MKS Instruments (MKSI) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 19, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	MKSI
Entity Registrant Name	MKS INSTRUMENTS INC
Entity Central Index Key	1,049,502
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		54,197,726
Entity Public Float			$ 5,217,380,580

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 644,345	$ 333,887
Short-term investments	73,826	209,434
Trade accounts receivable, net of allowance for doubtful accounts of $5,243 and $4,135 at December 31, 2018 and 2017, respectively	295,454	300,308
Inventories	384,689	339,081
Other current assets	65,790	53,543
Total current assets	1,464,104	1,236,253
Property, plant and equipment, net	194,367	171,782
Goodwill	586,996	591,047
Intangible assets, net	319,807	366,398
Long-term investments	10,290	10,655
Other assets	38,682	37,883
Total assets	2,614,246	2,414,018
Current liabilities:
Short-term debt	3,986	2,972
Accounts payable	83,825	82,518
Accrued compensation	82,350	96,147
Income taxes payable	16,358	21,398
Deferred revenue and customer advances	14,246	26,194
Other current liabilities	62,520	60,593
Total current liabilities	263,285	289,822
Long-term debt, net	343,842	389,993
Non-current deferred taxes	48,223	61,571
Non-current accrued compensation	55,598	51,700
Other liabilities	30,111	32,025
Total liabilities	741,059	825,111
Commitments and contingencies (Note 21)
Stockholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; none issued and outstanding
Common stock, no par value, 200,000,000 shares authorized; 54,039,554 and 54,355,535 shares issued and outstanding at December 31, 2018 and 2017, respectively	113	113
Additional paid-in capital	793,932	789,644
Retained earnings	1,084,797	795,698
Accumulated other comprehensive (loss) gain	(5,655)	3,452
Total stockholders' equity	1,873,187	1,588,907
Total liabilities and stockholders' equity	$ 2,614,246	$ 2,414,018

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 5,243	$ 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	54,039,554	54,355,535
Common stock, shares outstanding	54,039,554	54,355,535

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Revenues:
Net revenues		$ 2,075,108	$ 1,915,977	$ 1,295,342
Cost of revenues
Cost of revenues		1,095,632	1,024,526	729,723
Gross profit		979,476	891,451	565,619
Research and development		135,720	132,555	110,579
Selling, general and administrative		298,118	290,056	227,932
Acquisition and integration costs		3,113	5,332	27,279
Restructuring		3,567	3,920	642
Environmental costs		1,000
Asset impairment			6,719	5,000
Fees and expenses related to repricing of term loan		378	492	1,239
Amortization of intangible assets		43,521	45,743	35,681
Income from operations		494,059	406,634	157,267
Interest income		5,775	3,021	2,560
Interest expense		16,942	30,990	30,611
Gain on sale of business			74,856
Other expense, net		1,942	5,896	1,239
Income before income taxes		480,950	447,625	127,977
Provision for income taxes		88,054	108,493	23,168
Net income		392,896	339,132	104,809
Other comprehensive income:
Changes in value of financial instruments designated as cash flow hedges, net of tax expense (benefit)	[1]	4,942	(4,568)	3,380
Foreign currency translation adjustments, net of tax of $0 for 2018, 2017 and 2016		(14,161)	37,172	(22,713)
Unrecognized pension gain (loss), net of tax benefit	[2]	149	323	(266)
Unrealized (loss) gain on investments, net of tax (benefit) expense	[3]	(37)	1,072	223
Total comprehensive income		$ 383,789	$ 373,131	$ 85,433
Net income per share:
Basic		$ 7.22	$ 6.26	$ 1.96
Diluted		7.14	6.16	1.94
Cash dividends paid per common share		$ 0.78	$ 0.71	$ 0.68
Weighted average common shares outstanding:
Basic		54,406	54,137	53,472
Diluted		54,992	55,074	54,051
Products [Member]
Net Revenues:
Net revenues		$ 1,835,202	$ 1,701,301	$ 1,118,579
Cost of revenues
Cost of revenues		969,288	906,369	630,208
Services [Member]
Net Revenues:
Net revenues		239,906	214,676	176,763
Cost of revenues
Cost of revenues		$ 126,344	$ 118,157	$ 99,515
[1]	Tax expense (benefit) was $1,347, $(1,468), and $2,535 for the years ended December 31, 2018, 2017 and 2016, respectively.
[2]	Tax expense (benefit) was $86, $(88) and $(199) for the years ended December 31, 2018, 2017 and 2016, respectively.
[3]	Tax expense (benefit) was $2, $(769), and $167 for the years ended December 31, 2018, 2017 and 2016, respectively.

Consolidated Statements of Op_2

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Tax expense (benefit) on changes in value of financial instruments designated as cash flow hedges	$ 1,347	$ (1,468)	$ 2,535
Tax on foreign currency translation adjustments	0	0	0
Tax benefit (expense) on unrecognized pension gain (loss)	86	(88)	(199)
Tax (benefit) expense on unrealized gain (loss) on investments	$ 2	$ (769)	$ 167

Consolidated Statements of Stoc

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, 2015	$ 1,160,881	$ 113	$ 744,725	$ 427,214	$ (11,171)
Beginning Balance, Shares at Dec. 31, 2015		53,199,720
Net issuance under stock-based plans	6,902		6,902
Net issuance under stock-based plans, Shares		517,939
Stock-based compensation	25,228		25,228
Tax effect from stock-based plans	1,254		1,254
Stock repurchase	$ (1,545)		(627)	(918)
Stock repurchase, shares	44,798	(44,798)
Cash dividend	$ (36,361)			(36,361)
Comprehensive income (net of tax):
Net income	104,809			104,809
Other comprehensive loss	(19,376)				(19,376)
Ending Balance at Dec. 31, 2016	1,241,792	$ 113	777,482	494,744	(30,547)
Ending Balance, Shares at Dec. 31, 2016		53,672,861
Net issuance under stock-based plans	(12,216)		(12,216)
Net issuance under stock-based plans, Shares		682,674
Stock-based compensation	$ 24,378		24,378
Stock repurchase, shares	0
Cash dividend	$ (38,178)			(38,178)
Comprehensive income (net of tax):
Net income	339,132			339,132
Other comprehensive loss	33,999				33,999
Ending Balance at Dec. 31, 2017	1,588,907	$ 113	789,644	795,698	3,452
Ending Balance, Shares at Dec. 31, 2017		54,355,535
Net issuance under stock-based plans	(11,104)		(11,104)
Net issuance under stock-based plans, Shares		502,150
Stock-based compensation	27,262		27,262
Stock repurchase	$ (75,000)		(11,870)	(63,130)
Stock repurchase, shares	818,000	(818,131)
Cash dividend	$ (42,405)			(42,405)
Accounting Standards Codification Topic 606 adjustment	1,738			1,738
Comprehensive income (net of tax):
Net income	392,896			392,896
Other comprehensive loss	(9,107)				(9,107)
Ending Balance at Dec. 31, 2018	$ 1,873,187	$ 113	$ 793,932	$ 1,084,797	$ (5,655)
Ending Balance, Shares at Dec. 31, 2018		54,039,554

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 392,896	$ 339,132	$ 104,809
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	79,853	82,556	65,926
Amortization of inventory step-up adjustment to fair value			15,090
Amortization of debt issuance cost and original issue discount	4,718	10,699	9,265
Stock-based compensation	27,262	24,378	25,228
Provision for excess and obsolete inventory	22,324	20,213	16,039
Provision for doubtful accounts	1,435	825	1,109
Deferred income taxes	(19,388)	(4,831)	(38,822)
Excess tax benefits from stock-based compensation			(1,468)
Asset impairment		6,719	5,000
Gain on sale of business		(74,856)
Other	2,649	824	256
Changes in operating assets and liabilities:
Trade accounts receivable	(546)	(44,077)	(58,111)
Inventories	(73,779)	(72,471)	(13,798)
Income taxes	(11,430)	12,805	30,914
Other current and non-current assets	(1,639)	(8,631)	(12,165)
Accrued compensation	(8,649)	32,502	10,965
Other current and non-current liabilities	(3,948)	18,030	3,681
Accounts payable	2,023	11,405	16,180
Net cash provided by operating activities	413,781	355,222	180,098
Cash flows from investing activities:
Acquisition of business, net of cash acquired			(939,591)
Net proceeds from sale of business		72,509
Purchases of investments	(253,598)	(229,557)	(268,458)
Maturities of investments	181,749	157,342	160,917
Sales of investments	207,542	53,564	338,996
Purchases of property, plant and equipment	(62,941)	(31,287)	(19,123)
Other		66	273
Net cash provided by (used in) investing activities	72,752	22,637	(726,986)
Cash flows from financing activities:
Proceeds from short-term borrowings	67,629	28,360	18,964
Payments of short-term borrowings	(67,163)	(29,711)	(11,742)
Proceeds from long-term borrowings	40	191	744,653
Payments of long-term borrowings	(50,003)	(228,141)	(153,395)
Repurchases of common stock	(75,000)		(1,545)
Net proceeds related to employee stock awards	(11,104)	(12,216)	(1,922)
Dividend payments	(42,405)	(38,178)	(36,361)
Excess tax benefit from stock-based compensation			1,468
Net cash (used in) provided by financing activities	(178,006)	(279,695)	560,120
Effect of exchange rate changes on cash and cash equivalents	1,931	1,813	(6,896)
Increase in cash and cash equivalents	310,458	99,977	6,336
Cash and cash equivalents, including restricted cash, at beginning of year	333,887	233,910	227,574
Cash and cash equivalents, including restricted cash, at end of year	644,345	333,887	233,910
Cash paid during the period for:
Interest	14,593	20,467	20,839
Income taxes	$ 91,765	$ 104,691	$ 44,967

Business Description

Business Description	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description	1) Business Description MKS Instruments, Inc. (“MKS” or the “Company”) was founded in 1961 and 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. 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 The Company has two reportable segments: Vacuum & Analysis and Light & Motion.

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	2) Basis of Presentation The consolidated financial statements include the accounts of MKS Instruments, Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of these 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 financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going 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 it service 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. Twelve Months Ended December 31, 2017 As previously Adjustment As revised Net revenues: Products $ 1,723,433 $ (22,132 ) $ 1,701,301 Services 192,544 22,132 214,676 Total net revenues 1,915,977 — 1,915,977 Cost of revenues: Cost of products 901,546 4,823 906,369 Cost of services 122,980 (4,823 ) 118,157 Total cost of revenues $ 1,024,526 $ — $ 1,024,526 Twelve Months Ended December 31, 2016 As previously Adjustment As revised Net revenues: Products $ 1,134,013 $ (15,434 ) $ 1,118,579 Services 161,329 15,434 176,763 Total net revenues 1,295,342 — 1,295,342 Cost of revenues: Cost of products 627,850 2,358 630,208 Cost of services 101,873 (2,358 ) 99,515 Total cost of revenues $ 729,723 $ — $ 729,723

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3) Summary of Significant Accounting Policies 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 twelve months ended December 31, 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 year ended December 31, 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 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 December 31, 2018 contained a significant financing component. Contract assets as of January 1 and December 31, 2018 were $3,065 and $3,624, 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 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 December 31, 2018, as the majority have a duration of less than one year. A rollforward of the Company’s deferred revenue and customer advances is as follows: Year Ended Beginning balance, January 1(1) $ 27,800 Amount of deferred revenue and customer advances recognized in income(3) (83,497 ) Additions to deferred revenue and customer advances 73,171 Ending balance, December 31(2) $ 17,474 (1) Beginning deferred revenue and customer advances as of January 1, 2018 included $12,842 of current deferred revenue, $3,126 of long-term deferred revenue and $13,352 of current customer advances, net of a $1,520 adjustment related to the adoption of ASC 606. (2) Ending deferred revenue and customer advances as of December 31, 2018 included $8,134 of current deferred revenue, $3,228 of long-term deferred revenue and $6,112 of current customer advances. (3) The deferred revenue and customers advances recognized in income that relates to fiscal year 2018 was $61,012. 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: Year Ended December 31, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,080,343 $ 754,859 $ 1,835,202 Services 180,519 59,387 239,906 Total net revenues $ 1,260,862 $ 814,246 $ 2,075,108 Year Ended December 31, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,047,639 $ 653,662 $ 1,701,301 Services 159,818 54,858 214,676 Total net revenues $ 1,207,457 $ 708,520 $ 1,915,977 Year Ended December 31, 2016 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 731,364 $ 387,215 $ 1,118,579 Services 140,927 35,836 176,763 Total net revenues $ 872,291 $ 423,051 $ 1,295,342 Product revenue, excluding revenue from certain custom products, is recorded at a point in time, while the majority of service revenue and revenue from certain custom products is recorded over time. Refer to Note 19 for revenue by reportable segment, geography and groupings of similar products. Accounts Receivable Allowances Accounts receivable allowances include sales returns and bad debt allowances. The Company monitors and tracks the amount of product returns and reduces revenue at the time of shipment for the estimated amount of such 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. Research and Development Research and development costs are expensed as incurred and consist mainly of compensation-related expenses and project materials. The Company’s research and development efforts include numerous projects, which generally have a duration of 3 to 30 months. Acquired in-process Advertising Costs Advertising costs are expensed as incurred and were immaterial in 2018, 2017 and 2016. Stock-Based Compensation The accounting for share-based compensation expense requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and directors based on estimated fair values. For restricted stock units (“RSUs”), the fair value is the fair value on the date of grant that normally vests over a three year period. The Company also provides employees the opportunity to purchase shares through an employee stock purchase plan. For shares issued under its employee stock purchase plan, the Company has estimated the fair value on the date of grant using the Black Scholes pricing model, which is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, expected life, risk-free interest rate and expected dividends. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Management determined that blended volatility, a combination of historical and implied volatility, is more reflective of market conditions and a better indicator of expected volatility than historical or implied volatility alone. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and the Company uses different assumptions, its stock-based compensation expense could be materially different in the future. Accumulated Other Comprehensive Income For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the year. Translation adjustments resulting from this process are recorded to Accumulated Other Comprehensive Income (“OCI”). Unrealized gains and losses on securities classified as available-for-sale Net Income Per Share Basic net income per share is based on the weighted average number of common shares outstanding, and diluted net income per share is based on the weighted average number of common shares outstanding and all potential dilutive common equivalent shares outstanding. The dilutive effect of options is determined under the treasury stock method using the average market price for the period. Common equivalent shares are included in the per share calculations when the effect of their inclusion would be dilutive. Cash and Cash Equivalents and Investments All highly liquid investments with a maturity date of three months or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities is determined at the time of purchase. Debt securities that the Company does not have the intent and ability to hold to maturity are classified as “available-for-sale” The Company classifies investments with maturity dates greater than twelve months in short-term investments rather than long-term investments. This method classifies these securities as current based on the nature of the securities and the availability for use in current operations. The Company believes this method is preferable because it is more reflective of the Company’s assessment of its overall liquidity position. The Company reviews its investment portfolio on a quarterly basis to identify and evaluate individual investments that have indications of possible impairment. The factors considered in determining whether a loss is other-than-temporary include: the length of time and extent to which fair market value has been below the cost basis, the financial condition and near-term prospects of the issuer, credit quality, and the Company’s ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in fair value. Concentrations of Credit Risk The Company’s significant concentrations of credit risk consist principally of cash and cash equivalents, investments, forward exchange contracts and trade accounts receivable. The Company maintains cash and cash equivalents with financial institutions including some banks with which it had borrowings. The Company maintains investments primarily in U.S. Treasury and government agency securities and corporate debt securities. The Company enters into forward currency contracts with high credit-quality financial institutions in order to minimize credit risk exposure. The Company’s largest customers are primarily concentrated in the semiconductor industry, and a limited number of these customers account for a significant portion of the Company’s revenues. The Company regularly monitors the creditworthiness of its customers and believes it has adequately provided for potential credit loss exposures. Credit is extended for all customers based primarily on financial condition, and collateral is not required. The Company had one customer, Applied Materials, Inc., comprising 12%, 13% and 14% of net revenues for 2018, 2017 and 2016, respectively, and another customer, Lam Research Corporation, comprising 11%, 12% and 11% of net revenues for 2018, 2017 and 2016, respectively. During the years 2018, 2017 and 2016, approximately 55%, 57% and 56% of the Company’s net revenues, respectively, were from sales to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were no customers that represented 10% or more of the Company’s accounts receivable balance as of December 31, 2018. One customer, Applied Materials, Inc., represented 10% or more of the Company’s accounts receivable balance as of December 31, 2017. Inventories Inventories are stated at the lower of cost or market, cost being determined using a standard costing system which approximates cost based on a first-in, first-out Property, Plant and Equipment Property, plant and equipment are stated at cost. Expenditures for major renewals and betterments that extend the useful lives of property, plant and equipment are capitalized. Expenditures for maintenance and repairs are charged to expense as incurred. When assets are sold or otherwise disposed of, the cost and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is recognized in earnings. Depreciation is provided on the straight-line method over the estimated useful lives of ten to fifty years for buildings and three to sixteen years for machinery and equipment, furniture and fixtures and office equipment, which includes enterprise resource planning software. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the leased asset. Intangible Assets Intangible assets resulting from the acquisitions of businesses are estimated by management based on the fair value of assets acquired. These include acquired customer lists, technology, patents, trade names, covenants not to compete and IPR&D. Intangible assets are amortized from one to eighteen years on a straight-line basis which represents the estimated periods of benefit and the expected pattern of consumption. Goodwill Goodwill is the amount by which the cost of acquired net assets exceeded the fair value of those net assets on the date of acquisition. The Company allocates goodwill to reporting units at the time of acquisition or when there is a change in the reporting structure and bases that allocation on which reporting units will benefit from the acquired assets and liabilities. Reporting units are defined as operating segments or one level below an operating segment, referred to as a component. The Company assesses goodwill for impairment on an annual basis as of October 31 or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The estimated fair value of the Company’s reporting units are based on discounted cash flow models derived from internal earnings and internal and external market forecasts. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates, projected revenues and projected profit margins. Discount rates are based on a weighted average cost of capital (“WACC”), which represents the average rate a business must pay its providers of debt and equity. The WACC used to test goodwill is derived from a group of comparable companies. Assumptions in estimating future cash flows are subject to a high degree of judgment and complexity. The Company makes every effort to forecast these future cash flows as accurately as possible with the information available at the time the forecast is developed. In performing the Company’s annual goodwill impairment test, the Company is permitted to first assess qualitative factors to determine whether it is more likely than not that the fair value of our reporting unit is less than its carrying amount, including goodwill. In performing the qualitative assessment, the Company considers certain events and circumstances specific to the reporting unit and to the entity as a whole, such as macroeconomic conditions, industry and market considerations, overall financial performance and cost factors when evaluating whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. The Company is also permitted to bypass the qualitative assessment and proceed directly to the quantitative test. If the Company chooses to undertake the qualitative assessment and concludes that it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the Company would then proceed to the quantitative impairment test. In the quantitative assessment, the Company compares the fair value of the reporting unit to its carrying amount, which includes goodwill. If the fair value exceeds the carrying value, no impairment loss exists. If the fair value is less than the carrying amount, a goodwill impairment loss is measured and recorded. 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 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. As of October 31, 2018, the Company performed its annual impairment assessment of goodwill using the qualitative assessment and determined that it is more likely than not that the fair values of the reporting units exceed their carrying amount. Impairment of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets whenever events and changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. This periodic review may result in an adjustment of estimated depreciable lives or asset impairment. When indicators of impairment are present, the carrying values of the asset are evaluated in relation to their operating performance and future undiscounted cash flows of the underlying business. If the future undiscounted cash flows are less than their carrying value, impairment exists. The impairment is measured as the difference between the carrying value and the fair value of the underlying asset. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk. In 2017, the Company recorded an impairment charge of $6,719 related to certain long-lived assets as a result of consolidating two manufacturing plants. Foreign Exchange The functional currency of the majority of the Company’s foreign subsidiaries is the applicable local currency. For those subsidiaries, assets and liabilities are translated to U.S. dollars at year-end Net foreign exchange losses resulting from re-measurement re-measurement Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and also for operating loss and tax credit carry-forwards. On a quarterly basis, the Company evaluates both the positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income in each jurisdiction of the right type to realize the assets. The Company records a valuation allowance to reduce its net deferred tax assets to the amount that is expected to be realized. To the extent the Company establishes a valuation allowance an expense will be recorded as a component of the provision for income taxes on the statement of operations. During 2016, the Company increased its valuation allowance by $6,400 primarily related to the addition of historical valuation allowances for Newport Corporation (“Newport”) and its subsidiaries which were included as a result of the acquisition in April 2016. As a result, the valuation allowance was $12,527 at December 31, 2016. During 2017, the Company increased its valuation allowance by $1,102, primarily related to certain state tax credits. As a result, the valuation allowance was $13,629 at December 31, 2017. During 2018, the Company increased its valuation allowance by $4,307 which is attributable to certain tax credit and net operating loss carry forward amounts. As a result, the valuation allowance was $17,936 at December 31, 2018. Accounting for income taxes requires a two-step re-evaluates On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (the “Act”), which included significant changes to U.S. tax law. Some of the more significant changes impacting the Company are the reduction of the U.S. federal corporate income tax rate from 35.0% to 21.0% as of January 1, 2018, the implementation of a territorial tax system and the imposition of a transition tax on deemed repatriated cumulative earnings of foreign subsidiaries (“Transition Tax”). Income tax effects resulting from changes in tax are generally accounted for by the Company in the period in which the law is enacted and the effects are recorded as a component of provision for income taxes from continuing operations. On December 22, 2017, the Securities and Exchange Commission Staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to provide guidance for reporting entities’ ability to timely complete the accounting for certain income tax effects of the Act and allowed a measurement period up to one year from the enactment date of the “Act”. The Company has obtained, prepared and analyzed the information needed to complete the accounting requirements under Accounting Standards Codification (“ASC”) Topic 740 and as a result, in accordance with SAB 118, the Company has finalized and recorded the effects of the Act during the quarter ended December 31, 2018. The ultimate impact of the Act on the Company is based upon the Company’s understanding and interpretation of the regulatory guidance that has been issued regarding the Act.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	12 Months Ended
	Dec. 31, 2018
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	4) Recently Issued Accounting Pronouncements In October 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-16, In August 2018, the FASB issued ASU 2018-15, Other-Internal-Use 350-40): internal-use internal-use In March 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-05, In August 2017, the FASB issued ASU 2017-12, In May 2017, the FASB issued ASU 2017-09, In March 2017, the FASB issued ASU 2017-07, In November 2016, the FASB issued ASU 2016-18, 2016-15. beginning-of-period end-of-period 2016-15. In October 2016, the FASB issued ASU 2016-16, In August 2016, the FASB issued ASU 2016-15, In February 2016, the FASB issued ASU 2016-02, 2018-01 2018-10 2018-11 right-of-use In January 2016, the FASB issued ASU 2016-01, “Financial 825-10)-Recognition In May 2014, the FASB issued ASU 2014-09, 2016-08 2016-10 2016-12 2016-20 2017-13 2017-14

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	5) Investments Investments classified as short-term consist of the following: Years Ended December 31, 2018 2017 Available-for-sale Time deposits and certificates of deposit $ 102 $ 9,757 Bankers’ acceptance drafts 989 5,330 Asset-backed securities 9,113 36,990 Commercial paper 19,359 13,750 Corporate obligations 9,352 77,821 Municipal bonds — 1,970 U.S. treasury obligations 13,298 28,078 U.S. agency obligations 21,613 35,738 $ 73,826 $ 209,434 Investments classified as long-term consist of the following: Years Ended December 31, 2018 2017 Available-for-sale Group insurance contracts $ 5,890 $ 6,255 Cost method investments: Minority interest in a private company 4,400 4,400 $ 10,290 $ 10,655 The following table shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale As of December 31, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Short-term investments: Available-for-sale Time deposits and certificates of deposit $ 102 $ — $ — $ 102 Bankers’ acceptance drafts 989 — — 989 Asset-backed securities 9,121 1 (9 ) 9,113 Commercial paper 19,504 — (145 ) 19,359 Corporate obligations 9,367 — (15 ) 9,352 U.S. treasury obligations 13,294 4 — 13,298 U.S. agency obligations 21,617 2 (6 ) 21,613 $ 73,994 $ 7 $ (175 ) $ 73,826 As of December 31, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale Group insurance contracts $ 5,546 $ 344 $ — $ 5,890 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale 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 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 Interest income is accrued as earned. Dividend income is recognized as income on the date the stock trades “ex-dividend.”

