,000 54,282,000 54,539,000 54,076,000 Effect of dilutive securities: Restricted stock units, stock appreciation rights and shares issued under employee stock purchase plan 478,000 819,000 632,000 944,000 Shares used in net income per common share – diluted 54,954,000 55,101,000 55,171,000 55,020,000 Net income per common share: Basic $ 1.71 $ 1.40 $ 5.89 $ 4.84 Diluted $ 1.70 $ 1.38 $ 5.82 $ 4.75 Basic earnings per share (“EPS”) is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding during the period. The computation of diluted EPS is similar to the computation of basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding (using the treasury stock method) if securities containing potentially dilutive common shares (restricted stock units and stock appreciation rights) had been converted to such common shares, and if such assumed conversion is dilutive. For the three and nine months ended September 30, 2018, there were approximately 159,800 and 68,800 weighted-average restricted stock units, respectively, that would have had an anti-dilutive effect on EPS, and would thus need to be excluded from the computation of diluted weighted-average shares. For the three and nine months ended September 30, 2017, there were approximately 200 and 2,100 weighted-average restricted stock units, respectively, that would have had an anti-dilutive effect on EPS, and would thus need to be excluded from the computation of diluted weighted-average shares.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2018
Federal Home Loan Banks [Abstract]
Stockholders' Equity	15 ) Stockholders’ Equity Share Repurchase Program On July 25, 2011, the Company’s Board of Directors approved a share repurchase program for the repurchase of up to an aggregate of $200,000 of its outstanding common stock from time to time in open market purchases, privately negotiated transactions or through other appropriate means. The timing and quantity of any shares repurchased will depend upon a variety of factors, including business conditions, stock market conditions and business development activities, including, but not limited to, merger and acquisition opportunities. These repurchases may be commenced, suspended or discontinued at any time without prior notice. During the nine months ended September 30, 2018, the Company repurchased approximately 818,000 shares of its common stock for $75,000, or an average price of $91.67. During the nine months ended September 30, 2017, the Company did not repurchase any shares of common stock. The Company has repurchased approximately 2,588,000 shares of common stock for approximately $127,000 pursuant to the program since its adoption. Cash Dividends Holders of the Company’s common stock are entitled to receive dividends when they are declared by the Company’s Board of Directors. The Company’s Board of Directors declared a cash dividend of $0.18 per share during the first quarter of 2018 and $0.20 per share during the second and third quarters of 2018, which totaled $31,608 or $0.58 per share. The Company’s Board of Directors declared a cash dividend of $0.175 per share during the first, second and third quarters of 2017, which totaled $28,403 or $0.525 per share. On October 29, 2018, the Company’s Board of Directors declared a quarterly cash dividend of $0.20 per share to be paid on December 7, 2018 to shareholders of record as of November 26, 2018. Future dividend declarations, if any, as well as the record and payment dates for such dividends, are subject to the final determination of the Company’s Board of Directors. In addition, under the terms of the Company’s senior secured Term Loan Facility and its senior secured asset-based revolving credit facility, the Company may be restricted from paying dividends under certain circumstances.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	16 ) Stock-Based Compensation The Company grants restricted stock units (“RSUs”) to employees and directors under the 2014 Stock Incentive Plan (the “2014 Plan”). The 2014 Plan is administered by the Compensation Committee of the Company’s Board of Directors. The 2014 Plan is intended to attract and retain employees and directors, and to provide an incentive for these individuals to assist the Company to achieve long-range performance goals and to enable these individuals to participate in the long-term growth of the Company. In connection with the completion of the Newport Merger, the Company assumed: • all RSUs granted under any Newport equity plan that were outstanding immediately prior to the effective time of the Newport Merger, and as to which shares of Newport common stock were not fully distributed in connection with the closing of the Newport Merger, and • all stock appreciation rights (“SARs”) granted under any Newport equity plan, whether vested or unvested, that were outstanding immediately prior to the effective time of the Newport Merger. During the nine months ended September 30, 2018, the Company granted 260,341 RSUs with a weighted average grant date fair value of $112.49. During the nine months ended September 30, 2017, the Company granted 388,137 RSUs with a weighted average grant date fair value of $67.58. There were no SARs granted during the nine months ended September 30, 2018 or 2017. The total stock-based compensation expense included in the Company’s consolidated statements of income and comprehensive income was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of revenues $ 170 $ 1,016 $ 2,664 $ 3,133 Research and development expense 708 712 2,249 2,284 Selling, general and administrative expense 4,335 3,117 17,092 14,417 Total pre-tax stock-based compensation expense $ 5,213 $ 4,845 $ 22,005 $ 19,834 At September 30, 2018, the total compensation expense related to unvested stock-based awards granted to employees and directors under the 2014 Plan that had not been recognized was $23,738, net of estimated forfeitures. The future compensation expense for time-based awards is recognized on a straight-line basis and the future compensation expense for performance-based awards is recognized using the accelerated graded vesting method, both of which expense over the requisite service period, net of estimated forfeitures, except for retirement eligible employees, in which case the Company expenses the fair value of the grant in the period the grant is issued. The Company considers many factors when estimating expected forfeitures, including types of awards and historical experience. Actual results and future changes in estimates may differ substantially from the Company’s current estimates. The following table presents the activity for RSUs under the Plan: Nine Months Ended September 30, 2018 Outstanding RSUs Weighted Average Grant Date Fair Value RSUs – beginning of period 943,379 $ 47.57 Accrued dividend shares 46 $ 105.26 Granted 260,341 $ 112.49 Vested (487,856 ) $ 44.60 Forfeited (62,021 ) $ 65.37 RSUs – end of period 653,889 $ 73.95 The following table presents the activity for SARs under the Plan: Nine Months Ended September 30, 2018 Outstanding SARs Weighted Average Grant Date Fair Value SARs – beginning of period 282,907 $ 28.62 Exercised (100,683 ) $ 28.77 Forfeited or expired (1,950 ) $ 29.00 SARs Outstanding – end of period 180,274 $ 28.52

Business Segment, Geographic Ar

Business Segment, Geographic Area, Product and Significant Customer Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Business Segment, Geographic Area, Product and Significant Customer Information	17 ) Business Segment, Geographic Area, Product and Significant Customer Information The Company is a global provider of instruments, subsystems and process control solutions that measure, monitor, deliver, analyze, power and control critical parameters of advanced manufacturing processes to improve process performance and productivity for its customers. The Company’s products are derived from its core competencies in pressure measurement and control, flow measurement and control, gas and vapor delivery, gas composition analysis, residual gas analysis, leak detection, control technology, ozone generation and delivery, power, reactive gas generation, vacuum technology, lasers, photonics, sub-micron positioning, vibration control, and optics. The Company also provides services related to the maintenance and repair of its products, installation services and training. The Company’s primary served markets are manufacturers of capital equipment for semiconductor manufacturing, industrial technologies, life and health sciences, as well as research and defense. The Company’s Chief Operating Decision Maker (“CODM”) utilizes financial information to make decisions about allocating resources and assessing performance for the entire Company, which is used in the decision making process to assess performance. Based upon the information provided to the CODM, the Company has determined it has two reportable segments. The Company’s two reportable segments are: Vacuum & Analysis and Light & Motion. The Vacuum & Analysis segment provides a broad range of instruments, components and subsystems which are derived from the Company’s core competencies in pressure measurement and control, flow measurement and control, gas and vapor delivery, gas composition analysis, residual gas analysis, leak detection, control technology, ozone generation and delivery, RF & DC power, reactive gas generation and vacuum technology. The Light & Motion segment provides a broad range of instruments, components and subsystems which are derived from the Company’s core competencies in lasers, photonics, sub-micron positioning, vibration control, and optics. The Company derives its segment results directly from the manner in which results are reported in its management reporting system. The accounting policies that the Company uses to derive reportable segment results are substantially the same as those used for external reporting purposes. The Company does not disclose external or intersegment revenues separately by reportable segment as this information is not presented to the CODM for decision making purposes. The following are net revenues by reportable segment: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Vacuum & Analysis $ 286,038 $ 308,269 $ 1,002,710 $ 896,214 Light & Motion 201,114 177,998 611,857 507,963 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177 The following is a reconciliation of segment gross profit to consolidated net income: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Gross profit by reportable segment: Vacuum & Analysis $ 132,835 $ 141,438 $ 462,418 $ 410,228 Light & Motion 99,025 86,557 307,174 242,897 Total gross profit by reportable segment 231,860 227,995 769,592 653,125 Operating expenses: Research and development 31,898 32,548 103,259 99,510 Selling, general and administrative 70,822 71,347 229,952 217,546 Acquisition and integration costs 36 2,466 (1,132 ) 4,698 Restructuring 1,364 10 3,374 2,596 Asset impairment — — — 6,719 Fees and expenses related to repricing of term loan — 492 378 492 Environmental Costs — — 1,000 — Amortization of intangible assets 10,695 10,977 32,786 34,946 Income from operations 117,045 110,155 399,975 286,618 Gain on sale of business — — — 74,856 Interest and other expense, net 2,529 8,784 10,173 24,846 Income before income taxes 114,516 101,371 389,802 336,628 Provision for income taxes 21,239 25,377 68,542 75,134 Net income $ 93,277 $ 75,994 $ 321,260 $ 261,494 The following is capital expenditures by reportable segment for the three and nine months ended September 30, 2018 and 2017: Vacuum & Analysis Light & Motion Total Three Months Ended September 30, 2018: Capital expenditures $ 9,532 $ 5,535 $ 15,067 Nine Months Ended September 30, 2018: Capital expenditures $ 22,701 $ 14,184 $ 36,885 Three Months Ended September 30, 2017: Capital expenditures $ 4,212 $ 3,906 $ 8,118 Nine Months Ended September 30, 2017: Capital expenditures $ 10,114 $ 7,743 $ 17,857 The following is depreciation and amortization by reportable segment for the three and nine months ended September 30, 2018 and 2017: Vacuum & Analysis Light & Motion Total Three Months Ended September 30, 2018: Depreciation and amortization $ 5,083 $ 14,446 $ 19,529 Nine Months Ended September 30, 2018 Depreciation and amortization $ 15,180 $ 44,726 $ 59,906 Three Months Ended September 30, 2017: Depreciation and amortization $ 5,058 $ 15,071 $ 20,129 Nine Months Ended September 30, 2017: Depreciation and amortization $ 15,277 $ 47,273 $ 62,550 Total income tax expense is not presented by reportable segment because the necessary information is not available or used by the CODM. The following are segment assets by reportable segment: September 30, 2018: Vacuum & Analysis Light & Motion Corporate, Eliminations & Other Total Segment assets: Accounts receivable $ 195,244 $ 138,599 $ (15,373 ) $ 318,470 Inventory, net 235,253 163,783 41 399,077 Total segment assets $ 430,497 $ 302,382 $ (15,332 ) $ 717,547 December 31, 2017: Vacuum & Analysis Light & Motion Corporate, Eliminations & Other Total Segment assets: Accounts receivable $ 201,318 $ 119,934 $ (20,944 ) $ 300,308 Inventory, net 197,831 141,250 — 339,081 Total segment assets $ 399,149 $ 261,184 $ (20,944 ) $ 639,389 A reconciliation of segment assets to consolidated total assets is as follows: September 30, 2018 December 31, 2017 Total segment assets $ 717,547 $ 639,389 Cash and cash equivalents, restricted cash and investments 630,030 553,976 Other current assets 75,298 53,543 Property, plant and equipment, net 180,182 171,782 Goodwill and intangible assets, net 919,149 957,445 Other assets 42,390 37,883 Consolidated total assets $ 2,564,596 $ 2,414,018 Geographic Information about the Company’s operations in different geographic regions is presented in the tables below. Net revenues to unaffiliated customers are based on the location in which the sale originated. Transfers between geographic areas are at tax transfer prices and have been eliminated from consolidated net revenues. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net revenues: United States $ 243,273 $ 237,592 $ 801,811 $ 700,291 Korea 43,468 60,908 164,462 165,613 Japan 38,964 38,411 151,325 113,068 Asia (excluding Korea and Japan) 105,336 94,084 313,913 273,957 Europe 56,111 55,272 183,056 151,248 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177 Long-lived assets: (1) September 30, 2018 December 31, 2017 United States $ 138,549 $ 124,689 Europe 26,188 28,820 Asia 49,801 49,645 $ 214,538 $ 203,154 (1) Long-lived assets include property, plant and equipment, net and certain other long-term assets, excluding long-term tax related accounts. Goodwill associated with each of the Company’s reportable segments is as follows: September 30, 2018 December 31, 2017 Reportable segment: Vacuum & Analysis $ 197,193 $ 197,617 Light & Motion 390,668 393,430 Total goodwill $ 587,861 $ 591,047 Worldwide Product Information Because the reportable segment information above does not reflect worldwide sales of the Company’s products, the Company groups its products into six groups of similar products based upon the similarity of product function. The following table sets forth worldwide net revenue for each group of products: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Analytical and Control Solutions Products $ 26,727 $ 33,068 $ 91,932 $ 97,689 Power, Plasma and Reactive Gas Solutions Products 132,469 193,808 487,286 549,999 Vacuum Solutions Products 126,842 81,300 423,492 248,291 Lasers Products 63,999 56,623 209,459 153,866 Optics Products 57,836 52,548 169,415 149,759 Photonics Products 79,279 68,920 232,983 204,573 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177 Sales of Analytical and Control Solutions Products; Power, Plasma and Reactive Gas Solutions Products; and Vacuum Solutions Products are included in the Company’s Vacuum & Analysis segment. Sales of Laser Products; Optics Products; and Photonics Products are included in the Light & Motion segment. Major Customers The Company had two customers with net revenues greater than 10% of total net revenues in the periods shown below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Applied Materials, Inc. 12 % 12 % 13 % 13 % LAM Research Corporation 8 % 11 % 11 % 12 %

