MKS Instruments (MKSI) 10-K 25 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 18, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	MKSI
Entity Registrant Name	MKS INSTRUMENTS INC
Entity Central Index Key	1049502
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		53,199,337
Entity Public Float			$1,656,697,531

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$305,437	$288,902
Short-term investments	129,594	300,715
Trade accounts receivable, net of allowances of $2,250 and $1,924 at December 31, 2014 and 2013, respectively	106,362	116,744
Inventories	155,169	142,727
Deferred income taxes	14,017	13,428
Other current assets	27,512	16,715
Total current assets	738,091	879,231
Property, plant and equipment, net	72,776	77,536
Long-term investments	157,201	60,405
Goodwill	192,381	150,909
Intangible assets, net	46,389	13,090
Other assets	17,206	31,847
Total assets	1,224,044	1,213,018
Current liabilities:
Accounts payable	34,166	40,074
Accrued compensation	26,970	43,662
Income taxes payable	6,702	10,444
Other current liabilities	35,789	34,242
Total current liabilities	103,627	128,422
Other liabilities	38,595	63,073
Commitments and contingencies (Note 23)
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; 53,154,666 and 53,363,450 shares issued and outstanding at December 31, 2014 and 2013, respectively	113	113
Additional paid-in capital	734,732	730,571
Retained earnings	349,061	278,966
Accumulated other comprehensive income/(loss)	-2,084	11,873
Total stockholders' equity	1,081,822	1,021,523
Total liabilities and stockholders' equity	$1,224,044	$1,213,018

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowances for trade accounts receivable	$2,250	$1,924
Preferred Stock, par value	$0.01	$0.01
Preferred Stock, shares authorized	2,000,000	2,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$0	$0
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares issued	53,154,666	53,363,450
Common Stock, shares outstanding	53,154,666	53,363,450

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Net Revenues:
Products	$673,819		$568,317		$536,774
Services	107,050		101,103		106,734
Total net revenues	780,869		669,420		643,508
Cost of revenues:
Cost of products	374,200		337,464		310,485
Cost of service	68,903		65,382		63,544
Total cost of revenues (exclusive of amortization shown separately below)	443,103		402,846		374,029
Gross profit	337,766		266,574		269,479
Research and development	62,888		63,570		60,118
Selling, general and administrative	131,828		142,014		127,185
Litigation					5,316
Insurance reimbursement			-1,071
Acquisition costs	499		171		1,258
Restructuring	2,464		1,364		343
Amortization of intangible assets	4,945		2,139		1,036
Income from operations	135,142		58,387		74,223
Interest income	1,323		999		1,059
Interest expense	72		85		146
Income before income taxes	136,393		59,301		75,136
Provision for income taxes	20,615		23,525		27,107
Net income	115,778		35,776		48,029
Other comprehensive income:
Changes in value of financial instruments designated as cash flow hedges, net of tax expense	1,210	[1]	62	[1]	150	[1]
Foreign currency translation adjustments, net of tax of $0 for 2014, 2013 and 2012	-14,707		-3,604		1,664
Unrealized (loss) gain on investments, net of tax (benefit) expense	-460	[2]	-40	[2]	31	[2]
Total comprehensive income	$101,821		$32,194		$49,874
Net income per share:
Basic	$2.17		$0.67		$0.91
Diluted	$2.16		$0.67		$0.90
Cash dividends paid per common share	$0.66		$0.64		$0.62
Weighted average common shares outstanding:
Basic	53,232		53,061		52,686
Diluted	53,515		53,481		53,234
[1]	Tax expense was $144, $551 and $88 for the years ended December 31, 2014, 2013 and 2012, respectively.
[2]	Tax (benefit) expense was $(55), $(355), and $19 for the years ended December 31, 2014, 2013 and 2012, respectively.

Consolidated_Statements_of_Ope1

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Tax expense (benefit) on changes in value of financial instruments designated as cash flow hedges	$144	$551	$88
Tax on foreign currency translation adjustments	0	0	0
Tax (benefit) expense on unrealized (loss) gain on investments	($55)	($355)	$19

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]
In Thousands, except Share data, unless otherwise specified
Beginning Balance at Dec. 31, 2011	$990,012	$113	$707,419	$268,870	$13,610
Beginning Balance, Shares at Dec. 31, 2011		52,491,948
Net issuance under stock-based plans	1,564		1,564
Net issuance under stock-based plans, Shares		691,501
Stock-based compensation	13,031		13,031
Tax effect from stock-based plans	1,862		1,862
Stock repurchase	-11,501		-5,871	-5,630
Stock repurchase, Shares		-434,600
Cash dividend	-32,686			-32,686
Comprehensive income (net of tax):
Net income	48,029			48,029
Other comprehensive income (loss)	1,845				1,845
Ending Balance at Dec. 31, 2012	1,012,156	113	718,005	278,583	15,455
Ending Balance, Shares at Dec. 31, 2012		52,748,849
Net issuance under stock-based plans	-464		-464
Net issuance under stock-based plans, Shares		721,601
Stock-based compensation	13,992		13,992
Tax effect from stock-based plans	495		495
Stock repurchase	-2,875		-1,457	-1,418
Stock repurchase, Shares	-107,000	-107,000
Cash dividend	-33,975			-33,975
Comprehensive income (net of tax):
Net income	35,776			35,776
Other comprehensive income (loss)	-3,582				-3,582
Ending Balance at Dec. 31, 2013	1,021,523	113	730,571	278,966	11,873
Ending Balance, Shares at Dec. 31, 2013		53,363,450
Net issuance under stock-based plans	2,492		2,492
Net issuance under stock-based plans, Shares		519,128
Stock-based compensation	11,315		11,315
Tax effect from stock-based plans	331		331
Stock repurchase	-20,809		-9,977	-10,832
Stock repurchase, Shares	-727,912	-727,912
Cash dividend	-34,851			-34,851
Comprehensive income (net of tax):
Net income	115,778			115,778
Other comprehensive income (loss)	-13,957				-13,957
Ending Balance at Dec. 31, 2014	$1,081,822	$113	$734,732	$349,061	($2,084)
Ending Balance, Shares at Dec. 31, 2014		53,154,666

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$115,778	$35,776	$48,029
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	20,514	17,102	14,442
Stock-based compensation	11,315	13,992	13,031
Provision for excess and obsolete inventory	12,131	21,671	15,028
Provision for doubtful accounts	668	631	888
Deferred income taxes	5,264	-3,089	3,819
Excess tax benefits from stock-based compensation	-447	-935	-2,105
Other	139	200	41
Changes in operating assets and liabilities:
Trade accounts receivable	6,103	-36,153	38,288
Inventories	-20,910	-29,797	5,341
Income taxes	-32,744	24,441	-3,126
Other current and non-current assets	-325	1,355	7,689
Accrued compensation	-13,563	13,677	2,759
Other current and non-current liabilities	3,469	-5,956	1,324
Accounts payable	-5,478	23,172	-8,281
Net cash provided by operating activities	101,914	76,087	137,167
Cash flows from investing activities:
Acquisition of business, net of cash acquired	-86,950	-2,326	-22,607
Purchases of investments	-360,813	-550,076	-435,961
Maturities of investments	249,359	417,566	313,298
Sales of investments	185,186	110,928	46,559
Purchases of property, plant and equipment	-13,183	-12,410	-17,705
Other	1,593	-216	-1,451
Net cash used in investing activities	-24,808	-36,534	-117,867
Cash flows from financing activities:
Proceeds from short-term borrowings		6	2,896
Payments on short-term borrowings		-776	-9,348
Repurchases of common stock	-20,809	-2,875	-11,501
Net proceeds related to employee stock awards	2,492	-464	1,564
Dividend payments	-34,851	-33,975	-32,686
Excess tax benefit from stock-based compensation	447	935	2,105
Net cash used in financing activities	-52,721	-37,149	-46,970
Effect of exchange rate changes on cash and cash equivalents	-7,850	-1,090	2,342
Increase (decrease) in cash and cash equivalents	16,535	1,314	-25,328
Cash and cash equivalents at beginning of year	288,902	287,588	312,916
Cash and cash equivalents at end of year	305,437	288,902	287,588
Cash paid during the period for:
Interest	44	60	212
Income taxes	$47,948	$11,878	$18,335

Business_Description

Business Description	12 Months Ended
	Dec. 31, 2014
Accounting Policies [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, control, power, monitor and analyze critical parameters of advanced manufacturing processes to improve process performance and productivity of advanced manufacturing processes. MKS groups its products into three product groups based upon the similarity of the product function, type of product and manufacturing processes. These three groups of products are: Instruments, Control and Vacuum Products; Power and Reactive Gas Products; and Analytical Solutions Group Products. MKS’ products are derived from its core competencies in pressure measurement and control, materials delivery, gas composition analysis, control and information technology, power and reactive gas generation and vacuum technology.
	The Company has four reportable segments: Advanced Manufacturing Capital Equipment; Analytical Solutions Group; Europe Region Sales & Service; and Asia Region Sales & Service.

Basis_of_Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2014
Accounting Policies [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.
	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 basis, management evaluates its estimates and judgments, including those related to revenue recognition and allowance for doubtful accounts, inventory valuation, warranty costs, stock-based compensation, intangible assets, goodwill, other long-lived assets, in process research and development and other acquisition expenses and income taxes. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.
	Reclassifications
	Certain prior year amounts have been reclassified to be consistent with current year classifications.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3)	Summary of Significant Accounting Policies
	Revenue Recognition and Accounts Receivable Allowances
	Revenue from product sales is recorded upon transfer of title and risk of loss to the customer provided that there is evidence of an arrangement, the sales price is fixed or determinable, and collection of the related receivable is reasonably assured. In most transactions, the Company has no obligations to customers after the date products are shipped other than pursuant to warranty obligations. In some instances, the Company provides installation, training, support and services to customers after the product has been shipped. The Company does not frequently enter into arrangements with multiple deliverables; however, for those revenue arrangements with multiple deliverables, the Company allocates revenue to each element based upon its relative selling price using vendor-specific objective evidence (“VSOE”), or third-party evidence (“TPE”) or based upon the relative selling price using estimated prices if VSOE or TPE does not exist. The Company then recognizes revenue on each deliverable in accordance with its policies for product and service revenue recognition. The Company provides for the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. Shipping and handling fees, if any, billed to customers are recognized as revenue. The related shipping and handling costs are recognized in cost of revenues. 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 research and development (“IPR&D”) expenses, which are capitalized at fair value as an intangible asset until the related project is completed, are then amortized over the estimated useful life of the product. The Company monitors projects and, if they are abandoned, the Company immediately writes them off.
	Advertising Costs
	Advertising costs are expensed as incurred and were immaterial in 2014, 2013 and 2012.
	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 vest 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 are included in OCI in consolidated stockholders’ equity.
	For derivative instruments designated as cash-flow hedges, the effective portion of the derivative’s gain (loss) is initially reported as a component of OCI and is subsequently recognized in earnings when the hedged exposure is recognized in earnings.
	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” and are carried at fair value. Mutual funds that are bought and held principally for the purpose of selling them in the near term are classified as “trading” and are carried at fair value.
	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 customers are primarily concentrated in the semiconductor industry, and a limited number of 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 comprising 19%, 17% and 14% of net revenues for 2014, 2013 and 2012, respectively, and another customer comprising 13%, 12% and 10% of net revenues for 2014, 2013, and 2012, respectively. During the years 2014, 2013 and 2012, approximately 70%, 68% and 62% of the Company’s net revenues, respectively, were to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were two customers comprising 10% or more of the Company’s accounts receivable balance as of December 31, 2014.
	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 method. The Company regularly reviews inventory quantities on hand and records a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on its estimated forecast of product demand.
	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 twenty to thirty-one and one-half years for buildings and three to seven 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 two to ten 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 were 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 and the amount and timing of expected future cash flows. 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.
	The Company has the option of first assessing qualitative factors to determine whether it is necessary to perform the current two-step impairment test or the Company can perform the two-step impairment test without performing the qualitative assessment. For the reporting units that did not experience any significant adverse changes in their business or reporting structures or any other adverse changes, and the reporting unit’s fair value substantially exceeded its amount from the prior year assessment, the Company performed the qualitative “Step 0” assessment. In performing the qualitative Step 0 assessment, the Company considered 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. For the remaining reporting units that did not meet these criteria, the Company performed the two-step goodwill impairment test. Under the two-step goodwill impairment test, the Company compared the fair value of each reporting unit to its respective carrying amount, including goodwill. If the fair value of the reporting unit exceeds the fair value, the second step of the goodwill impairment test must be completed to measure the amount of impairment loss, if any. The second step compares the implied fair value of goodwill with the carrying value of goodwill. The implied fair value is determined by allocating the fair value of the reporting unit to all of the assets and liabilities of that unit, the excess of the fair value of the amounts assigned to its assets and liabilities it the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount of goodwill, an impairment loss is recognized equal to the difference.
	As of October 31, 2014, the Company performed its annual impairment assessment of goodwill 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.
	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 exchange rates. Income and expense accounts are translated at the average exchange rates prevailing during the year. The resulting translation adjustments are included in accumulated other comprehensive income in consolidated stockholders’ equity. Foreign exchange transaction gains and losses, which arise from transaction activity, are reflected in selling, general and administrative expenses in the statement of operations. Net foreign exchange gains and losses resulting from re-measurement are included in selling general and administrative expense and were a loss of $314, a loss of $1,937 and a gain of $301, respectively, for the years ended December 31, 2014, 2013 and 2012. These amounts do not reflect the corresponding gain (loss) from foreign exchange contracts. See Note 7 “Derivatives” regarding foreign exchange contracts.
	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 more likely than not 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 2012, the Company increased its valuation allowance by $1,022 primarily related to an increase in state tax credit carry forwards as management determined it is more likely than not that the deferred tax assets related to these attributes will not be realized. As a result, the valuation allowance was $27,497 at December 31, 2012. During 2013, the Company decreased its valuation allowance by $395 primarily related to the expiration of U.S. capital loss carry forwards. As a result, the valuation allowance was $27,102 at December 31, 2013. During 2014, the Company decreased its valuation allowance by $339 primarily related to the effective settlement of a foreign tax audit. As a result, the valuation allowance was $26,763 at December 31, 2014.
	Accounting for income taxes requires a two-step approach to recognize and measure uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolutions of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement. The Company re-evaluates these uncertain tax positions on a quarterly basis. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision.