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	6) 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 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. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2018, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 180,340 $ 180,340 $ — $ — Time deposits and certificates of deposit 850 — 850 — Commercial paper 2,687 — 2,687 — U.S. agency obligations 3,418 — 3,418 — Restricted cash – money market funds 110 110 — — Available-for-sale Time deposits and certificates of deposit 102 — 102 — Bankers’ acceptance drafts 989 — 989 — Asset-backed securities 9,113 — 9,113 — Commercial paper 19,359 — 19,359 — Corporate obligations 9,352 — 9,352 — U.S. treasury obligations 13,298 — 13,298 — U.S. agency obligations 21,613 — 21,613 — Group insurance contracts 5,890 — 5,890 — Derivatives – currency forward contracts 2,485 — 2,485 — Funds in investments and other assets: Israeli pension assets 14,408 — 14,408 — Derivatives – interest rate hedge – non-current 6,083 — 6,083 — Total assets $ 290,097 $ 180,450 $ 109,647 $ — Liabilities: Derivatives – currency forward contracts $ 1,168 $ — $ 1,168 $ — Reported as follows: Assets: Cash and cash equivalents, including restricted cash(1) $ 187,405 $ 180,450 $ 6,955 $ — Short-term investments 73,826 — 73,826 — Other current assets 2,485 — 2,485 — Total current assets $ 263,716 $ 180,450 $ 83,266 $ Long-term investments(2) $ 5,890 $ — $ 5,890 $ — Other assets 20,491 — 20,491 — Total long-term assets $ 26,381 $ — $ 26,381 $ — Liabilities: Other current liabilities $ 1,168 $ — $ 1,168 $ — (1) The cash and cash equivalent amounts presented in the table above does not include cash of $456,940 as of December 31, 2018. (2) The long-term investments presented in the table above do not include our minority interest investment in a private company, which is accounted for under the cost method. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2017, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2017 Quoted Prices in Active Markets for Identical Assets (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 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 – currency forward 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 – currency forward contracts $ 6,198 $ — $ 6,198 $ — Reported as follows: 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 (2) The long-term investments presented in the table above do not include our 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 As of December 31, 2018, available-for-sale The Company measures its debt and equity investments at fair value. The Company’s available-for-sale 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

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	7) 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 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 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 term loan balance, as described further in Note 13. This hedge fixes the interest rate paid on the hedged debt at 1.198% per annum plus the credit spread, which was 1.75% as of December 31, 2018, through September 30, 2020. The interest rate swap will be recorded at fair value on the balance sheet and changes in the fair value will be recognized in 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 $6,083 at December 31, 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 As of December 31, 2018 and 2017, the Company had outstanding forward foreign exchange contracts with gross notional values of $159,394 and $208,922, respectively. The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of December 31, 2018 and 2017: December 31, 2018 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value(1) U.S. Dollar/Japanese Yen $ 43,770 $ (478 ) U.S. Dollar/South Korean Won 59,149 570 U.S. Dollar/Euro 23,515 688 U.S. Dollar/U.K. Pound Sterling 11,827 323 U.S. Dollar/Taiwan Dollar 21,133 214 Total $ 159,394 $ 1,317 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: Years Ended December 31, Derivatives Designated as Hedging Instruments 2018 2017 Derivative assets: Forward exchange contracts(1) $ 2,485 $ 168 Foreign currency interest rate hedge(2) 6,083 6,179 Derivative liabilities: Forward exchange contracts(1) (1,168 ) (6,198 ) Total net derivative asset designated as hedging instruments $ 7,400 $ 149 (1) The derivative asset of $2,485 and derivative liability of $1,168 related to the forward foreign exchange contracts are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2018. The derivative asset of $168 and derivative liability of $6,198 related to the forward foreign exchange contracts are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2017. These forward 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 foreign currency interest rate hedge asset of $6,083 and $6,179 is classified in other assets in the consolidated balance sheet as of December 31, 2018 and 2017, respectively. The net amount of existing gains as of December 31, 2018 that is expected to be reclassified from OCI into earnings within the next 12 months is immaterial. The following table provides a summary of the gains (losses) on derivatives designated as cash flow hedging instruments: Years Ended December 31, Derivatives Designated as Cash Flow Hedging Instruments 2018 2017 2016 Forward exchange contracts: Net gain (loss) recognized in OCI(1) $ 6,289 $ (6,036 ) $ 5,914 Net loss reclassified from OCI into income(2) $ (3,367 ) $ (2,685 ) $ (1,414 ) (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified as cost of products. The following table provides a summary of losses on derivatives not designated as cash flow hedging instruments: Years Ended December 31, Derivatives Not Designated as Hedging Instruments 2018 2017 2016 Forward exchange contracts: Net gain (loss) recognized in income (1) $ 105 $ (3,416 ) $ (31 ) (1) The Company enters into forward 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 cash flow hedging instruments and gains or losses from these derivatives are recorded immediately in other expense, net in 2018 and 2017.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Inventories	8) Inventories Inventories consist of the following: Years Ended December 31, 2018 2017 Raw material $ 235,593 $ 191,351 Work-in-process 61,908 54,050 Finished goods 87,188 93,680 $ 384,689 $ 339,081 Inventory-related excess and obsolete charges of $22,324, $20,213 and $16,039 were recorded in cost of products in the years ended December 31, 2018, 2017 and 2016, respectively.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	9) Property, Plant and Equipment Property, plant and equipment consist of the following: Years Ended December 31, 2018 2017 Land $ 11,448 $ 11,650 Buildings 104,023 103,563 Machinery and equipment 330,821 317,073 Furniture and fixtures, office equipment and software 149,145 145,945 Leasehold improvements 66,569 65,293 Construction in progress 44,823 13,619 706,829 657,143 Less: accumulated depreciation 512,462 485,361 $ 194,367 $ 171,782 Depreciation of property, plant and equipment totaled $36,332, $36,813 and $30,245 for the years ended 2018, 2017 and 2016, respectively.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisitions and Dispositions	10) Acquisitions and Dispositions Electro Scientific Industries, Inc. See Note 22 for information on the acquisition of Electro Scientific Industries, Inc. Newport Corporation On April 29, 2016, the Company completed its acquisition of Newport pursuant to an Agreement and Plan of Merger, dated as of February 22, 2016 (the “Merger Agreement”), by and among the Company, PSI Equipment, Inc., a wholly owned subsidiary of the Company (“Merger Sub”), and Newport (the “Newport Merger”). At the effective time of the Newport Merger and pursuant to the terms and conditions of the Merger Agreement, each share of Newport’s common stock that was issued and outstanding immediately prior to the effective time of the Newport Merger was converted into the right to receive $23.00 in cash, without interest and subject to deduction for any required withholding tax. Newport’s innovative solutions leverage its expertise in advanced technologies, including lasers, photonics and precision motion equipment, and optical components and sub-systems, The purchase price of Newport consisted of the following: Cash paid for outstanding shares(1) $ 905,254 Settlement of share-based compensation awards(2) 8,824 Cash paid for Newport debt(3) 93,200 Total purchase price $ 1,007,278 Less: cash and cash equivalents acquired (61,463 ) Total purchase price, net of cash and cash equivalents acquired $ 945,815 (1) Represents cash paid of $23.00 per share for approximately 39,359,000 shares of Newport common stock, without interest and subject to a deduction for any required withholding tax. (2) Represents the vested but unissued portion of Newport share-based compensation awards as of the acquisition date of April 29, 2016. (3) Represents the cash paid for the outstanding balance of Newport’s senior secured revolving credit agreement. The Company funded the payment of the aggregate consideration with a combination of the Company’s available cash on hand and the proceeds from the Company’s senior secured term loan facility, as described in Note 13. Under the acquisition method of accounting, the total estimated acquisition consideration is allocated to the acquired tangible and intangible assets and assumed liabilities of Newport based on their fair values as of the acquisition date. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill. Goodwill and intangible assets will not be amortizable for tax purposes. The following table summarizes the allocation of the purchase price to the fair values assigned to assets acquired and liabilities assumed at the date of the Newport Merger: Current assets (including cash) $ 186,137 Inventory 142,714 Intangible assets 404,506 Goodwill 396,027 Property, plant and equipment 119,932 Long-term assets 22,725 Total assets acquired 1,272,041 Current liabilities 95,156 Intangible liability 4,302 Other long-term liabilities 165,305 Total liabilities assumed 264,763 Fair value of assets acquired and liabilities assumed 1,007,278 Less: cash and cash equivalents acquired (61,463 ) Total purchase price, net of cash and cash equivalents acquired $ 945,815 The fair value write-up write-up The fair value write-up value-in-use, The acquired intangible assets are being amortized on a straight-line basis, which approximates the economic use of the asset. The following table reflects the allocation of the acquired intangible assets and liabilities and related estimate of useful lives: Order backlog $ 12,100 1 year Customer relationships 247,793 6-18 Trademarks and trade names 55,900 Indefinite Developed technology 75,386 4-8 In-process 6,899 Undefined (1) Leasehold interest (favorable) 6,428 4-5 Total intangible assets $ 404,506 Leasehold interest (unfavorable) $ 4,302 (1) The useful lives of in-process The fair value of the acquired intangibles was determined using the income approach. In performing these valuations, the key underlying probability-adjusted assumptions of the discounted cash flows were projected revenues, gross margin expectations and operating cost estimates. The valuations were based on the information that was available as of the acquisition date and the expectations and assumptions that have been deemed reasonable by the Company’s management. There are inherent uncertainties and management judgment required in these determinations. This acquisition resulted in a purchase price that exceeded the estimated fair value of tangible and intangible assets, the excess amount of which was allocated to goodwill. The Company believes the amount of goodwill relative to identifiable intangible assets relates to several factors including: (1) potential buyer-specific synergies related to market opportunities for a combined product offering; and (2) potential to leverage the Company’s sales force to attract new customers and revenue and cross sell to existing customers. The results of this acquisition were included in the Company’s consolidated operations beginning on April 29, 2016. Newport constitutes the Company’s Light & Motion reportable segment (Note 19). Certain executives from Newport had severance provisions in their respective Newport employment agreements. The agreements included terms that were accounted for as dual-trigger arrangements. Through the Company’s acquisition accounting, the expense relating to these benefits was recognized in the combined entity’s financial statements, however, the benefit itself will not be distributed until the final provision is met by each eligible executive. The Company recorded costs of $6,635 and $3,334 as compensation expense and stock-based compensation expense, respectively, during 2016 in connection with these severance provisions. The shares underlying the restricted stock units and stock appreciation rights that are eligible for accelerated vesting if the executive exercises his rights are not issued as of each reporting period-end Pro Forma Results The following unaudited pro forma financial information presents the combined results of operations of the Company as if the Newport Merger had occurred on January 1, 2015. The unaudited pro forma financial information is not necessarily indicative of what the Company’s condensed consolidated results of operations actually would have been had the acquisition occurred at the beginning of each year. In addition, the unaudited pro forma financial information does not attempt to project the future results of operations of the combined company. 2016 Total net revenues $ 1,475,637 Net income 111,076 Net income per share: Basic $ 2.08 Diluted $ 2.06 The unaudited pro forma financial information above gives effect primarily to the following: (1) Incremental amortization and depreciation expense related to the estimated fair value of identifiable intangible assets and property, plant and equipment from the purchase price allocation. (2) Revenue adjustments as a result of the reduction in deferred revenue related to its estimated fair value. (3) Incremental interest expense related to the Company’s term loan credit agreement. (4) The exclusion of acquisition costs and inventory step-up (5) The estimated tax impact of the above adjustments. Cost Method Investment in a Private Company In April 2016, the Company invested $9,300 for a minority interest in a private company, which operates in the field of semiconductor process equipment instrumentation. The Company accounted for this investment using the cost method of accounting. During the fourth quarter of 2016, the Company recognized an impairment loss on this investment of $5,000 based upon financial information of this private company. In July 2017, the Company invested an additional $100 in this private company. 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	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	11) 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 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 losses were as follows: 2018 2017 Gross Carrying Amount Accumulated Impairment Loss Net Gross Carrying Amount Accumulated Impairment Loss Net Beginning balance at January $ 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 (4,051 ) — (4,051 ) 10,439 — 10,439 Ending balance at December 31 $ 731,272 $ (144,276 ) $ 586,996 $ 735,323 $ (144,276 ) $ 591,047 (1) In 2017, the Company sold its Data Analytics business and, as a result, charged the related goodwill of $3,115 to the gain on sale of business. (2) In 2017, the Company recorded an impairment loss of $4,862 related to the write-off Intangible Assets The Company is required to test certain long-lived assets when indicators of impairment are present. For the purposes of the impairment test, long-lived assets are grouped with other assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. During 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. Components of the Company’s acquired intangible assets are comprised of the following: As of December 31, 2018 Gross Impairment Charges(1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (137,283 ) $ (73 ) $ 34,970 Customer relationships 282,744 (1,406 ) (63,788 ) (269 ) 217,281 Patents, trademarks, trade names and other 110,523 — (42,954 ) (13 ) 67,556 $ 565,698 $ (1,511 ) $ (244,025 ) $ (355 ) $ 319,807 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 Aggregate amortization expense related to acquired intangible assets for the years 2018, 2017 and 2016 was $43,521, $45,743 and $35,681, respectively. The amortization expense in 2018, 2017 and 2016 is net of $885, $811 and $569, 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: Year Amount 2019 $ 40,073 2020 $ 28,076 2021 $ 20,206 2022 $ 17,584 2023 $ 17,220 Thereafter $ 138,693

Product Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2018
Guarantees and Product Warranties [Abstract]
Product Warranties	12) Product Warranties The Company provides for 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: Years Ended December 31, 2018 2017 Beginning balance $ 10,104 $ 8,261 Provision for product warranties 15,987 15,884 Direct and other charges to warranty liability (15,692 ) (14,041 ) Ending balance(1) $ 10,399 $ 10,104 (1) Short-term product warranty of $9,986 and long-term product warranty of $413, each as of December 31, 2018, are included within other current liabilities and other liabilities, respectively, within the accompanying consolidated balance sheet. Short-term product warranty of $9,719 and long-term product warranty of $385 as of December 31, 2017, are included within other current liabilities and other liabilities, respectively, within the accompanying consolidated balance sheet.

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	13) Debt Term Loan Credit Agreement In connection with the completion of 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 in the original principal amount of $780,000, subject to increase at the Company’s option and subject to receipt of lender commitments 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 December 31, 2018. The notional amount of this transaction was $290,000 and had a fair value of $6,083 at December 31, 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 December 31, 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 December 31, 2018 was 4.1%. 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 December 31, 2018, the remaining balance of the deferred finance fees, original issue discount and repricing fee related to the Term Loan Facility was $4,708. 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. As a result of our Total Leverage Ratio, we were not required to make a prepayment of excess cash flow for the fiscal year end 2018. 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 December 31, 2018 on the Term Loan Facility we had in place as of December 31, 2018. The Company is no longer required to make any scheduled principal payments on the Term Loan Facility we had in place as of December 31, 2018 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 December 31, 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 December 31, 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 during 2018 was immaterial. Commencing with the completion of the first fiscal quarter ending after the closing of the ABL Facility, the commitment fee is subject to downward adjustment based on the amount of average unutilized commitments for the three month period immediately preceding such adjustment date. The Company must also pay customary letter of credit fees and agency fees. 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 December 31, 2018 of up to an equivalent of $20,856 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. There were no borrowings outstanding under these arrangements at December 31, 2018 and 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 December 31, 2018 of up to an equivalent of $11,335 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 $3,389 and $2,965 at December 31, 2018 and 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%—2.00%. December 31, 2018 December 31, 2017 Short-term debt: Japanese lines of credit $ 2,724 $ 2,750 Japanese receivables financing facility 665 215 Other debt 597 7 $ 3,986 $ 2,972 December 31, 2018 December 31, 2017 Long-term debt: Austrian loans due through March 2020 and other debt $ 86 $ 714 Term Loan Facility, net (1) 343,756 389,279 $ 343,842 $ 389,993 (1) Net of deferred financing fees, original issuance discount and re-pricing The Company recognized interest expense of $16,942, $30,990 and $30,611 for the twelve months ended December 31, 2018, 2017 and 2016, respectively. Contractual maturities of the Company’s debt obligations as of December 31, 2018 are as follows: Year Amount 2019 $ 3,986 2020 $ 72 2021 $ 14 2022 $ — 2023 $ 348,464