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Restructuring	18 ) Restructuring The Company recorded restructuring charges of $1,364 and $3,374 during the three and nine months ended September 30, 2018. The restructuring charges for the three months ended September 30, 2018, primarily related to severance costs related to a moderate reduction in workforce. The restructuring charges for the nine months ended September 30, 2018 also includes severance costs related to transferring a portion of our shared accounting functions in the United States to a third party as well as the consolidation of certain shared accounting functions in Asia. The Company recorded restructuring charges of $2,596 during the nine months ended September 30, 2017, which primarily relate to: (i) the discontinuation of a product line resulting in the consolidation of two manufacturing plants related to our Light & Motion segment, (ii) the restructuring of one of our international facilities and (iii) the consolidation of two sales offices. Restructuring activities were as follows: Nine Months Ended September 30, 2018 2017 Beginning of period $ 3,244 $ 540 Charged to expense 3,374 2,596 Payments and adjustments (3,963 ) (608 ) End of period $ 2,655 $ 2,528

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	19 ) Commitments and Contingencies In March 2016, two putative class actions lawsuit captioned Dixon Chung v. Newport Corp., et al., Case No. A-16-733154-C and Hubert C. Pincon v. Newport Corp., et al., Case No. A-16-734039-B were filed in the District Court, Clark County, Nevada on behalf of a putative class of stockholders of Newport for claims related to the Merger Agreement between the Company, Newport, and Merger Sub. The lawsuits named as defendants the Company, Newport, Merger Sub, and certain then current and former members of Newport’s board of directors. Both complaints alleged that Newport directors breached their fiduciary duties to Newport’s stockholders by agreeing to sell Newport through an inadequate and unfair process, which led to inadequate and unfair consideration, by agreeing to unfair deal protection devices and by omitting material information from the proxy statement. The complaints also alleged that the Company, Newport, and Merger Sub aided and abetted the directors’ alleged breaches of their fiduciary duties. The complaints sought injunctive relief, including to enjoin or rescind the Merger Agreement, and an award of attorneys’ and other fees and costs, among other relief. On April 14, 2016, the Court consolidated the actions. On October 19, 2016, plaintiffs in the consolidated action filed an amended complaint captioned In re Newport Corporation Shareholder Litigation, Case No. A-16-733154-B, in the District Court, Clark County, Nevada, on behalf of a putative class of Newport’s stockholders for claims related to the Merger Agreement. The amended complaint contained substantially similar allegations related to Newport’s former board of directors’ alleged breaches of their fiduciary duties to Newport’s stockholders. The amended complaint sought monetary damages, including pre- and post-judgment interest. On June 22, 2017, the Court granted Defendants’ motion to dismiss and dismissed the amended complaint against all defendants but granted plaintiffs leave to amend. On July 27, 2017, plaintiffs filed a second amended complaint containing substantially similar allegations but naming only Newport’s former directors as defendants. On August 8, 2017, the Court dismissed the Company and Newport from the action. The second amended complaint seeks monetary damages, including pre- and post-judgment interest. The Court granted a motion for class certification on September 27, 2018, appointing Mr. Pincon and Locals 302 and 612 of the International Union of Operating Engineers - Employers Construction Industry Retirement Trust as class representatives. On June 11, 2018, plaintiff Dixon Chung was voluntarily dismissed from the litigation. Discovery is ongoing in this action. We are subject to various legal proceedings and claims, which have arisen in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on our results of operations, financial condition or cash flows.

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	20) Subsequent Event – Announcement of the Acquisition of Electro Scientific Industries, Inc. (amounts not in thousands) On October 29, 2018, the Company entered into a definitive merger agreement to acquire Electro Scientific Industries, Inc. (“ESI”), an innovator in laser-based manufacturing solutions for the micro-machining industry. Pursuant to the merger agreement, the Company agreed to pay $30.00 per share in cash for all of the outstanding shares of ESI, for total cash consideration of approximately $1 billion. The Company intends to fund the transaction with a combination of available cash on hand and up to $650 million in committed term loan debt financing. The acquisition is expected to close in the first quarter of 2019, subject to the satisfaction of customary closing conditions, including receipt of required regulatory approvals and approval by ESI’s shareholders. The Company’s obligations to complete the acquisition are not subject to any financing condition. Also, on October 29, 2018, the Company entered into a commitment letter to provide for a $100 million asset-based revolving credit facility for working capital purposes to replace the existing $50 million asset-based revolving credit facility.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Revised Presentation of Previously Issued Financial Statements	The Company has historically recorded the revenue and related cost of revenue for the sale of its spare parts within Products in its Statements of Operations for the Vacuum & Analysis segment. The Company has now determined that these items are better presented within revenue and related cost of revenue within Services for the Vacuum & Analysis segment in its Statements of Operations to align with the current manner in which the Company operates its services business, and has elected to reclassify these amounts in previously issued financial statements as shown below. This change in presentation has no impact on total revenue or total cost of revenue. Three Months Ended September 30, 2017 As previously reported Adjustment As reclassified Net revenues: Products $ 434,710 $ (5,819 ) $ 428,891 Services 51,557 5,819 57,376 Total net revenues 486,267 — 486,267 Cost of revenues: Cost of products 225,174 1,271 226,445 Cost of services 33,098 (1,271 ) 31,827 Total cost of revenues $ 258,272 $ — $ 258,272 Nine Months Ended September 30, 2017 As previously reported Adjustment As reclassified Net revenues: Products $ 1,259,582 $ (16,436 ) $ 1,243,146 Services 144,595 16,436 161,031 Total net revenues 1,404,177 — 1,404,177 Cost of revenues: Cost of products 659,538 3,447 662,985 Cost of services 91,514 (3,447 ) 88,067 Total cost of revenues $ 751,052 $ — $ 751,052