Recently_Issued_Accounting_Pro

Recently Issued Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	4)	Recently Issued Accounting Pronouncements
	In May 2014 the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods and services to customers in an amount that reflects the consideration that the company expects to be entitled to in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and assets recognized from costs incurred to obtain or fulfill a contract. This pronouncement is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The two permitted transition methods under the new standard are the full retrospective method, in which case the standard would be applied to each prior reporting period presented, or the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has not yet selected a transition method. The Company is currently evaluating the requirements of ASU No. 2014-09 and has not yet determined its impact on the Company’s consolidated financial statements.
	In August 2014, the Financial Accounting Standards Board issued ASU No. 2014-15, “Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. This ASU is not expected to have an impact on the Company’s financial statements or disclosures.

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	5)	Investments
	The fair value of short-term investments with maturities or estimated lives of less than one year consists of the following:
			Years Ended December 31,
			2014		2013
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	20,900	$	64,989
	Bankers acceptance drafts			82		491
	Commercial paper			—		53,434
	Corporate obligations			24,020		18,351
	Municipal bonds			2,099		—
	U.S. agency obligations			82,493		162,450
				129,594		299,715
	Trading securities:
	Mutual funds (1)			—		1,000
			$	129,594	$	300,715
	-1	The mutual funds are associated with the Company’s supplemental defined contribution retirement obligations.
	The fair value of long-term available-for-sale investments with maturities or estimated lives of more than one year consists of the following:
			Years Ended December 31,
			2014		2013
	Time deposits and certificates of deposit		$	48	$	54
	Asset-backed securities			75,674		—
	Corporate obligations			64,669		—
	Municipal bonds			1,254		—
	U.S. agency obligations			15,556		60,351
			$	157,201	$	60,405
	The following table shows the gross unrealized gains and (losses) aggregated by investment category for short-term and long-term available-for-sale investments:
			Cost		Gross		Gross			Estimated Fair
					Unrealized		Unrealized			Value
					Gains		(Losses)
	As of December 31, 2014:
	Short-term investments:
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	20,901	$	—	$	(1	)	$	20,900
	Bankers acceptance drafts			82		—		—			82
	Corporate obligations			24,029		2		(11	)		24,020
	Municipal bonds			2,100		—		(1	)		2,099
	U.S. agency obligations			82,488		14		(9	)		82,493
			$	129,600	$	16	$	(22	)	$	129,594
	Long-term investments:
	Time deposits		$	48	$	—	$	—		$	48
	Asset-backed securities			75,778		5		(109	)		75,674
	Corporate obligations			64,842		1		(174	)		64,669
	Municipal bonds			1,258		—		(4	)		1,254
	U.S. agency obligations			15,563		2		(9	)		15,556
			$	157,489	$	8	$	(296	)	$	157,201
			Cost		Gross		Gross			Estimated Fair
					Unrealized		Unrealized			Value
					Gains		(Losses)
	As of December 31, 2013:
	Short-term investments:
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	64,983	$	10	$	(4	)	$	64,989
	Bankers acceptance drafts			491		—		—			491
	Commercial paper			53,429		5		—			53,434
	Corporate obligations			18,360		—		(9	)		18,351
	U.S. agency obligations			162,430		22		(2	)		162,450
			$	299,693	$	37	$	(15	)	$	299,715
	Long-term investments:
	Time deposits and certificates of deposit		$	54	$	—	$	—		$	54
	U.S. agency obligations			60,374		9		(32	)		60,351
			$	60,428	$	9	$	(32	)	$	60,405
	Interest income is accrued as earned. Dividend income is recognized as income on the date the stock trades “ex-dividend.” The cost of marketable securities sold is determined by the specific identification method and realized gains or losses are reflected in income and was not material in 2014, 2013 and 2012.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
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, 2014, are summarized as follows:
					Fair Value Measurements at Reporting Date Using
	Description		December 31,		Quoted Prices in		Significant Other		Significant
			2014		Active Markets for		Observable		Unobservable
					Identical Assets		Inputs		Inputs
					(Level 1)		(Level 2)		(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	129,092	$	129,092	$	—	$	—
	Bankers acceptance drafts			131		—		131		—
	Corporate obligations			700		—		700		—
	Available-for-sale securities:
	Time deposits and certificates of deposit			20,948		—		20,948		—
	Asset-backed securities			75,674		—		75,674		—
	Bankers acceptance drafts			82		—		82		—
	Corporate obligations			88,689		—		88,689		—
	Municipal bonds			3,353		—		3,353		—
	U.S. agency obligations			98,049		—		98,049		—
	Derivatives — currency forward contracts			2,110		—		2,110		—
	Total assets		$	418,828	$	129,092	$	289,736	$	—
	Liabilities:
	Derivatives — currency forward contracts		$	—	$	—	$	—	$	—
	Reported as follows:
	Assets:
	Cash and cash equivalents (1)		$	129,923	$	129,092	$	831	$	—
	Short-term investments			129,594		—		129,594		—
	Other current assets			2,110		—		2,110		—
			$	261,627	$	129,092	$	132,535	$	—
	Long-term investments		$	157,201	$	—	$	157,201	$	—
	Liabilities:
	Other current liabilities		$	—	$	—	$	—	$	—
	-1	The cash and cash equivalent amounts presented in the table above do not include cash of $167,517 and non-negotiable time deposits of $7,997 as of December 31, 2014.
	Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2013, are summarized as follows:
					Fair Value Measurements at Reporting Date Using
	Description		December 31,		Quoted Prices in		Significant Other		Significant
			2013		Active Markets for		Observable		Unobservable
					Identical Assets		Inputs		Inputs
					(Level 1)		(Level 2)		(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	38,166	$	38,166	$	—	$	—
	Time deposits and certificates of deposit			7,050		—		7,050		—
	Bankers acceptance drafts			32		—		32		—
	Commercial paper			3,350		—		3,350		—
	Trading securities:
	Mutual funds			1,000		1,000		—		—
	Available-for-sale securities:
	Time deposits and certificates of deposit			65,043		—		65,043		—
	Bankers acceptance drafts			491		—		491		—
	Commercial paper			53,434		—		53,434		—
	Corporate obligations			18,351		—		18,351		—
	U.S. agency obligations			222,801		—		222,801		—
	Derivatives — currency forward contracts			920		—		920		—
	Total assets		$	410,638	$	39,166	$	371,472	$	—
	Liabilities:
	Derivatives — currency forward contracts		$	656	$	—	$	656	$	—
	Reported as follows:
Assets:
Cash and cash equivalents (1)		$	48,598	$	38,166	$	10,432	$	—
Short-term investments			300,715		1,000		299,715		—
Other current assets			920		—		920		—
		$	350,233	$	39,166	$	311,067	$	—
Long-term investments		$	60,405	$	—	$	60,405	$	—
Liabilities:
Other current liabilities		$	656	$	—	$	656	$	—
-1	The cash and cash equivalent amounts presented in the table above do not include cash of $234,675 and non-negotiable time deposits of $5,629 as of December 31, 2013.
Money Market Funds
Money market funds are cash and cash equivalents, and are classified within Level 1 of the fair value hierarchy.
Trading Securities
As of December 31, 2013, trading securities consisted of certain U.S. and international equity mutual funds and government agency fixed income mutual funds.
Available-For-Sale Investments
As of December 31, 2014, available-for-sale investments consisted of time deposits and drafts denominated in the Euro currency, certificates of deposit, asset-backed securities (which include auto loans, credit card receivables and equipment trust receivables), corporate obligations, U.S. treasury obligations and U.S. agency obligations. As of December 31, 2013, available-for-sale investments consisted of time deposits and drafts denominated in the Euro currency, commercial paper, certificates of deposit, corporate obligations, and U.S. agency obligations.
The Company measures its debt and equity investments at fair value. The Company’s available-for-sale investments are classified within Level 1 and 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, which may adversely affect its operating results and financial position. When deemed appropriate, the Company minimizes its risks from foreign currency exchange rate fluctuations through the use of derivative financial instruments. The principal market in which the Company executes its foreign currency contracts is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large commercial banks. The forward foreign currency exchange contracts are valued using broker quotations, or market transactions and are classified within Level 2 of the fair value hierarchy.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2014
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.
	By nature, all financial instruments involve market and credit risks. The Company enters into derivative instruments with major investment grade financial institutions and no collateral is required. The Company has policies to monitor the credit risk of these counterparties. While there can be no assurance, the Company does not anticipate any material non-performance by any of these counterparties.
	The Company hedges a portion of its forecasted foreign currency denominated intercompany sales of inventory, over a maximum period of eighteen months, using forward foreign exchange contracts accounted for as cash-flow hedges related to Japanese, South Korean, British, Euro and Taiwanese currencies. To the extent these derivatives are effective in off-setting the variability of the hedged cash flows, and otherwise meet the hedge accounting criteria, changes in the derivatives’ fair value are not included in current earnings but are included in OCI in stockholders’ equity. These changes in fair value will subsequently be reclassified into earnings, as applicable, when the forecasted transaction occurs. To the extent that a previously designated hedging transaction is no longer an effective hedge, any ineffectiveness measured in the hedging relationship is recorded currently in earnings in the period it occurs. The cash flows resulting from forward exchange contracts are classified in the consolidated statements of cash flows as part of cash flows from operating activities. The Company does not enter into derivative instruments for trading or speculative purposes.
	To the extent the hedge accounting criteria is not met, the related foreign currency forward contracts are considered as economic hedges and changes in the fair value of these contracts are recorded immediately in earnings in the period in which they occur. These include hedges that are used to reduce exchange rate risks arising from the change in fair value of certain foreign currency denominated assets and liabilities (i.e., payables, receivables) and other economic hedges where the hedge accounting criteria were not met.
	As of December 31, 2014 and 2013, the Company had outstanding forward foreign exchange contracts with gross notional values of $28,650 and $21,018, respectively. The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of December 31, 2014 and 2013:
			December 31, 2014
	Currency Hedged (Buy/Sell)		Gross Notional			Fair Value (1)
			Value
	U.S. Dollar/Japanese Yen		$	8,035		$	1,107
	U.S. Dollar/South Korean Won			12,512			372
	U.S. Dollar/Euro			2,060			185
	U.S. Dollar/U.K. Pound Sterling			1,308			70
	U.S. Dollar/Taiwan Dollar			4,735			232
	Total		$	28,650		$	1,966
			December 31, 2013
	Currency Hedged (Buy/Sell)		Gross Notional			Fair Value (1)
			Value
	U.S. Dollar/Japanese Yen		$	7,191		$	920
	U.S. Dollar/South Korean Won			9,254			(521	)
	U.S. Dollar/Euro			2,806			(85	)
	U.S. Dollar/U.K. Pound Sterling			1,767			(50	)
	Total		$	21,018		$	264
	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		2014			2013
	Derivative assets:
	Forward exchange contracts		$	1,966		$	920
	Derivative liabilities:
	Forward exchange contracts			—			(656	)
	Total net derivative asset designated as hedging instruments (1)		$	1,966		$	264
	-1	The derivative asset of $1,966 is classified in other current assets in the consolidated balance sheet as of December 31, 2014. The derivative asset of $920 and derivative liability of $(656) are classified in other current assets and other current liabilities, respectively, in the consolidated balance sheet as of December 31, 2013.
	The net amount of existing gains as of December 31, 2014 that is expected to be reclassified from OCI into earnings within the next twelve months is immaterial.
	The following table provides a summary of the (losses) gains on derivatives designated as hedging instruments:
			Years Ended December 31,
	Derivatives Designated as Cash Flow Hedging Relationships		2014			2013			2012
	Forward exchange contracts:
	Net (loss) gain recognized in OCI (1)		$	(984	)	$	(48	)	$	936
	Net (loss) gain reclassified from OCI into income (2)		$	(160	)	$	1,086		$	(930	)
	-1	Net change in the fair value of the effective portion classified in OCI.
	-2	Effective portion classified as cost of products in 2014 and 2013 and selling, general and administrative in 2012.
	The following table provides a summary of gains (losses) on derivatives not designated as hedging instruments:
			Years Ended December 31,
	Derivatives Not Designated as Hedging Instruments		2014			2013			2012
	Forward exchange contracts:
	Net gain (loss) recognized in income (1)		$	101		$	(215	)	$	(1,606	)
	-1	The Company enters into foreign exchange contracts to hedge against changes in the balance sheet, including accounts receivable and intercompany loans, for certain subsidiaries. These derivatives are not designated as hedging instruments.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories	8)	Inventories
	Inventories consist of the following:
			Years Ended December 31,
			2014		2013
	Raw material		$	81,121	$	75,687
	Work-in-process			26,604		24,304
	Finished goods			47,444		42,736
			$	155,169	$	142,727
	Inventory related excess and obsolete charges of $12,131, $21,671 and $15,028 were recorded in cost of products in the years ended December 31, 2014, 2013 and 2012, respectively. Included in excess and obsolete charges for 2013 was $6,423 of special charges for obsolete inventory related to a unique product in a solar application as a result of slowing market conditions, which provided uncertainty as to the net realizable value of this inventory.