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	14) Income Taxes The Act, which was enacted on December 22, 2017, reduced the U.S. federal corporate tax rate from 35% to 21% effective January 1, 2018, required companies to pay a one-time For the year ended December 31, 2018, the Company recognized a tax benefit of $625 related to an adjustment of the provisional estimates that had been previously recorded for the Act and included these adjustments as a component of income tax expense from continuing operations. The global intangible low-taxed A reconciliation of the Company’s effective tax rate to the U.S. federal statutory rate is as follows: Years Ended December 31, 2018 2017 2016 U.S. Federal income tax statutory rate 21.0 % 35.0 % 35.0 % Federal tax credits (0.7 ) (0.7 ) (1.8 ) State income taxes, net of federal benefit 1.3 1.0 0.8 Effect of foreign operations taxed at various rates (1.3 ) (12.1 ) (12.7 ) Qualified production activity tax benefit — (1.4 ) (2.9 ) Foreign derived intangible income (2.1 ) — — Global intangible low taxed income, net of foreign tax credits 0.4 — — Transition tax, net of foreign tax credits (0.1 ) 6.4 — Revaluation of U.S. deferred income taxes (0.3 ) (5.0 ) — Revaluation of prepaid taxes 1.6 — — Stock based compensation (1.3 ) (2.5 ) — Deferred tax asset valuation allowance — (0.1 ) 2.1 Release of income tax reserves (including interest) (0.4 ) (0.4 ) (2.4 ) Taxes on foreign dividends, net of foreign tax credits (1.0 ) 3.3 (2.2 ) Acquisition and integration related costs — — 1.5 Other 1.2 0.7 0.7 18.3 % 24.2 % 18.1 % The components of income from operations before income taxes and the related provision for income taxes consist of the following: Years Ended December 31, 2018 2017 2016 Income from operations before income taxes: United States $ 287,309 $ 224,979 $ 42,491 Foreign 193,641 222,646 85,486 $ 480,950 $ 447,625 $ 127,977 Current taxes: United States $ 41,428 $ 77,023 $ 17,693 State 8,094 6,149 2,359 Foreign 57,920 30,152 41,938 107,442 113,324 61,990 Deferred taxes: United States (2,533 ) (16,250 ) (23,604 ) State and Foreign (16,855 ) 11,419 (15,218 ) (19,388 ) (4,831 ) (38,822 ) Provision for income taxes $ 88,054 $ 108,493 $ 23,168 The significant components of the deferred tax assets and deferred tax liabilities are as follows: Years Ended December 31, 2018 2017 Deferred tax assets: Carry-forward losses and credits $ 23,675 $ 25,834 Inventory and warranty reserves 17,945 17,734 Accrued expenses and other reserves 10,260 15,393 Stock-based compensation 5,351 5,092 Executive supplemental retirement benefits 5,972 4,984 Other 2,396 597 Total deferred tax assets $ 65,599 $ 69,634 Deferred tax liabilities: Acquired intangible assets $ (74,120 ) $ (83,092 ) Depreciation and amortization (8,332 ) (10,150 ) Loan costs (1,108 ) (2,157 ) Foreign withholding taxes (3,176 ) (16,206 ) Unrealized gain (1,952 ) (469 ) Total deferred tax liabilities (88,688 ) (112,074 ) Valuation allowance (17,936 ) (13,629 ) Net deferred tax (liabilities) assets $ (41,025 ) $ (56,069 ) Due to the reduction in U.S. federal statutory tax rate resulting from the enactment of the Act, the Company recorded a provisional adjustment reducing its net deferred tax liabilities by $22,345 as of December 31, 2017. This provisional adjustment was finalized during the year ended December 31, 2018 and an additional tax provision of $2,614 was recorded. As of December 31, 2018, the Company has federal, state and foreign gross research and other tax credit carry-forwards of $29,858. Included in the total carry-forward are $15,081 of credits that can be carried forward indefinitely and the remaining credits expire at various dates through 2035. The Company also had, state and foreign gross net operating loss and capital loss carry-forwards of $43,715. Included in the total carry-forward are $36,057 of losses that can be carried forward indefinitely while the remaining losses expire at various dates through 2035. Although the Company believes that its tax positions are consistent with applicable U.S. federal, state and international laws, it maintains certain tax reserves as of December 31, 2018 in the event its tax positions were to be challenged by the applicable tax authority and additional tax assessed upon audit. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: Years Ended December 31, 2018 2017 2016 Balance at beginning of year $ 27,345 $ 25,465 $ 4,332 Increases/(decreases) for prior years 934 640 (195 ) Increases for the current year 6,091 4,340 23,940 Reductions related to expiration of statutes of limitations and audit settlements (1,686 ) (3,100 ) (2,612 ) Balance at end of year $ 32,684 $ 27,345 $ 25,465 As of December 31, 2018, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $32,684. As of December 31, 2017, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $27,345. The net increase from December 31, 2017 was primarily attributable to the addition of reserves for the federal transition tax from the Act along with certain non-U.S. The Company accrues interest and, if applicable, penalties for any uncertain tax positions. Interest and penalties are classified as a component of income tax expense. As of December 31, 2018, 2017 and 2016, the Company had accrued interest on unrecognized tax benefits of approximately $568, $327 and $491, respectively. Over the next 12 months it is reasonably possible that the Company may recognize approximately $2,150 of previously net unrecognized tax benefits, excluding interest and penalties, related to various U.S. federal, state and foreign tax positions primarily due to 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 IRS 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 United States 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 proposed adjustments through December 31, 2018. 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 2013 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. On a quarterly basis, the Company evaluates both positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income to realize the assets. During 2018, the Company increased its valuation allowance by $4,307, primarily attributable to certain tax credit and net operating loss carryforward amounts. During 2017, the Company increased its valuation allowance by $1,102, primarily related to certain state tax credits. During 2016, the Company increased its valuation allowance by $6,400, primarily related to the addition of historical valuation allowances for Newport and its subsidiaries which were included as a result of the acquisition in April 2016. The Act provided for a mandatory one-time No provision has been made for the deferred taxes related to certain outside basis differences in the Company’s non-US The Company’s Israeli subsidiaries have elected to be treated under a preferential Israeli tax regime under which their taxable income is taxed at reduced rates. These reduced rates range anywhere between 7.5% and 16%. One of the Company’s Israeli subsidiaries effectively settled an examination for tax years 2012 and 2013 during the quarter ended June 30, 2017.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Stockholders' Equity	15) Stockholders’ Equity Stock 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 2018, the Company repurchased approximately 818,000 shares of its common stock for $75,000 at an average price of $91.67 per share. During 2017, there were no repurchases of common stock. During 2016, the Company repurchased 44,798 shares of its common stock for $1,545 at an average price of $34.50 per share. 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 and if 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, third and fourth quarters of 2018, which totaled $42,405. The Company’s board of directors declared a cash dividend of $0.175 per share during the first, second, and third quarters of 2017, and $0.18 per share during the fourth quarter of 2017, which totaled $38,178. 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. On February 11, 2019, the Company’s Board of Directors declared a quarterly cash dividend of $0.20 per share to be paid on March 8, 2019 to Stockholders of record as of February 25, 2019.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	16) Stock-Based Compensation Employee Stock Purchase Plans The 2014 ESPP Plan was adopted by the Board of Directors on February 10, 2014 and approved by the Company’s stockholders on May 5, 2014. The 2014 ESPP Plan authorizes the issuance of up to an aggregate of 2,500,000 shares of common stock to participating employees. Offerings under the 2014 ESPP Plan commence on June 1 and December 1 and terminate, respectively, on November 30 and May 31. Historically, under the 2014 ESPP Plan, eligible employees could purchase shares of common stock through payroll deductions of up to 10% of their compensation or up to an annual maximum amount of $21,250. The price at which an employee’s purchase option was exercised for each offering period was the lower of (1) 85% of the closing price of the common stock on the Nasdaq Global Select Market on the day that each offering commences, or (2) 85% of the closing price on the day that the offering terminated. On January 31, 2017, the Compensation Committee of the Board of Directors approved an increase in the exercise price to the lower of (1) 90% of the closing price of the common stock on the Nasdaq Global Select Market on the day that each offering commences, or (2) 90% of the closing price on the day that each offering terminates. The increase in the exercise price became effective for the Offering commencing on June 1, 2017. As a result of this change, the annual maximum payroll deduction was increased from $21,250 to $22,500. During 2018, 2017, and 2016, the Company issued 105,672, 105,506, and 139,079 shares, respectively, of common stock to employees who participated in the 2014 ESPP Plan at exercise prices of $84.11 and $70.61 per share in 2018, $46.37 and $74.12 per share in 2017, and $31.40 and $35.16 per share in 2016. As of December 31, 2018, there were 1,926,731 shares reserved for future issuance under the 2014 ESPP Plan. Equity Incentive Plans The Company has granted 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. The 2014 Plan was adopted by the Board of Directors on February 10, 2014 and was approved by the Company’s stockholders on May 5, 2014. Up to 18,000,000 shares of common stock (subject to adjustment in the event of stock splits and other similar events) may be issued pursuant to awards granted under the 2014 Plan. The Company may grant options, RSUs, restricted stock, stock appreciation rights (“SARs”) and other stock-based awards to employees, officers, directors, consultants and advisors under the 2014 Plan. Any full-value awards granted under the 2014 Plan will be counted against the shares reserved for issuance under the 2014 Plan as 2.4 shares for each share of common stock subject to such award and any award granted under the 2014 Plan that is not a full-value award (including, without limitation, any option or SAR) will be counted against the shares reserved for issuance under the plan as one share for each one share of common stock subject to such award. “Full-value award” means any RSU, or other stock-based award with a per share price or per unit purchase price lower than 100% of fair market value on the date of grant. To the extent a share that was subject to an award that counted as one share is returned to the 2014 Plan, each applicable share reserve will be credited with one share. To the extent that a share that was subject to an award that counts as 2.4 shares is returned to the 2014 Plan, each applicable share reserve will be credited with 2.4 shares. As of December 31, 2018, there were 14,079,849 shares reserved for future issuance under the 2014 Plan. The Company’s 2004 Stock Incentive Plan (the “2004 Plan”) expired in March 2014 and no further awards may be granted under the 2004 Plan, although there are still outstanding RSUs which may vest under the 2004 Plan. The 2004 Plan, the 1995 Plan, the 1997 Director Stock Plan and the 2014 Plan are referred to herein as the “Plans.” RSUs granted to employees in 2018, 2017 and 2016 generally vest 33% per year on the anniversary of the date of grant. RSUs granted to certain employees who are at least 60 years old and have a minimum of 10 Years of Service (as defined in the applicable RSU agreement) are expensed immediately. RSUs granted to directors generally vest at the earliest of (1) one day prior to the next annual meeting, (2) 13 months from date of grant, or (3) the effective date of a change in control of the Company. Certain RSUs are subject to performance conditions (“performance shares”) under the Company’s 2004 Plan and 2014 Plan. Such performance shares are available, subject to time-based vesting conditions, if, and to the extent that, financial or operational performance criteria for the applicable period are achieved. Accordingly, the number of performance shares earned will vary based on the level of achievement of financial or operational performance objectives for the applicable period. 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 granted under any Newport equity plan, whether vested or unvested, that were outstanding immediately prior to the effective time of the Newport Merger. As of the effective time of the Newport Merger, based on a formula provided in the Merger Agreement, (a) the Newport RSUs were converted automatically into RSUs with respect to 360,674 shares of the Company’s common stock (the “Assumed RSUs”), and (b) the Newport stock appreciation rights were converted automatically into SARs with respect to 899,851 shares of the Company’s common stock (the “Assumed SARs”). Included in the total number of Assumed RSUs were 36,599 RSUs for outside directors that were part of the Newport Deferred Compensation Plan (the “DC Plan”), from which 19,137 underlying shares were released in May 2016, 5,515 shares were released in May 2017 and 5,561 shares were released in May 2018. As of December 31, 2018, 6,694 Company RSUs remained outstanding under the DC Plan, and an additional 66 shares of the Company’s common stock were added to the DC Plan due to reinvested dividends. As of December 31, 2017, 12,134 Company RSUs remained outstanding under the DC Plan, and an additional 122 shares of the Company’s common stock were added to the DC Plan due to reinvested dividends. As of December 31, 2016, 17,462 Company RSUs remained outstanding under the DC Plan, and an additional 187 shares of the Company’s common stock were added to the DC Plan due to reinvested dividends. These Assumed RSUs will not become issued shares until their respective release dates. The shares of the Company’s common stock that are subject to the Assumed SARs and the Assumed RSUs are issuable pursuant to the Company’s 2014 Plan. The 1,260,525 shares of the Company’s common stock that are issuable pursuant to the Assumed RSUs and the Assumed SARs under the 2014 Plan were registered under the Securities Act of 1933, as amended (“Securities Act”), on a registration statement on Form S-8. S-8. The following table presents the activity for RSUs under the Plans: Year Ended December 31, 2018 Non-vested RSUs Weighted Average Grant Date Fair Value Non-vested 943,379 $ 47.57 Accrued dividend shares 66 $ 94.11 Granted 266,411 $ 111.64 Vested (490,453 ) $ 44.70 Forfeited or expired (72,009 ) $ 66.22 Non-vested 647,394 $ 74.04 The following table presents the activity for SARs under the Plans: Year Ended December 31, 2018 Non-vested SARs Weighted Average Base Value SARs — beginning of period 282,907 $ 28.62 Exercised (103,419 ) $ 28.78 Forfeited or expired (1,950 ) $ 29.00 SARs Outstanding — end of period 177,538 $ 28.52 At December 31, 2018, the Company’s outstanding and exercisable SARs, the weighted-average base value, the weighted average remaining contractual life and the aggregate intrinsic value thereof, were as follows: Number Weighted Average Weighted Average Aggregate Intrinsic Value SARs outstanding and exercisable 177,538 $ 28.52 2.4 $ 6,408 The Company settles employee RSU vesting and SARs exercises with newly issued shares of the Company’s common stock. Stock-Based Compensation Expense The Company recognized the full impact of its share-based payment plans in the consolidated statements of operations and comprehensive income for the years 2018, 2017 and 2016. As of December 31, 2018, 2017, and 2016, the Company capitalized $471 of such cost on its consolidated balance sheet. The following table reflects the effect of recording stock-based compensation for the years 2018, 2017 and 2016: Years Ended December 31, 2018 2017 2016 Stock-based compensation expense by type of award: RSUs $ 24,883 $ 22,428 $ 23,302 SARs 98 529 700 Employee stock purchase plan 2,281 1,421 1,226 Total stock-based compensation $ 27,262 24,378 25,228 Windfall tax effect on stock-based compensation (8,277 ) (11,071 ) — Net effect on net income $ 18,985 $ 13,307 $ 25,228 Effect on net earnings per share: Basic $ 0.35 $ 0.25 $ 0.47 Diluted $ 0.35 $ 0.24 $ 0.47 The pre-tax Years Ended December 31, 2018 2017 2016 Cost of revenues $ 3,516 $ 3,894 $ 2,997 Research and development expense 2,750 2,816 2,529 Selling, general and administrative expense 20,996 17,668 19,702 Total pre-tax $ 27,262 $ 24,378 $ 25,228 Valuation Assumptions The Company determines the fair value of RSUs based on the closing market price of the Company’s common stock on the date of the award, and estimates the fair value of employee stock purchase plan rights using the Black-Scholes valuation model. Such values are recognized as expense on a straight-line basis for time-based awards and using the accelerated graded vesting method for performance-based awards, both over the requisite service periods, net of estimated forfeitures except for retirement eligible employees in which the Company expenses the fair value of the grant in the period the grant is issued. The estimation of stock-based awards that will ultimately vest requires significant judgment. 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 weighted average fair value per share of employee stock purchase plan rights granted in 2018, 2017 and 2016 was $21.74, $13.14, and $8.52, respectively. The fair value of the employees’ purchase plan rights was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions: Years Ended December 31, 2018 2017 2016 Employee stock purchase plan rights: Expected life (years) 0.5 0.5 0.5 Risk-free interest rate 1.8 % 0.8 % 0.5 % Expected volatility 38.6 % 26.5 % 25.4 % Expected annual dividends per share $ 0.76 $ 0.69 $ 0.68 Expected volatilities for 2018, 2017 and 2016 are based on a combination of implied and historical volatilities of the Company’s common stock; the expected life represents the weighted average period of time that options granted are expected to be outstanding giving consideration to vesting schedules and the Company’s historical exercise patterns; and the risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. The total intrinsic value of SARs exercised and the total fair value of RSUs vested during 2018, 2017 and 2016 was approximately $61,626, $60,302 and $18,844, respectively. As of December 31, 2018, the unrecognized compensation cost related to RSUs and SARs was approximately $19,039 and will be recognized over and estimated weighted average amortization period of 0.91 years.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Postemployment Benefits [Abstract]
Employee Benefit Plans	17) Employee Benefit Plans The Company has a 401(k) profit-sharing plan for U.S. employees meeting certain requirements in which eligible employees may contribute between 1% and 50% of their annual compensation to this plan, and, with respect to employees who are age 50 and older, certain specified additional amounts, limited by an annual maximum amount determined by the Internal Revenue Service. The Company, at its discretion, makes certain matching contributions to these plans based on participating employees’ contributions to the plans and their total compensation. The Company’s contributions were $6,093, $5,651 and $6,524 for 2018, 2017 and 2016, respectively. The Company maintains a bonus plan which provides cash awards to key employees, at the discretion of the compensation committee of the Board of Directors, based upon operating results and employee performance. In addition, the Company’s foreign locations also have various bonus plans based upon local operating results and employee performance. The total bonus expense was $38,254, $46,783 and $28,097 for 2018, 2017 and 2016, respectively. The Company provides supplemental retirement benefits for one of its current executive officers and a number of former retired executives. The total cost of these benefits was $4,609, $3,478 and $1,805 for 2018, 2017 and 2016, respectively. The accumulated benefit obligation was $20,644 and $15,929 at December 31, 2018 and 2017, respectively, which was included in other long-term liabilities. The Company also has a deferred compensation plan for certain Light & Motion segment executives. Defined Benefit Pension Plans As a result of the Newport Merger, the Company 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 assets and liabilities relating to former employees in the United Kingdom. The German plan is unfunded, as permitted under the plan and applicable laws. For financial reporting purposes, the calculation of net periodic pension costs was based upon a number of actuarial assumptions including a discount rate for plan obligations, an assumed rate of return on pension plan assets and an assumed rate of compensation increase for employees covered by the plan. All of these assumptions were based upon management’s judgment, considering all known trends and uncertainties. Actual results that differ from these assumptions would impact future expense recognition and the cash funding requirements of the Company’s pension plans. The net periodic benefit costs for the plans included the following components: Year Ended December 31, 2018 2017 Service cost $ 657 $ 708 Interest cost on projected benefit obligations 433 458 Expected return on plan assets (115 ) (116 ) Amortization of actuarial net loss 127 400 $ 1,102 $ 1,450 The changes in projected benefit obligations and plan assets, as well as the ending balance sheet amounts for the Company’s defined benefit plans, were as follows: Year Ended December 31, 2018 2017 Change in projected benefit obligations: Projected benefit obligations, beginning of year $ 25,736 $ 23,450 Service cost 657 708 Interest cost 433 458 Actuarial gain (98 ) (312 ) Benefits paid (895 ) (1,271 ) Currency translation adjustments (948 ) 2,703 Projected benefit obligations, end of year $ 24,885 $ 25,736 Change in plan assets: Fair value of plan assets, beginning of year $ 8,152 $ 7,672 Company contributions 324 324 (Loss) gain on plan assets (56 ) 177 Benefits paid (369 ) (722 ) Currency translation adjustments (229 ) 701 Fair value of plan assets, end of year 7,822 8,152 Net underfunded status $ (17,063 ) $ (17,584 ) Changes in plan assets and benefit obligations recognized in other comprehensive income included the following components: Year Ended December 31, 2018 2017 Amounts recognized in accumulated comprehensive income: Accumulated net actuarial gain $ 235 $ 235 Income tax (expense) benefit (86 ) 88 Accumulated other comprehensive gain $ 149 $ 323 As of December 31, 2018, the estimated benefit payments for the Company’s defined benefit plans for the next 10 years were as follows: Estimated benefit payments 2019 $ 1,046 2020 $ 1,252 2021 $ 1,210 2022 $ 1,312 2023 $ 1,129 2024-2028 $ 7,313 $ 13,262 The Company expects to contribute $1,660 to the plans during 2019. The weighted-average rates used to determine the net periodic benefit costs were as follows: December 31, 2018 Discount rate 1.9 % Rate of increase in salary levels 2.1 % Expected long-term rate of return on assets 1.9 % In determining the expected long-term rate of return on plan assets, the Company considers the relative weighting of plan assets, the historical performance of total plan assets and individual asset classes, and economic and other indicators of future performance. Plan assets were held in the following categories as a percentage of total plan assets: Year Ended December 31, 2018 Amount Percentage Cash $ 193 2.00 % Debt securities 4,855 62 Equity securities 1,342 17 Other 1,432 19 $ 7,822 100 % In general, the Company’s asset management objectives include maintaining an adequate level of diversification to reduce interest rate and market risk while providing adequate liquidity to meet immediate and future benefit payment requirements. In Japan, assets are primarily invested in pooled funds of insurance companies. The expected long-term rate of return on these assets is approximately 1.5%, which is based on the general yield environment for high quality instruments in Japan. The United Kingdom pension plan invests in a combination of equity and bond funds. The allocation mix is designed to minimize risk while providing a rate of return that will provide asset growth which will be sufficient to cover expected liabilities. The expected long-term rate of return on these assets is approximately 2.6%, which is a combination of long dated government and corporate bond yields for the bond funds, and long dated government and corporate bond yields with an allowance for out-performance The Company’s Israeli plans account for the deferred vested benefits using the shut-down method of accounting, which resulted in assets of $14,409 and vested benefit obligations of $17,552, as of December 31, 2018 and assets of $15,048 and vested benefit obligations of $17,932, as of December 31, 2017. Under the shut-down method, the liability is calculated as if it were payable as of the balance sheet date, on an undiscounted basis. Other Pension-Related Assets As of December 31, 2018 and 2017, the Company had assets with an aggregate market value of $5,890 and $6,255, respectively, which it has set aside in connection with its German pension plans. These assets are invested in group insurance contracts through the insurance companies administering these plans, in accordance with applicable pension laws. The Germany contracts have a guaranteed minimum rate of return ranging from 2.25% to 4.25%, depending on the contract. Because the assets were not separate legal assets of the pension plan, they were not included in the Company’s plan assets shown above. However, the Company has designated such assets to pay pension benefits. Such assets are included in other assets in the accompanying consolidated balance sheet.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Income Per Share	18) Net Income Per Share The following is a reconciliation of basic to diluted net income per share: Years Ended December 31, 2018 2017 2016 Numerator: Net income $ 392,896 $ 339,132 $ 104,809 Denominator: Shares used in net income per common share — basic $ 54,406,000 54,137,000 53,472,000 Effect of dilutive securities 586,000 937,000 579,000 Shares used in net income per common share — diluted 54,992,000 55,074,000 54,051,000 Net income per common share: Basic $ 7.22 $ 6.26 $ 1.96 Diluted $ 7.14 $ 6.16 $ 1.94 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 (RSUs and SARs) had been converted to such common shares, and if such assumed conversion is dilutive. In 2018, 2017 and 2016, the potential dilutive effect of 79,500, 404 and 508 weighted average shares, respectively, of RSUs, were excluded from the computation of diluted weighted-average shares outstanding, as the shares would have had an anti-dilutive effect on EPS, and would thus need to be excluded from the computation of diluted weighted-average shares.