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Schedule of Deferred Revenue by Arrangement	A rollforward of the Company’s deferred revenue is as follows: Nine Months Ended September 30, 2018 Beginning balance, January 1 (1) $ 14,448 Amount of deferred revenue recognized in income (15,846 ) Additions to deferred revenue 13,869 Ending balance, September 30 (2) $ 12,471 (1) (2)
Summary of Revenue from Contracts with Customers	The following table summarizes revenue from contracts with customers: Three Months Ended September 30, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 239,924 $ 186,331 $ 426,255 Services 46,114 14,783 60,897 Total net revenues $ 286,038 $ 201,114 $ 487,152 Three Months Ended September 30, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 265,136 $ 163,755 $ 428,891 Services 43,133 14,243 57,376 Total net revenues $ 308,269 $ 177,998 $ 486,267 Nine Months Ended September 30, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 865,714 $ 567,217 $ 1,432,931 Services 136,996 44,640 181,636 Total net revenues $ 1,002,710 $ 611,857 $ 1,614,567 Nine Months Ended September 30, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 776,256 466,890 $ 1,243,146 Services 119,958 41,073 161,031 Total net revenues $ 896,214 $ 507,963 $ 1,404,177

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Short-Term and Long-Term Investments Available-for-Sale and Cost Method Investments	The fair value of investments classified as short-term consists of the following: September 30, 2018 December 31, 2017 Available-for-sale investments: Time deposits and certificates of deposit $ 14,552 $ 9,757 Bankers’ acceptance drafts 2,107 5,330 Asset-backed securities 38,947 36,990 Commercial paper 32,057 13,750 Corporate obligations 71,971 77,821 Municipal bonds 1,288 1,970 U.S. treasury obligations 28,208 28,078 U.S. agency obligations 30,646 35,738 $ 219,776 $ 209,434 Investments classified as long-term consist of the following: September 30, 2018 December 31, 2017 Available-for-sale investments: Group insurance contracts $ 6,004 $ 6,255 Cost method investments: Minority interest in a private company 4,400 4,400 $ 10,404 $ 10,655
Gross Unrealized Gains and (Losses) Aggregated by Investment Category	The following tables show the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments: As of September 30, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 14,552 $ — $ — $ 14,552 Bankers’ acceptance drafts 2,107 — — 2,107 Asset-backed securities 38,961 11 (25 ) 38,947 Commercial paper 32,238 — (181 ) 32,057 Corporate obligations 71,931 59 (19 ) 71,971 Municipal bonds 1,290 — (2 ) 1,288 U.S. treasury obligations 28,200 10 (2 ) 28,208 U.S. agency obligations 30,649 4 (7 ) 30,646 $ 219,928 $ 84 $ (236 ) $ 219,776 As of September 30, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale investments: Group insurance contracts $ 6,010 $ — $ (6 ) $ 6,004 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 9,756 $ 1 $ — $ 9,757 Bankers acceptance drafts 5,330 — — 5,330 Asset-backed securities 37,017 15 (42 ) 36,990 Commercial paper 13,810 — (60 ) 13,750 Corporate obligations 77,788 58 (25 ) 77,821 Municipal bonds 1,970 — — 1,970 U.S. treasury obligations 28,054 24 — 28,078 U.S. agency obligations 35,728 10 — 35,738 $ 209,453 $ 108 $ (127 ) $ 209,434 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale investments: Group insurance contracts $ 6,006 $ 249 $ — $ 6,255

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	Assets and liabilities of the Company are measured at fair value on a recurring basis as of September 30, 2018 and are summarized as follows: Fair Value Measurements at Reporting Date Using Description September 30, 2018 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 17,584 $ 17,584 $ — $ — Commercial paper 13,283 — 13,283 — Corporate obligations 4,373 — 4,373 — U.S. agency obligations 2,244 — 2,244 — Restricted cash – money market funds 114 114 — — Available-for-sale investments: Time deposits and certificates of deposit 14,552 — 14,552 — Bankers acceptance drafts 2,107 — 2,107 — Asset-backed securities 38,947 — 38,947 — Commercial paper 32,057 — 32,057 — Corporate obligations 71,971 — 71,971 — Municipal bonds 1,288 — 1,288 — U.S. treasury obligations 28,208 — 28,208 — U.S. agency obligations 30,646 — 30,646 — Group insurance contracts 6,004 — 6,004 — Derivatives – foreign exchange contracts 3,434 — 3,434 — Funds in investments and other assets: Israeli pension assets 15,815 — 15,815 — Derivatives – interest rate hedge – non-current 8,539 — 8,539 — Total assets $ 291,166 $ 17,698 $ 273,468 $ — Liabilities: Derivatives – foreign exchange contracts $ 343 $ — $ 343 $ — Reported as follows: Assets: Cash and cash equivalents, including restricted cash ( 1) $ 37,598 $ 17,698 $ 19,900 $ — Short-term investments 219,776 — 219,776 — Other current assets 3,434 — 3,434 — Total current assets $ 260,808 $ 17,698 $ 243,110 $ — Long-term investments ( 2) $ 6,004 $ — $ 6,004 $ — Other assets 24,354 — 24,354 — Total long-term assets $ 30,358 $ — $ 30,358 $ — Liabilities: Other current liabilities $ 343 $ — $ 343 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $362,252 as of September 30, 2018. (2) The long-term investments presented in the table above do not include the Company’s minority interest investment in a private company, which is accounted for under the cost method. Assets and liabilities of the Company are measured at fair value on a recurring basis as of December 31, 2017 and are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2017 Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 4,987 $ 4,987 $ — $ — Time deposits and certificates of deposit 2,100 — 2,100 — Commercial paper 30,475 — 30,475 — Restricted cash – money market funds 119 119 — — Available-for-sale investments: Time deposits and certificates of deposit 9,757 — 9,757 — Bankers acceptance drafts 5,330 — 5,330 — Asset-backed securities 36,990 — 36,990 — Commercial paper 13,750 — 13,750 — Corporate obligations 77,821 — 77,821 — Municipal bonds 1,970 — 1,970 — U.S. treasury obligations 28,078 — 28,078 — U.S. agency obligations 35,738 — 35,738 — Group insurance contracts 6,255 — 6,255 — Derivatives – foreign exchange contracts 168 — 168 — Funds in investments and other assets: Israeli pension assets 15,048 — 15,048 — Derivatives – interest rate hedge – non-current 6,179 — 6,179 — Total assets $ 274,765 $ 5,106 $ 269,659 $ — Liabilities: Derivatives – foreign exchange contracts $ 6,198 $ — $ 6,198 $ — Assets: Cash and cash equivalents, including restricted cash ( 1) $ 37,681 $ 5,106 $ 32,575 $ — Short-term investments 209,434 — 209,434 — Other current assets 168 — 168 — Total current assets $ 247,283 $ 5,106 $ 242,177 $ — Long-term investments ( 2) $ 6,255 $ — $ 6,255 $ — Other assets 21,227 — 21,227 — Total long-term assets $ 27,482 $ — $ 27,482 $ — Liabilities: Other current liabilities $ 6,198 $ — $ 6,198 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $292,808 and non-negotiable time deposits of $3,398 as of December 31, 2017. (2) The long-term investments presented in the table above do not include the Company’s minority interest investment in a private company, which is accounted for under the cost method.

Derivatives (Tables)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Summary of Primary Net Hedging Positions and Corresponding Fair Values	The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of September 30, 2018 and December 31, 2017: September 30, 2018 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value (1) U.S. Dollar/Japanese Yen $ 40,004 $ 1,143 U.S. Dollar/South Korean Won 56,628 759 U.S. Dollar/Euro 23,678 612 U.S. Dollar/U.K. Pound Sterling 10,001 314 U.S. Dollar/Taiwan Dollar 18,777 263 Total $ 149,088 $ 3,091 December 31, 2017 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value (1) U.S. Dollar/Japanese Yen $ 70,175 $ (233 ) U.S. Dollar/South Korean Won 79,672 (3,799 ) U.S. Dollar/Euro 26,140 (1,047 ) U.S. Dollar/U.K. Pound Sterling 12,104 (337 ) U.S. Dollar/Taiwan Dollar 20,831 (614 ) Total $ 208,922 $ (6,030 ) (1) Represents the receivable (payable) amount included in the consolidated balance sheet.
Summary of Fair Value Amounts of Company's Derivative Instruments	The following table provides a summary of the fair value amounts of the Company’s derivative instruments: Derivatives Designated as Hedging Instruments September 30, 2018 December 31, 2017 Derivative assets: Foreign exchange contracts (1) $ 3,434 $ 168 Foreign currency interest rate hedge (2) 8,539 6,179 Derivative liabilities: Foreign exchange contracts (1) (343 ) (6,198 ) Total net derivative asset designated as hedging instruments $ 11,630 $ 149 (1) The derivative asset of $3,434 and $168 as of September 30, 2018 and December 31, 2017, respectively, related to foreign exchange contracts and is classified in other current assets in the consolidated balance sheet. The derivative liability of $(343) and $(6,198) as of September 30, 2018 and December 31, 2017, respectively, is classified in other current liabilities in the consolidated balance sheet. These foreign exchange contracts are subject to a master netting agreement with one financial institution. However, the Company has elected to record these contracts on a gross basis in the balance sheet. (2) The interest rate hedge assets of $8,539 and $6,179 as of September 30, 2018 and December 31, 2017, respectively, are classified in other assets in the consolidated balance sheet.
Summary of Gains (Losses) on Derivatives Designated as Cash Flow Hedging Instruments	The following table provides a summary of the gains (losses) on derivatives designated as cash flow hedging instruments: Three Months Ended September 30, Nine Months Ended September 30, Derivatives Designated as Cash Flow Hedging Instruments 2018 2017 2018 2017 Forward exchange contracts: Net gain (loss) recognized in OCI (1) $ 212 $ (220 ) $ 10,357 $ (4,462 ) Net gain (loss) reclassified from accumulated OCI into income (2) $ 306 $ (1,360 ) $ (4,882 ) $ (1,842 ) (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified in cost of products for the three and nine months ended September 30, 2018 and 2017. The tax effect of the gains or losses reclassified from accumulated OCI into income is immaterial.
Summary of (Losses) Gains on Derivatives Not Designated as Cash Flow Hedging Instruments	The following table provides a summary of the (losses) gains on derivatives not designated as hedging instruments: Three Months Ended September 30, Nine Months Ended September 30, Derivatives Not Designated as Hedging Instruments 2018 2017 2018 2017 Forward exchange contracts: Net (loss) gain recognized in income (1) $ (111 ) $ (877 ) $ 12 $ (2,559 ) (1) The Company enters into foreign exchange contracts to hedge against changes in the balance sheet for certain subsidiaries to mitigate the risk associated with certain foreign currency transactions in the ordinary course of business. These derivatives are not designated as hedging instruments and gains or losses from these derivatives are recorded immediately in other (expense) income.