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
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,
			2014		2013
	Land		$	8,650	$	9,225
	Buildings			66,885		68,569
	Machinery and equipment			122,720		116,475
	Furniture and fixtures, office equipment and software			59,972		59,068
	Leasehold improvements			21,353		20,590
	Construction in progress			3,647		3,702
				283,227		277,629
	Less: accumulated depreciation			210,451		200,093
			$	72,776	$	77,536
	Depreciation of property, plant and equipment totaled $15,569, $14,964 and $13,406 for the years ended 2014, 2013 and 2012, respectively.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	10)	Acquisitions
	Granville-Phillips
	On May 30, 2014, the Company acquired Granville-Phillips (“GP”), a division of Brooks Automation, Inc. (“Brooks”), for $87,000, which included $86,950 in cash and $50 in contingent consideration. MKS will pay contingent consideration if it does not cease use of certain of Brooks’ administrative services by a pre-defined date in accordance with a transition services agreement. GP is a leading global provider of vacuum measurement and control instruments to the semiconductor, thin film and general industrial markets. The Company believes that the amount of goodwill relative to identifiable intangible assets relates to several factors, including: a well-regarded leader in indirect vacuum gauges, a premium brand, an excellent reputation for quality, reliability and performance and an assembled workforce. The acquisition aligns with the Company’s current strategy to grow its semiconductor business, while diversifying into other high growth advanced markets.
	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition:
	Inventory		$	6,223
	Property and equipment			299
	Other assets			191
	Intangible assets			38,850
	Goodwill			41,612
	Warranty liability			(175	)
	Total purchase price		$	87,000
	The entire purchase price is expected to be deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Customer relationships		$	21,250		7 years
	Trademark and trade names			1,900		12 years
	Developed technology			15,700		9-12 years
			$	38,850
	This transaction resulted in an amount of purchase price that exceeded the estimated fair value of tangible and intangible assets, which was allocated to goodwill. The Company believes that 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; (2) potential to leverage the Company’s sales force and intellectual property to attract new customers and revenue and (3) potential to strengthen the Company’s position in the vacuum gauge market.
	The results of this acquisition were included in the Company’s consolidated operations beginning on May 30, 2014. The pro forma consolidated statements reflecting the operating results of GP, had it been acquired as of January 1, 2013, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2014. GP is included in the Company’s Instruments, Control and Vacuum Products group and the Advanced Manufacturing Capital Equipment reportable segment.
	Alter S.r.l
	On March 12, 2013, the Company acquired Alter S.r.l. (“Alter”), located in Reggio Emilia, Italy. The aggregate purchase price, net of cash acquired and after final debt and working capital adjustments was $2,426. Total cash paid as of June 30, 2013, net of cash acquired of $21 was $2,058. During June 2013, one of two holdback provisions was met and the Company released $123. The Company will pay the remaining $368 subject to a final holdback provision being met. Alter develops advanced microwave power generators, components and systems for industrial microwave heating, microwave plasma coating and semiconductor applications. This acquisition strengthens the Company’s existing microwave plasma expertise and product portfolio, and extends its opportunity into high growth, non-plasma microwave applications for industrial processes, food and beverage manufacturing and other markets.
	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition:
	Current assets		$	1,053
	Property and equipment			211
	Intangible assets			2,806
	Goodwill			381
	Other assets			67
	Total assets acquired		$	4,518
	Debt (Note 15)			770
	Deferred taxes and other liabilities			1,301
	Total liabilities assumed		$	2,071
	Total purchase price		$	2,447
	Cash acquired			(21	)
	Total purchase price, net of cash acquired		$	2,426
	The intangible assets associated with the acquisition are not deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Current developed technology		$	2,208		9 year useful life
	Trademarks and trade names			598		3 year useful life
			$	2,806
	The results of this acquisition were included in the Company’s consolidated operations beginning on March 12, 2013. The pro forma consolidated statements reflecting the operating results of Alter, had it been acquired as of January 1, 2012, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2013. Alter is included in the Company’s Power and Reactive Gas Products group and the Advanced Manufacturing Capital Equipment reportable segment.
	Plasmart, Inc.
	On August 29, 2012, the Company acquired Plasmart, Inc. (“Plasmart”), located in Daejeon, Korea. Plasmart develops radio frequency (RF) plasma generation and monitoring systems for the semiconductor, flat panel display, active matrix organic light emitting diodes and solar photovoltaic industries. Plasmart’s expertise in RF systems and access to the important Korean market were key drivers in the selection of Plasmart for acquisition. The aggregate purchase price, net of cash acquired, consisted of $22,607, subject to final working capital adjustments in the fourth quarter of 2012 of $1,778. Acquisition related costs of $1,258 and step-up inventory of $303 were expensed as incurred.
	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition.
	Current assets		$	5,536
	Property, plant and equipment			3,565
	Other assets			554
	Intangible assets			10,745
	Goodwill			9,989
	Total assets acquired		$	30,389
	Debt (Note 15)			4,561
	Deferred taxes and other liabilities			3,128
	Total liabilities assumed		$	7,689
	Total purchase price		$	22,700
	Cash acquired			(93	)
	Total purchase price, net of cash acquired		$	22,607
	The goodwill and other intangible assets associated with the acquisition are not deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Current developed technology		$	5,029		7.5 – 9.5 years useful life
	Trade names			335		7 year useful life
	Customer relationships			5,381		10 year useful life
			$	10,745
	This transaction resulted in an amount of purchase price that exceeded the estimated fair value of tangible and intangible assets, which was allocated to goodwill. The Company believes that 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 and intellectual property to attract new customers and revenue.
	The results of this acquisition were included in the Company’s consolidated operations beginning on August 29, 2012. The pro forma consolidated statements reflecting the operating results of Plasmart, had they been acquired as of January 1, 2012, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2012. Plasmart is included in the Power and Reactive Gas Products group and the Advanced Manufacturing Capital Equipment reportable segment.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	11)	Goodwill and Intangible Assets
	Goodwill
	The changes in the carrying amount of goodwill and accumulated impairment losses were as follows:
			2014									2013
			Gross			Accumulated			Net			Gross		Accumulated			Net
			Carrying			Impairment						Carrying		Impairment
			Amount			Loss						Amount		Loss
	Beginning balance at January 1		$	290,323		$	(139,414	)	$	150,909		$	290,147	$	(139,414	)	$	150,733
	Acquired goodwill(1)			41,993			—			41,993			—		—			—
	Foreign currency translation			(521	)		—			(521	)		176		—			176
	Ending balance at December 31		$	331,795		$	(139,414	)	$	192,381		$	290,323	$	(139,414	)	$	150,909
	-1	During the second quarter of 2014, the Company recorded $41,612 of goodwill related to the May 30, 2014 GP acquisition. During the first quarter of 2014, the Company recorded a purchase accounting adjustment for $381 related to the March 12, 2013 purchase of Alter S.r.l.
	Goodwill associated with each the Company’s reportable segments is as follows:
			Years Ended December 31,
			2014			2013
	Reportable segment:
	Advanced Manufacturing Capital Equipment		$	184,234		$	142,065
	Analytical Solutions Group			8,668			8,668
	Europe Region Sales & Service			—			—
	Asia Region Sales & Service			—			—
	Foreign currency translation			(521	)		176
	Total goodwill		$	192,381		$	150,909
	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. There were no intangible asset impairment charges in 2014, 2013 or 2012.
	Components of the Company’s acquired intangible assets are comprised of the following:
	As of December 31, 2014		Gross			Accumulated			Foreign Currency			Net
						Amortization			Translation
	Completed technology(1)		$	100,380		$	(79,875	)	$	135		$	20,640
	Customer relationships(1)			35,821			(12,634	)		280			23,467
	Patents, trademarks, trade names and other(1)			27,536			(25,290	)		36			2,282
			$	163,737		$	(117,799	)	$	451		$	46,389
	-1	During 2014 the Company recorded $38,850 of separately identified intangible assets relating to the May 30, 2014 GP acquisition, of which $15,700 was completed technology, $21,250 was customer relationships and $1,900 was trademarks and trade names.
	As of December 31, 2013		Gross			Accumulated			Foreign Currency			Net
						Amortization			Translation
	Completed technology(1)		$	84,680		$	(78,072	)	$	519		$	7,127
	Customer relationships			14,571			(9,831	)		454			5,194
	Patents, trademarks, trade names and other (1)			25,636			(24,951	)		84			769
			$	124,887		$	(112,854	)	$	1,057		$	13,090
	-1	During 2013, the Company purchased $268 of net assets of which $388 was completed technology. In March 2013, the Company purchased Alter for $2,426, net of cash acquired. The Company recorded $2,806 of separately identified intangible assets, of which $2,208 was completed technology and $598 was trademarks and trade names.
	Aggregate amortization expense related to acquired intangible assets for the years 2014, 2013 and 2012 was $4,945, $2,139 and $1,036, respectively. Aggregate amortization expense related to acquired intangible assets for future years is:
	Year		Amount
	2015		$	6,451
	2016			6,226
	2017			6,173
	2018			6,164
	2019			6,121
	Thereafter			15,254