Business Segment, Geographic Ar

Business Segment, Geographic Area, Product and Significant Customer Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Business Segment, Geographic Area, Product and Significant Customer Information	19) 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, RF & DC power, reactive gas generation, vacuum technology, lasers, photonics, sub-micron 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 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: Years Ended December 31, 2018 2017 2016 Vacuum & Analysis $ 1,260,862 $ 1,207,457 $ 872,291 Light & Motion 814,246 708,520 423,051 $ 2,075,108 $ 1,915,977 $ 1,295,342 The following is a reconciliation of segment gross profit to consolidated net income: Years Ended December 31, 2018 2017 2016 Gross profit by reportable segment: Vacuum & Analysis $ 577,552 $ 551,078 $ 388,220 Light & Motion 401,924 340,373 177,399 Total gross profit by reportable segment 979,476 891,451 565,619 Operating expenses: Research and development 135,720 132,555 110,579 Selling, general and administrative 298,118 290,056 227,932 Acquisition and integration costs 3,113 5,332 27,279 Restructuring 3,567 3,920 642 Environmental costs 1,000 — — Asset impairment — 6,719 5,000 Fees and expenses related to repricing of term loan 378 492 1,239 Amortization of intangible assets 43,521 45,743 35,681 Income from operations 494,059 406,634 157,267 Interest income 5,775 3,021 2,560 Interest expense 16,942 30,990 30,611 Gain on sale of business — 74,856 — Other expense, net 1,942 5,896 1,239 Income before income taxes 480,950 447,625 127,977 Provision for income taxes 88,054 108,493 23,168 Net income $ 392,896 $ 339,132 $ 104,809 The following is capital expenditures by reportable segment for the years ended December 31, 2018, 2017 and 2016: Vacuum & Analysis Light & Motion Total December 31, 2018: Capital expenditures $ 40,144 $ 22,797 $ 62,941 December 31, 2017: Capital expenditures $ 17,111 $ 14,176 $ 31,287 December 31, 2016: Capital expenditures $ 11,732 $ 7,391 $ 19,123 The following is depreciation and amortization of intangible assets by reportable segment for the years ended December 31, 2018, 2017 and 2016: Vacuum & Analysis Light & Motion Total December 31, 2018: Depreciation and amortization $ 20,808 $ 59,045 $ 79,853 December 31, 2017: Depreciation and amortization $ 20,297 $ 62,259 $ 82,556 December 31, 2016: Depreciation and amortization $ 20,820 $ 45,106 $ 65,926 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: Vacuum & Analysis Light & Motion Corporate, Eliminations and Other Total December 31, 2018: Segment assets: Accounts receivable $ 171,604 $ 140,658 $ (16,808 ) $ 295,454 Inventory 222,965 161,658 66 384,689 Total segment assets $ 394,569 $ 302,316 $ (16,742 ) $ 680,143 Vacuum & Analysis Light & Motion Corporate, Eliminations and Other Total December 31, 2017: Segment assets: Accounts receivable $ 201,318 $ 119,934 $ (20,944 ) $ 300,308 Inventory 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: Years Ended December 31, 2018 2017 Total segment assets $ 680,143 $ 639,389 Cash and cash equivalents, restricted cash and investments 728,461 553,976 Other current assets 65,790 53,543 Property, plant and equipment, net 194,367 171,782 Goodwill and intangible assets, net 906,803 957,445 Other assets 38,682 37,883 Consolidated total assets $ 2,614,246 $ 2,414,018 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 negotiated transfer prices and have been eliminated from consolidated net revenues. Years Ended December 31, Net revenues: 2018 2017 2016 United States $ 1,022,660 $ 955,284 $ 675,601 South Korea 203,567 212,763 112,432 Japan 193,264 167,318 96,954 Europe 244,009 209,912 156,365 Asia (excluding South Korea and Japan) 411,608 370,700 253,990 $ 2,075,108 $ 1,915,977 $ 1,295,342 Years Ended December 31, Long-lived assets:(1) 2018 2017 United States $ 146,687 $ 124,689 Europe 26,794 28,820 Asia 50,572 49,645 $ 224,053 $ 203,154 (1) Long-lived assets include property, plant and equipment, net and certain other assets, and exclude goodwill and intangibles and long-term tax-related Goodwill associated with each of our reportable segments is as follows: Years Ended December 31, 2018 2017 Reportable segment: Vacuum & Analysis $ 197,126 $ 197,617 Light & Motion 389,870 393,430 Total goodwill $ 586,996 $ 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. Worldwide net revenue for each group of products is as follows: Years Ended December 31, 2018 2017 2016 Analytical and Control Solutions Products $ 116,183 $ 131,376 $ 115,758 Power, Plasma and Reactive Gas Solutions Products 610,111 564,343 367,665 Vacuum Solutions Products 534,568 511,738 388,868 Laser Products 274,815 225,168 124,432 Optics Products 227,577 203,775 124,218 Photonics Products 311,854 279,577 174,401 $ 2,075,108 $ 1,915,977 $ 1,295,342 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 as follows: Years Ended December 31, 2018 2017 2016 Applied Materials, Inc. 11.7 % 12.7 % 13.6 % Lam Research Corporation 10.8 % 11.7 % 11.2 % Net revenues for each of our reportable segments include revenues from each of the two customers, which represent net revenues greater than 10% of total net revenues.

Restructurings

Restructurings	12 Months Ended
	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Restructurings	20) Restructurings During 2018, the Company recorded restructuring charges of $3,567, primarily related to severance costs related to a worldwide reduction in workforce including 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. During 2017, the Company recorded restructuring charges of $3,920. The restructuring charges were primarily severance and facility costs related to the consolidation of two manufacturing plants, a restructuring of one of our international facilities and the consolidation of sales offices. The activity related to the Company’s restructuring accrual is shown below: 2018 2017 Balance at January 1 $ 3,244 $ 540 Charged to expense 3,567 3,920 Payments and adjustment (4,179 ) (1,216 ) Balance at December 31 $ 2,632 $ 3,244

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	21) Commitments and Contingencies Newport Litigation In March 2016, two putative class actions lawsuit captioned Dixon Chung v. Newport Corp., et al., Case No. A-16-733154-C A-16-734039-B 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, pre- 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- ESI Litigation On November 29, 2018, a complaint captioned Brian Morris et. al. v. Electro Scientific Industries, Inc. et al. was filed in the U.S. District Court for the District of Oregon by alleged former stockholders of ESI in connection with the acquisition of ESI by the Company. The complaint named the Company’s subsidiary, ESI, and the former members of ESI’s board of director as defendants. Five additional complaints were subsequently filed, two in the U.S. District Court for the District of Oregon and three in the Multnomah County Circuit Court in the State of Oregon. The cases filed in the U.S. District Court were dated December 6, 2018 and December 12, 2018 and captioned Melvyn Klein et. al. v. Electro Scientific Industries, Inc. et al. and Donald Mager et. al. v. Electro Scientific Industries, Inc. et al., respectively. The complaints filed in Multnomah County Circuit Court were dated December 5, 2018, December 5, 2018 and December 13, 2018 and captioned Michael Kent et. al v. Electro Scientific Industries, Inc. et al., Christopher Stanley et. al v. Electro Scientific Industries, Inc. et al. and Eduardo Colmenares et. al. v. Electro Scientific Industries, Inc., MKS Instruments, Inc., et al., respectively. These lawsuits are purported class actions brought on behalf of former ESI stockholders, asserting various claims against the former members of the ESI board of directors, ESI, MKS, and MKS’ merger subsidiary, including breach of fiduciary duty and aiding and abetting the breach of fiduciary duty. The lawsuits allege that the consideration paid to the ESI shareholders did not appropriately value ESI, and that ESI’s merger related disclosures failed to disclose certain material information regarding the merger. These complaints purport to seek unspecified damages. The Company believes that the claims in these complaints are without merit and intends to vigorously defend this litigation. ESI provided supplemental merger related disclosures to eliminate the burden and expense of litigation and to avoid any possible disruption to the merger that could result from further litigation. The Company is 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. The Company leases certain of its facilities and machinery and equipment under operating leases expiring in various years through 2026. Generally, the facility leases require the Company to pay maintenance, insurance and real estate taxes. Rental expense under operating leases totaled $20,912, $19,693 and $16,253 for 2018, 2017 and 2016, respectively. Minimum lease payments under operating leases are as follows: Year Ending December 31, Operating Leases 2019 $ 20,106 2020 $ 17,142 2021 $ 10,325 2022 $ 5,573 2023 $ 4,410 Thereafter $ 8,739 Total minimum lease payments $ 66,295 As of December 31, 2018, the Company has entered into purchase commitments for certain inventory components and other equipment and services used in its normal operations. The majority of these purchase commitments covered by these arrangements are for periods of less than one year and aggregate to approximately $254,069. To the extent permitted by Massachusetts law, the Company’s Restated Articles of Organization, as amended, require the Company to indemnify any of its current or former officers or directors or any person who has served or is serving in any capacity with respect to any of the Company’s employee benefit plans. The Company believes that the estimated exposure for these indemnification obligations is currently not material. Accordingly, the Company has no material liabilities recorded for these requirements as of December 31, 2018. The Company also enters into agreements in the ordinary course of business which include indemnification provisions. Pursuant to these agreements, the Company indemnifies, holds harmless and agrees to reimburse the indemnified party, generally its customers, for losses suffered or incurred by the indemnified party in connection with certain patent or other intellectual property infringement claims, and, in some instances, other claims, by any third party with respect to the Company’s products. The term of these indemnification obligations is generally perpetual after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in some instances, not contractually limited. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification obligations. As a result, the Company believes the estimated fair value of these obligations is minimal. Accordingly, the Company has no liabilities recorded for these obligations as of December 31, 2018. As part of past acquisitions and divestitures of businesses or assets, the Company has provided a variety of indemnifications to the sellers and purchasers for certain events or occurrences that took place prior to the date of the acquisition or divestiture. Typically, certain of the indemnifications expire after a defined period of time following the transaction, but certain indemnifications may survive indefinitely. The maximum potential amount of future payments the Company could be required to make for such obligations is undeterminable at this time. Other than obligations recorded as liabilities at the time of the acquisitions, historically the Company has not made significant payments for these indemnifications. Accordingly, no material liabilities have been recorded for these obligations. In conjunction with certain asset sales, the Company may provide routine indemnifications whose terms range in duration and often are not explicitly defined. Where appropriate, an obligation for such indemnification is recorded as a liability. Because the amounts of liability under these types of indemnifications are not explicitly stated, the overall maximum amount of the obligation under such indemnifications cannot be reasonably estimated. Other than obligations recorded as liabilities at the time of the asset sale, historically the Company has not made significant payments for these indemnifications.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	22) Subsequent Event Acquisition of Electro Scientific Industries, Inc (amounts not in thousands, except per share data). On February 1, 2019, the Company completed its previously announced acquisition of Electro Scientific Industries, Inc., an Oregon corporation (“ESI”), pursuant to the Agreement and Plan of Merger (the “ESI Merger”). ESI is an innovator in laser-based manufacturing solutions for micro-machining applications. Micro-machining applications are used extensively in the manufacture of mobile devices, electronic components, thin film devices and semiconductor packaging. At the effective time of the ESI Merger and pursuant to the terms and conditions of the Agreement and Plan of Merger, each share of ESI’s common stock issued and outstanding as of immediately prior to the effective time of the ESI Merger, was converted into the right to receive $30.00 per share in cash, without interest and subject to deduction for any required withholding tax. The Company paid to the former ESI stockholders aggregate consideration of approximately $1 billion, excluding related transaction fees and expenses. The Company funded the payment of the aggregate consideration with a combination of its available cash on hand and the proceeds from the term loan facility described below. The Company was not able to include certain required disclosures in its annual report on Form 10-K In connection with the completion of the ESI Merger, the Company entered into an amendment (“Amendment No. 5”) to the Term Loan Credit agreement with Barclays Bank PLC as administrative agent and collateral agent, that provided additional tranche B-5 Also, in connection with the completion of the ESI Merger, the Company terminated its $50.0 million asset-based credit agreement with Deutsche Bank AG New York Branch as administrative and collateral agent, and the Company entered into an asset-based credit agreement with Barclays Bank PLC, as administrative agent and collateral agent, that provides senior secured revolving credit financing of up to $100.0 million, subject to a borrowing base limitation.

Supplemental Financial Data

Supplemental Financial Data	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Supplemental Financial Data	MKS Instruments, Inc. Supplemental Financial Data Quarter Ended March 31 June 30 Sept. 30 Dec. 31 (Table in thousands, except per share data) (Unaudited) 2018 Statement of Operations Data Net revenues $ 554,275 $ 573,140 $ 487,152 $ 460,541 Gross profit 262,855 274,877 231,860 209,884 Income from operations 131,639 151,291 117,045 94,084 Net income $ 105,121 $ 122,862 $ 93,277 $ 71,636 Net income per share: Basic $ 1.93 $ 2.25 $ 1.71 $ 1.33 Diluted $ 1.90 $ 2.22 $ 1.70 $ 1.32 Cash dividends paid per common share $ 0.18 $ 0.20 $ 0.20 $ 0.20 2017 Statement of Operations Data Net revenues $ 437,153 $ 480,757 $ 486,267 $ 511,800 Gross profit 205,547 219,583 227,995 238,326 Income from operations 83,580 92,883 110,155 120,016 Net income $ 65,060 $ 120,440 $ 75,994 $ 77,638 Net income per share: Basic $ 1.21 $ 2.22 $ 1.40 $ 1.43 Diluted $ 1.18 $ 2.19 $ 1.38 $ 1.41 Cash dividends paid per common share $ 0.175 $ 0.175 $ 0.175 $ 0.18

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	MKS INSTRUMENTS, INC. SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS Additions Description Balance at Beginning Acquisition Beginning Balance Charged to Costs and Expenses Charged Accounts Deductions & Write-offs Balance at End of Year (in thousands) Allowance for doubtful accounts: Years ended December 31, 2018 $ 4,135 $ — $ 1,435 $ — $ (327 ) $ 5,243 2017 $ 3,909 $ — $ 825 $ — $ (599 ) $ 4,135 2016 $ 1,760 $ 1,292 $ 1,109 $ (66 ) $ (186 ) $ 3,909 Additions Description Balance at Beginning Acquisition Beginning Balance Charged to Costs and Expenses Charged Accounts Deductions & Write-offs Balance at End of Year (in thousands) Allowance for sales returns: Years ended December 31, 2018 $ 1,295 $ — $ 124 $ — $ (386 ) $ 1,033 2017 $ 1,138 $ — $ (142 ) $ — $ 299 $ 1,295 2016 $ 601 $ 423 $ 2,262 $ — $ (2,148 ) $ 1,138 Additions Description Balance at Beginning Acquisition Beginning Balance Charged to Costs and Expenses Charged Accounts Deductions Balance at End of Year (in thousands) Valuation allowance on deferred tax asset: Years ended December 31, 2018 $ 13,629 $ — $ 4,825 $ — $ (518 ) $ 17,936 2017 $ 12,527 $ — $ 1,603 $ — $ (501 ) $ 13,629 2016 $ 6,127 $ 3,769 $ 2,719 $ — $ (88 ) $ 12,527