Inventories, net (Tables)

Inventories, net (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consist of the following: September 30, 2018 December 31, 2017 Raw materials $ 237,547 $ 191,351 Work-in-process 66,635 54,050 Finished goods 94,895 93,680 $ 399,077 $ 339,081

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	The changes in the carrying amount of goodwill and accumulated impairment loss during the nine months ended September 30, 2018 and year ended December 31, 2017 were as follows: Nine Months Ended September 30, 2018 Twelve Months Ended December 31, 2017 Gross Carrying Amount Accumulated Impairment Loss Net Gross Carrying Amount Accumulated Impairment Loss Net Beginning balance at January 1 $ 735,323 $ (144,276 ) $ 591,047 $ 727,999 $ (139,414 ) $ 588,585 Sale of business ( 1) — — — (3,115 ) — (3,115 ) Impairment loss ( 2) — — — — (4,862 ) (4,862 ) Foreign currency translation (3,186 ) — (3,186 ) 10,439 — 10,439 Ending balance at September 30, 2018 and December 31, 2017 $ 732,137 $ (144,276 ) $ 587,861 $ 735,323 $ (144,276 ) $ 591,047 (1) (2)
Intangible Assets	Components of the Company’s intangible assets are comprised of the following: As of September 30, 2018: Gross Impairment Charges ( 1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (131,840 ) $ — $ 40,486 Customer relationships 282,744 (1,406 ) (59,260 ) 174 222,252 Patents, trademarks, trade names and other 110,523 — (41,970 ) (3 ) 68,550 $ 565,698 $ (1,511 ) $ (233,070 ) $ 171 $ 331,288 As of December 31, 2017: Gross Impairment Charges ( 1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (115,371 ) $ 333 $ 57,288 Customer relationships 282,744 (1,406 ) (45,518 ) 1,571 237,391 Patents, trademarks, trade names and other 110,523 — (38,730 ) (74 ) 71,719 $ 565,698 $ (1,511 ) $ (199,619 ) $ 1,830 $ 366,398 (1) In 2017, the Company recorded impairment charges of $1,511 related to the write-off of intangible assets as a result of the discontinuation of a product line and consolidation of two manufacturing plants.
Estimated Net Amortization Expense	Aggregate net amortization expense related to acquired intangible assets and unfavorable lease commitments for future years is as follows: Year Amount 2018 (remaining) $ 10,760 2019 $ 40,144 2020 $ 28,125 2021 $ 20,248 2022 $ 17,619 2023 $ 17,253 Thereafter $ 138,955

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Short-Term Debt	September 30, 2018 December 31, 2017 Short-term debt: Japanese lines of credit $ 5,524 $ 2,750 Japanese receivables financing facility — 215 Austrian loans due through March 2020 606 — Other debt — 7 $ 6,130 $ 2,972
Schedule of Long-Term Debt	September 30, 2018 December 31, 2017 Long-term debt: Austrian loans due through March 2020 and other debt $ 87 $ 714 Term Loan Facility, net ( 1) 342,883 389,279 $ 342,970 $ 389,993 (1) Net of deferred financing fees, original issuance discount and repricing fee of
Schedule of Contractual Maturities of Debt Obligations	Contractual maturities of the Company’s debt obligations as of September 30, 2018 are as follows: Year Amount 2018 (remaining) $ 5,524 2019 $ 606 2020 $ 73 2021 $ 14 2022 $ — 2023 $ — Thereafter $ 348,464

Product Warranties (Tables)

Product Warranties (Tables)	9 Months Ended
	Sep. 30, 2018
Guarantees And Product Warranties [Abstract]
Product Warranty Activities	Product warranty activities were as follows: Nine Months Ended September 30, 2018 2017 Beginning of period $ 10,104 $ 8,261 Provision for product warranties 11,448 11,941 Direct and other charges to warranty liability (11,072 ) (10,080 ) End of period ( 1) $ 10,480 $ 10,122 (1) Short-term product warranty of $10,067 and long-term product warranty of $413 as of September 30, 2018, are included within other current liabilities and other liabilities, respectively, within the accompanying condensed consolidated balance sheet. Short-term product warranty of $9,725 and long-term product warranty of $397 as of September 30, 2017, are included within other current liabilities and other liabilities, respectively, within the accompanying condensed consolidated balance sheet.

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income Per Share	The following table sets forth the computation of basic and diluted net income per share: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net income $ 93,277 $ 75,994 $ 321,260 $ 261,494 Denominator: Shares used in net income per common share – basic 54,476,000 54,282,000 54,539,000 54,076,000 Effect of dilutive securities: Restricted stock units, stock appreciation rights and shares issued under employee stock purchase plan 478,000 819,000 632,000 944,000 Shares used in net income per common share – diluted 54,954,000 55,101,000 55,171,000 55,020,000 Net income per common share: Basic $ 1.71 $ 1.40 $ 5.89 $ 4.84 Diluted $ 1.70 $ 1.38 $ 5.82 $ 4.75

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule of Total Stock-Based Compensation Expense Included in Company's Consolidated Statements of Income and Comprehensive Income	The total stock-based compensation expense included in the Company’s consolidated statements of income and comprehensive income was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of revenues $ 170 $ 1,016 $ 2,664 $ 3,133 Research and development expense 708 712 2,249 2,284 Selling, general and administrative expense 4,335 3,117 17,092 14,417 Total pre-tax stock-based compensation expense $ 5,213 $ 4,845 $ 22,005 $ 19,834
Summary of Activity for RSUs	The following table presents the activity for RSUs under the Plan: Nine Months Ended September 30, 2018 Outstanding RSUs Weighted Average Grant Date Fair Value RSUs – beginning of period 943,379 $ 47.57 Accrued dividend shares 46 $ 105.26 Granted 260,341 $ 112.49 Vested (487,856 ) $ 44.60 Forfeited (62,021 ) $ 65.37 RSUs – end of period 653,889 $ 73.95
Stock Appreciation Rights (SARs) [Member]
Summary of Activity for Outstanding and Exercisable Stock Appreciation Rights	The following table presents the activity for SARs under the Plan: Nine Months Ended September 30, 2018 Outstanding SARs Weighted Average Grant Date Fair Value SARs – beginning of period 282,907 $ 28.62 Exercised (100,683 ) $ 28.77 Forfeited or expired (1,950 ) $ 29.00 SARs Outstanding – end of period 180,274 $ 28.52

Business Segment, Geographic _2

Business Segment, Geographic Area, Product and Significant Customer Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Net Revenues, Assets and Goodwill by Reportable Segment	The following are net revenues by reportable segment: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Vacuum & Analysis $ 286,038 $ 308,269 $ 1,002,710 $ 896,214 Light & Motion 201,114 177,998 611,857 507,963 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177 The following are segment assets by reportable segment: September 30, 2018: Vacuum & Analysis Light & Motion Corporate, Eliminations & Other Total Segment assets: Accounts receivable $ 195,244 $ 138,599 $ (15,373 ) $ 318,470 Inventory, net 235,253 163,783 41 399,077 Total segment assets $ 430,497 $ 302,382 $ (15,332 ) $ 717,547 December 31, 2017: Vacuum & Analysis Light & Motion Corporate, Eliminations & Other Total Segment assets: Accounts receivable $ 201,318 $ 119,934 $ (20,944 ) $ 300,308 Inventory, net 197,831 141,250 — 339,081 Total segment assets $ 399,149 $ 261,184 $ (20,944 ) $ 639,389 Goodwill associated with each of the Company’s reportable segments is as follows: September 30, 2018 December 31, 2017 Reportable segment: Vacuum & Analysis $ 197,193 $ 197,617 Light & Motion 390,668 393,430 Total goodwill $ 587,861 $ 591,047
Reconciliation of Segment Gross Profit to Consolidated Net Income	The following is a reconciliation of segment gross profit to consolidated net income: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Gross profit by reportable segment: Vacuum & Analysis $ 132,835 $ 141,438 $ 462,418 $ 410,228 Light & Motion 99,025 86,557 307,174 242,897 Total gross profit by reportable segment 231,860 227,995 769,592 653,125 Operating expenses: Research and development 31,898 32,548 103,259 99,510 Selling, general and administrative 70,822 71,347 229,952 217,546 Acquisition and integration costs 36 2,466 (1,132 ) 4,698 Restructuring 1,364 10 3,374 2,596 Asset impairment — — — 6,719 Fees and expenses related to repricing of term loan — 492 378 492 Environmental Costs — — 1,000 — Amortization of intangible assets 10,695 10,977 32,786 34,946 Income from operations 117,045 110,155 399,975 286,618 Gain on sale of business — — — 74,856 Interest and other expense, net 2,529 8,784 10,173 24,846 Income before income taxes 114,516 101,371 389,802 336,628 Provision for income taxes 21,239 25,377 68,542 75,134 Net income $ 93,277 $ 75,994 $ 321,260 $ 261,494
Schedule of Capital Expenditures, Depreciation and Amortization Expense by Reportable Segment	The following is capital expenditures by reportable segment for the three and nine months ended September 30, 2018 and 2017: Vacuum & Analysis Light & Motion Total Three Months Ended September 30, 2018: Capital expenditures $ 9,532 $ 5,535 $ 15,067 Nine Months Ended September 30, 2018: Capital expenditures $ 22,701 $ 14,184 $ 36,885 Three Months Ended September 30, 2017: Capital expenditures $ 4,212 $ 3,906 $ 8,118 Nine Months Ended September 30, 2017: Capital expenditures $ 10,114 $ 7,743 $ 17,857 The following is depreciation and amortization by reportable segment for the three and nine months ended September 30, 2018 and 2017: Vacuum & Analysis Light & Motion Total Three Months Ended September 30, 2018: Depreciation and amortization $ 5,083 $ 14,446 $ 19,529 Nine Months Ended September 30, 2018 Depreciation and amortization $ 15,180 $ 44,726 $ 59,906 Three Months Ended September 30, 2017: Depreciation and amortization $ 5,058 $ 15,071 $ 20,129 Nine Months Ended September 30, 2017: Depreciation and amortization $ 15,277 $ 47,273 $ 62,550
Reconciliation of Segment Assets to Consolidated Total Assets	A reconciliation of segment assets to consolidated total assets is as follows: September 30, 2018 December 31, 2017 Total segment assets $ 717,547 $ 639,389 Cash and cash equivalents, restricted cash and investments 630,030 553,976 Other current assets 75,298 53,543 Property, plant and equipment, net 180,182 171,782 Goodwill and intangible assets, net 919,149 957,445 Other assets 42,390 37,883 Consolidated total assets $ 2,564,596 $ 2,414,018
Schedule of Net Revenues and Long-Lived Assets by Geographic Regions	Transfers between geographic areas are at tax transfer prices and have been eliminated from consolidated net revenues. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net revenues: United States $ 243,273 $ 237,592 $ 801,811 $ 700,291 Korea 43,468 60,908 164,462 165,613 Japan 38,964 38,411 151,325 113,068 Asia (excluding Korea and Japan) 105,336 94,084 313,913 273,957 Europe 56,111 55,272 183,056 151,248 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177 Long-lived assets: (1) September 30, 2018 December 31, 2017 United States $ 138,549 $ 124,689 Europe 26,188 28,820 Asia 49,801 49,645 $ 214,538 $ 203,154 (1) Long-lived assets include property, plant and equipment, net and certain other long-term assets, excluding long-term tax related accounts.
Worldwide Net Revenue for Each Group of Products	The following table sets forth worldwide net revenue for each group of products: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Analytical and Control Solutions Products $ 26,727 $ 33,068 $ 91,932 $ 97,689 Power, Plasma and Reactive Gas Solutions Products 132,469 193,808 487,286 549,999 Vacuum Solutions Products 126,842 81,300 423,492 248,291 Lasers Products 63,999 56,623 209,459 153,866 Optics Products 57,836 52,548 169,415 149,759 Photonics Products 79,279 68,920 232,983 204,573 $ 487,152 $ 486,267 $ 1,614,567 $ 1,404,177
Customers with Net Revenues Greater than 10% of Total Net Revenues	The Company had two customers with net revenues greater than 10% of total net revenues in the periods shown below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Applied Materials, Inc. 12 % 12 % 13 % 13 % LAM Research Corporation 8 % 11 % 11 % 12 %