Other_Assets

Other Assets	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	12)	Other Assets
			Years Ended December 31,
			2014		2013
	Other Current Assets:
	Income tax receivable		$	10,322	$	39
	Other			17,190		16,676
	Total other current assets		$	27,512	$	16,715
	Other Assets:
	Deferred tax assets, net		$	7,202	$	9,208
	Long-term income tax receivable			8,092		20,516
	Other			1,912		2,123
	Total other assets		$	17,206	$	31,847

Other_Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Other Liabilities	13)	Other Liabilities
			Years Ended December 31,
			2014		2013
	Other Current Liabilities:
	Product warranties		$	6,266	$	6,956
	Deferred revenue			8,283		5,556
	Other			21,240		21,730
	Total other current liabilities		$	35,789	$	34,242
	Other Liabilities:
	Long-term income tax payable		$	20,203	$	46,745
	Accrued compensation			12,068		9,646
	Other			6,324		6,682
	Total other liabilities		$	38,595	$	63,073

Product_Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Product Warranties	14)	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. The product warranty liability is included in other current liabilities in the consolidated balance sheets.
	Product warranty activities were as follows:
			Years Ended December 31,
			2014			2013
	Beginning balance		$	6,956		$	8,266
	Provisions for product warranties			2,713			2,755
	Direct charges to warranty liability			(3,271	)		(3,987	)
	Foreign currency translation			(132	)		(78	)
	Ending balance		$	6,266		$	6,956