Basis of Presentation (Policies

Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Use of Estimates	The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of these 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 financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going
Revenue from Contracts with Customers	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 twelve months ended December 31, 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 year ended December 31, 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 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 December 31, 2018 contained a significant financing component. Contract assets as of January 1 and December 31, 2018 were $3,065 and $3,624, 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 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 December 31, 2018, as the majority have a duration of less than one year. A rollforward of the Company’s deferred revenue and customer advances is as follows: Year Ended Beginning balance, January 1(1) $ 27,800 Amount of deferred revenue and customer advances recognized in income(3) (83,497 ) Additions to deferred revenue and customer advances 73,171 Ending balance, December 31(2) $ 17,474 (1) Beginning deferred revenue and customer advances as of January 1, 2018 included $12,842 of current deferred revenue, $3,126 of long-term deferred revenue and $13,352 of current customer advances, net of a $1,520 adjustment related to the adoption of ASC 606. (2) Ending deferred revenue and customer advances as of December 31, 2018 included $8,134 of current deferred revenue, $3,228 of long-term deferred revenue and $6,112 of current customer advances. (3) The deferred revenue and customers advances recognized in income that relates to fiscal year 2018 was $61,012. 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: Year Ended December 31, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,080,343 $ 754,859 $ 1,835,202 Services 180,519 59,387 239,906 Total net revenues $ 1,260,862 $ 814,246 $ 2,075,108 Year Ended December 31, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,047,639 $ 653,662 $ 1,701,301 Services 159,818 54,858 214,676 Total net revenues $ 1,207,457 $ 708,520 $ 1,915,977 Year Ended December 31, 2016 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 731,364 $ 387,215 $ 1,118,579 Services 140,927 35,836 176,763 Total net revenues $ 872,291 $ 423,051 $ 1,295,342 Product revenue, excluding revenue from certain custom products, is recorded at a point in time, while the majority of service revenue and revenue from certain custom products is recorded over time. Refer to Note 19 for revenue by reportable segment, geography and groupings of similar products.
Accounts Receivable Allowances	Accounts Receivable Allowances Accounts receivable allowances include sales returns and bad debt allowances. The Company monitors and tracks the amount of product returns and reduces revenue at the time of shipment for the estimated amount of such 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.
Research and Development	Research and Development Research and development costs are expensed as incurred and consist mainly of compensation-related expenses and project materials. The Company’s research and development efforts include numerous projects, which generally have a duration of 3 to 30 months. Acquired in-process
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and were immaterial in 2018, 2017 and 2016.
Stock-Based Compensation	Stock-Based Compensation The accounting for share-based compensation expense requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and directors based on estimated fair values. For restricted stock units (“RSUs”), the fair value is the fair value on the date of grant that normally vests over a three year period. The Company also provides employees the opportunity to purchase shares through an employee stock purchase plan. For shares issued under its employee stock purchase plan, the Company has estimated the fair value on the date of grant using the Black Scholes pricing model, which is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, expected life, risk-free interest rate and expected dividends. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Management determined that blended volatility, a combination of historical and implied volatility, is more reflective of market conditions and a better indicator of expected volatility than historical or implied volatility alone. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and the Company uses different assumptions, its stock-based compensation expense could be materially different in the future.
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the year. Translation adjustments resulting from this process are recorded to Accumulated Other Comprehensive Income (“OCI”). Unrealized gains and losses on securities classified as available-for-sale
Net Income Per Share	Net Income Per Share Basic net income per share is based on the weighted average number of common shares outstanding, and diluted net income per share is based on the weighted average number of common shares outstanding and all potential dilutive common equivalent shares outstanding. The dilutive effect of options is determined under the treasury stock method using the average market price for the period. Common equivalent shares are included in the per share calculations when the effect of their inclusion would be dilutive.
Cash and Cash Equivalents and Investments	Cash and Cash Equivalents and Investments All highly liquid investments with a maturity date of three months or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities is determined at the time of purchase. Debt securities that the Company does not have the intent and ability to hold to maturity are classified as “available-for-sale” The Company classifies investments with maturity dates greater than twelve months in short-term investments rather than long-term investments. This method classifies these securities as current based on the nature of the securities and the availability for use in current operations. The Company believes this method is preferable because it is more reflective of the Company’s assessment of its overall liquidity position. The Company reviews its investment portfolio on a quarterly basis to identify and evaluate individual investments that have indications of possible impairment. The factors considered in determining whether a loss is other-than-temporary include: the length of time and extent to which fair market value has been below the cost basis, the financial condition and near-term prospects of the issuer, credit quality, and the Company’s ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in fair value.
Concentrations of Credit Risk	Concentrations of Credit Risk The Company’s significant concentrations of credit risk consist principally of cash and cash equivalents, investments, forward exchange contracts and trade accounts receivable. The Company maintains cash and cash equivalents with financial institutions including some banks with which it had borrowings. The Company maintains investments primarily in U.S. Treasury and government agency securities and corporate debt securities. The Company enters into forward currency contracts with high credit-quality financial institutions in order to minimize credit risk exposure. The Company’s largest customers are primarily concentrated in the semiconductor industry, and a limited number of these customers account for a significant portion of the Company’s revenues. The Company regularly monitors the creditworthiness of its customers and believes it has adequately provided for potential credit loss exposures. Credit is extended for all customers based primarily on financial condition, and collateral is not required. The Company had one customer, Applied Materials, Inc., comprising 12%, 13% and 14% of net revenues for 2018, 2017 and 2016, respectively, and another customer, Lam Research Corporation, comprising 11%, 12% and 11% of net revenues for 2018, 2017 and 2016, respectively. During the years 2018, 2017 and 2016, approximately 55%, 57% and 56% of the Company’s net revenues, respectively, were from sales to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were no customers that represented 10% or more of the Company’s accounts receivable balance as of December 31, 2018. One customer, Applied Materials, Inc., represented 10% or more of the Company’s accounts receivable balance as of December 31, 2017.
Inventories	Inventories Inventories are stated at the lower of cost or market, cost being determined using a standard costing system which approximates cost based on a first-in, first-out
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Expenditures for major renewals and betterments that extend the useful lives of property, plant and equipment are capitalized. Expenditures for maintenance and repairs are charged to expense as incurred. When assets are sold or otherwise disposed of, the cost and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is recognized in earnings. Depreciation is provided on the straight-line method over the estimated useful lives of ten to fifty years for buildings and three to sixteen years for machinery and equipment, furniture and fixtures and office equipment, which includes enterprise resource planning software. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the leased asset.
Intangible Assets	Intangible Assets Intangible assets resulting from the acquisitions of businesses are estimated by management based on the fair value of assets acquired. These include acquired customer lists, technology, patents, trade names, covenants not to compete and IPR&D. Intangible assets are amortized from one to eighteen years on a straight-line basis which represents the estimated periods of benefit and the expected pattern of consumption.
Goodwill	Goodwill Goodwill is the amount by which the cost of acquired net assets exceeded the fair value of those net assets on the date of acquisition. The Company allocates goodwill to reporting units at the time of acquisition or when there is a change in the reporting structure and bases that allocation on which reporting units will benefit from the acquired assets and liabilities. Reporting units are defined as operating segments or one level below an operating segment, referred to as a component. The Company assesses goodwill for impairment on an annual basis as of October 31 or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The estimated fair value of the Company’s reporting units are based on discounted cash flow models derived from internal earnings and internal and external market forecasts. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates, projected revenues and projected profit margins. Discount rates are based on a weighted average cost of capital (“WACC”), which represents the average rate a business must pay its providers of debt and equity. The WACC used to test goodwill is derived from a group of comparable companies. Assumptions in estimating future cash flows are subject to a high degree of judgment and complexity. The Company makes every effort to forecast these future cash flows as accurately as possible with the information available at the time the forecast is developed. In performing the Company’s annual goodwill impairment test, the Company is permitted to first assess qualitative factors to determine whether it is more likely than not that the fair value of our reporting unit is less than its carrying amount, including goodwill. In performing the qualitative assessment, the Company considers certain events and circumstances specific to the reporting unit and to the entity as a whole, such as macroeconomic conditions, industry and market considerations, overall financial performance and cost factors when evaluating whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. The Company is also permitted to bypass the qualitative assessment and proceed directly to the quantitative test. If the Company chooses to undertake the qualitative assessment and concludes that it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the Company would then proceed to the quantitative impairment test. In the quantitative assessment, the Company compares the fair value of the reporting unit to its carrying amount, which includes goodwill. If the fair value exceeds the carrying value, no impairment loss exists. If the fair value is less than the carrying amount, a goodwill impairment loss is measured and recorded. 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 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. As of October 31, 2018, the Company performed its annual impairment assessment of goodwill using the qualitative assessment and determined that it is more likely than not that the fair values of the reporting units exceed their carrying amount.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets whenever events and changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. This periodic review may result in an adjustment of estimated depreciable lives or asset impairment. When indicators of impairment are present, the carrying values of the asset are evaluated in relation to their operating performance and future undiscounted cash flows of the underlying business. If the future undiscounted cash flows are less than their carrying value, impairment exists. The impairment is measured as the difference between the carrying value and the fair value of the underlying asset. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk. In 2017, the Company recorded an impairment charge of $6,719 related to certain long-lived assets as a result of consolidating two manufacturing plants.
Foreign Exchange	Foreign Exchange The functional currency of the majority of the Company’s foreign subsidiaries is the applicable local currency. For those subsidiaries, assets and liabilities are translated to U.S. dollars at year-end Net foreign exchange losses resulting from re-measurement re-measurement
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and also for operating loss and tax credit carry-forwards. On a quarterly basis, the Company evaluates both the positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income in each jurisdiction of the right type to realize the assets. The Company records a valuation allowance to reduce its net deferred tax assets to the amount that is expected to be realized. To the extent the Company establishes a valuation allowance an expense will be recorded as a component of the provision for income taxes on the statement of operations. During 2016, the Company increased its valuation allowance by $6,400 primarily related to the addition of historical valuation allowances for Newport Corporation (“Newport”) and its subsidiaries which were included as a result of the acquisition in April 2016. As a result, the valuation allowance was $12,527 at December 31, 2016. During 2017, the Company increased its valuation allowance by $1,102, primarily related to certain state tax credits. As a result, the valuation allowance was $13,629 at December 31, 2017. During 2018, the Company increased its valuation allowance by $4,307 which is attributable to certain tax credit and net operating loss carry forward amounts. As a result, the valuation allowance was $17,936 at December 31, 2018. Accounting for income taxes requires a two-step re-evaluates On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (the “Act”), which included significant changes to U.S. tax law. Some of the more significant changes impacting the Company are the reduction of the U.S. federal corporate income tax rate from 35.0% to 21.0% as of January 1, 2018, the implementation of a territorial tax system and the imposition of a transition tax on deemed repatriated cumulative earnings of foreign subsidiaries (“Transition Tax”). Income tax effects resulting from changes in tax are generally accounted for by the Company in the period in which the law is enacted and the effects are recorded as a component of provision for income taxes from continuing operations. On December 22, 2017, the Securities and Exchange Commission Staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to provide guidance for reporting entities’ ability to timely complete the accounting for certain income tax effects of the Act and allowed a measurement period up to one year from the enactment date of the “Act”. The Company has obtained, prepared and analyzed the information needed to complete the accounting requirements under Accounting Standards Codification (“ASC”) Topic 740 and as a result, in accordance with SAB 118, the Company has finalized and recorded the effects of the Act during the quarter ended December 31, 2018. The ultimate impact of the Act on the Company is based upon the Company’s understanding and interpretation of the regulatory guidance that has been issued regarding the Act.
Recently Issued Accounting Pronouncements	In October 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-16, In August 2018, the FASB issued ASU 2018-15, Other-Internal-Use 350-40): internal-use internal-use In March 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-05, In August 2017, the FASB issued ASU 2017-12, In May 2017, the FASB issued ASU 2017-09, In March 2017, the FASB issued ASU 2017-07, In November 2016, the FASB issued ASU 2016-18, 2016-15. beginning-of-period end-of-period 2016-15. In October 2016, the FASB issued ASU 2016-16, In August 2016, the FASB issued ASU 2016-15, In February 2016, the FASB issued ASU 2016-02, 2018-01 2018-10 2018-11 right-of-use In January 2016, the FASB issued ASU 2016-01, “Financial 825-10)-Recognition In May 2014, the FASB issued ASU 2014-09, 2016-08 2016-10 2016-12 2016-20 2017-13 2017-14

Basis of Presentation (Tables)

Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 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 it service 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. Twelve Months Ended December 31, 2017 As previously Adjustment As revised Net revenues: Products $ 1,723,433 $ (22,132 ) $ 1,701,301 Services 192,544 22,132 214,676 Total net revenues 1,915,977 — 1,915,977 Cost of revenues: Cost of products 901,546 4,823 906,369 Cost of services 122,980 (4,823 ) 118,157 Total cost of revenues $ 1,024,526 $ — $ 1,024,526 Twelve Months Ended December 31, 2016 As previously Adjustment As revised Net revenues: Products $ 1,134,013 $ (15,434 ) $ 1,118,579 Services 161,329 15,434 176,763 Total net revenues 1,295,342 — 1,295,342 Cost of revenues: Cost of products 627,850 2,358 630,208 Cost of services 101,873 (2,358 ) 99,515 Total cost of revenues $ 729,723 $ — $ 729,723

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Deferred Revenue and Customer Advances by Arrangement	A rollforward of the Company’s deferred revenue and customer advances is as follows: Year Ended Beginning balance, January 1(1) $ 27,800 Amount of deferred revenue and customer advances recognized in income(3) (83,497 ) Additions to deferred revenue and customer advances 73,171 Ending balance, December 31(2) $ 17,474 (1) Beginning deferred revenue and customer advances as of January 1, 2018 included $12,842 of current deferred revenue, $3,126 of long-term deferred revenue and $13,352 of current customer advances, net of a $1,520 adjustment related to the adoption of ASC 606. (2) Ending deferred revenue and customer advances as of December 31, 2018 included $8,134 of current deferred revenue, $3,228 of long-term deferred revenue and $6,112 of current customer advances. (3) The deferred revenue and customers advances recognized in income that relates to fiscal year 2018 was $61,012.
Summary of Revenue from Contracts with Customers	The following table summarizes revenue from contracts with customers: Year Ended December 31, 2018 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,080,343 $ 754,859 $ 1,835,202 Services 180,519 59,387 239,906 Total net revenues $ 1,260,862 $ 814,246 $ 2,075,108 Year Ended December 31, 2017 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 1,047,639 $ 653,662 $ 1,701,301 Services 159,818 54,858 214,676 Total net revenues $ 1,207,457 $ 708,520 $ 1,915,977 Year Ended December 31, 2016 Vacuum & Analysis Light & Motion Total Net revenues: Products $ 731,364 $ 387,215 $ 1,118,579 Services 140,927 35,836 176,763 Total net revenues $ 872,291 $ 423,051 $ 1,295,342

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Short-Term and Long-Term Investments Available-for-Sale and Cost Method Investments	Investments classified as short-term consist of the following: Years Ended December 31, 2018 2017 Available-for-sale Time deposits and certificates of deposit $ 102 $ 9,757 Bankers’ acceptance drafts 989 5,330 Asset-backed securities 9,113 36,990 Commercial paper 19,359 13,750 Corporate obligations 9,352 77,821 Municipal bonds — 1,970 U.S. treasury obligations 13,298 28,078 U.S. agency obligations 21,613 35,738 $ 73,826 $ 209,434 Investments classified as long-term consist of the following: Years Ended December 31, 2018 2017 Available-for-sale Group insurance contracts $ 5,890 $ 6,255 Cost method investments: Minority interest in a private company 4,400 4,400 $ 10,290 $ 10,655
Gross Unrealized Gains and (Losses) Aggregated by Investment Category	The following table shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale As of December 31, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Short-term investments: Available-for-sale Time deposits and certificates of deposit $ 102 $ — $ — $ 102 Bankers’ acceptance drafts 989 — — 989 Asset-backed securities 9,121 1 (9 ) 9,113 Commercial paper 19,504 — (145 ) 19,359 Corporate obligations 9,367 — (15 ) 9,352 U.S. treasury obligations 13,294 4 — 13,298 U.S. agency obligations 21,617 2 (6 ) 21,613 $ 73,994 $ 7 $ (175 ) $ 73,826 As of December 31, 2018: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Long-term investments: Available-for-sale Group insurance contracts $ 5,546 $ 344 $ — $ 5,890 As of December 31, 2017: Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value Short-term investments: Available-for-sale 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 Group insurance contracts $ 6,006 $ 249 $ — $ 6,255

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2018, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Cash equivalents: Money market funds $ 180,340 $ 180,340 $ — $ — Time deposits and certificates of deposit 850 — 850 — Commercial paper 2,687 — 2,687 — U.S. agency obligations 3,418 — 3,418 — Restricted cash – money market funds 110 110 — — Available-for-sale Time deposits and certificates of deposit 102 — 102 — Bankers’ acceptance drafts 989 — 989 — Asset-backed securities 9,113 — 9,113 — Commercial paper 19,359 — 19,359 — Corporate obligations 9,352 — 9,352 — U.S. treasury obligations 13,298 — 13,298 — U.S. agency obligations 21,613 — 21,613 — Group insurance contracts 5,890 — 5,890 — Derivatives – currency forward contracts 2,485 — 2,485 — Funds in investments and other assets: Israeli pension assets 14,408 — 14,408 — Derivatives – interest rate hedge – non-current 6,083 — 6,083 — Total assets $ 290,097 $ 180,450 $ 109,647 $ — Liabilities: Derivatives – currency forward contracts $ 1,168 $ — $ 1,168 $ — Reported as follows: Assets: Cash and cash equivalents, including restricted cash(1) $ 187,405 $ 180,450 $ 6,955 $ — Short-term investments 73,826 — 73,826 — Other current assets 2,485 — 2,485 — Total current assets $ 263,716 $ 180,450 $ 83,266 $ Long-term investments(2) $ 5,890 $ — $ 5,890 $ — Other assets 20,491 — 20,491 — Total long-term assets $ 26,381 $ — $ 26,381 $ — Liabilities: Other current liabilities $ 1,168 $ — $ 1,168 $ — (1) The cash and cash equivalent amounts presented in the table above does not include cash of $456,940 as of December 31, 2018. (2) The long-term investments presented in the table above do not include our minority interest investment in a private company, which is accounted for under the cost method. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2017, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, 2017 Quoted Prices in Active Markets for Identical Assets (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 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 – currency forward 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 – currency forward contracts $ 6,198 $ — $ 6,198 $ — Reported as follows: 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 (2) The long-term investments presented in the table above do not include our minority interest investment in a private company, which is accounted for under the cost method.

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2018 and 2017: December 31, 2018 Currency Hedged (Buy/Sell) Gross Notional Value Fair Value(1) U.S. Dollar/Japanese Yen $ 43,770 $ (478 ) U.S. Dollar/South Korean Won 59,149 570 U.S. Dollar/Euro 23,515 688 U.S. Dollar/U.K. Pound Sterling 11,827 323 U.S. Dollar/Taiwan Dollar 21,133 214 Total $ 159,394 $ 1,317 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: Years Ended December 31, Derivatives Designated as Hedging Instruments 2018 2017 Derivative assets: Forward exchange contracts(1) $ 2,485 $ 168 Foreign currency interest rate hedge(2) 6,083 6,179 Derivative liabilities: Forward exchange contracts(1) (1,168 ) (6,198 ) Total net derivative asset designated as hedging instruments $ 7,400 $ 149 (1) The derivative asset of $2,485 and derivative liability of $1,168 related to the forward foreign exchange contracts are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2018. The derivative asset of $168 and derivative liability of $6,198 related to the forward foreign exchange contracts are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2017. These forward 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 foreign currency interest rate hedge asset of $6,083 and $6,179 is classified in other assets in the consolidated balance sheet as of December 31, 2018 and 2017, respectively.
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: Years Ended December 31, Derivatives Designated as Cash Flow Hedging Instruments 2018 2017 2016 Forward exchange contracts: Net gain (loss) recognized in OCI(1) $ 6,289 $ (6,036 ) $ 5,914 Net loss reclassified from OCI into income(2) $ (3,367 ) $ (2,685 ) $ (1,414 ) (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified as cost of products.
Summary of Losses on Derivatives Not Designated as Cash Flow Hedging Instruments	The following table provides a summary of losses on derivatives not designated as cash flow hedging instruments: Years Ended December 31, Derivatives Not Designated as Hedging Instruments 2018 2017 2016 Forward exchange contracts: Net gain (loss) recognized in income (1) $ 105 $ (3,416 ) $ (31 ) (1) The Company enters into forward 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 cash flow hedging instruments and gains or losses from these derivatives are recorded immediately in other expense, net in 2018 and 2017.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consist of the following: Years Ended December 31, 2018 2017 Raw material $ 235,593 $ 191,351 Work-in-process 61,908 54,050 Finished goods 87,188 93,680 $ 384,689 $ 339,081

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment consist of the following: Years Ended December 31, 2018 2017 Land $ 11,448 $ 11,650 Buildings 104,023 103,563 Machinery and equipment 330,821 317,073 Furniture and fixtures, office equipment and software 149,145 145,945 Leasehold improvements 66,569 65,293 Construction in progress 44,823 13,619 706,829 657,143 Less: accumulated depreciation 512,462 485,361 $ 194,367 $ 171,782

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2018
Newport [Member]
Summary of Purchase Price	The purchase price of Newport consisted of the following: Cash paid for outstanding shares(1) $ 905,254 Settlement of share-based compensation awards(2) 8,824 Cash paid for Newport debt(3) 93,200 Total purchase price $ 1,007,278 Less: cash and cash equivalents acquired (61,463 ) Total purchase price, net of cash and cash equivalents acquired $ 945,815 (1) Represents cash paid of $23.00 per share for approximately 39,359,000 shares of Newport common stock, without interest and subject to a deduction for any required withholding tax. (2) Represents the vested but unissued portion of Newport share-based compensation awards as of the acquisition date of April 29, 2016. (3) Represents the cash paid for the outstanding balance of Newport’s senior secured revolving credit agreement.
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the allocation of the purchase price to the fair values assigned to assets acquired and liabilities assumed at the date of the Newport Merger: Current assets (including cash) $ 186,137 Inventory 142,714 Intangible assets 404,506 Goodwill 396,027 Property, plant and equipment 119,932 Long-term assets 22,725 Total assets acquired 1,272,041 Current liabilities 95,156 Intangible liability 4,302 Other long-term liabilities 165,305 Total liabilities assumed 264,763 Fair value of assets acquired and liabilities assumed 1,007,278 Less: cash and cash equivalents acquired (61,463 ) Total purchase price, net of cash and cash equivalents acquired $ 945,815
Schedule of Unaudited Pro Forma Financial Information	The following unaudited pro forma financial information presents the combined results of operations of the Company as if the Newport Merger had occurred on January 1, 2015. The unaudited pro forma financial information is not necessarily indicative of what the Company’s condensed consolidated results of operations actually would have been had the acquisition occurred at the beginning of each year. In addition, the unaudited pro forma financial information does not attempt to project the future results of operations of the combined company. 2016 Total net revenues $ 1,475,637 Net income 111,076 Net income per share: Basic $ 2.08 Diluted $ 2.06
Precisive, LLC [Member]
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and liabilities and related estimate of useful lives: Order backlog $ 12,100 1 year Customer relationships 247,793 6-18 Trademarks and trade names 55,900 Indefinite Developed technology 75,386 4-8 In-process 6,899 Undefined (1) Leasehold interest (favorable) 6,428 4-5 Total intangible assets $ 404,506 Leasehold interest (unfavorable) $ 4,302

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	The changes in the carrying amount of goodwill and accumulated impairment losses were as follows: 2018 2017 Gross Carrying Amount Accumulated Impairment Loss Net Gross Carrying Amount Accumulated Impairment Loss Net Beginning balance at January $ 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 (4,051 ) — (4,051 ) 10,439 — 10,439 Ending balance at December 31 $ 731,272 $ (144,276 ) $ 586,996 $ 735,323 $ (144,276 ) $ 591,047 (1) In 2017, the Company sold its Data Analytics business and, as a result, charged the related goodwill of $3,115 to the gain on sale of business. (2) In 2017, the Company recorded an impairment loss of $4,862 related to the write-off
Intangible Assets	Components of the Company’s acquired intangible assets are comprised of the following: As of December 31, 2018 Gross Impairment Charges(1) Accumulated Amortization Foreign Currency Translation Net Completed technology $ 172,431 $ (105 ) $ (137,283 ) $ (73 ) $ 34,970 Customer relationships 282,744 (1,406 ) (63,788 ) (269 ) 217,281 Patents, trademarks, trade names and other 110,523 — (42,954 ) (13 ) 67,556 $ 565,698 $ (1,511 ) $ (244,025 ) $ (355 ) $ 319,807 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
Estimated Net Amortization Expense	Aggregate net amortization expense related to acquired intangible assets and unfavorable lease commitments for future years is: Year Amount 2019 $ 40,073 2020 $ 28,076 2021 $ 20,206 2022 $ 17,584 2023 $ 17,220 Thereafter $ 138,693

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2018
Guarantees and Product Warranties [Abstract]
Product Warranty Activities	Product warranty activities were as follows: Years Ended December 31, 2018 2017 Beginning balance $ 10,104 $ 8,261 Provision for product warranties 15,987 15,884 Direct and other charges to warranty liability (15,692 ) (14,041 ) Ending balance(1) $ 10,399 $ 10,104 (1) Short-term product warranty of $9,986 and long-term product warranty of $413, each as of December 31, 2018, are included within other current liabilities and other liabilities, respectively, within the accompanying consolidated balance sheet. Short-term product warranty of $9,719 and long-term product warranty of $385 as of December 31, 2017, are included within other current liabilities and other liabilities, respectively, within the accompanying consolidated balance sheet.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Short-Term Debt	December 31, 2018 December 31, 2017 Short-term debt: Japanese lines of credit $ 2,724 $ 2,750 Japanese receivables financing facility 665 215 Other debt 597 7 $ 3,986 $ 2,972
Schedule of Long-Term Debt	December 31, 2018 December 31, 2017 Long-term debt: Austrian loans due through March 2020 and other debt $ 86 $ 714 Term Loan Facility, net (1) 343,756 389,279 $ 343,842 $ 389,993 (1) Net of deferred financing fees, original issuance discount and re-pricing
Schedule of Contractual Maturities of Debt Obligations	Contractual maturities of the Company’s debt obligations as of December 31, 2018 are as follows: Year Amount 2019 $ 3,986 2020 $ 72 2021 $ 14 2022 $ — 2023 $ 348,464