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Schedule of Company's Restructuring Activity	Restructuring activities were as follows: Nine Months Ended September 30, 2018 2017 Beginning of period $ 3,244 $ 540 Charged to expense 3,374 2,596 Payments and adjustments (3,963 ) (608 ) End of period $ 2,655 $ 2,528

Basis of Presentation - Revised

Basis of Presentation - Revised Presentation of Previously Issued Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net revenues:
Total net revenues	$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Cost of revenues:
Total cost of revenues	255,292	258,272	844,975	751,052
Products [Member]
Net revenues:
Total net revenues	426,255	428,891	1,432,931	1,243,146
Cost of revenues:
Total cost of revenues	219,311	226,445	747,522	662,985
Services [Member]
Net revenues:
Total net revenues	60,897	57,376	181,636	161,031
Cost of revenues:
Total cost of revenues	$ 35,981	31,827	$ 97,453	88,067
As Previously Reported [Member]
Net revenues:
Total net revenues		486,267		1,404,177
Cost of revenues:
Total cost of revenues		258,272		751,052
As Previously Reported [Member] | Products [Member]
Net revenues:
Total net revenues		434,710		1,259,582
Cost of revenues:
Total cost of revenues		225,174		659,538
As Previously Reported [Member] | Services [Member]
Net revenues:
Total net revenues		51,557		144,595
Cost of revenues:
Total cost of revenues		33,098		91,514
Adjustment [Member] | Products [Member]
Net revenues:
Total net revenues		(5,819)		(16,436)
Cost of revenues:
Total cost of revenues		1,271		3,447
Adjustment [Member] | Services [Member]
Net revenues:
Total net revenues		5,819		16,436
Cost of revenues:
Total cost of revenues		$ (1,271)		$ (3,447)

Revenue From Contracts With C_3

Revenue From Contracts With Customers - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Retained earnings opening balance sheet adjustment for Topic 606 adoption	$ 1,023,959		$ 795,698
Accounting Standards Update 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Retained earnings opening balance sheet adjustment for Topic 606 adoption		$ 1,809
Contract assets	$ 3,951	$ 3,065
Accounting Standards Update 2014-09 [Member] | Maximum [Member]
Disaggregation of Revenue [Line Items]
Term of installation services	14 days
Company's normal payment terms	60 days
Warranty period	24 months
Term of separately priced contracts	60 months
Accounting Standards Update 2014-09 [Member] | Minimum [Member]
Disaggregation of Revenue [Line Items]
Company's normal payment terms	30 days
Warranty period	12 months
Term of separately priced contracts	12 months

Revenue From Contracts With C_4

Revenue From Contracts With Customers - Schedule of Deferred Revenue by Arrangement (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Change In Contract With Customer Liability [Abstract]
Beginning balance, January 1	$ 14,448
Amount of deferred revenue recognized in income	(15,846)
Additions to deferred revenue	13,869
Ending balance, September 30	$ 12,471

Revenue From Contracts With C_5

Revenue From Contracts With Customers - Schedule of Deferred Revenue by Arrangement (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Change In Contract With Customer Liability [Abstract]
Deferred revenue, current	$ 9,136	$ 11,322	$ 12,842
Long-term deferred revenue	$ 3,335	$ 3,126

Revenue From Contracts With C_6

Revenue From Contracts With Customers - Summary of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total net revenues	$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	286,038	308,269	1,002,710	896,214
Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	201,114	177,998	611,857	507,963
Products [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	426,255	428,891	1,432,931	1,243,146
Products [Member] | Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	239,924	265,136	865,714	776,256
Products [Member] | Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	186,331	163,755	567,217	466,890
Services [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	60,897	57,376	181,636	161,031
Services [Member] | Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	46,114	43,133	136,996	119,958
Services [Member] | Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Total net revenues	$ 14,783	$ 14,243	$ 44,640	$ 41,073

Investments - Investments Class

Investments - Investments Classified as Short-Term Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 219,776	$ 209,434
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	14,552	9,757
Bankers Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	2,107	5,330
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	38,947	36,990
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	32,057	13,750
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	71,971	77,821
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	1,288	1,970
U.S. Treasury Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	28,208	28,078
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 30,646	$ 35,738

Investments - Investments Cla_2

Investments - Investments Classified as Long-Term Available-for-Sale Investments and Long-Term Cost Method Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items]
Investments classified as long-term	$ 10,404	$ 10,655
Group Insurance Contracts [Member]
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items]
Investments classified as long-term	6,004	6,255
Minority Interest in Private Company [Member]
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items]
Investments classified as long-term	$ 4,400	$ 4,400

Investments - Gross Unrealized

Investments - Gross Unrealized Gains and (Losses) Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	$ 219,928	$ 209,453
Investments, Gross Unrealized Gains	84	108
Investments, Gross Unrealized (Losses)	(236)	(127)
Investments, Estimated Fair Value	219,776	209,434
Time Deposits and Certificates of Deposit [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	14,552	9,756
Investments, Gross Unrealized Gains		1
Investments, Estimated Fair Value	14,552	9,757
Bankers Acceptance Drafts [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	2,107	5,330
Investments, Estimated Fair Value	2,107	5,330
Asset-Backed Securities [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	38,961	37,017
Investments, Gross Unrealized Gains	11	15
Investments, Gross Unrealized (Losses)	(25)	(42)
Investments, Estimated Fair Value	38,947	36,990
Commercial Paper [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	32,238	13,810
Investments, Gross Unrealized (Losses)	(181)	(60)
Investments, Estimated Fair Value	32,057	13,750
Corporate Obligations [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	71,931	77,788
Investments, Gross Unrealized Gains	59	58
Investments, Gross Unrealized (Losses)	(19)	(25)
Investments, Estimated Fair Value	71,971	77,821
Municipal Bonds [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	1,290	1,970
Investments, Gross Unrealized (Losses)	(2)
Investments, Estimated Fair Value	1,288	1,970
U.S. Treasury Obligations [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	28,200	28,054
Investments, Gross Unrealized Gains	10	24
Investments, Gross Unrealized (Losses)	(2)
Investments, Estimated Fair Value	28,208	28,078
U.S. Agency Obligations [Member] | Short Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	30,649	35,728
Investments, Gross Unrealized Gains	4	10
Investments, Gross Unrealized (Losses)	(7)
Investments, Estimated Fair Value	30,646	35,738
Group Insurance Contracts [Member] | Long Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	6,010	6,006
Investments, Gross Unrealized Gains		249
Investments, Gross Unrealized (Losses)	(6)
Investments, Estimated Fair Value	$ 6,004	$ 6,255