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	15)	Debt
	Credit Agreements and Short-Term Borrowings
	The Company’s Japanese subsidiary has lines of credit and short-term borrowing arrangements with two financial institutions which generally expire and are renewed at three month intervals. The lines of credit provided for aggregate borrowings as of December 31, 2014 of up to an equivalent of $19,250 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, 2014 and 2013.
	The Company also had various lines of credit and short and long-term borrowing arrangements as a result of its acquisitions of Plasmart in 2012 and Alter in March 2013. All of these lines of credit and borrowing arrangements were paid off and terminated in 2013. There were no outstanding balances at December 31, 2013.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	16)	Income Taxes
	A reconciliation of the Company’s effective tax rate to the U.S. federal statutory rate is as follows:
			Years Ended December 31,
			2014			2013			2012
	U.S. Federal income tax statutory rate			35	%		35	%		35	%
	Federal tax credits			(1.0	)		(1.8	)		—
	State income taxes, net of federal benefit			2			1.3			1.3
	Effect of foreign operations taxed at various rates			(7.3	)		0.3			(2.6	)
	Qualified production activity tax benefit			(1.8	)		(1.4	)		(0.5	)
	Deferred tax asset valuation allowance			(0.5	)		(0.7	)		1.4
	Release of income tax reserves (including interest)			(10.7	)		—			—
	Foreign tax credits in excess of taxes on foreign dividends			(1.0	)		—			—
	Income tax charges on accumulated foreign earnings			—			10.9			—
	Tax benefit related to reinstatement of tax incentives			—			(4.0	)		—
	Other			0.4			0.1			1.5
				15.1	%		39.7	%		36.1	%
	The components of income from continuing operations before income taxes and the related provision for income taxes consist of the following:
			Years Ended December 31,
			2014			2013			2012
	Income from continuing operations before income taxes:
	United States		$	86,015		$	29,546		$	28,652
	Foreign			50,378			29,755			46,484
			$	136,393		$	59,301		$	75,136
	Current taxes:
	United States		$	8,361		$	11,338		$	14,745
	State			1,124			1,159			783
	Foreign			5,866			14,117			7,760
				15,351			26,614			23,288
	Deferred taxes:
	United States			8,908			(1,730	)		2,019
	State and Foreign			(3,644	)		(1,359	)		1,800
				5,264			(3,089	)		3,819
	Provision for income taxes		$	20,615		$	23,525		$	27,107
	The significant components of the deferred tax assets and deferred tax liabilities are as follows:
			Years Ended December 31,
			2014			2013
	Deferred tax assets:
	Loss carry-forwards and credits		$	30,523		$	28,138
	Inventory and warranty reserves			15,015			10,890
	Accounts receivable and other accruals			2,726			2,615
	Stock-based compensation			3,255			3,581
	Executive supplemental retirement benefits			3,321			8,026
	Other			—			63
	Total deferred tax assets		$	54,840		$	53,313
	Deferred tax liabilities:
	Acquired intangible assets			(2,833	)		(2,782	)
	Depreciation and amortization			(6,537	)		(5,085	)
	Other			(2,002	)		(1,202	)
	Total deferred tax liabilities			(11,372	)		(9,069	)
	Valuation allowance			(26,763	)		(27,102	)
	Net deferred tax assets		$	16,705		$	17,142
	At December 31, 2014, the Company had gross Massachusetts research and other tax credit carry forwards of $8,762. These credit carry forwards will expire at various dates through 2028. In addition, at December 31, 2014, the Company had U.S. federal capital loss carry forwards of $59,275 that will expire in 2015.
	The Company recorded the benefit of a previously unavailable German net operating loss in 2014 as a result of a change in tax status of a German subsidiary. Starting in 2015, the Company will be able to utilize the net operating loss against the profits of the German subsidiary. The German net operating loss is approximately $9,869 and can be carried forward indefinitely.
	Although the Company believes that its tax positions are consistent with applicable U.S. federal, state and international laws, it maintains certain tax reserves at December 31, 2014 in the event its tax positions were to be challenged by the applicable tax authority and additional tax assessed on audit.
	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:
			Years Ended December 31,
			2014			2013			2012
	Balance at beginning of year		$	47,684		$	40,674		$	36,540
	Decreases for prior years			(13	)		—			—
	Increases for the current year			550			7,308			4,134
	Reductions related to settlements with taxing authorities			(18,235	)		—			—
	Reductions related to expiration of statute of limitations			(10,376	)		(298	)		—
	Balance at end of year		$	19,610		$	47,684		$	40,674
	At December 31, 2014, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $19,610. The net decrease from December 31, 2013 was primarily attributable to current year releases in reserves for existing uncertain tax positions. At December 31, 2014, excluding interest and penalties, there are $11,533 of net unrecognized tax benefits that, if recognized, would affect the Company’s annual effective tax rate. In 2014, the Company recorded a net benefit to income tax expense of $13,380, excluding interest and penalties, due to the release of income tax reserves related to the expiration of the statute of limitations for a previously open tax year and the effective settlement of a U.S. and foreign income tax audit.
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. At December 31, 2014, 2013 and 2012, the Company had accrued interest on unrecognized tax benefits of approximately $578, $2,159 and $1,571, respectively.
Over the next 12 months it is reasonably possible that the Company may recognize approximately $134 of previously net unrecognized tax benefits related to various U.S. federal, state and foreign tax positions primarily as a result of the expiration of certain statutes of limitations. The Company is subject to examination by U.S. federal, state and foreign tax authorities. The United States Internal Revenue Service commenced an examination of the Company’s U.S. federal tax filings for open tax years 2007 through 2009 during the quarter ended June 30, 2012. This audit was effectively settled in the fourth quarter upon the receipt of an audit approval letter from the Joint Committee on Taxation. Due to the consents to extend the statute of limitation executed by the Company during the audit, the U.S. statue of limitations remains open for tax years 2007 through 2009 until December 31, 2015. The Company was notified of an audit of its U.S. federal tax filings for tax years 2011 through 2013 on February 3, 2015. The U.S. statute of limitations remains open between tax years 2011 through present. The statute of limitations for the Company’s tax filings in other jurisdictions varies between fiscal years 2008 through 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 2014, the Company decreased its valuation allowance by $339 primarily related to the effective settlement of a foreign tax audit. During 2013, the Company decreased its valuation allowance by $395 primarily related to the expiration of U.S. capital loss carry forwards. In 2012, the Company increased its valuation allowance by $1,022 primarily related to an increase in state tax credit carry forwards because the Company determined it is more likely than not that the deferred tax assets related to these attributes will not be realized.
Through December 31, 2014, the Company has not provided deferred income taxes on the undistributed earnings of its foreign subsidiaries because such earnings were intended to be permanently reinvested outside the U.S. Determination of the potential deferred income tax liability on these undistributed earnings is not practicable because such liability, if any, is dependent on circumstances existing and tax planning choices available when remittance occurs. At December 31, 2014, the Company had approximately $471,155 of undistributed earnings in its foreign subsidiaries which are considered to be indefinitely reinvested.
The Company’s Israeli subsidiary elected to be treated under a preferential Israeli tax regime under which a reduced tax rate of 10% applied for 2012, was reduced to 7% for 2013, and increased to 9% for 2014 for a portion of its taxable income. The Company’s other operations in Israel are also taxed at a preferential rate under the tax regime at 16%. The Company’s Israeli subsidiary effectively settled an examination for tax years 2009 through 2011 during the quarter ended March 31, 2014.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	17)	Stockholders’ Equity
	Stock Repurchase
	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 2014, the Company repurchased 727,912 shares of its Common Stock for $20,809 at an average price of $28.59 per share. During 2013, the Company repurchased 107,000 shares of its Common Stock for $2,875 at an average price of $26.87 per share.
	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. During 2014, the board of directors authorized one quarterly dividend of $0.16 per share and three quarterly dividends of $0.165 per share which totaled $34,851. 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 9, 2015, the Company’s board of directors declared a quarterly cash dividend of $0.165 per share to be paid on March 13, 2015 to shareholders of record as of March 2, 2015.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	18)	Stock-Based Compensation
	Employee Stock Purchase Plans
	The Company’s Fourth Restated 1999 Employee Stock Purchase Plan (the “Purchase Plan”) authorized the issuance of up to an aggregate of 1,950,000 shares of Common Stock to participating employees. Offerings under the Purchase Plan commenced on June 1 and December 1 and terminated, respectively, on November 30 and May 31. Under the Purchase Plan, eligible employees purchased 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 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 commenced, or (2) 85% of the closing price on the day that each offering terminates. During 2014 and 2013, the Company issued 69,474 and 138,674 shares, respectively, of Common Stock to employees who participated in the Purchase Plan at an exercise price of $24.52 per share in 2014 and $20.42 and $23.96 per share in 2013. As of June 1, 2014, the Purchase Plan was replaced by the 2014 Employee Stock Purchase Plan (the “2014 ESPP Plan”).
	The Company’s Third Amended and Restated International Employee Stock Purchase Plan (the “Foreign Purchase Plan”) authorized the issuance of up to an aggregate of 400,000 shares of Common Stock to participating employees. Offerings under the Foreign Purchase Plan commenced on June 1 and December 1 and terminated, respectively, on November 30 and May 31. Under the Foreign Purchase Plan, eligible employees purchased 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 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 commenced, or (2) 85% of the closing price on the day that each offering terminated. During 2014 and 2013, the Company issued 20,053 and 33,929 shares, respectively, of Common Stock to employees who participated in the Foreign Purchase Plan at exercise prices of $24.52 per share in 2014 and $20.42 and $23.96 per share in 2013. As of June 1, 2014, the Foreign Purchase Plan was replaced by the 2014 ESPP Plan.
	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. Under the 2014 ESPP Plan, eligible employees may 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 is exercised is 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 each offering terminates. During 2014, the Company issued 82,481 shares of Common Stock to employees who participated in the 2014 ESPP Plan at an exercise price of $24.33 per share. As of December 31, 2014, there were 2,417,519 shares reserved for future issuance under the 2014 ESPP Plan.
	Equity Incentive Plans
	The Company has granted options to employees under the 2004 Stock Incentive Plan (the “2004 Plan”) and the Second Restated 1995 Stock Incentive Plan (the “1995 Plan”), and to directors under the 1997 Director Stock Plan (the “1997 Director Plan”); the Company has also granted restricted stock units (“RSUs”) to employees and directors under the 2004 Plan and the 2014 Stock Incentive Plan (the “2014 Plan”) and together with the 2004 Plan, the 1995 Plan, and the 1997 Director Plan, (the “Plans”). The Plans are administered by the Compensation Committee of the Company’s Board of Directors.
	The Plans are intended to attract and retain employees and to provide an incentive for them to assist the Company to achieve long-range performance goals and to enable them to participate in the long-term growth of the Company. Employees may be granted RSUs, options to purchase shares of the Company’s stock and other equity incentives under the Plans.
	The Company’s 2014 Plan was adopted by the Board of Directors on February 10, 2014 and 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 appreciation rights 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, 2014, there were 17,876,234 shares reserved for future issuance under the 2014 Plan.
	The Company’s 2004 Plan expired in March 2014 and no further awards may be granted under the 2004 Plan, although there are still outstanding options which may be exercised and outstanding RSUs which may vest under the 2004 Plan.
	The Company’s 1995 Plan expired in November 2005 and no further awards may be granted under the 1995 Plan, although there are still outstanding options which may be exercised under the 1995 Plan.
	The Company’s 1997 Director Plan expired in February 2007 and no further awards may be granted under the 1997 Director Plan, although there are still outstanding options which may be exercised under the 1997 Director Plan.
	Stock options are granted at an exercise price equal to 100% of the fair value of the Company’s Common Stock on the date of grant. Generally, stock options granted to employees under the 1995 Plan and the 2004 Plan from 2001 to 2006, vested 25% after one year and 6.25% per quarter thereafter, and expired 10 years after the grant date. Options granted to directors generally vested at the earliest of (1) one day prior to the next annual meeting, (2) 13 months from the date of grant, or (3) the effective date of an acquisition. All outstanding stock options were fully vested as of December 31, 2014. RSUs granted to employees in 2014 and 2013 generally vest 33.3% per year on the anniversary of the date of grant. RSUs granted to employees in 2010, generally vest three years from the date of grant. RSUs granted to employees who are at least 60 years old and have a combined years of age plus Years of Service (as defined in the applicable RSU agreement) equal to 70 years or more 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 an acquisition. 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.
	The following table presents the activity for RSUs under the Plans:
			Year Ended December 31, 2014
			Non-vested RSUs			Weighted
						Average
						Grant  Date
						Fair Value
	Non-vested RSUs — beginning of period			732,034		$	28.08
	Granted			442,836		$	29.44
	Vested			(375,354	)	$	28.53
	Forfeited or expired			(82,802	)	$	28.24
	Non-vested RSUs — end of period			716,714		$	28.67
	The following table presents the activity for options under the Plans:
			Year Ended December 31, 2014
			Options			Weighted
						Average Exercise
						Price
	Outstanding — beginning of period			135,733		$	20.88
	Exercised			(83,336	)	$	19.26
	Forfeited or expired			(22,173	)	$	28.64
	Outstanding — end of period			30,224		$	19.67
	Exercisable at end of period			30,224		$	19.67
	The following table summarizes information with respect to options outstanding and exercisable under the Plans at December 31, 2014:
	Range of Exercise Prices		Options Outstanding and Exercisable
			Number			Weighted Average			Weighted  Average			Aggregate Intrinsic
			of Shares			Exercise  Price			Remaining			Value
									Contractual Life			(In Thousands)
									(In Years)
	$15.84 – $24.35			30,224		$	19.67			0.85		$	511,728
	The weighted average remaining contractual life of options exercisable was 0.85 years at December 31, 2014.
	The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value, based on the Company’s closing stock price of $36.60 as of December 31, 2014, which would have been received by the option holders had all option holders exercised their options as of that date. The total number of in-the-money options exercisable as of December 31, 2014 was 30,224.
	The total cash received from employees as a result of employee stock option exercises during the years 2014 and 2013 were approximately $1,605 and $1,869, respectively. In connection with these exercises, the tax benefit realized by the Company for the years 2014 and 2013 were approximately $175 and $94, respectively.
	The Company settles employee stock option exercises and restricted stock unit vesting with newly issued common shares.
	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 2014, 2013 and 2012. As of December 31, 2014 and 2013, 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 2014, 2013 and 2012:
			Years Ended December 31,
			2014			2013			2012
	Stock-based compensation expense by type of award:
	Restricted stock units		$	10,203		$	12,982		$	11,836
	Employee stock purchase plan			1,112			1,010			1,195
	Total stock-based compensation			11,315			13,992			13,031
	Tax effect on stock-based compensation			(331	)		(495	)		(1,862	)
	Net effect on net income		$	10,984		$	13,497		$	11,169
	Effect on net earnings per share:
	Basic		$	0.21		$	0.25		$	0.21
	Diluted		$	0.21		$	0.25		$	0.21
	The pre-tax effect within the consolidated statements of operations and comprehensive income of recording stock-based compensation for the years 2014, 2013 and 2012 was as follows:
			Years Ended December 31,
			2014			2013			2012
	Cost of revenues		$	1,960		$	2,038		$	1,867
	Research and development expense			1,659			1,902			2,278
	Selling, general and administrative expense			7,696			10,052			8,886
Total pre-tax stock-based compensation expense		$	11,315		$	13,992		$	13,031
Valuation Assumptions
The Company determines the fair value of restricted stock units based on the closing market price of the Company’s Common Stock on the date of the award, and estimates the fair value of stock options and employee stock purchase plan rights using the Black-Scholes valuation model. Such values are recognized as expense on a straight-line basis 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 Company did not grant options during 2014, 2013 and 2012. The total intrinsic value of options exercised during 2014, 2013 and 2012 was approximately $958, $684 and $1,228, respectively.
The weighted average fair value per share of employee stock purchase plan rights granted in 2014, 2013 and 2012 was $6.37, $5.76 and $7.24, 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,
		2014			2013			2012
Employee stock purchase plan rights:
Expected life (years)			0.5			0.5			0.5
Risk-free interest rate			0.1	%		0.1	%		0.1	%
Expected volatility			26.4	%		27.7	%		32.2	%
Expected annual dividends per share		$	0.655		$	0.64		$	0.62
Expected volatilities for 2014, 2013 and 2012 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 options exercised and the total fair value of options vested during 2014, 2013 and 2012 was approximately $12,106, $19,221 and $16,498, respectively. As of December 31, 2014, the unrecognized compensation cost related to restricted stock units was approximately $11,618, and will be recognized over an estimated weighted average amortization period of 1.27 years.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Postemployment Benefits [Abstract]
Employee Benefit Plans	19)	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, may provide a matching contribution of 50% of each participant’s contributions up to 6% of eligible salary. At the discretion of the board of directors, the Company may also make additional contributions for the benefit of all eligible employees. The Company’s contributions were $2,484, $2,334 and $2,245 for 2014, 2013 and 2012, respectively.
	The Company has one foreign defined benefit plan which is frozen for Company contributions. The total accrual and projected benefit obligation is not material for this plan.
	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, its foreign locations also have various bonus plans based upon local operating results and employee performance. The total bonus expense was $14,434, $16,006 and $8,855 for 2014, 2013 and 2012, 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 $2,258, $4,988 and $3,454 for 2014, 2013 and 2012, respectively. The accumulated benefit obligation was $8,941 at December 31, 2014 which was included in other long-term liabilities. The accumulated benefit obligation was $21,403 at December 31, 2013, of which $14,517 was included in other current liabilities and $6,886 was included in other long-term liabilities.
	In the fourth quarter of 2013, the Company’s Chief Executive Officer (“CEO”) retired. In June 2014, the Company made a payment of $13,921 including interest to its former CEO related to these accrued supplemental retirement benefits.

Net_Income_Per_Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income Per Share	20)	Net Income Per Share
	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 (stock options and restricted stock units) had been converted to such common shares, and if such assumed conversion is dilutive.
	The following is a reconciliation of basic to diluted net income per share:
			Years Ended December 31,
			2014		2013		2012
	Numerator:
	Net income		$	115,778	$	35,776	$	48,029
	Denominator:
	Shares used in net income per common share — basic			53,232,000		53,061,000		52,686,000
	Effect of dilutive securities:
	Stock options, restricted stock and employee stock purchase plan			283,000		420,000		548,000
	Shares used in net income per common share — diluted			53,515,000		53,481,000		53,234,000
	Net income per common share:
	Basic		$	2.17	$	0.67	$	0.91
	Diluted		$	2.16	$	0.67	$	0.9
	As of December 31, 2014, 2013 and 2012, stock options and restricted stock units relating to an aggregate of approximately 747,000, 868,000 and 1,198,000 shares, respectively, were outstanding. In 2014, 2013 and 2012, the potential dilutive effect of 600, 83,000 and 204,000 weighted average shares, respectively, of stock options were excluded from the computation of diluted weighted-average shares outstanding as the shares would have an anti-dilutive effect on EPS.