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Reconciliation of Company's Effective Tax Rate to U.S. Federal Statutory Rate	A reconciliation of the Company’s effective tax rate to the U.S. federal statutory rate is as follows: Years Ended December 31, 2018 2017 2016 U.S. Federal income tax statutory rate 21.0 % 35.0 % 35.0 % Federal tax credits (0.7 ) (0.7 ) (1.8 ) State income taxes, net of federal benefit 1.3 1.0 0.8 Effect of foreign operations taxed at various rates (1.3 ) (12.1 ) (12.7 ) Qualified production activity tax benefit — (1.4 ) (2.9 ) Foreign derived intangible income (2.1 ) — — Global intangible low taxed income, net of foreign tax credits 0.4 — — Transition tax, net of foreign tax credits (0.1 ) 6.4 — Revaluation of U.S. deferred income taxes (0.3 ) (5.0 ) — Revaluation of prepaid taxes 1.6 — — Stock based compensation (1.3 ) (2.5 ) — Deferred tax asset valuation allowance — (0.1 ) 2.1 Release of income tax reserves (including interest) (0.4 ) (0.4 ) (2.4 ) Taxes on foreign dividends, net of foreign tax credits (1.0 ) 3.3 (2.2 ) Acquisition and integration related costs — — 1.5 Other 1.2 0.7 0.7 18.3 % 24.2 % 18.1 %
Components of Income from Operations Before Income Taxes and Related Provision for Income Taxes	The components of income from operations before income taxes and the related provision for income taxes consist of the following: Years Ended December 31, 2018 2017 2016 Income from operations before income taxes: United States $ 287,309 $ 224,979 $ 42,491 Foreign 193,641 222,646 85,486 $ 480,950 $ 447,625 $ 127,977 Current taxes: United States $ 41,428 $ 77,023 $ 17,693 State 8,094 6,149 2,359 Foreign 57,920 30,152 41,938 107,442 113,324 61,990 Deferred taxes: United States (2,533 ) (16,250 ) (23,604 ) State and Foreign (16,855 ) 11,419 (15,218 ) (19,388 ) (4,831 ) (38,822 ) Provision for income taxes $ 88,054 $ 108,493 $ 23,168
Significant Components of Deferred Tax Assets and Deferred Tax Liabilities	The significant components of the deferred tax assets and deferred tax liabilities are as follows: Years Ended December 31, 2018 2017 Deferred tax assets: Carry-forward losses and credits $ 23,675 $ 25,834 Inventory and warranty reserves 17,945 17,734 Accrued expenses and other reserves 10,260 15,393 Stock-based compensation 5,351 5,092 Executive supplemental retirement benefits 5,972 4,984 Other 2,396 597 Total deferred tax assets $ 65,599 $ 69,634 Deferred tax liabilities: Acquired intangible assets $ (74,120 ) $ (83,092 ) Depreciation and amortization (8,332 ) (10,150 ) Loan costs (1,108 ) (2,157 ) Foreign withholding taxes (3,176 ) (16,206 ) Unrealized gain (1,952 ) (469 ) Total deferred tax liabilities (88,688 ) (112,074 ) Valuation allowance (17,936 ) (13,629 ) Net deferred tax (liabilities) assets $ (41,025 ) $ (56,069 )
Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: Years Ended December 31, 2018 2017 2016 Balance at beginning of year $ 27,345 $ 25,465 $ 4,332 Increases/(decreases) for prior years 934 640 (195 ) Increases for the current year 6,091 4,340 23,940 Reductions related to expiration of statutes of limitations and audit settlements (1,686 ) (3,100 ) (2,612 ) Balance at end of year $ 32,684 $ 27,345 $ 25,465

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Activity for RSUs	The following table presents the activity for RSUs under the Plans: Year Ended December 31, 2018 Non-vested RSUs Weighted Average Grant Date Fair Value Non-vested 943,379 $ 47.57 Accrued dividend shares 66 $ 94.11 Granted 266,411 $ 111.64 Vested (490,453 ) $ 44.70 Forfeited or expired (72,009 ) $ 66.22 Non-vested 647,394 $ 74.04
Summary of Activity for Outstanding and Exercisable Stock Appreciation Rights	At December 31, 2018, the Company’s outstanding and exercisable SARs, the weighted-average base value, the weighted average remaining contractual life and the aggregate intrinsic value thereof, were as follows: Number Weighted Average Weighted Average Aggregate Intrinsic Value SARs outstanding and exercisable 177,538 $ 28.52 2.4 $ 6,408
Effect of Recording Stock-Based Compensation	The following table reflects the effect of recording stock-based compensation for the years 2018, 2017 and 2016: Years Ended December 31, 2018 2017 2016 Stock-based compensation expense by type of award: RSUs $ 24,883 $ 22,428 $ 23,302 SARs 98 529 700 Employee stock purchase plan 2,281 1,421 1,226 Total stock-based compensation $ 27,262 24,378 25,228 Windfall tax effect on stock-based compensation (8,277 ) (11,071 ) — Net effect on net income $ 18,985 $ 13,307 $ 25,228 Effect on net earnings per share: Basic $ 0.35 $ 0.25 $ 0.47 Diluted $ 0.35 $ 0.24 $ 0.47
Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation	The pre-tax Years Ended December 31, 2018 2017 2016 Cost of revenues $ 3,516 $ 3,894 $ 2,997 Research and development expense 2,750 2,816 2,529 Selling, general and administrative expense 20,996 17,668 19,702 Total pre-tax $ 27,262 $ 24,378 $ 25,228
Fair Value of Employees' Purchase Rights Estimated using Black-Scholes Option-Pricing Model	The fair value of the employees’ purchase plan rights was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions: Years Ended December 31, 2018 2017 2016 Employee stock purchase plan rights: Expected life (years) 0.5 0.5 0.5 Risk-free interest rate 1.8 % 0.8 % 0.5 % Expected volatility 38.6 % 26.5 % 25.4 % Expected annual dividends per share $ 0.76 $ 0.69 $ 0.68
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 Plans: Year Ended December 31, 2018 Non-vested SARs Weighted Average Base Value SARs — beginning of period 282,907 $ 28.62 Exercised (103,419 ) $ 28.78 Forfeited or expired (1,950 ) $ 29.00 SARs Outstanding — end of period 177,538 $ 28.52

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Postemployment Benefits [Abstract]
Summary of Net Periodic Benefit Costs	The net periodic benefit costs for the plans included the following components: Year Ended December 31, 2018 2017 Service cost $ 657 $ 708 Interest cost on projected benefit obligations 433 458 Expected return on plan assets (115 ) (116 ) Amortization of actuarial net loss 127 400 $ 1,102 $ 1,450
Summary of Changes in Projected Benefit Obligations and Plan Assets, and Ending Balances of Defined Benefit Plans	The changes in projected benefit obligations and plan assets, as well as the ending balance sheet amounts for the Company’s defined benefit plans, were as follows: Year Ended December 31, 2018 2017 Change in projected benefit obligations: Projected benefit obligations, beginning of year $ 25,736 $ 23,450 Service cost 657 708 Interest cost 433 458 Actuarial gain (98 ) (312 ) Benefits paid (895 ) (1,271 ) Currency translation adjustments (948 ) 2,703 Projected benefit obligations, end of year $ 24,885 $ 25,736 Change in plan assets: Fair value of plan assets, beginning of year $ 8,152 $ 7,672 Company contributions 324 324 (Loss) gain on plan assets (56 ) 177 Benefits paid (369 ) (722 ) Currency translation adjustments (229 ) 701 Fair value of plan assets, end of year 7,822 8,152 Net underfunded status $ (17,063 ) $ (17,584 )
Summary of Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income	Changes in plan assets and benefit obligations recognized in other comprehensive income included the following components: Year Ended December 31, 2018 2017 Amounts recognized in accumulated comprehensive income: Accumulated net actuarial gain $ 235 $ 235 Income tax (expense) benefit (86 ) 88 Accumulated other comprehensive gain $ 149 $ 323
Summary of Estimated Benefit Payments for Defined Benefit Plans for Next 10 Years	As of December 31, 2018, the estimated benefit payments for the Company’s defined benefit plans for the next 10 years were as follows: Estimated benefit payments 2019 $ 1,046 2020 $ 1,252 2021 $ 1,210 2022 $ 1,312 2023 $ 1,129 2024-2028 $ 7,313 $ 13,262
Schedule of Weighted Average Rates Used to Determine Net Periodic Benefit Costs	The weighted-average rates used to determine the net periodic benefit costs were as follows: December 31, 2018 Discount rate 1.9 % Rate of increase in salary levels 2.1 % Expected long-term rate of return on assets 1.9 %
Schedule of Defined Benefit Plan Assets	Plan assets were held in the following categories as a percentage of total plan assets: Year Ended December 31, 2018 Amount Percentage Cash $ 193 2.00 % Debt securities 4,855 62 Equity securities 1,342 17 Other 1,432 19 $ 7,822 100 %

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Net Income Per Share	The following is a reconciliation of basic to diluted net income per share: Years Ended December 31, 2018 2017 2016 Numerator: Net income $ 392,896 $ 339,132 $ 104,809 Denominator: Shares used in net income per common share — basic $ 54,406,000 54,137,000 53,472,000 Effect of dilutive securities 586,000 937,000 579,000 Shares used in net income per common share — diluted 54,992,000 55,074,000 54,051,000 Net income per common share: Basic $ 7.22 $ 6.26 $ 1.96 Diluted $ 7.14 $ 6.16 $ 1.94

Business Segment, Geographic _2

Business Segment, Geographic Area, Product and Significant Customer Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Net Revenues, Assets and Goodwill by Reportable Segment	The following are net revenues by reportable segment: Years Ended December 31, 2018 2017 2016 Vacuum & Analysis $ 1,260,862 $ 1,207,457 $ 872,291 Light & Motion 814,246 708,520 423,051 $ 2,075,108 $ 1,915,977 $ 1,295,342 The following are segment assets by reportable segment: Vacuum & Analysis Light & Motion Corporate, Eliminations and Other Total December 31, 2018: Segment assets: Accounts receivable $ 171,604 $ 140,658 $ (16,808 ) $ 295,454 Inventory 222,965 161,658 66 384,689 Total segment assets $ 394,569 $ 302,316 $ (16,742 ) $ 680,143 Vacuum & Analysis Light & Motion Corporate, Eliminations and Other Total December 31, 2017: Segment assets: Accounts receivable $ 201,318 $ 119,934 $ (20,944 ) $ 300,308 Inventory 197,831 141,250 — 339,081 Total segment assets $ 399,149 $ 261,184 $ (20,944 ) $ 639,389 Goodwill associated with each of our reportable segments is as follows: Years Ended December 31, 2018 2017 Reportable segment: Vacuum & Analysis $ 197,126 $ 197,617 Light & Motion 389,870 393,430 Total goodwill $ 586,996 $ 591,047
Reconciliation of Segment Gross Profit to Consolidated Net Income	The following is a reconciliation of segment gross profit to consolidated net income: Years Ended December 31, 2018 2017 2016 Gross profit by reportable segment: Vacuum & Analysis $ 577,552 $ 551,078 $ 388,220 Light & Motion 401,924 340,373 177,399 Total gross profit by reportable segment 979,476 891,451 565,619 Operating expenses: Research and development 135,720 132,555 110,579 Selling, general and administrative 298,118 290,056 227,932 Acquisition and integration costs 3,113 5,332 27,279 Restructuring 3,567 3,920 642 Environmental costs 1,000 — — Asset impairment — 6,719 5,000 Fees and expenses related to repricing of term loan 378 492 1,239 Amortization of intangible assets 43,521 45,743 35,681 Income from operations 494,059 406,634 157,267 Interest income 5,775 3,021 2,560 Interest expense 16,942 30,990 30,611 Gain on sale of business — 74,856 — Other expense, net 1,942 5,896 1,239 Income before income taxes 480,950 447,625 127,977 Provision for income taxes 88,054 108,493 23,168 Net income $ 392,896 $ 339,132 $ 104,809
Schedule of Capital Expenditures, Depreciation and Amortization Expense of Intangible Assets by Reportable Segment	The following is capital expenditures by reportable segment for the years ended December 31, 2018, 2017 and 2016: Vacuum & Analysis Light & Motion Total December 31, 2018: Capital expenditures $ 40,144 $ 22,797 $ 62,941 December 31, 2017: Capital expenditures $ 17,111 $ 14,176 $ 31,287 December 31, 2016: Capital expenditures $ 11,732 $ 7,391 $ 19,123 The following is depreciation and amortization of intangible assets by reportable segment for the years ended December 31, 2018, 2017 and 2016: Vacuum & Analysis Light & Motion Total December 31, 2018: Depreciation and amortization $ 20,808 $ 59,045 $ 79,853 December 31, 2017: Depreciation and amortization $ 20,297 $ 62,259 $ 82,556 December 31, 2016: Depreciation and amortization $ 20,820 $ 45,106 $ 65,926
Reconciliation of Segment Assets to Consolidated Total Assets	A reconciliation of segment assets to consolidated total assets is as follows: Years Ended December 31, 2018 2017 Total segment assets $ 680,143 $ 639,389 Cash and cash equivalents, restricted cash and investments 728,461 553,976 Other current assets 65,790 53,543 Property, plant and equipment, net 194,367 171,782 Goodwill and intangible assets, net 906,803 957,445 Other assets 38,682 37,883 Consolidated total assets $ 2,614,246 $ 2,414,018
Schedule of Net Revenues and Long-Lived Assets by Geographic Regions	Transfers between geographic areas are at negotiated transfer prices and have been eliminated from consolidated net revenues. Years Ended December 31, Net revenues: 2018 2017 2016 United States $ 1,022,660 $ 955,284 $ 675,601 South Korea 203,567 212,763 112,432 Japan 193,264 167,318 96,954 Europe 244,009 209,912 156,365 Asia (excluding South Korea and Japan) 411,608 370,700 253,990 $ 2,075,108 $ 1,915,977 $ 1,295,342 Years Ended December 31, Long-lived assets:(1) 2018 2017 United States $ 146,687 $ 124,689 Europe 26,794 28,820 Asia 50,572 49,645 $ 224,053 $ 203,154 (1) Long-lived assets include property, plant and equipment, net and certain other assets, and exclude goodwill and intangibles and long-term tax-related
Worldwide Net Revenue for Each Group of Products	Worldwide net revenue for each group of products is as follows: Years Ended December 31, 2018 2017 2016 Analytical and Control Solutions Products $ 116,183 $ 131,376 $ 115,758 Power, Plasma and Reactive Gas Solutions Products 610,111 564,343 367,665 Vacuum Solutions Products 534,568 511,738 388,868 Laser Products 274,815 225,168 124,432 Optics Products 227,577 203,775 124,218 Photonics Products 311,854 279,577 174,401 $ 2,075,108 $ 1,915,977 $ 1,295,342
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 as follows: Years Ended December 31, 2018 2017 2016 Applied Materials, Inc. 11.7 % 12.7 % 13.6 % Lam Research Corporation 10.8 % 11.7 % 11.2 %

Restructurings (Tables)

Restructurings (Tables)	12 Months Ended
	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Schedule of Company's Restructuring Activity	The activity related to the Company’s restructuring accrual is shown below: 2018 2017 Balance at January 1 $ 3,244 $ 540 Charged to expense 3,567 3,920 Payments and adjustment (4,179 ) (1,216 ) Balance at December 31 $ 2,632 $ 3,244

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Minimum Lease Payments under Operating Lease	Minimum lease payments under operating leases are as follows: Year Ending December 31, Operating Leases 2019 $ 20,106 2020 $ 17,142 2021 $ 10,325 2022 $ 5,573 2023 $ 4,410 Thereafter $ 8,739 Total minimum lease payments $ 66,295

Supplemental Financial Data (Ta

Supplemental Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Supplemental Financial Data	MKS Instruments, Inc. Supplemental Financial Data Quarter Ended March 31 June 30 Sept. 30 Dec. 31 (Table in thousands, except per share data) (Unaudited) 2018 Statement of Operations Data Net revenues $ 554,275 $ 573,140 $ 487,152 $ 460,541 Gross profit 262,855 274,877 231,860 209,884 Income from operations 131,639 151,291 117,045 94,084 Net income $ 105,121 $ 122,862 $ 93,277 $ 71,636 Net income per share: Basic $ 1.93 $ 2.25 $ 1.71 $ 1.33 Diluted $ 1.90 $ 2.22 $ 1.70 $ 1.32 Cash dividends paid per common share $ 0.18 $ 0.20 $ 0.20 $ 0.20 2017 Statement of Operations Data Net revenues $ 437,153 $ 480,757 $ 486,267 $ 511,800 Gross profit 205,547 219,583 227,995 238,326 Income from operations 83,580 92,883 110,155 120,016 Net income $ 65,060 $ 120,440 $ 75,994 $ 77,638 Net income per share: Basic $ 1.21 $ 2.22 $ 1.40 $ 1.43 Diluted $ 1.18 $ 2.19 $ 1.38 $ 1.41 Cash dividends paid per common share $ 0.175 $ 0.175 $ 0.175 $ 0.18

Business Description - Addition

Business Description - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018SegmentProduct
Number Of Product Groups And Reportable Segments [Abstract]
Number of product groups | Product	6
Number of reportable segments | Segment	2

Basis of Presentation - Revised

Basis of Presentation - Revised Presentation of Previously Issued Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Revenues:
Total net revenues	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Cost of revenues:
Total cost of revenues									1,095,632	1,024,526	729,723
Products [Member]
Net Revenues:
Total net revenues									1,835,202	1,701,301	1,118,579
Cost of revenues:
Total cost of revenues									969,288	906,369	630,208
Services [Member]
Net Revenues:
Total net revenues									239,906	214,676	176,763
Cost of revenues:
Total cost of revenues									$ 126,344	118,157	99,515
As Previously Reported [Member]
Net Revenues:
Total net revenues										1,915,977	1,295,342
Cost of revenues:
Total cost of revenues										1,024,526	729,723
As Previously Reported [Member] | Products [Member]
Net Revenues:
Total net revenues										1,723,433	1,134,013
Cost of revenues:
Total cost of revenues										901,546	627,850
As Previously Reported [Member] | Services [Member]
Net Revenues:
Total net revenues										192,544	161,329
Cost of revenues:
Total cost of revenues										122,980	101,873
Adjustment [Member] | Products [Member]
Net Revenues:
Total net revenues										(22,132)	(15,434)
Cost of revenues:
Total cost of revenues										4,823	2,358
Adjustment [Member] | Services [Member]
Net Revenues:
Total net revenues										22,132	15,434
Cost of revenues:
Total cost of revenues										$ (4,823)	$ (2,358)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Customer	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Jan. 01, 2018USD ($)
Change in Contract with Customer, Liability [Line Items]
Retained earnings opening balance sheet adjustment for Topic 606 adoption	$ 1,084,797	$ 795,698
Minimum period of company's research and development projects	3 months
Maximum period of company's research and development projects	30 months
Vesting period	3 years
Maximum maturity period of liquid investments	3 years
Maturity dates for short-term investments	12 months
Amortization period of leasehold improvements	Shorter of the lease term or the estimated useful life of the leased asset.
Asset impairment charge		6,719	$ 5,000
Increase (decrease) in valuation allowance on state tax credit carryforwards	$ 4,307	1,102	6,400
Valuation allowance	$ 17,936	$ 13,629	$ 12,527
Minimum percentage of recognition of tax benefits from uncertain tax positions	50.00%
U.S. federal corporate income tax rate	21.00%	35.00%	35.00%
Accounting Standards Codification Topic 606 adjustment [Member]
Change in Contract with Customer, Liability [Line Items]
Retained earnings opening balance sheet adjustment for Topic 606 adoption				$ 1,809
Contract assets	$ 3,624			$ 3,065
Other Expense [Member]
Change in Contract with Customer, Liability [Line Items]
Net foreign exchange losses from re-measurement	$ 2,497	$ 6,132
Selling, General and Administrative Expenses [Member]
Change in Contract with Customer, Liability [Line Items]
Net foreign exchange losses from re-measurement			$ 2,823
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Change in Contract with Customer, Liability [Line Items]
Number of customers comprising of Accounts Receivable | Customer	1
Customer Concentration Risk [Member] | Customer A [Member] | Sales Revenue, Net [Member]
Change in Contract with Customer, Liability [Line Items]
Concentration risk, percentage	12.00%	13.00%	14.00%
Customer Concentration Risk [Member] | Customer B [Member] | Sales Revenue, Net [Member]
Change in Contract with Customer, Liability [Line Items]
Concentration risk, percentage	11.00%	12.00%	11.00%
Customer Concentration Risk [Member] | Semiconductor Products [Member] | Sales Revenue, Net [Member]
Change in Contract with Customer, Liability [Line Items]
Concentration risk, percentage	55.00%	57.00%	56.00%
Minimum [Member]
Change in Contract with Customer, Liability [Line Items]
Intangible assets amortized period	1 year
Minimum [Member] | Accounting Standards Codification Topic 606 adjustment [Member]
Change in Contract with Customer, Liability [Line Items]
Company's normal payment terms	30 days
Warranty period	12 months
Term of separately priced contracts	12 months
Minimum [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member]
Change in Contract with Customer, Liability [Line Items]
Concentration risk, percentage	10.00%	10.00%
Minimum [Member] | Buildings [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	10 years
Minimum [Member] | Machinery and Equipment [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Office Equipment [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	3 years
Maximum [Member]
Change in Contract with Customer, Liability [Line Items]
Intangible assets amortized period	18 years
Maximum [Member] | Accounting Standards Codification Topic 606 adjustment [Member]
Change in Contract with Customer, Liability [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
Maximum [Member] | Buildings [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	50 years
Maximum [Member] | Machinery and Equipment [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	16 years
Maximum [Member] | Furniture and Fixtures [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	16 years
Maximum [Member] | Office Equipment [Member]
Change in Contract with Customer, Liability [Line Items]
Estimated useful lives	16 years

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Deferred Revenue and Customer Advances by Arrangement (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Change in Contract with Customer, Liability [Abstract]
Beginning balance, January 1	$ 27,800
Amount of deferred revenue and customer advances recognized in income	(83,497)
Additions to deferred revenue and customer advances	73,171
Ending balance, December 31	$ 17,474