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	$ 219,776	$ 209,434
Short-term investments	219,776	209,434
Other assets	42,390	37,883
Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - contracts	3,434	168
Derivatives - liabilities	343	6,198
Interest Rate Hedge [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - contracts	8,539	6,179
Derivatives – interest rate hedge – non-current	8,539	6,179
Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6,004	6,255
Derivatives - contracts	3,434	168
Total assets	291,166	274,765
Derivatives - liabilities	343	6,198
Cash and cash equivalents, including restricted cash	37,598	37,681
Short-term investments	219,776	209,434
Total current assets	260,808	247,283
Other assets	24,354	21,227
Total long-term assets	30,358	27,482
Fair Value Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - contracts	3,434	168
Derivatives - liabilities	343	6,198
Fair Value Measurements, Recurring [Member] | Interest Rate Hedge [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives – interest rate hedge – non-current	8,539	6,179
Money Market Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	17,584	4,987
Restricted cash	114	119
Time Deposits and Certificates of Deposit [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,552	2,100
Available-for-sale investments		9,757
U.S. Agency Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	2,244
Available-for-sale investments	30,646	35,738
Bankers Acceptance Drafts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	2,107	5,330
Asset-Backed Securities [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	38,947	36,990
U.S. Treasury Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	28,208	28,078
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	32,057	13,750
Commercial Paper [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	13,283	30,475
Available-for-sale investments	32,057	13,750
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	71,971	77,821
Corporate Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	4,373
Available-for-sale investments	71,971	77,821
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	1,288	1,970
Municipal Bonds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	1,288	1,970
Group Insurance Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6,004	6,255
Group Insurance Contracts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6,004	6,255
Israeli Pension Assets [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension assets	15,815	15,048
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	17,698	5,106
Cash and cash equivalents, including restricted cash	17,698	5,106
Total current assets	17,698	5,106
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Money Market Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	17,584	4,987
Restricted cash	114	119
Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6,004	6,255
Derivatives - contracts	3,434	168
Total assets	273,468	269,659
Derivatives - liabilities	343	6,198
Cash and cash equivalents, including restricted cash	19,900	32,575
Short-term investments	219,776	209,434
Total current assets	243,110	242,177
Other assets	24,354	21,227
Total long-term assets	30,358	27,482
Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - contracts	3,434	168
Derivatives - liabilities	343	6,198
Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member] | Interest Rate Hedge [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives – interest rate hedge – non-current	8,539	6,179
Significant Other Observable Inputs (Level 2) [Member] | Time Deposits and Certificates of Deposit [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	14,552	2,100
Available-for-sale investments		9,757
Significant Other Observable Inputs (Level 2) [Member] | U.S. Agency Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	2,244
Available-for-sale investments	30,646	35,738
Significant Other Observable Inputs (Level 2) [Member] | Bankers Acceptance Drafts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	2,107	5,330
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	38,947	36,990
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	28,208	28,078
Significant Other Observable Inputs (Level 2) [Member] | Commercial Paper [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	13,283	30,475
Available-for-sale investments	32,057	13,750
Significant Other Observable Inputs (Level 2) [Member] | Corporate Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	4,373
Available-for-sale investments	71,971	77,821
Significant Other Observable Inputs (Level 2) [Member] | Municipal Bonds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	1,288	1,970
Significant Other Observable Inputs (Level 2) [Member] | Group Insurance Contracts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	6,004	6,255
Significant Other Observable Inputs (Level 2) [Member] | Israeli Pension Assets [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension assets	$ 15,815	$ 15,048

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Cash [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash/Non-negotiable time deposits - not subject to fair value disclosure requirements	$ 362,252	$ 292,808
Non-Negotiable Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash/Non-negotiable time deposits - not subject to fair value disclosure requirements		$ 3,398

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) - USD ($)	Sep. 30, 2016	Sep. 30, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maximum period for hedging a portion of forecasted foreign currency denominated intercompany sales of inventory		18 months
Gross notional values of outstanding forward foreign exchange contracts		$ 149,088,000	$ 208,922,000
Accumulated other comprehensive income realization period		12 months
Interest Rate Hedge [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of debt which is subject to interest rate swap fixed rate	50.00%
Interest rate swap agreement, credit spread rate		1.75%
Interest rate swap agreement, maturity date	Sep. 30, 2020
Interest rate swap agreement, notional amount		$ 290,000,000	305,000,000
Interest rate swap agreement, interest rate description		The Company entered into an interest rate swap agreement to fix the rate on approximately 50% of its then-outstanding balance under the Credit Agreement, as described further in Note 10. This hedge fixes the interest rate paid on the hedged debt at 1.198% per annum plus the applicable credit spread, which was 1.75% as of September 30, 2018, through September 30, 2020.
Interest rate swap agreement, fair value		$ 8,539,000	$ 6,179,000
Interest Rate Hedge [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest rate swap agreement, interest rate	1.198%

Derivatives - Summary of Primar

Derivatives - Summary of Primary Net Hedging Positions and Corresponding Fair Values (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	$ 149,088	$ 208,922
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	3,091	(6,030)
Forward Exchange Contracts [Member] | U.S. Dollar/Japanese Yen [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	40,004	70,175
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	1,143	(233)
Forward Exchange Contracts [Member] | U.S. Dollar/South Korean Won [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	56,628	79,672
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	759	(3,799)
Forward Exchange Contracts [Member] | U.S. Dollar/Euro [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	23,678	26,140
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	612	(1,047)
Forward Exchange Contracts [Member] | U.S. Dollar/U.K. Pound Sterling [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	10,001	12,104
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	314	(337)
Forward Exchange Contracts [Member] | U.S. Dollar/Taiwan Dollar [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	18,777	20,831
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	$ 263	$ (614)

Derivatives - Summary of Fair V

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Total net derivative asset designated as hedging instruments	$ 3,091	$ (6,030)
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,434	168
Derivative liabilities	(343)	(6,198)
Interest Rate Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	8,539	6,179
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total net derivative asset designated as hedging instruments	11,630	149
Derivatives Designated as Hedging Instruments [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,434	168
Derivative liabilities	(343)	(6,198)
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	$ 8,539	$ 6,179

Derivatives - Summary of Fair_2

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative asset classified in other current assets	$ 3,434	$ 168
Derivative liability classified in other current liabilities	(343)	(6,198)
Interest Rate Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative asset classified in other current assets	$ 8,539	$ 6,179

Derivatives - Summary of Gains

Derivatives - Summary of Gains (Losses) on Derivatives Designated as Cash Flow Hedging Instruments (Detail) - Forward Exchange Contracts [Member] - Cash Flow Hedging [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in OCI	$ 212	$ (220)	$ 10,357	$ (4,462)
Net gain (loss) reclassified from accumulated OCI into income(2)	$ 306	$ (1,360)	$ (4,882)	$ (1,842)

Derivatives - Summary of (Losse

Derivatives - Summary of (Losses) gains on Derivatives Not Designated as Cash Flow Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Forward Exchange Contracts [Member]
Derivative Instruments Gain Loss Not Designated As Hedging Instruments [Line Items]
Net (loss) gain recognized in income	$ (111)	$ (877)	$ 12	$ (2,559)

Inventories, net - Summary of I

Inventories, net - Summary of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 237,547	$ 191,351
Work-in-process	66,635	54,050
Finished goods	94,895	93,680
Inventories	$ 399,077	$ 339,081

Dispositions - Additional Infor

Dispositions - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Total proceeds from sale of business unit, net of cash sold	$ 72,509				$ 72,509
Pre-tax gain	$ 74,856				74,856
Net revenues		$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Data Analytics Solutions Business [Member]
Business Acquisition [Line Items]
Net revenues						$ 12,700

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning balance, Goodwill Gross Carrying Amount	$ 735,323	$ 727,999
Sale of business, Gross Carrying Amount		(3,115)
Foreign currency translation, Gross Carrying Amount	(3,186)	10,439
Ending balance, Goodwill Gross Carrying Amount	732,137	735,323
Beginning balance, Accumulated Impairment Loss	(144,276)	(139,414)
Impairment loss, Accumulated Impairment Loss		(4,862)
Foreign currency translation, Accumulated Impairment Loss	0	0
Ending balance, Accumulated Impairment Loss	(144,276)	(144,276)
Beginning balance, Goodwill Net	591,047	588,585
Sale of business, Net		(3,115)
Impairment loss, Net		(4,862)
Foreign currency translation, Net	(3,186)	10,439
Ending balance, Goodwill Net	$ 587,861	$ 591,047

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Goodwill (Parenthetical) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Goodwill [Line Items]
Goodwill related to the sale of business unit	$ 3,115
Goodwill impairment loss	(4,862)
Data Analytics Solutions Business [Member]
Goodwill [Line Items]
Goodwill related to the sale of business unit	$ (3,115)

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 565,698	$ 565,698
Impairment Charges	(1,511)	(1,511)
Accumulated Amortization	(233,070)	(199,619)
Foreign Currency Translation	171	1,830
Intangible assets, net	331,288	366,398
Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	172,431	172,431
Impairment Charges	(105)	(105)
Accumulated Amortization	(131,840)	(115,371)
Foreign Currency Translation		333
Intangible assets, net	40,486	57,288
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	282,744	282,744
Impairment Charges	(1,406)	(1,406)
Accumulated Amortization	(59,260)	(45,518)
Foreign Currency Translation	174	1,571
Intangible assets, net	222,252	237,391
Patents, Trademarks, Trade Names and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	110,523	110,523
Accumulated Amortization	(41,970)	(38,730)
Foreign Currency Translation	(3)	(74)
Intangible assets, net	$ 68,550	$ 71,719

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment Charges	$ 1,511	$ 1,511

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 10,695	$ 10,977	$ 32,786	$ 34,946
Amortization income from unfavorable lease commitments			$ 665	$ 588

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets - Estimated Net Amortization Expense (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2018 (remaining)	$ 10,760
2,019	40,144
2,020	28,125
2,021	20,248
2,022	17,619
2,023	17,253
Thereafter	$ 138,955

Debt - Additional Information (

Debt - Additional Information (Detail)

Apr. 11, 2018

Jul. 06, 2017

Dec. 14, 2016

Sep. 30, 2016USD ($)

Jun. 09, 2016USD ($)

Sep. 30, 2016USD ($)

Sep. 30, 2018USD ($)Institution

Dec. 31, 2017USD ($)

Mar. 31, 2018USD ($)

Nov. 30, 2017USD ($)

Aug. 30, 2017USD ($)

Jul. 31, 2017USD ($)

Mar. 31, 2017USD ($)

Nov. 30, 2016USD ($)

Debt Instrument [Line Items]

Applicable margin for Term Loan Credit agreement

1.75%

2.25%

Leverage ratio

1.25%

Floor rate

0.75%

0.75%

Decrease in base rate borrowings margin

0.75%

1.25%

Description of applicable margin

On April 11, 2018, the Company entered into Amendment No. 4 (the “Repricing Amendment 4”) to the Credit Agreement by and among the Company, the Lenders and Barclays Bank PLC, as administrative agent and collateral agent for the Lenders. The Repricing Amendment 4 decreased the applicable margin for the Company’s LIBOR rate term loan under the Credit Agreement to 1.75%, with a LIBOR rate floor of 0.75%. The margin for base rate borrowings decreased to 0.75% with a base rate floor of 1.75%. The period during which a prepayment premium may be required for a Repricing Transaction was reset to six months after the effective date of the Repricing Amendment 4.