Business_Segment_Geographic_Ar

Business Segment, Geographic Area, Product and Significant Customer Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Business Segment, Geographic Area, Product and Significant Customer Information	21)	Business Segment, Geographic Area, Product and Significant Customer Information
	The Company develops, manufactures, sells and services products that measure, control, power and monitor critical parameters of advanced manufacturing processes. The Company’s Chief Operating Decision Maker (“CODM”) utilizes consolidated financial information to make decisions about allocating resources and assessing performance for the entire Company. In addition, certain disaggregated financial information is also provided to the CODM. Based upon the information provided to the CODM, the Company has determined it has nine operating segments and four reportable segments.
	The nine operating segments are PFMC Products, Controls Products, ASTeX Products, Granville-Phillips Products, ENI Products, HPS Products (Vacuum Products), Analytical Solutions Group, Europe Region Sales & Service and Asia Region Sales & Service.
	PFMC Products, Controls Products, ASTeX Products, Granville-Phillips Products, ENI Products and HPS Products comprise a single reportable segment due to the similarities of the segments. This reportable segment, Advanced Manufacturing Capital Equipment, includes the development, manufacturing, sales and servicing of instruments and control products, power and reactive gas products and vacuum products, all of which are utilized in semiconductor processing and other similar advanced manufacturing processes. Sales in this segment include both external sales and intercompany sales (which are stated at agreed upon transfer prices). External sales of these products made in Europe or Asia are reported as sales in the Europe Region Sales & Service or Asia Region Sales & Service segments.
	Analytical Solutions Group, Europe Region Sales & Service and Asia Region Sales & Service are each separate reportable segments. The Company has reported corporate expenses and certain intercompany pricing transactions in a Corporate, Eliminations and Other reconciling column. The Analytical Solutions Group includes gas composition analysis and information technology products and custom fabrication services. The Europe and Asia sales and service segments mainly resell and service the Advanced Manufacturing Capital Equipment and Analytical Solutions Group products sold in their respective regions.
	MKS derives the segment results directly from the manner in which results are reported in its management reporting system. The accounting policies MKS uses to derive reportable segment results are substantially the same as those used for external reporting purposes except that a substantial portion of the sales of the Advanced Manufacturing Capital Equipment and Analytical Solutions Group segments are intercompany sales to the regions at tax-based transfer prices and certain significant costs, including stock-based compensation and management incentive compensation, are not allocated to the segments and are included in Corporate, Eliminations and Other. The CODM reviews several metrics of each operating segment, including net revenues and gross profit (loss).
	The following is net revenues by reportable segment:
			Years Ended December 31,
			2014			2013			2012
	Advanced Manufacturing Capital Equipment		$	639,623		$	526,027		$	479,751
	Analytical Solutions Group			61,161			56,324			62,765
	Europe Region Sales & Service(1)			55,115			48,518			51,440
	Asia Region Sales & Service(1)			240,772			218,048			229,731
	Corporate, Eliminations and Other			(215,802	)		(179,497	)		(180,179	)
			$	780,869		$	669,420		$	643,508
	The following is a reconciliation of segment gross profit to consolidated net income:
			Years Ended December 31,
			2014			2013			2012
	Gross profit by reportable segment:
	Advanced Manufacturing Capital Equipment			260,669			187,685			171,308
	Analytical Solutions Group			30,787			29,431			32,741
	Europe Region Sales & Service(1)			15,467			13,600			15,156
	Asia Region Sales & Service(1)			40,717			42,948			36,962
	Corporate, Eliminations and Other			(9,874	)		(7,090	)		13,312
	Total gross profit by reportable segment			337,766			266,574			269,479
	Operating expenses:
	Research and development			62,888			63,570			60,118
	Selling, general and administrative			131,828			142,014			127,185
	Litigation			—			—			5,316
	Insurance reimbursement			—			(1,071	)		—
	Acquisition costs			499			171			1,258
	Restructuring			2,464			1,364			343
	Amortization of intangible assets			4,945			2,139			1,036
	Income from operations			135,142			58,387			74,223
	Net interest income			1,251			914			913
	Income before income taxes			136,393			59,301			75,136
	Provision for income taxes			20,615			23,525			27,107
	Net income		$	115,778		$	35,776		$	48,029
	-1	The Europe and Asia sales and service operations do not represent total geographical Europe and Asia financial information. These sales and service operations only represent the sales from the resale and service of Advanced Manufacturing Capital Equipment and Analytical Solutions Group products in their respective regions. The Advanced Manufacturing Capital Equipment and Analytical Solutions Group segments both have sales in each region. Accordingly, total geographical sales include sales from multiple reportable segments.
	The following is capital expenditures by reportable segment for the years ended December 31, 2014, 2013 and 2012:
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2014:
	Capital expenditures		$	8,634		$	1,763		$	183		$	690	$	1,913		$	13,183
	December 31, 2013:
	Capital expenditures		$	8,729		$	513		$	250		$	857	$	2,061		$	12,410
	December 31, 2012:
	Capital expenditures		$	11,817		$	1,228		$	132		$	886	$	3,642		$	17,705
	The following is depreciation and amortization expense by reportable segment for the years ended December 31, 2014, 2013 and 2012:
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2014:
	Depreciation and amortization		$	15,119		$	1,101		$	488		$	1,241	$	2,565		$	20,514
	December 31, 2013:
	Depreciation and amortization		$	11,836		$	1,252		$	348		$	1,177	$	2,489		$	17,102
	December 31, 2012:
Depreciation and amortization		$	9,594		$	1,176		$	326		$	1,711	$	1,635		$	14,442
Total income tax expense is impracticable to present by reportable segment because the necessary information is not available or used by the CODM.
The following is segment assets by reportable segment:
		Product Groups						Foreign Sales & Service
								Operations
		Advanced			Analytical			Europe			Asia		Corporate,			Total
		Manufacturing			Solutions								Eliminations
		Capital			Group								and Other
		Equipment
December 31, 2014:
Segment assets:
Accounts receivable		$	15,296		$	5,335		$	6,503		$	39,046	$	40,182		$	106,362
Inventory			128,345			3,915			3,241			24,619		(4,951	)		155,169
Total segment assets		$	143,641		$	9,250		$	9,744		$	63,665	$	35,231		$	261,531
		Product Groups						Foreign Sales & Service
								Operations
		Advanced			Analytical			Europe			Asia		Corporate,			Total
		Manufacturing			Solutions								Eliminations
		Capital			Group								and Other
		Equipment
December 31, 2013:
Segment assets:
Accounts receivable		$	20,767		$	5,603		$	6,538		$	44,207	$	39,629		$	116,744
Inventory			117,822			4,391			4,254			25,094		(8,834	)		142,727
Total segment assets		$	138,589		$	9,994		$	10,792		$	69,301	$	30,795		$	259,471
A reconciliation of segment assets to consolidated total assets is as follows:
		Years Ended December 31,
		2014			2013
Total segment assets		$	261,531		$	259,471
Cash and cash equivalents and investments			592,232			650,022
Other current assets			41,529			30,143
Property, plant and equipment, net			72,776			77,536
Goodwill and intangible assets, net			238,770			163,999
Other assets			17,206			31,847
Consolidated total assets		$	1,224,044		$	1,213,018
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,
		2014			2013			2012
Net revenues:
United States		$	448,452		$	363,948		$	326,894
Korea			97,323			75,401			64,541
Japan			61,092			56,978			81,883
Europe			80,659			77,910			85,362
Asia (excluding Korea and Japan)			93,343			95,183			84,828
		$	780,869		$	669,420		$	643,508
		Years Ended December 31,
		2014			2013
Long-lived assets:(1)
United States		$	57,701		$	60,700
Europe			6,099			5,484
Asia			10,887			13,475
		$	74,687		$	79,659
-1	Long-lived assets include property, plant and equipment, net and certain other assets, excluding long-term income tax receivable in the U.S.
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 three 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,
		2014			2013			2012
Instruments, Control and Vacuum Products		$	383,863		$	341,375		$	324,939
Power and Reactive Gas Products			335,271			273,357			251,669
Analytical Solutions Group Products			61,735			54,688			66,900
		$	780,869		$	669,420		$	643,508
Sales of Instruments, Control Products and Vacuum Products, Power and Reactive Gas Products are included in the Company’s Advanced Manufacturing Capital Equipment Products segment as well as in the foreign sales and service operations because the products are sold through the foreign sales and service operations in their respective regions. Sales of the Analytical Solutions Group Products are included in the Analytical Solutions Group Products segment as well as in the foreign sales and service operations because the products are sold through the foreign sales and service operations in their respective regions.
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,
		2014			2013			2012
Applied Materials, Inc.			19.1	%		17	%		14.5	%
Lam Research Corporation			12.9	%		12.3	%		10.1	%
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, 2014
Restructuring and Related Activities [Abstract]
Restructurings	22)	Restructurings
	During 2014, the Company recorded restructuring charges of $2,464. The restructuring charges were primarily for severance associated with the reduction in workforce of approximately 131 people throughout the Company. These restructuring charges impacted each of our reportable segments.
	The activity related to the Company’s restructuring accrual is shown below:
			2014
	Balance at January 1		$	—
	Charged to expense			2,464
	Payments			(2,372	)
	Balance at December 31		$	92
	During the first quarter of 2014, the Company re-classified certain assets from property, plant and equipment to current assets classified as held for sale, as these assets met the criteria for classification as held for sale. These assets relate to the Company closing one of its facilities in Colorado, as part of restructuring activities announced during the third quarter of 2013. The Company sold this building during the third quarter of 2014 for $1,316, net of commissions, and recorded an immaterial loss.
	During 2013, the Company initiated restructuring plans to consolidate a sales office and an engineering facility into other MKS facilities. The plans included a reduction in headcount. The Company recorded restructuring charges of $1,364 during 2013. The restructuring charges were primarily for severance and other charges associated with the reductions in workforce. The restructuring was substantially complete at December 31, 2013.
	During 2012, the Company implemented a workforce reduction plan as a result of a continued slowdown in the business. The Company reduced its worldwide workforce by 84 people and recorded a restructuring charge of $343.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	23)	Commitments and Contingencies
	During 2012, the Company settled litigation with shareholders of its former subsidiary for $5,316. The complaint alleged certain claims against the Company including breach of contract and implied covenants, and statutory violations. The claims sought unspecified damages and equitable relief. The Company believed that it had meritorious factual and legal defenses to the allegations raised, but reached a settlement primarily to eliminate future legal expenses related to the suit. In 2013, the Company recovered $1,071 from its insurance company relating to the 2012 litigation settlement.
	The Company is subject to various other 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 the Company’s 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 2022. Generally, the facility leases require the Company to pay maintenance, insurance and real estate taxes. Rental expense under operating leases totaled $6,909, $7,896 and $8,219 for 2014, 2013 and 2012, respectively.
	Minimum lease payments under operating leases are as follows:
			Operating Leases
	Year ending December 31,
	2015		$	6,197
	2016			4,935
	2017			4,102
	2018			3,111
	2019			2,170
	Thereafter			2,201
	Total minimum lease payments		$	22,716
	As of December 31, 2014, 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 $137,683.
	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, 2014.
	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, 2014.
	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.

Supplemental_Financial_Data

Supplemental Financial Data	12 Months Ended
	Dec. 31, 2014
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)
	2014
	Statement of Operations Data
	Net revenues	$	206,353	$	184,697	$	186,798	$	203,021
	Gross profit		89,372		79,635		79,325		89,434
	Income from operations		37,778		30,660		28,150		38,554
	Net income	$	31,245	$	21,224	$	29,117	$	34,192
	Net income per share:
	Basic	$	0.58	$	0.4	$	0.55	$	0.64
	Diluted	$	0.58	$	0.4	$	0.55	$	0.64
	Cash dividends paid per common share	$	0.16	$	0.165	$	0.165	$	0.165
	2013
	Statement of Operations Data
	Net revenues	$	141,645	$	156,928	$	166,453	$	204,394
	Gross profit		54,702		61,958		62,234		87,680
	Income from operations		4,676		10,427		12,332		30,952
	Net income	$	5,761	$	7,320	$	2,458	$	20,237
	Net income per share:
	Basic	$	0.11	$	0.14	$	0.05	$	0.38
	Diluted	$	0.11	$	0.14	$	0.05	$	0.38
	Cash dividends paid per common share	$	0.16	$	0.16	$	0.16	$	0.16

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	MKS INSTRUMENTS, INC.
	SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS
				Additions
	Description	Balance at		Charged to			Charged to			Deductions &			Balance at
		Beginning of		Costs and			Other Accounts			Write-offs			End of Year
		Year		Expenses
		(in thousands)
	Allowance for doubtful acounts:
	Years ended December 31,
	2014	$	1,924	$	668		$	12		$	(354	)	$	2,250
	2013	$	2,078	$	631		$	(62	)	$	(723	)	$	1,924
	2012	$	1,349	$	888		$	—		$	(159	)	$	2,078
				Additions
	Description	Balance at		Charged to			Charged to			Deductions &			Balance at
		Beginning of		Costs and			Other Accounts			Write-offs			End of Year
		Year		Expenses
		(in thousands)
	Allowance for sales returns:
	Years ended December 31,
	2014	$	827	$	2,223		$	—		$	(2,320	)	$	730
	2013	$	801	$	1,933		$	(36	)	$	(1,871	)	$	827
	2012	$	1,167	$	2,564		$	—		$	(2,930	)	$	801
				Additions
	Description	Balance at		Charged to			Charged to			Deductions			Balance at
		Beginning of		Costs and			Other Accounts						End of Year
		Year		Expenses
		(in thousands)
	Valuation allowance on deferred tax asset:
	Years ended December 31,
	2014	$	27,102	$	—		$	—		$	(339	)	$	26,763
	2013	$	27,497	$	—		$	—		$	(395	)	$	27,102
	2012	$	26,475	$	(44	)	$	1,066			—		$	27,497