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Deferred Revenue and Customer Advances by Arrangement (Parenthetical) (Detail) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017
Change in Contract with Customer, Liability [Line Items]
Deferred revenue and customer advances		$ 14,246	$ 26,194
Long-term deferred revenue	$ 3,126	3,228
Deferred revenue and customer advances recognized in income		83,497
Deferred Revenue [Member]
Change in Contract with Customer, Liability [Line Items]
Deferred revenue and customer advances	12,842	14,246
Customer Advances [Member]
Change in Contract with Customer, Liability [Line Items]
Deferred revenue and customer advances	13,352	6,112
ASC 606 [Member]
Change in Contract with Customer, Liability [Line Items]
Adjustment in deferred revenue and customer advances	$ (1,520)
Deferred revenue and customer advances recognized in income		$ 61,012

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									1,260,862	1,207,457	872,291
Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									814,246	708,520	423,051
Products [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									1,835,202	1,701,301	1,118,579
Products [Member] | Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									1,080,343	1,047,639	731,364
Products [Member] | Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									754,859	653,662	387,215
Services [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									239,906	214,676	176,763
Services [Member] | Vacuum & Analysis [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									180,519	159,818	140,927
Services [Member] | Light & Motion [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue									$ 59,387	$ 54,858	$ 35,836

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements - Additional Information (Detail) - Accounting Standards Update 2016-02 [Member]	Jan. 01, 2019USD ($)
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 60,000
Lease liability	60,000
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	65,000
Lease liability	$ 65,000

Investments - Investments Class

Investments - Investments Classified as Short-Term Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 73,826	$ 209,434
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	102	9,757
Bankers' Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	989	5,330
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	9,113	36,990
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	19,359	13,750
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	9,352	77,821
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments		1,970
U.S. Treasury Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	13,298	28,078
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 21,613	$ 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	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items]
Investments classified as long-term	$ 10,290	$ 10,655
Available-for-Sale Investments [Member] | Group Insurance Contracts [Member]
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items]
Investments classified as long-term	5,890	6,255
Cost-method Investments [Member] | 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	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	$ 73,994	$ 209,453
Investments, Gross Unrealized Gains	7	108
Investments, Gross Unrealized (Losses)	(175)	(127)
Investments, Estimated Fair Value	73,826	209,434
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	102	9,756
Investments, Gross Unrealized Gains		1
Investments, Estimated Fair Value	102	9,757
Bankers' Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	989	5,330
Investments, Estimated Fair Value	989	5,330
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	9,121	37,017
Investments, Gross Unrealized Gains	1	15
Investments, Gross Unrealized (Losses)	(9)	(42)
Investments, Estimated Fair Value	9,113	36,990
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	19,504	13,810
Investments, Gross Unrealized (Losses)	(145)	(60)
Investments, Estimated Fair Value	19,359	13,750
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	9,367	77,788
Investments, Gross Unrealized Gains		58
Investments, Gross Unrealized (Losses)	(15)	(25)
Investments, Estimated Fair Value	9,352	77,821
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost		1,970
Investments, Estimated Fair Value		1,970
U.S. Treasury Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	13,294	28,054
Investments, Gross Unrealized Gains	4	24
Investments, Estimated Fair Value	13,298	28,078
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	21,617	35,728
Investments, Gross Unrealized Gains	2	10
Investments, Gross Unrealized (Losses)	(6)
Investments, Estimated Fair Value	21,613	35,738
Group Insurance Contracts [Member] | Long Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	5,546	6,006
Investments, Gross Unrealized Gains	344	249
Investments, Estimated Fair Value	$ 5,890	$ 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	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	$ 73,826	$ 209,434
Short-term investments	73,826	209,434
Derivatives - currency forward contracts		168
Other assets	38,682	37,883
Derivatives - liabilities		6,198
Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts	2,485
Derivatives - liabilities	1,168
Interest Rate Hedge [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - interest rate hedge - non-current	6,083	6,179
Derivatives - currency forward contracts	6,083	6,179
Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	290,097	274,765
Cash and cash equivalents, including restricted cash (1)	187,405	37,681
Short-term investments	73,826	209,434
Derivatives - currency forward contracts	2,485	168
Total current assets	263,716	247,283
Available-for-sale investments	5,890	6,255
Other assets	20,491	21,227
Total long-term assets	26,381	27,482
Derivatives - liabilities	1,168	6,198
Fair Value Measurements, Recurring [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts	2,485
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	6,083	6,179
Fair Value Measurements, Recurring [Member] | Currency Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts		168
Derivatives - liabilities	1,168	6,198
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	180,340	4,987
Restricted cash - money market funds	110	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	850	2,100
Available-for-sale investments	102	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	3,418
Available-for-sale investments	21,613	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	989	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	9,113	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	13,298	28,078
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	180,450	5,106
Cash and cash equivalents, including restricted cash (1)	180,450	5,106
Total current assets	180,450	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	180,340	4,987
Restricted cash - money market funds	110	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]
Total assets	109,647	269,659
Cash and cash equivalents, including restricted cash (1)	6,955	32,575
Short-term investments	73,826	209,434
Derivatives - currency forward contracts	2,485	168
Total current assets	83,266	242,177
Available-for-sale investments	5,890	6,255
Other assets	20,491	21,227
Total long-term assets	26,381	27,482
Derivatives - liabilities	1,168	6,198
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 - currency forward contracts	2,485
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	6,083	6,179
Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member] | Currency Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts		168
Derivatives - liabilities	1,168	6,198
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	850	2,100
Available-for-sale investments	102	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	3,418
Available-for-sale investments	21,613	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	989	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	9,113	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	13,298	28,078
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	19,359	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	2,687	30,475
Available-for-sale investments	19,359	13,750
Commercial Paper [Member] | 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]
Cash and cash equivalents	2,687	30,475
Available-for-sale investments	19,359	13,750
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	9,352	77,821
Corporate Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	9,352	77,821
Corporate Obligations [Member] | 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	9,352	77,821
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	5,890	6,255
Group Insurance Contracts [Member] | 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	5,890	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	14,408	15,048
Israeli Pension Assets [Member] | 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]
Pension assets	$ 14,408	15,048
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments		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		1,970
Municipal Bonds [Member] | 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		$ 1,970

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	Dec. 31, 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	$ 456,940	$ 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	Dec. 31, 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		$ 159,394,000	$ 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 term loan balance, as described further in Note 13. This hedge fixes the interest rate paid on the hedged debt at 1.198% per annum plus the credit spread, which was 1.75% as of December 31, 2018, through September 30, 2020.
Interest rate swap agreement, fair value		$ 6,083,000	$ 6,179,000
Cash Flow Hedging [Member] | Interest Rate Hedge [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	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	$ 159,394	$ 208,922
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	1,317	(6,030)
Forward Exchange Contracts [Member] | U.S. Dollar/Japanese Yen [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	43,770	70,175
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	(478)	(233)
Forward Exchange Contracts [Member] | U.S. Dollar/South Korean Won [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	59,149	79,672
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	570	(3,799)
Forward Exchange Contracts [Member] | U.S. Dollar/Euro [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	23,515	26,140
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	688	(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	11,827	12,104
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	323	(337)
Forward Exchange Contracts [Member] | U.S. Dollar/Taiwan Dollar [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	21,133	20,831
Currency Hedged (Buy/Sell), Fair Value, (Liability)/Asset, Net	$ 214	$ (614)

Derivatives - Summary of Fair V

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets		$ 168
Derivative liabilities		(6,198)
Total net derivative asset designated as hedging instruments	$ 1,317	(6,030)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total net derivative asset designated as hedging instruments	7,400	149
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	2,485
Derivative liabilities	(1,168)
Foreign Exchange Contracts [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	2,485	168
Derivative liabilities	(1,168)	(6,198)
Interest Rate Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	6,083	6,179
Interest Rate Hedge [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	$ 6,083	$ 6,179

Derivatives - Summary of Fair_2

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative asset classified in other current assets		$ 168
Derivative liability classified in other current liabilities		6,198
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative asset classified in other current assets	$ 2,485
Derivative liability classified in other current liabilities	1,168
Interest Rate Hedge [Member]
Derivatives, Fair Value [Line Items]
Derivative asset classified in other current assets	$ 6,083	$ 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	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in OCI	$ 6,289	$ (6,036)	$ 5,914
Net loss reclassified from OCI into income	$ (3,367)	$ (2,685)	$ (1,414)

Derivatives - Summary of Losses

Derivatives - Summary of Losses on Derivatives Not Designated as Cash Flow Hedging Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Forward Exchange Contracts [Member]
Derivative Instruments Gain Loss Not Designated As Hedging Instruments [Line Items]
Net gain (loss) recognized in income	$ 105	$ (3,416)	$ (31)

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw material	$ 235,593	$ 191,351
Work-in-process	61,908	54,050
Finished goods	87,188	93,680
Inventories	$ 384,689	$ 339,081

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventory related excess and obsolete charges	$ 22,324	$ 20,213	$ 16,039

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 706,829	$ 657,143
Less: accumulated depreciation	512,462	485,361
Property, plant and equipment, net	194,367	171,782
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	11,448	11,650
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	104,023	103,563
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	330,821	317,073
Furniture and Fixtures, Office Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	149,145	145,945
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	66,569	65,293
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 44,823	$ 13,619

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation of property, plant and equipment	$ 36,332	$ 36,813	$ 30,245

Acquisitions and Dispositions -

Acquisitions and Dispositions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended									12 Months Ended
	Jul. 31, 2017	Apr. 30, 2017	Apr. 30, 2016	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Apr. 29, 2016
Business Acquisition [Line Items]
Business acquisition share price																$ 23
Stock-based compensation expense													$ 27,262	$ 24,378	$ 25,228
Total proceeds from sale of business unit, net of cash sold		$ 72,509												72,509
Pre-tax gain		$ 74,856												74,856
Net revenues				$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153		2,075,108	$ 1,915,977	1,295,342
Data Analytics Solutions Business [Member]
Business Acquisition [Line Items]
Net revenues															12,700
Minority Interest in Private Company [Member]
Business Acquisition [Line Items]
Investments in minority interest	$ 100		$ 9,300
Impairment charges												$ 5,000
Newport [Member]
Business Acquisition [Line Items]
Business acquisition share price																$ 23
Fair value write-up of acquired finished goods inventory				15,090									15,090
Incremental costs of sales charge															15,090
Fair value write-up of acquired property, plant and equipment				$ 36,242									$ 36,242
Compensation expense															6,635
Stock-based compensation expense															$ 3,334

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Summary of Purchase Price (Detail) - USD ($) $ in Thousands	Apr. 29, 2016	Dec. 31, 2016
Acquisition Date [Line Items]
Total purchase price, net of cash and cash equivalents acquired		$ 939,591
Newport [Member]
Acquisition Date [Line Items]
Cash paid for outstanding shares	$ 905,254
Settlement of share-based compensation awards	8,824
Cash paid for Newport debt	93,200
Total purchase price	1,007,278
Less: cash and cash equivalents acquired	(61,463)
Total purchase price, net of cash and cash equivalents acquired	$ 945,815

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Summary of Purchase Price (Parenthetical) (Detail)	Apr. 29, 2016$ / sharesshares
Business Combinations [Abstract]
Business acquisition share price | $ / shares	$ 23
Business acquisition number of shares acquired | shares	39,359,000

Acquisitions and Dispositions_4

Acquisitions and Dispositions - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Apr. 29, 2016	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Acquisition Date [Line Items]
Goodwill		$ 588,585	$ 586,996	$ 591,047
Total purchase price, net of cash and cash equivalents acquired		$ 939,591
Newport [Member]
Acquisition Date [Line Items]
Current assets (including cash)	$ 186,137
Inventory	142,714
Intangible assets	404,506
Goodwill	396,027
Property, plant and equipment	119,932
Long-term assets	22,725
Total assets acquired	1,272,041
Current liabilities	95,156
Intangible liability	4,302
Other long-term liabilities	165,305
Total liabilities assumed	264,763
Fair value of assets acquired and liabilities assumed	1,007,278
Less: cash and cash equivalents acquired	(61,463)
Total purchase price, net of cash and cash equivalents acquired	$ 945,815

Acquisitions and Dispositions_5

Acquisitions and Dispositions - Allocation of Acquired Intangible Assets and Liabilities Related Estimates of Useful Lives (Detail) - USD ($) $ in Thousands	Apr. 29, 2016	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 404,506
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets		1 year
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets		18 years
Order Backlog [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 12,100
Estimated useful life of finite-lived intangible assets	1 year
Customer Relationships [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 247,793
Customer Relationships [Member] | Newport [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	6 years
Customer Relationships [Member] | Newport [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	18 years
Trademarks and Trade Names [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 55,900
Estimated useful life of finite-lived intangible assets	Indefinite
Developed Technology [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 75,386
Developed Technology [Member] | Newport [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	4 years
Developed Technology [Member] | Newport [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	8 years
In-process Research and Development [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 6,899
Estimated useful life of finite-lived intangible assets	Undefined
Leasehold Interest Favorable [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 6,428
Leasehold Interest Favorable [Member] | Newport [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	4 years
Leasehold Interest Favorable [Member] | Newport [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets	5 years
Leasehold Interest Unfavorable [Member] | Newport [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 4,302

Acquisitions and Dispositions_6

Acquisitions and Dispositions - Schedule of Unaudited Pro Forma Financial Information (Detail) - Newport [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / shares
Acquisition Date [Line Items]
Total net revenues | $	$ 1,475,637
Net income | $	$ 111,076
Net income per share:
Basic | $ / shares	$ 2.08
Diluted | $ / shares	$ 2.06

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 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	(4,051)	10,439
Ending balance, Goodwill Gross Carrying Amount	731,272	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	(4,051)	10,439
Ending balance, Goodwill Net	$ 586,996	$ 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 - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment charges	$ 1,511	$ 1,511
Amortization of intangible assets	43,521	45,743	$ 35,681
Amortization income from unfavorable lease commitments	$ 885	$ 811	$ 569

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 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	(244,025)	(199,619)
Foreign Currency Translation	(355)	1,830
Intangible assets, net	319,807	366,398
Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	172,431	172,431
Impairment Charges	(105)	(105)
Accumulated Amortization	(137,283)	(115,371)
Foreign Currency Translation	(73)	333
Intangible assets, net	34,970	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	(63,788)	(45,518)
Foreign Currency Translation	(269)	1,571
Intangible assets, net	217,281	237,391
Patents, Trademarks, Trade Names and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	110,523	110,523
Accumulated Amortization	(42,954)	(38,730)
Foreign Currency Translation	(13)	(74)
Intangible assets, net	$ 67,556	$ 71,719

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 43,521	$ 45,743	$ 35,681
Completed Technology [Member] | Data Analytics Solutions Business [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets		$ 1,511

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets - Estimated Net Amortization Expense (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,019	$ 40,073
2,020	28,076
2,021	20,206
2,022	17,584
2,023	17,220
Thereafter	$ 138,693

Product Warranties - Product Wa

Product Warranties - Product Warranty Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Guarantees [Abstract]
Beginning balance	$ 10,104	$ 8,261
Provision for product warranties	15,987	15,884
Direct and other charges to warranty liability	(15,692)	(14,041)
Ending balance	$ 10,399	$ 10,104

Product Warranties - Product _2

Product Warranties - Product Warranty Activities (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Guarantees [Abstract]
Short-term product warranty	$ 9,986	$ 9,719
Long-term product warranty	$ 413	$ 385

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 ($)

Dec. 31, 2018USD ($)Institution

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Mar. 31, 2018USD ($)

Nov. 30, 2017USD ($)

Aug. 31, 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

1.251%

LIBOR floor rate

0.75%

0.75%

Decrease in base rate borrowings margin

0.75%

1.25%

Description of applicable margin

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 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

$ 16,942,000

$ 30,990,000

$ 30,611,000

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

$ 11,335,000

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

Debt Instrument [Line Items]

Line of credit base interest rate

1.25%

Japan [Member]

Debt Instrument [Line Items]

Borrowing capacity in the form of letters of credit

$ 20,856,000

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

$ 0

0

Austria [Member]

Debt Instrument [Line Items]

Interest on loans payable

Semi-annually

Austria [Member] | Maximum [Member]

Debt Instrument [Line Items]

Loan interest rate

2.00%

Austria [Member] | Minimum [Member]

Debt Instrument [Line Items]

Loan interest rate

0.75%

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

Debt Instrument [Line Items]

Total borrowings outstanding

$ 3,389,000

$ 2,965,000

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

4,708,000

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

$ 6,083,000

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] | 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, interest rate

4.10%

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

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] | 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] | 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] | LIBOR [Member]

Debt Instrument [Line Items]

Debt instrument, interest rate

1.75%

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] | 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	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Short term debt	$ 3,986	$ 2,972
Other Debt [Member]
Short-term Debt [Line Items]
Short term debt	597	7
Japan [Member] | Line of Credit [Member]
Short-term Debt [Line Items]
Short term debt	2,724	2,750
Japan [Member] | Receivables Financing Facility [Member]
Short-term Debt [Line Items]
Short term debt	$ 665	$ 215

Debt - Schedule of Long Term De

Debt - Schedule of Long Term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long term debt	$ 343,842	$ 389,993
Term Loan Facility, Net [Member]
Debt Instrument [Line Items]
Long term debt	343,756	389,279
Loans Due Through March 2020 and other debt [Member] | Austria [Member]
Debt Instrument [Line Items]
Long term debt	$ 86	$ 714

Debt - Schedule of Long Term _2

Debt - Schedule of Long Term Debt (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Term Loan Facility, Net [Member]
Debt Instrument [Line Items]
Deferred financing fees, original issuance discount and re-pricing fee	$ 4,708	$ 9,185

Debt - Schedule of Contractual

Debt - Schedule of Contractual Maturities of Debt Obligations (Detail)	Dec. 31, 2018USD ($)
Maturities of Long-term Debt [Abstract]
2,019	$ 3,986
2,020	72
2,021	14
2,022	0
2,023	$ 348,464

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
U.S. federal corporate income tax rate	21.00%	35.00%	35.00%
Adjustment to provisional tax benefit	$ 625,000
Increase of effective tax rate	0.40%
Additional deferred tax provision	$ 2,614	$ 22,345
Gross tax research other tax credit carryforwards	29,858,000
Accrued interest on unrecognized tax benefits	568,000	327,000	$ 491,000
Gross unrecognized tax benefits excluding interest and penalties	32,684,000	27,345,000	25,465,000	$ 4,332,000
Net unrecognized tax benefits, excluding interest and penalties, related to foreign tax positions	2,150,000
Change in valuation allowance	4,307,000	1,102,000	$ 6,400,000
Undistributed earnings of foreign subsidiaries	521,000,000	560,000,000
Tax expense related to repatriation of foreign earnings	$ 4,624,000	$ 27,610,000
Minimum [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	7.50%
Maximum [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	16.00%
Indefinite [Member]
Income Taxes [Line Items]
Gross tax research other tax credit carryforwards	$ 15,081,000
Federal State and Foreign [Member]
Income Taxes [Line Items]
Tax credit expiration period	2,035
Federal State and Foreign [Member] | Indefinite [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 36,057,000
Federal State and Foreign [Member] | 2017 [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 43,715,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Company's Effective Tax Rate to U.S. Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. Federal income tax statutory rate	21.00%	35.00%	35.00%
Federal tax credits	(0.70%)	(0.70%)	(1.80%)
State income taxes, net of federal benefit	1.30%	1.00%	0.80%
Effect of foreign operations taxed at various rates	(1.30%)	(12.10%)	(12.70%)
Qualified production activity tax benefit		(1.40%)	(2.90%)
Foreign derived intangible income	(2.10%)
Global intangible low taxed income, net of foreign tax credits	0.40%
Transition tax, net of foreign tax credits	(0.10%)	6.40%
Revaluation of U.S. deferred income taxes	(0.30%)	(5.00%)
Revaluation of prepaid taxes	1.60%
Stock based compensation	(1.30%)	(2.50%)
Deferred tax asset valuation allowance		(0.10%)	2.10%
Release of income tax reserves (including interest)	(0.40%)	(0.40%)	(2.40%)
Taxes on foreign dividends, net of foreign tax credits	(1.00%)	3.30%	(2.20%)
Acquisition and integration related costs			1.50%
Other	1.20%	0.70%	0.70%
Total	18.30%	24.20%	18.10%

Income Taxes - Components of In

Income Taxes - Components of Income from Operations Before Income Taxes and Related Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income from continuing operations before income taxes:
United States	$ 287,309	$ 224,979	$ 42,491
Foreign	193,641	222,646	85,486
Income from continuing operations before income taxes	480,950	447,625	127,977
Current taxes:
United States	41,428	77,023	17,693
State	8,094	6,149	2,359
Foreign	57,920	30,152	41,938
Current taxes, Total	107,442	113,324	61,990
Deferred taxes:
United States	(2,533)	(16,250)	(23,604)
State and Foreign	(16,855)	11,419	(15,218)
Deferred taxes, Total	(19,388)	(4,831)	(38,822)
Provision for income taxes	$ 88,054	$ 108,493	$ 23,168