The Repricing Amendment 3 decreased the applicable margin for the Company’s term loan under the Credit Agreement to 2.25% for LIBOR rate loans when the Total Leverage Ratio (as defined in the Credit Agreement) was at or above 1.25:1 and decreased to 2.00% when the Total Leverage Ratio was below 1.25:1, both with a LIBOR floor of 0.75%. The margin for base rate borrowings decreased to 1.25% when the Total Leverage Ratio is at or above 1.25:1 and to 1.00% when the Total Leverage Ratio is below 1.25:1.

Interest expense

$ 13,071,000

$ 23,001,000

Japan [Member]

Debt Instrument [Line Items]

Borrowing capacity in the form of letters of credit

$ 35,623,000

Number of financial institutions for available lines of credit and borrowing arrangements | Institution

2

Aggregate borrowings expire and renewed

3 month intervals

Total borrowings outstanding

$ 484,000

0

Austria [Member]

Debt Instrument [Line Items]

Interest on loans payable

Semi-annually

Maximum [Member] | Austria [Member]

Debt Instrument [Line Items]

Loan interest rate

2.00%

Minimum [Member] | Austria [Member]

Debt Instrument [Line Items]

Loan interest rate

0.75%

Interest Rate Hedge [Member]

Debt Instrument [Line Items]

Interest rate swap agreement, maturity date

Sep. 30, 2020

Interest rate swap agreement, notional amount

$ 290,000,000

305,000,000

Interest rate swap agreement, credit spread rate

1.75%

Revolving Lines of Credit [Member]

Debt Instrument [Line Items]

Borrowing capacity in the form of letters of credit

$ 10,995,000

Revolving Lines of Credit [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Line of credit base interest rate

1.25%

Newport [Member] | Revolving Lines of Credit [Member]

Debt Instrument [Line Items]

Total borrowings outstanding

$ 5,040,000

$ 2,965,000

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt [Member]

Debt Instrument [Line Items]

Secured term loan, face amount

$ 780,000,000

Debt instrument, interest rate terms

Borrowings under the Term Loan Facility bear interest per annum at one of the following rates selected by the Company: (a) a base rate determined by reference to the highest of (1) the federal funds effective rate plus 0.50%, (2) the “prime rate” quoted in The Wall Street Journal, (3) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month adjusted for certain additional costs, plus 1.00%, and (4) a floor of 1.75%, plus, in each case, an applicable margin; or (b) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing adjusted for certain additional costs, subject to a LIBOR rate floor of 0.75%, plus an applicable margin. The Company has elected the interest rate as described in clause (b). The Credit Agreement provides that all loans will be determined by reference to the Base Rate if the LIBOR rate cannot be ascertained, if regulators impose material restrictions on the authority of a lender to make LIBOR rate loans, or for other reasons. The Term Loan Facility was issued with original issue discount of 1.00% of the principal amount thereof.

Debt instrument, issue discount percentage on principal

1.00%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt [Member] | Federal Funds Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

0.50%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt [Member] | Adjusted One Month LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.00%

Period of Libor measurement

1 month

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt [Member] | Floor Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.75%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt [Member] | LIBOR Floor Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

0.75%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 1 [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

2.50%

Debt instrument, pre-payment premium percentage

1.00%

Debt instrument, pre-payment premium

$ 7,300,000

Debt instrument, prepaid principal amount

$ 50,000,000

Debt instrument, prepaid amount

$ 60,000,000

Deferred finance fees, original issue discount and re-pricing fee, gross

$ 28,747,000

Deferred finance fees, original issue discount and re-pricing fee, net

$ 5,581,000

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 1 [Member] | Maximum [Member]

Debt Instrument [Line Items]

Debt instrument, quarterly payment percentage

0.25

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 1 [Member] | Interest Rate Hedge [Member]

Debt Instrument [Line Items]

Interest rate swap agreement, maturity date

Sep. 30, 2020

Interest rate swap agreement, notional amount

$ 335,000,000

$ 335,000,000

$ 290,000,000

Interest rate swap agreement, interest rate

1.198%

1.198%

Interest rate swap agreement, credit spread rate

1.75%

Interest rate swap agreement, fair value

$ 8,539,000

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 1 [Member] | LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

3.50%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 2 [Member]

Debt Instrument [Line Items]

Secured term loan, face amount

348,464,000

Debt instrument, prepaid principal amount

425,000,000

$ 50,000,000

$ 50,000,000

$ 75,000,000

$ 50,000,000

$ 50,000,000

$ 40,000,000

Debt instrument, prepaid principal amount

$ 6,536,000

Debt instrument, stated percentage

3.80%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 2 [Member] | LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

2.75%

Newport [Member] | Term Loan Credit Agreement [Member] | Secured Debt Repricing Amendment 2 [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.75%

Newport [Member] | Asset Based Credit Agreement [Member]

Debt Instrument [Line Items]

Debt issuance cost capitalized

$ 1,201,000

Contractual term

5 years

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member]

Debt Instrument [Line Items]

Secured term loan, face amount

$ 50,000,000

Debt instrument, interest rate terms

Borrowings under the ABL Facility bear interest per annum at one of the following rates selected by the Company: (a) a base rate determined by reference to the highest of (1) the federal funds effective rate plus 0.50%, (2) the “prime rate” quoted in The Wall Street Journal, and (3) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for an interest period of one month adjusted for certain additional costs, plus 1.00%, plus, in each case, an initial applicable margin of 0.75%; and (b) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing adjusted for certain additional costs, plus an initial applicable margin of 1.75%.

Percentage of borrowing based on eligible accounts

85.00%

Percentage of borrowing based on lower of cost or market value of certain eligible inventory

65.00%

Percentage of borrowing based on net orderly liquidation value of certain eligible inventory

85.00%

Percentage of borrowing base

30.00%

Initial commitment fee percentage

0.375%

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member] | Maximum [Member]

Debt Instrument [Line Items]

Percentage of borrowing based on book value of certain eligible accounts

70.00%

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member] | Federal Funds Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

0.50%

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member] | Adjusted One Month LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.00%

Period of Libor measurement

1 month

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member] | LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.75%

Newport [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member] | Initial Margin Rate [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

0.75%

Newport [Member] | Asset Based Credit Agreement [Member] | Letter of Credit [Member]

Debt Instrument [Line Items]

Borrowing capacity in the form of letters of credit

$ 15,000,000

Debt - Schedule of Short Term D

Debt - Schedule of Short Term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Short term debt	$ 6,130	$ 2,972
Other Debt [Member]
Short-term Debt [Line Items]
Short term debt		7
Japan [Member] | Line of Credit [Member]
Short-term Debt [Line Items]
Short term debt	5,524	2,750
Japan [Member] | Receivables Financing Facility [Member]
Short-term Debt [Line Items]
Short term debt		$ 215
Austria [Member] | Loans Due Through March 2020 [Member]
Short-term Debt [Line Items]
Short term debt	$ 606

Debt - Schedule of Long Term De

Debt - Schedule of Long Term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long term debt	$ 342,970	$ 389,993
Term Loan Facility, Net [Member]
Debt Instrument [Line Items]
Long term debt	342,883	389,279
Austria [Member] | Loans Due Through March 2020 and Other Debt [Member]
Debt Instrument [Line Items]
Long term debt	$ 87	$ 714

Debt - Schedule of Long Term _2

Debt - Schedule of Long Term Debt (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Term Loan Facility, Net [Member]
Debt Instrument [Line Items]
Deferred financing fees, original issuance discount and re-pricing fee	$ 5,581	$ 9,185

Debt - Schedule of Contractual

Debt - Schedule of Contractual Maturities of Debt Obligations (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Maturities Of Long Term Debt [Abstract]
2018 (remaining)	$ 5,524
2,019	606
2,020	73
2,021	14
2,022	0
2,023	0
Thereafter	$ 348,464

Product Warranties - Product Wa

Product Warranties - Product Warranty Activities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Guarantees [Abstract]
Beginning of period	$ 10,104	$ 8,261
Provision for product warranties	11,448	11,941
Direct and other charges to warranty liability	(11,072)	(10,080)
End of period	$ 10,480	$ 10,122

Product Warranties - Product _2

Product Warranties - Product Warranty Activities (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Guarantees [Abstract]
Short-term product warranty	$ 10,067	$ 9,725
Long-term product warranty	$ 413	$ 397

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal corporate income tax rate		35.00%	21.00%	35.00%	35.00%
Adjustment to provisional tax expense	$ 863
Adjustment increase of effective tax rate			0.30%
Effective tax rate	18.50%	25.00%	17.60%	22.30%
Accrued interest on unrecognized tax benefits	$ 511		$ 511		$ 327
Gross unrecognized tax benefits excluding interest and penalties	32,535		32,535		$ 27,345
Net unrecognized tax benefit excluding interest and penalties that would impact effective tax rate	$ 25,008		25,008
Net unrecognized tax benefits, excluding interest and penalties, related to foreign tax positions			$ 1,521

Net Income Per Share - Computat

Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income	$ 93,277	$ 75,994	$ 321,260	$ 261,494
Denominator:
Shares used in net income per common share – basic	54,476,000	54,282,000	54,539,000	54,076,000
Effect of dilutive securities:
Restricted stock units, stock appreciation rights and shares issued under employee stock purchase plan	478,000	819,000	632,000	944,000
Shares used in net income per common share – diluted	54,954,000	55,101,000	55,171,000	55,020,000
Net income per common share:
Basic	$ 1.71	$ 1.40	$ 5.89	$ 4.84
Diluted	$ 1.70	$ 1.38	$ 5.82	$ 4.75

Net Income Per Share - Addition

Net Income Per Share - Additional Information (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Number of shares excluded from computation of diluted earnings per share	159,800	200	68,800	2,100