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Revenue Recognition and Accounts Receivable Allowances	Revenue Recognition and Accounts Receivable Allowances
	Revenue from product sales is recorded upon transfer of title and risk of loss to the customer provided that there is evidence of an arrangement, the sales price is fixed or determinable, and collection of the related receivable is reasonably assured. In most transactions, the Company has no obligations to customers after the date products are shipped other than pursuant to warranty obligations. In some instances, the Company provides installation, training, support and services to customers after the product has been shipped. The Company does not frequently enter into arrangements with multiple deliverables; however, for those revenue arrangements with multiple deliverables, the Company allocates revenue to each element based upon its relative selling price using vendor-specific objective evidence (“VSOE”), or third-party evidence (“TPE”) or based upon the relative selling price using estimated prices if VSOE or TPE does not exist. The Company then recognizes revenue on each deliverable in accordance with its policies for product and service revenue recognition. The Company provides for the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. Shipping and handling fees, if any, billed to customers are recognized as revenue. The related shipping and handling costs are recognized in cost of revenues. 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 research and development (“IPR&D”) expenses, which are capitalized at fair value as an intangible asset until the related project is completed, are then amortized over the estimated useful life of the product. The Company monitors projects and, if they are abandoned, the Company immediately writes them off.
Advertising Costs	Advertising Costs
	Advertising costs are expensed as incurred and were immaterial in 2014, 2013 and 2012.
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 vest 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 are included in OCI in consolidated stockholders’ equity.
	For derivative instruments designated as cash-flow hedges, the effective portion of the derivative’s gain (loss) is initially reported as a component of OCI and is subsequently recognized in earnings when the hedged exposure is recognized in earnings.
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” and are carried at fair value. Mutual funds that are bought and held principally for the purpose of selling them in the near term are classified as “trading” and are carried at fair value.
	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 customers are primarily concentrated in the semiconductor industry, and a limited number of 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 comprising 19%, 17% and 14% of net revenues for 2014, 2013 and 2012, respectively, and another customer comprising 13%, 12% and 10% of net revenues for 2014, 2013, and 2012, respectively. During the years 2014, 2013 and 2012, approximately 70%, 68% and 62% of the Company’s net revenues, respectively, were to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were two customers comprising 10% or more of the Company’s accounts receivable balance as of December 31, 2014.
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 method. The Company regularly reviews inventory quantities on hand and records a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on its estimated forecast of product demand.
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 twenty to thirty-one and one-half years for buildings and three to seven 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 two to ten 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 were 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 and the amount and timing of expected future cash flows. 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.
	The Company has the option of first assessing qualitative factors to determine whether it is necessary to perform the current two-step impairment test or the Company can perform the two-step impairment test without performing the qualitative assessment. For the reporting units that did not experience any significant adverse changes in their business or reporting structures or any other adverse changes, and the reporting unit’s fair value substantially exceeded its amount from the prior year assessment, the Company performed the qualitative “Step 0” assessment. In performing the qualitative Step 0 assessment, the Company considered 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. For the remaining reporting units that did not meet these criteria, the Company performed the two-step goodwill impairment test. Under the two-step goodwill impairment test, the Company compared the fair value of each reporting unit to its respective carrying amount, including goodwill. If the fair value of the reporting unit exceeds the fair value, the second step of the goodwill impairment test must be completed to measure the amount of impairment loss, if any. The second step compares the implied fair value of goodwill with the carrying value of goodwill. The implied fair value is determined by allocating the fair value of the reporting unit to all of the assets and liabilities of that unit, the excess of the fair value of the amounts assigned to its assets and liabilities it the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount of goodwill, an impairment loss is recognized equal to the difference.
	As of October 31, 2014, the Company performed its annual impairment assessment of goodwill 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.
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 exchange rates. Income and expense accounts are translated at the average exchange rates prevailing during the year. The resulting translation adjustments are included in accumulated other comprehensive income in consolidated stockholders’ equity. Foreign exchange transaction gains and losses, which arise from transaction activity, are reflected in selling, general and administrative expenses in the statement of operations. Net foreign exchange gains and losses resulting from re-measurement are included in selling general and administrative expense and were a loss of $314, a loss of $1,937 and a gain of $301, respectively, for the years ended December 31, 2014, 2013 and 2012. These amounts do not reflect the corresponding gain (loss) from foreign exchange contracts. See Note 7 “Derivatives” regarding foreign exchange contracts.
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 more likely than not 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 2012, the Company increased its valuation allowance by $1,022 primarily related to an increase in state tax credit carry forwards as management determined it is more likely than not that the deferred tax assets related to these attributes will not be realized. As a result, the valuation allowance was $27,497 at December 31, 2012. During 2013, the Company decreased its valuation allowance by $395 primarily related to the expiration of U.S. capital loss carry forwards. As a result, the valuation allowance was $27,102 at December 31, 2013. During 2014, the Company decreased its valuation allowance by $339 primarily related to the effective settlement of a foreign tax audit. As a result, the valuation allowance was $26,763 at December 31, 2014.
	Accounting for income taxes requires a two-step approach to recognize and measure uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolutions of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement. The Company re-evaluates these uncertain tax positions on a quarterly basis. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision.
Recently Issued Accounting Pronouncements	In May 2014 the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods and services to customers in an amount that reflects the consideration that the company expects to be entitled to in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and assets recognized from costs incurred to obtain or fulfill a contract. This pronouncement is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The two permitted transition methods under the new standard are the full retrospective method, in which case the standard would be applied to each prior reporting period presented, or the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has not yet selected a transition method. The Company is currently evaluating the requirements of ASU No. 2014-09 and has not yet determined its impact on the Company’s consolidated financial statements.
	In August 2014, the Financial Accounting Standards Board issued ASU No. 2014-15, “Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. This ASU is not expected to have an impact on the Company’s financial statements or disclosures.

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Fair Value of Short-Term Available-for-Sale and Trading Investments	The fair value of short-term investments with maturities or estimated lives of less than one year consists of the following:
			Years Ended December 31,
			2014		2013
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	20,900	$	64,989
	Bankers acceptance drafts			82		491
	Commercial paper			—		53,434
	Corporate obligations			24,020		18,351
	Municipal bonds			2,099		—
	U.S. agency obligations			82,493		162,450
				129,594		299,715
	Trading securities:
	Mutual funds (1)			—		1,000
			$	129,594	$	300,715
	-1	The mutual funds are associated with the Company’s supplemental defined contribution retirement obligations.
Fair Value of Long-Term Available-for-Sale Investments	The fair value of long-term available-for-sale investments with maturities or estimated lives of more than one year consists of the following:
			Years Ended December 31,
			2014		2013
	Time deposits and certificates of deposit		$	48	$	54
	Asset-backed securities			75,674		—
	Corporate obligations			64,669		—
	Municipal bonds			1,254		—
	U.S. agency obligations			15,556		60,351
			$	157,201	$	60,405
Gross Unrealized Gains and (Losses) Aggregated by Investment Category Short-Term and Long-Term Securities	The following table shows the gross unrealized gains and (losses) aggregated by investment category for short-term and long-term available-for-sale investments:
			Cost		Gross		Gross			Estimated Fair
					Unrealized		Unrealized			Value
					Gains		(Losses)
	As of December 31, 2014:
	Short-term investments:
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	20,901	$	—	$	(1	)	$	20,900
	Bankers acceptance drafts			82		—		—			82
	Corporate obligations			24,029		2		(11	)		24,020
	Municipal bonds			2,100		—		(1	)		2,099
	U.S. agency obligations			82,488		14		(9	)		82,493
			$	129,600	$	16	$	(22	)	$	129,594
	Long-term investments:
	Time deposits		$	48	$	—	$	—		$	48
	Asset-backed securities			75,778		5		(109	)		75,674
	Corporate obligations			64,842		1		(174	)		64,669
	Municipal bonds			1,258		—		(4	)		1,254
	U.S. agency obligations			15,563		2		(9	)		15,556
			$	157,489	$	8	$	(296	)	$	157,201
			Cost		Gross		Gross			Estimated Fair
					Unrealized		Unrealized			Value
					Gains		(Losses)
	As of December 31, 2013:
	Short-term investments:
	Available-for-sale investments:
	Time deposits and certificates of deposit		$	64,983	$	10	$	(4	)	$	64,989
	Bankers acceptance drafts			491		—		—			491
	Commercial paper			53,429		5		—			53,434
	Corporate obligations			18,360		—		(9	)		18,351
	U.S. agency obligations			162,430		22		(2	)		162,450
			$	299,693	$	37	$	(15	)	$	299,715
	Long-term investments:
	Time deposits and certificates of deposit		$	54	$	—	$	—		$	54
	U.S. agency obligations			60,374		9		(32	)		60,351
			$	60,428	$	9	$	(32	)	$	60,405

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
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, 2014, are summarized as follows:
					Fair Value Measurements at Reporting Date Using
	Description		December 31,		Quoted Prices in		Significant Other		Significant
			2014		Active Markets for		Observable		Unobservable
					Identical Assets		Inputs		Inputs
					(Level 1)		(Level 2)		(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	129,092	$	129,092	$	—	$	—
	Bankers acceptance drafts			131		—		131		—
	Corporate obligations			700		—		700		—
	Available-for-sale securities:
	Time deposits and certificates of deposit			20,948		—		20,948		—
	Asset-backed securities			75,674		—		75,674		—
	Bankers acceptance drafts			82		—		82		—
	Corporate obligations			88,689		—		88,689		—
	Municipal bonds			3,353		—		3,353		—
	U.S. agency obligations			98,049		—		98,049		—
	Derivatives — currency forward contracts			2,110		—		2,110		—
	Total assets		$	418,828	$	129,092	$	289,736	$	—
	Liabilities:
	Derivatives — currency forward contracts		$	—	$	—	$	—	$	—
	Reported as follows:
	Assets:
	Cash and cash equivalents (1)		$	129,923	$	129,092	$	831	$	—
	Short-term investments			129,594		—		129,594		—
	Other current assets			2,110		—		2,110		—
			$	261,627	$	129,092	$	132,535	$	—
	Long-term investments		$	157,201	$	—	$	157,201	$	—
	Liabilities:
	Other current liabilities		$	—	$	—	$	—	$	—
	-1	The cash and cash equivalent amounts presented in the table above do not include cash of $167,517 and non-negotiable time deposits of $7,997 as of December 31, 2014.
	Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2013, are summarized as follows:
					Fair Value Measurements at Reporting Date Using
	Description		December 31,		Quoted Prices in		Significant Other		Significant
			2013		Active Markets for		Observable		Unobservable
					Identical Assets		Inputs		Inputs
					(Level 1)		(Level 2)		(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	38,166	$	38,166	$	—	$	—
	Time deposits and certificates of deposit			7,050		—		7,050		—
	Bankers acceptance drafts			32		—		32		—
	Commercial paper			3,350		—		3,350		—
	Trading securities:
	Mutual funds			1,000		1,000		—		—
	Available-for-sale securities:
	Time deposits and certificates of deposit			65,043		—		65,043		—
	Bankers acceptance drafts			491		—		491		—
	Commercial paper			53,434		—		53,434		—
	Corporate obligations			18,351		—		18,351		—
	U.S. agency obligations			222,801		—		222,801		—
	Derivatives — currency forward contracts			920		—		920		—
	Total assets		$	410,638	$	39,166	$	371,472	$	—
	Liabilities:
	Derivatives — currency forward contracts		$	656	$	—	$	656	$	—
	Reported as follows:
	Assets:
	Cash and cash equivalents (1)		$	48,598	$	38,166	$	10,432	$	—
	Short-term investments			300,715		1,000		299,715		—
	Other current assets			920		—		920		—
			$	350,233	$	39,166	$	311,067	$	—
	Long-term investments		$	60,405	$	—	$	60,405	$	—
	Liabilities:
Other current liabilities		$	656	$	—	$	656	$	—
-1	The cash and cash equivalent amounts presented in the table above do not include cash of $234,675 and non-negotiable time deposits of $5,629 as of December 31, 2013.