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Carry-forward losses and credits	$ 23,675	$ 25,834
Inventory and warranty reserves	17,945	17,734
Accrued expenses and other reserves	10,260	15,393
Stock-based compensation	5,351	5,092
Executive supplemental retirement benefits	5,972	4,984
Other	2,396	597
Total deferred tax assets	65,599	69,634
Deferred tax liabilities:
Acquired intangible assets	(74,120)	(83,092)
Depreciation and amortization	(8,332)	(10,150)
Loan costs	(1,108)	(2,157)
Foreign withholding taxes	(3,176)	(16,206)
Unrealized gain	(1,952)	(469)
Total deferred tax liabilities	(88,688)	(112,074)
Valuation allowance	(17,936)	(13,629)	$ (12,527)
Net deferred tax (liabilities) assets	$ (41,025)	$ (56,069)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 27,345	$ 25,465	$ 4,332
Increases/(decreases) for prior years	934	640	(195)
Increases for the current year	6,091	4,340	23,940
Reductions related to expiration of statutes of limitations and audit settlements	(1,686)	(3,100)	(2,612)
Balance at end of year	$ 32,684	$ 27,345	$ 25,465

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Feb. 11, 2019	Jul. 25, 2011	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders Equity [Line Items]
Common stock, value of shares authorized to repurchase		$ 200,000,000
Stock repurchase, shares		2,588,000									818,000	0	44,798
Value of shares repurchased		$ 127,000,000									$ 75,000,000		$ 1,545,000
Average price of repurchased shares											$ 91.67		$ 34.50
Cash dividends per common share			$ 0.200	$ 0.200	$ 0.200	$ 0.180	$ 0.180	$ 0.175	$ 0.175	$ 0.175	$ 0.78	$ 0.71	$ 0.68
Dividend payment to common shareholders			$ 42,405,000	$ 42,405,000	$ 42,405,000	$ 42,405,000	$ 38,178,000	$ 38,178,000	$ 38,178,000	$ 38,178,000	$ 42,405,000	$ 38,178,000	$ 36,361,000
Subsequent Event [Member]
Stockholders Equity [Line Items]
Dividend declared date	Feb. 11, 2019
Cash dividend to be paid	$ 0.20
Dividend to be paid date	Mar. 8, 2019
Dividend declared, shareholders of record date	Feb. 25, 2019

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	Jun. 01, 2017	Jan. 31, 2017	Apr. 29, 2016	May 31, 2018	May 31, 2017	May 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued							54,039,554	54,355,535
Common stock reserved for issuance							18,000,000
Vesting period							3 years
Capitalization of share based payment costs							$ 471,000	$ 471,000	$ 471,000
Restricted stock units, weighted average grant date fair value							$ 21.74	$ 13.14	$ 8.52
2014 ESPP Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance							2,500,000
Percentage of payroll deduction to compensation							Up to 10%
Percentage of Common Stock through payroll deductions							10.00%
Amount of payroll deduction	$ 22,500,000						$ 21,250,000
Amount of payroll deduction increased							$ 22,500,000
Percentage of closing price of the Common Stock		90.00%					85.00%
Common stock, shares issued							105,672	105,506	139,079
Common stock reserved for issuance							1,926,731
2014 ESPP Plan [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock		90.00%					85.00%
2014 ESPP Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price							$ 84.11	$ 46.37	$ 31.40
2014 ESPP Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price							$ 70.61	$ 74.12	$ 35.16
Stock Incentive Plan 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance							14,079,849
Shares available for future grant							18,000,000
Percentage of exercise price fair value option grant in period							100.00%
Number of shares returned for each common stock							2.4
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued as per merger agreement							1,260,525
Number of RSUs outstanding							6,694	12,134	17,462
Dividend reinvestment							66	122	187
Restricted stock units, weighted average grant date fair value							$ 111.64
Total intrinsic value of options, stock appreciation rights exercised and fair value of RSUs vested							$ 61,626,000	$ 60,302,000	$ 18,844,000
Total compensation expense related to restricted stock unites and stock appreciation rights							$ 19,039,000
Estimated weighted average amortization period							10 months 28 days
Restricted Stock Units (RSUs) [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage per year of RSUs from date of grant							33.00%	33.00%	33.00%
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period							1 day
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period							13 months
Restricted Stock Units (RSUs) [Member] | Newport Deferred Compensation [Member] | Outside Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Newport RSUs converted to MKS RSUs at Merger date							36,599
Newport RSUs converted to MKS RSUs at Merger date and released				5,561	5,515	19,137
RSUs Granted to Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description							Employees who are at least 60 years old and have a minimum of 10 Years of Service (as defined in the applicable RSU agreement) are expensed immediately.
Minimum years of service for RSU							10 years
RSUs Granted to Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description							Earliest of (1) one day prior to the next annual meeting, (2) 13 months from date of grant, or (3) the effective date of a change in control of the Company.
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options, stock appreciation rights exercised and fair value of RSUs vested							$ 61,626,000	$ 60,302,000	$ 18,844,000
Total compensation expense related to restricted stock unites and stock appreciation rights							$ 19,039,000
Estimated weighted average amortization period							10 months 28 days
Newport [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued as per merger agreement			360,674
Newport [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued as per merger agreement			899,851

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity for RSUs (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, Granted	$ 21.74	$ 13.14	$ 8.52
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested RSUs/SARs - beginning of period	943,379
Granted	266,411
Vested	(490,453)
Forfeited or expired	(72,009)
Non-vested RSUs/SARs - end of period	647,394	943,379
RSUs/SARs, Weighted Average Grant Date Fair Value, Beginning of period	$ 47.57
Weighted Average Grant Date Fair Value, Granted	111.64
Weighted Average Grant Date Fair Value, Vested	44.70
Weighted Average Grant Date Fair Value, Forfeited or expired	66.22
RSUs/SARs, Weighted Average Grant Date Fair Value, end of period	$ 74.04	$ 47.57
Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrued dividend shares	66
Weighted Average Grant Date Fair Value, Accrued dividend shares	$ 94.11

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity for SARs (Detail) - Stock Appreciation Rights (SARs) [Member]	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested RSUs/SARs - beginning of period | shares	282,907
Exercised, Outstanding SARs | shares	(103,419)
Forfeited or expired, Outstanding SARs | shares	(1,950)
Non-vested RSUs/SARs - end of period | shares	177,538
RSUs/SARs, Weighted Average Grant Date Fair Value, Beginning of period | $ / shares	$ 28.62
Exercised, Weighted Average Grant Date Fair Value | $ / shares	28.78
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

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Activity for Outstanding and Exercisable SARs (Detail) - Stock Appreciation Rights (SARs) [Member]	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SARs outstanding and exercisable | shares	177,538
SARs outstanding and exercisable | $ / shares	$ 28.52
SARs outstanding and exercisable	2 years 4 months 24 days
SARs outstanding and exercisable | $	$ 6,408

Stock-Based Compensation - Effe

Stock-Based Compensation - Effect of Recording Stock-Based Compensation (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 27,262	$ 24,378	$ 25,228
Windfall tax effect on stock-based compensation	(8,277)	(11,071)
Net effect on net income	$ 18,985	$ 13,307	$ 25,228
Basic	$ 0.35	$ 0.25	$ 0.47
Diluted	$ 0.35	$ 0.24	$ 0.47
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 24,883	$ 22,428	$ 23,302
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	98	529	700
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 2,281	$ 1,421	$ 1,226

Stock-Based Compensation - Pre-

Stock-Based Compensation - Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$ 27,262	$ 24,378	$ 25,228
Cost of Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	3,516	3,894	2,997
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	2,750	2,816	2,529
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	$ 20,996	$ 17,668	$ 19,702

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Employees' Purchase Rights Estimated Using Black-Scholes Option-Pricing Model (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected life (years)	6 months	6 months	6 months
Risk-free interest rate	1.80%	0.80%	0.50%
Expected volatility	38.60%	26.50%	25.40%
Expected annual dividends per share	$ 0.76	$ 0.69	$ 0.68

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employee contribution to Company's profit sharing plan percentage	1.00%
Employee contribution to Company's profit sharing plan percentage	50.00%
Minimum age limit for specified additional amount	50 years
Company's contributions	$ 6,093	$ 5,651	$ 6,524
Bonus expense	38,254	46,783	28,097
Supplemental retirement benefits cost	4,609	3,478	$ 1,805
Accumulated benefit obligation	20,644	15,929
Defined benefit plan expected company contributions	$ 1,046
Expected long-term rate of return on assets	1.90%
Defined benefit plan, vested benefit obligations	$ 17,552	17,932
Israel [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets	$ 14,409	15,048
Japan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	1.50%
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	2.60%
France [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	1.60%
Germany [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets	$ 5,890	$ 6,255
Germany [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets guaranteed rate of return	2.25%
Germany [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets guaranteed rate of return	4.25%

Employee Benefit Plans - Summar

Employee Benefit Plans - Summary of Net Periodic Benefit Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 657	$ 708
Interest cost on projected benefit obligations	433	458
Expected return on plan assets	(115)	(116)
Amortization of actuarial net loss	127	400
Net periodic benefit costs	$ 1,102	$ 1,450

Employee Benefit Plans - Summ_2

Employee Benefit Plans - Summary of Changes in Projected Benefit Obligations and Plan Assets, and Ending Balances of Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Change in projected benefit obligations:
Service cost	$ 657	$ 708
Interest cost	433	458
Change in plan assets:
Company contributions	1,046
Fair value of plan assets, end of year	7,822
Newport [Member]
Change in projected benefit obligations:
Projected benefit obligations, beginning of year	25,736	23,450
Service cost	657	708
Interest cost	433	458
Actuarial gain	(98)	(312)
Benefits paid	(895)	(1,271)
Currency translation adjustments	(948)	2,703
Projected benefit obligations, end of year	24,885	25,736
Change in plan assets:
Fair value of plan assets, beginning of year	8,152	7,672
Company contributions	324	324
(Loss) gain on plan assets	(56)	177
Benefits paid	(369)	(722)
Currency translation adjustments	(229)	701
Fair value of plan assets, end of year	7,822	8,152
Net underfunded status	$ (17,063)	$ (17,584)

Employee Benefit Plans - Summ_3

Employee Benefit Plans - Summary of Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in accumulated comprehensive income:
Accumulated net actuarial gain		$ 235	$ 235
Income tax (expense) benefit		(86)	88
Accumulated other comprehensive gain	[1]	$ 149	$ 323	$ (266)
[1]	Tax expense (benefit) was $86, $(88) and $(199) for the years ended December 31, 2018, 2017 and 2016, respectively.

Employee Benefit Plans - Summ_4

Employee Benefit Plans - Summary of Estimated Benefit Payments for Defined Benefit Plans for Next 10 Years (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,019	$ 1,046
2,020	1,252
2,021	1,210
2,022	1,312
2,023	1,129
2024-2028	7,313
Estimated benefit payments for next 10 years, total	$ 13,262

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Weighted Average Rates Used to Determine Net Periodic Benefit Costs (Detail)	12 Months Ended
	Dec. 31, 2018
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	1.90%
Rate of increase in salary levels	2.10%
Expected long-term rate of return on assets	1.90%

Employee Benefit Plans - Sche_2

Employee Benefit Plans - Schedule of Defined Benefit Plan Assets (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 7,822
Defined benefit plan assets, percentage	100.00%
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 193
Defined benefit plan assets, percentage	2.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 4,855
Defined benefit plan assets, percentage	62.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 1,342
Defined benefit plan assets, percentage	17.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 1,432
Defined benefit plan assets, percentage	19.00%

Net Income Per Share - Reconcil

Net Income Per Share - Reconciliation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income	$ 71,636	$ 93,277	$ 122,862	$ 105,121	$ 77,638	$ 75,994	$ 120,440	$ 65,060	$ 392,896	$ 339,132	$ 104,809
Denominator:
Shares used in net income per common share - basic									54,406,000	54,137,000	53,472,000
Effect of dilutive securities									586,000	937,000	579,000
Shares used in net income per common share - diluted									54,992,000	55,074,000	54,051,000
Net income per common share:
Basic	$ 1.33	$ 1.71	$ 2.25	$ 1.93	$ 1.43	$ 1.40	$ 2.22	$ 1.21	$ 7.22	$ 6.26	$ 1.96
Diluted	$ 1.32	$ 1.70	$ 2.22	$ 1.90	$ 1.41	$ 1.38	$ 2.19	$ 1.18	$ 7.14	$ 6.16	$ 1.94

Net Income Per Share - Addition

Net Income Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted Stock Units (RSUs) [Member]
Earnings Per Share [Line Items]
Number of shares excluded from computation of diluted earnings per share	79,500	404	508

Business Segment, Geographic _3

Business Segment, Geographic Area, Product and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018CustomerSegmentProduct
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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total net revenues	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Total net revenues									1,260,862	1,207,457	872,291
Light & Motion [Member]
Segment Reporting Information [Line Items]
Total net revenues									$ 814,246	$ 708,520	$ 423,051

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								12 Months Ended
	Apr. 30, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Gross profit		$ 209,884	$ 231,860	$ 274,877	$ 262,855	$ 238,326	$ 227,995	$ 219,583	$ 205,547	$ 979,476	$ 891,451	$ 565,619
Research and development										135,720	132,555	110,579
Selling, general and administrative										298,118	290,056	227,932
Acquisition and integration costs										3,113	5,332	27,279
Restructuring										3,567	3,920	642
Environmental costs										1,000
Asset impairment											6,719	5,000
Fees and expenses related to repricing of term loan										378	492	1,239
Amortization of intangible assets										43,521	45,743	35,681
Income from operations		94,084	117,045	151,291	131,639	120,016	110,155	92,883	83,580	494,059	406,634	157,267
Interest income										5,775	3,021	2,560
Interest expense										16,942	30,990	30,611
Gain on sale of business	$ 74,856										74,856
Other expense, net										1,942	5,896	1,239
Income before income taxes										480,950	447,625	127,977
Provision for income taxes										88,054	108,493	23,168
Net income		$ 71,636	$ 93,277	$ 122,862	$ 105,121	$ 77,638	$ 75,994	$ 120,440	$ 65,060	392,896	339,132	104,809
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Gross profit										577,552	551,078	388,220
Light & Motion [Member]
Segment Reporting Information [Line Items]
Gross profit										$ 401,924	$ 340,373	$ 177,399

Business Segment, Geographic _6

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Capital Expenditures, Depreciation and Amortization Expense of Intangible Assets by Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Capital expenditures	$ 62,941	$ 31,287	$ 19,123
Depreciation and amortization	79,853	82,556	65,926
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Capital expenditures	40,144	17,111	11,732
Depreciation and amortization	20,808	20,297	20,820
Light & Motion [Member]
Segment Reporting Information [Line Items]
Capital expenditures	22,797	14,176	7,391
Depreciation and amortization	$ 59,045	$ 62,259	$ 45,106

Business Segment, Geographic _7

Business Segment, Geographic Area, Product and Significant Customer Information - Segment Assets by Reportable Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Accounts receivable	$ 295,454	$ 300,308
Inventory, net	384,689	339,081
Total assets	2,614,246	2,414,018
Operating Segments [Member]
Segment Reporting Information [Line Items]
Accounts receivable	295,454	300,308
Inventory, net	384,689	339,081
Total assets	680,143	639,389
Operating Segments [Member] | Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Accounts receivable	171,604	201,318
Inventory, net	222,965	197,831
Total assets	394,569	399,149
Operating Segments [Member] | Light & Motion [Member]
Segment Reporting Information [Line Items]
Accounts receivable	140,658	119,934
Inventory, net	161,658	141,250
Total assets	302,316	261,184
Corporate, Eliminations & Other [Member]
Segment Reporting Information [Line Items]
Accounts receivable	(16,808)	(20,944)
Inventory, net	66
Total assets	$ (16,742)	$ (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	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	$ 2,614,246	$ 2,414,018
Other current assets	65,790	53,543
Property, plant and equipment, net	194,367	171,782
Other assets	38,682	37,883
Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	680,143	639,389
Segment Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and cash equivalents, restricted cash and investments	728,461	553,976
Other current assets	65,790	53,543
Property, plant and equipment, net	194,367	171,782
Goodwill and intangible assets, net	906,803	957,445
Other assets	$ 38,682	$ 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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Long-lived assets	224,053				203,154				224,053	203,154
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									1,022,660	955,284	675,601
Long-lived assets	146,687				124,689				146,687	124,689
South Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									203,567	212,763	112,432
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									193,264	167,318	96,954
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									244,009	209,912	156,365
Long-lived assets	26,794				28,820				26,794	28,820
Asia (Excluding Korea and Japan) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									411,608	370,700	$ 253,990
Long-lived assets	$ 50,572				$ 49,645				$ 50,572	$ 49,645

Business Segment, Geographic_10

Business Segment, Geographic Area, Product and Significant Customer Information - Summary of Goodwill Associated with Reportable Segments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Goodwill	$ 586,996	$ 591,047	$ 588,585
Vacuum & Analysis [Member]
Segment Reporting Information [Line Items]
Goodwill	197,126	197,617
Light & Motion [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 389,870	$ 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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from External Customer [Line Items]
Net sales from product groups	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Analytical and Control Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									116,183	131,376	115,758
Power Plasma and Reactive Gas Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									610,111	564,343	367,665
Vacuum Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									534,568	511,738	388,868
Lasers Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									274,815	225,168	124,432
Optics Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									227,577	203,775	124,218
Photonics Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									$ 311,854	$ 279,577	$ 174,401

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]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Applied Materials, Inc. [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	11.70%	12.70%	13.60%
Lam Research Corporation [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	10.80%	11.70%	11.20%

Restructuring - Additional Info

Restructuring - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)FacilityPlant	Dec. 31, 2016USD ($)
Reorganizations [Abstract]
Restructuring charges | $	$ 3,567	$ 3,920	$ 642
Number of facilities consolidated | Facility		1
Number of manufacturing plants | Plant		2

Restructuring - Schedule of Com

Restructuring - Schedule of Company's Restructuring Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Beginning of period	$ 3,244	$ 540
Charged to expense	3,567	3,920	$ 642
Payments and adjustments	(4,179)	(1,216)
End of period	$ 2,632	$ 3,244	$ 540

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Lease expiration date	2,026
Rental expenses under operating leases	$ 20,912	$ 19,693	$ 16,253
Purchase commitments covered by aggregate value	$ 254,069
Purchase commitments	Less than one year

Commitments and Contingencies_2

Commitments and Contingencies - Minimum Lease Payments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,019	$ 20,106
2,020	17,142
2,021	10,325
2,022	5,573
2,023	4,410
Thereafter	8,739
Total minimum lease payments	$ 66,295

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - USD ($)	Feb. 01, 2019	Apr. 29, 2016
Subsequent Event [Line Items]
Business acquisition, share price		$ 23
Secured Debt [Member] | Electro Scientific Industries Inc [Member] | Asset Based Credit Agreement [Member] | Subsequent Event [Member] | Deutsche Bank AG New York [Member]
Subsequent Event [Line Items]
Secured term loan, terminated	$ 50,000,000
Secured Debt [Member] | Electro Scientific Industries Inc [Member] | Asset Based Credit Agreement [Member] | Subsequent Event [Member] | Barclays Bank PLC [Member]
Subsequent Event [Line Items]
Secured term loan, face amount	$ 100,000,000
Definitive Merger Agreement[Member] | Electro Scientific Industries Inc [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Business acquisition, share price	$ 30
Business acquisition, total cash consideration	$ 1,000,000,000
Definitive Merger Agreement[Member] | Maximum [Member] | Electro Scientific Industries Inc [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Business acquisition, term loan debt financing	$ 650,000,000

Supplemental Financial Data (De

Supplemental Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Operations Data
Net revenues	$ 460,541	$ 487,152	$ 573,140	$ 554,275	$ 511,800	$ 486,267	$ 480,757	$ 437,153	$ 2,075,108	$ 1,915,977	$ 1,295,342
Gross profit	209,884	231,860	274,877	262,855	238,326	227,995	219,583	205,547	979,476	891,451	565,619
Income from operations	94,084	117,045	151,291	131,639	120,016	110,155	92,883	83,580	494,059	406,634	157,267
Net income	$ 71,636	$ 93,277	$ 122,862	$ 105,121	$ 77,638	$ 75,994	$ 120,440	$ 65,060	$ 392,896	$ 339,132	$ 104,809
Net income per share:
Basic	$ 1.33	$ 1.71	$ 2.25	$ 1.93	$ 1.43	$ 1.40	$ 2.22	$ 1.21	$ 7.22	$ 6.26	$ 1.96
Diluted	1.32	1.70	2.22	1.90	1.41	1.38	2.19	1.18	7.14	6.16	1.94
Cash dividends paid per common share	$ 0.200	$ 0.200	$ 0.200	$ 0.180	$ 0.180	$ 0.175	$ 0.175	$ 0.175	$ 0.78	$ 0.71	$ 0.68

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 4,135	$ 3,909	$ 1,760
Additions Acquisition Beginning Balance			1,292
Additions Charged to Costs and Expenses	1,435	825	1,109
Additions Charged to Other Accounts			(66)
Deductions & Write-offs	(327)	(599)	(186)
Balance at End of Year	5,243	4,135	3,909
Valuation Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	1,295	1,138	601
Additions Acquisition Beginning Balance			423
Additions Charged to Costs and Expenses	124	(142)	2,262
Deductions & Write-offs	(386)	299	(2,148)
Balance at End of Year	1,033	1,295	1,138
Valuation Allowance on Deferred Tax Asset [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	13,629	12,527	6,127
Additions Acquisition Beginning Balance			3,769
Additions Charged to Costs and Expenses	4,825	1,603	2,719
Deductions & Write-offs	(518)	(501)	(88)
Balance at End of Year	$ 17,936	$ 13,629	$ 12,527