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Oct. 29, 2018	Jul. 25, 2011	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Stockholders Equity [Line Items]
Common stock, value of shares authorized to repurchase		$ 200,000,000
Stock repurchase, shares		2,588,000							818,000	0
Value of shares repurchased		$ 127,000,000	$ 75,000,000						$ 75,000,000
Average price of repurchased shares									$ 91.67
Cash dividends per common share			$ 0.20	$ 0.20	$ 0.18	$ 0.175	$ 0.175	$ 0.175	$ 0.58	$ 0.525
Dividend payment to common shareholders									$ 31,608,000	$ 28,403,000
Subsequent Event [Member]
Stockholders Equity [Line Items]
Dividend declared date	Oct. 29, 2018
Cash dividend to be paid	$ 0.20
Dividend to be paid date	Dec. 7, 2018
Dividend declared, shareholders of record date	Nov. 26, 2018

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense related to unvested stock-based awards granted to employees, officers and directors	$ 23,738
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, granted	260,341	388,137
Restricted stock units, weighted average grant date fair value	$ 112.49	$ 67.58
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, granted	0	0

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Total Stock-Based Compensation Expense Included in Company's Consolidated Statements of Income and Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$ 5,213	$ 4,845	$ 22,005	$ 19,834
Cost of Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	170	1,016	2,664	3,133
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	708	712	2,249	2,284
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$ 4,335	$ 3,117	$ 17,092	$ 14,417

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity for RSUs (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs/SARs – beginning of period	943,379
Granted	260,341	388,137
Vested	(487,856)
Forfeited	(62,021)
RSUs/SARs – end of period	653,889
RSUs/SARs, Weighted Average Grant Date Fair Value, Beginning of period	$ 47.57
Weighted Average Grant Date Fair Value, Granted	112.49	$ 67.58
Weighted Average Grant Date Fair Value, Vested	44.60
Weighted Average Grant Date Fair Value, Forfeited	65.37
RSUs/SARs, Weighted Average Grant Date Fair Value, end of period	$ 73.95
Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrued dividend shares	46
Weighted Average Grant Date Fair Value, Accrued dividend shares	$ 105.26

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity for SARs (Detail) - Stock Appreciation Rights (SARs) [Member]	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs/SARs – beginning of period | shares	282,907
Exercised, Outstanding SARs | shares	(100,683)
Forfeited or expired, Outstanding SARs | shares	(1,950)
RSUs/SARs – end of period | shares	180,274
RSUs/SARs, Weighted Average Grant Date Fair Value, Beginning of period | $ / shares	$ 28.62
Exercised, Weighted Average Grant Date Fair Value | $ / shares	28.77
Forfeited or expired, Weighted Average Grant Date Fair Value | $ / shares	29
RSUs/SARs, Weighted Average Grant Date Fair Value, end of period | $ / shares	$ 28.52

Business Segment, Geographic _3

Business Segment, Geographic Area, Product and Significant Customer Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018SegmentProductCustomer
Segment Reporting [Abstract]
Number of reportable segments | Segment	2
Number of product groups | Product	6
Number of customers with net revenues greater than 10% of total net revenues | Customer	2
Entity wide net revenue major customer percentage minimum	10.00%

Business Segment, Geographic _4

Business Segment, Geographic Area, Product and Significant Customer Information - Net Revenues by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total net revenues	$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Total net revenues	286,038	308,269	1,002,710	896,214
Light & Motion [Member]
Segment Reporting Information [Line Items]
Total net revenues	$ 201,114	$ 177,998	$ 611,857	$ 507,963

Business Segment, Geographic _5

Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Gross Profit to Consolidated Net Income (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Gross profit		$ 231,860	$ 227,995	$ 769,592	$ 653,125
Research and development		31,898	32,548	103,259	99,510
Selling, general and administrative		70,822	71,347	229,952	217,546
Acquisition and integration costs		36	2,466	(1,132)	4,698
Restructuring		1,364	10	3,374	2,596
Asset impairment					6,719
Fees and expenses related to repricing of term loan			492	378	492
Environmental costs				1,000
Amortization of intangible assets		10,695	10,977	32,786	34,946
Income from operations		117,045	110,155	399,975	286,618
Gain on sale of business	$ 74,856				74,856
Interest and other expense, net		2,529	8,784	10,173	24,846
Income before income taxes		114,516	101,371	389,802	336,628
Provision for income taxes		21,239	25,377	68,542	75,134
Net income		93,277	75,994	321,260	261,494
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Gross profit		132,835	141,438	462,418	410,228
Light & Motion [Member]
Segment Reporting Information [Line Items]
Gross profit		$ 99,025	$ 86,557	$ 307,174	$ 242,897

Business Segment, Geographic _6

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Capital Expenditures, Depreciation and Amortization Expense by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Capital expenditures	$ 15,067	$ 8,118	$ 36,885	$ 17,857
Depreciation and amortization	19,529	20,129	59,906	62,550
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Capital expenditures	9,532	4,212	22,701	10,114
Depreciation and amortization	5,083	5,058	15,180	15,277
Light & Motion [Member]
Segment Reporting Information [Line Items]
Capital expenditures	5,535	3,906	14,184	7,743
Depreciation and amortization	$ 14,446	$ 15,071	$ 44,726	$ 47,273

Business Segment, Geographic _7

Business Segment, Geographic Area, Product and Significant Customer Information - Segment Assets by Reportable Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Accounts receivable	$ 318,470	$ 300,308
Inventory, net	399,077	339,081
Total assets	2,564,596	2,414,018
Operating Segments [Member]
Segment Reporting Information [Line Items]
Accounts receivable	318,470	300,308
Inventory, net	399,077	339,081
Total assets	717,547	639,389
Operating Segments [Member] | Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Accounts receivable	195,244	201,318
Inventory, net	235,253	197,831
Total assets	430,497	399,149
Operating Segments [Member] | Light & Motion [Member]
Segment Reporting Information [Line Items]
Accounts receivable	138,599	119,934
Inventory, net	163,783	141,250
Total assets	302,382	261,184
Corporate, Eliminations & Other [Member]
Segment Reporting Information [Line Items]
Accounts receivable	(15,373)	(20,944)
Inventory, net	41
Total assets	$ (15,332)	$ (20,944)

Business Segment, Geographic _8

Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Assets to Consolidated Total Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	$ 2,564,596	$ 2,414,018
Other current assets	75,298	53,543
Property, plant and equipment, net	180,182	171,782
Other assets	42,390	37,883
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	717,547	639,389
Segment Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and cash equivalents, restricted cash and investments	630,030	553,976
Other current assets	75,298	53,543
Property, plant and equipment, net	180,182	171,782
Goodwill and intangible assets, net	919,149	957,445
Other assets	$ 42,390	$ 37,883

Business Segment, Geographic _9

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Net Revenues and Long-Lived Assets by Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Long-lived assets	214,538		214,538		$ 203,154
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	243,273	237,592	801,811	700,291
Long-lived assets	138,549		138,549		124,689
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	43,468	60,908	164,462	165,613
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	38,964	38,411	151,325	113,068
Asia (Excluding Korea and Japan) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	105,336	94,084	313,913	273,957
Long-lived assets	49,801		49,801		49,645
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	56,111	$ 55,272	183,056	$ 151,248
Long-lived assets	$ 26,188		$ 26,188		$ 28,820

Business Segment, Geographic_10

Business Segment, Geographic Area, Product and Significant Customer Information - Summary of Goodwill Associated with Reportable Segments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Goodwill	$ 587,861	$ 591,047	$ 588,585
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Goodwill	197,193	197,617
Light & Motion [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 390,668	$ 393,430

Business Segment, Geographic_11

Business Segment, Geographic Area, Product and Significant Customer Information - Worldwide Net Revenue for Each Group of Products (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue from External Customer [Line Items]
Net sales from product groups	$ 487,152	$ 486,267	$ 1,614,567	$ 1,404,177
Analytical and Control Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	26,727	33,068	91,932	97,689
Power Plasma and Reactive Gas Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	132,469	193,808	487,286	549,999
Vacuum Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	126,842	81,300	423,492	248,291
Lasers Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	63,999	56,623	209,459	153,866
Optics Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	57,836	52,548	169,415	149,759
Photonics Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups	$ 79,279	$ 68,920	$ 232,983	$ 204,573

Business Segment, Geographic_12

Business Segment, Geographic Area, Product and Significant Customer Information - Customers with Net Revenues Greater than 10% of Total Net Revenues (Detail) - Customer Concentration Risk [Member] - Sales Revenue, Net [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Applied Materials, Inc [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	12.00%	12.00%	13.00%	13.00%
LAM Research Corporation [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	8.00%	11.00%	11.00%	12.00%

Restructuring - Additional Info

Restructuring - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)PlantFacilityOffice
Reorganizations [Abstract]
Restructuring charges | $	$ 1,364	$ 10	$ 3,374	$ 2,596
Number of manufacturing plants | Plant				2
Number of facilities consolidated | Facility				1
Number of sales offices | Office				2

Restructuring - Schedule of Com

Restructuring - Schedule of Company's Restructuring Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring And Related Activities [Abstract]
Beginning of period			$ 3,244	$ 540
Charged to expense	$ 1,364	$ 10	3,374	2,596
Payments and adjustments			(3,963)	(608)
End of period	$ 2,655	$ 2,528	$ 2,655	$ 2,528

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - Electro Scientific Industries, Inc. [Member] - USD ($)	Oct. 29, 2018	Sep. 30, 2018
Asset Based Credit Agreement [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Secured term loan, face amount		$ 50,000,000
Subsequent Event [Member] | Asset Based Credit Agreement [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Secured term loan, face amount	$ 100,000,000
Subsequent Event [Member] | Definitive Merger Agreement [Member]
Subsequent Event [Line Items]
Business acquisition, share price	$ 30
Business acquisition, total cash consideration	$ 1,000,000,000
Subsequent Event [Member] | Maximum [Member] | Definitive Merger Agreement [Member]
Subsequent Event [Line Items]
Business acquisition, term loan debt financing	$ 650,000,000