Derivatives_Tables

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2014
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, 2014 and 2013:
			December 31, 2014
	Currency Hedged (Buy/Sell)		Gross Notional			Fair Value (1)
			Value
	U.S. Dollar/Japanese Yen		$	8,035		$	1,107
	U.S. Dollar/South Korean Won			12,512			372
	U.S. Dollar/Euro			2,060			185
	U.S. Dollar/U.K. Pound Sterling			1,308			70
	U.S. Dollar/Taiwan Dollar			4,735			232
	Total		$	28,650		$	1,966
			December 31, 2013
	Currency Hedged (Buy/Sell)		Gross Notional			Fair Value (1)
			Value
	U.S. Dollar/Japanese Yen		$	7,191		$	920
	U.S. Dollar/South Korean Won			9,254			(521	)
	U.S. Dollar/Euro			2,806			(85	)
	U.S. Dollar/U.K. Pound Sterling			1,767			(50	)
	Total		$	21,018		$	264
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		2014			2013
	Derivative assets:
	Forward exchange contracts		$	1,966		$	920
	Derivative liabilities:
	Forward exchange contracts			—			(656	)
	Total net derivative asset designated as hedging instruments (1)		$	1,966		$	264
	-1	The derivative asset of $1,966 is classified in other current assets in the consolidated balance sheet as of December 31, 2014. The derivative asset of $920 and derivative liability of $(656) are classified in other current assets and other current liabilities, respectively, in the consolidated balance sheet as of December 31, 2013.
Summary of (Losses) Gains on Derivatives Designated as Hedging Instruments	The following table provides a summary of the (losses) gains on derivatives designated as hedging instruments:
	Derivatives Designated as Cash Flow Hedging Relationships		Years Ended December 31,
			2014			2013			2012
	Forward exchange contracts:
	Net (loss) gain recognized in OCI (1)		$	(984	)	$	(48	)	$	936
	Net (loss) gain reclassified from OCI into income (2)		$	(160	)	$	1,086		$	(930	)
	-1	Net change in the fair value of the effective portion classified in OCI.
	-2	Effective portion classified as cost of products in 2014 and 2013 and selling, general and administrative in 2012.
Summary of Gains (Losses) on Derivatives Not Designated as Hedging Instruments	The following table provides a summary of gains (losses) on derivatives not designated as hedging instruments:
	Derivatives Not Designated as Hedging Instruments		Years Ended December 31,
			2014			2013			2012
	Forward exchange contracts:
	Net gain (loss) recognized in income (1)		$	101		$	(215	)	$	(1,606	)
	-1	The Company enters into foreign exchange contracts to hedge against changes in the balance sheet, including accounts receivable and intercompany loans, for certain subsidiaries. These derivatives are not designated as hedging instruments.

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consist of the following:
		Years Ended December 31,
		2014		2013
	Raw material	$	81,121	$	75,687
	Work-in-process		26,604		24,304
	Finished goods		47,444		42,736
		$	155,169	$	142,727

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment consist of the following:
		Years Ended December 31,
		2014		2013
	Land	$	8,650	$	9,225
	Buildings		66,885		68,569
	Machinery and equipment		122,720		116,475
	Furniture and fixtures, office equipment and software		59,972		59,068
	Leasehold improvements		21,353		20,590
	Construction in progress		3,647		3,702
			283,227		277,629
	Less: accumulated depreciation		210,451		200,093
		$	72,776	$	77,536

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Granville-Phillips [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition:
	Inventory	$	6,223
	Property and equipment		299
	Other assets		191
	Intangible assets		38,850
	Goodwill		41,612
	Warranty liability		(175	)
	Total purchase price	$	87,000
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Customer relationships	$	21,250			7 years
	Trademark and trade names		1,900			12 years
	Developed technology		15,700			9-12 years
		$	38,850
Alter S.r.l [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition:
	Current assets	$	1,053
	Property and equipment		211
	Intangible assets		2,806
	Goodwill		381
	Other assets		67
	Total assets acquired	$	4,518
	Debt (Note 15)		770
	Deferred taxes and other liabilities		1,301
	Total liabilities assumed	$	2,071
	Total purchase price	$	2,447
	Cash acquired		(21	)
	Total purchase price, net of cash acquired	$	2,426
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Current developed technology	$	2,208			9 year useful life
	Trademarks and trade names		598			3 year useful life
		$	2,806
Plasmart, Inc. [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition.
	Current assets	$	5,536
	Property, plant and equipment		3,565
	Other assets		554
	Intangible assets		10,745
	Goodwill		9,989
	Total assets acquired	$	30,389
	Debt (Note 15)		4,561
	Deferred taxes and other liabilities		3,128
	Total liabilities assumed	$	7,689
	Total purchase price	$	22,700
	Cash acquired		(93	)
	Total purchase price, net of cash acquired	$	22,607
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis.
	Current developed technology	$	5,029		7.5 – 9.5 years useful life
	Trade names		335		7 year useful life
	Customer relationships		5,381		10 year useful life
		$	10,745

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	The changes in the carrying amount of goodwill and accumulated impairment losses were as follows:
			2014									2013
			Gross			Accumulated			Net			Gross		Accumulated			Net
			Carrying			Impairment						Carrying		Impairment
			Amount			Loss						Amount		Loss
	Beginning balance at January 1		$	290,323		$	(139,414	)	$	150,909		$	290,147	$	(139,414	)	$	150,733
	Acquired goodwill(1)			41,993			—			41,993			—		—			—
	Foreign currency translation			(521	)		—			(521	)		176		—			176
	Ending balance at December 31		$	331,795		$	(139,414	)	$	192,381		$	290,323	$	(139,414	)	$	150,909
	-1	During the second quarter of 2014, the Company recorded $41,612 of goodwill related to the May 30, 2014 GP acquisition. During the first quarter of 2014, the Company recorded a purchase accounting adjustment for $381 related to the March 12, 2013 purchase of Alter S.r.l.
Goodwill Associated with Reportable Segments	Goodwill associated with each the Company’s reportable segments is as follows:
			Years Ended December 31,
			2014			2013
	Reportable segment:
	Advanced Manufacturing Capital Equipment		$	184,234		$	142,065
	Analytical Solutions Group			8,668			8,668
	Europe Region Sales & Service			—			—
	Asia Region Sales & Service			—			—
	Foreign currency translation			(521	)		176
	Total goodwill		$	192,381		$	150,909
Intangible Assets	Components of the Company’s acquired intangible assets are comprised of the following:
	As of December 31, 2014		Gross			Accumulated			Foreign Currency			Net
						Amortization			Translation
	Completed technology(1)		$	100,380		$	(79,875	)	$	135		$	20,640
	Customer relationships(1)			35,821			(12,634	)		280			23,467
	Patents, trademarks, trade names and other(1)			27,536			(25,290	)		36			2,282
			$	163,737		$	(117,799	)	$	451		$	46,389
	-1	During 2014 the Company recorded $38,850 of separately identified intangible assets relating to the May 30, 2014 GP acquisition, of which $15,700 was completed technology, $21,250 was customer relationships and $1,900 was trademarks and trade names.
	As of December 31, 2013		Gross			Accumulated			Foreign Currency			Net
						Amortization			Translation
	Completed technology(1)		$	84,680		$	(78,072	)	$	519		$	7,127
	Customer relationships			14,571			(9,831	)		454			5,194
	Patents, trademarks, trade names and other (1)			25,636			(24,951	)		84			769
			$	124,887		$	(112,854	)	$	1,057		$	13,090
	-1	During 2013, the Company purchased $268 of net assets of which $388 was completed technology. In March 2013, the Company purchased Alter for $2,426, net of cash acquired. The Company recorded $2,806 of separately identified intangible assets, of which $2,208 was completed technology and $598 was trademarks and trade names.
Estimated Amortization Expense	Aggregate amortization expense related to acquired intangible assets for future years is:
	Year		Amount
	2015		$	6,451
	2016			6,226
	2017			6,173
	2018			6,164
	2019			6,121
	Thereafter			15,254

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Assets
		Years Ended December 31,
		2014		2013
	Other Current Assets:
	Income tax receivable	$	10,322	$	39
	Other		17,190		16,676
	Total other current assets	$	27,512	$	16,715
	Other Assets:
	Deferred tax assets, net	$	7,202	$	9,208
	Long-term income tax receivable		8,092		20,516
	Other		1,912		2,123
	Total other assets	$	17,206	$	31,847

Other_Liabilities_Tables

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Schedule of Other Liabilities
		Years Ended December 31,
		2014		2013
	Other Current Liabilities:
	Product warranties	$	6,266	$	6,956
	Deferred revenue		8,283		5,556
	Other		21,240		21,730
	Total other current liabilities	$	35,789	$	34,242
	Other Liabilities:
	Long-term income tax payable	$	20,203	$	46,745
	Accrued compensation		12,068		9,646
	Other		6,324		6,682
	Total other liabilities	$	38,595	$	63,073

Product_Warranties_Tables

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Product Warranty Activities	Product warranty activities were as follows:
		Years Ended December 31,
		2014			2013
	Beginning balance	$	6,956		$	8,266
	Provisions for product warranties		2,713			2,755
	Direct charges to warranty liability		(3,271	)		(3,987	)
	Foreign currency translation		(132	)		(78	)
	Ending balance	$	6,266		$	6,956

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
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,
		2014			2013			2012
	U.S. Federal income tax statutory rate		35	%		35	%		35	%
	Federal tax credits		(1.0	)		(1.8	)		—
	State income taxes, net of federal benefit		2			1.3			1.3
	Effect of foreign operations taxed at various rates		(7.3	)		0.3			(2.6	)
	Qualified production activity tax benefit		(1.8	)		(1.4	)		(0.5	)
	Deferred tax asset valuation allowance		(0.5	)		(0.7	)		1.4
	Release of income tax reserves (including interest)		(10.7	)		—			—
	Foreign tax credits in excess of taxes on foreign dividends		(1.0	)		—			—
	Income tax charges on accumulated foreign earnings		—			10.9			—
	Tax benefit related to reinstatement of tax incentives		—			(4.0	)		—
	Other		0.4			0.1			1.5
			15.1	%		39.7	%		36.1	%
Components of Income from Continuing Operations Before Income Taxes and Related Provision for Income Taxes	The components of income from continuing operations before income taxes and the related provision for income taxes consist of the following:
		Years Ended December 31,
		2014			2013			2012
	Income from continuing operations before income taxes:
	United States	$	86,015		$	29,546		$	28,652
	Foreign		50,378			29,755			46,484
		$	136,393		$	59,301		$	75,136
	Current taxes:
	United States	$	8,361		$	11,338		$	14,745
	State		1,124			1,159			783
	Foreign		5,866			14,117			7,760
			15,351			26,614			23,288
	Deferred taxes:
	United States		8,908			(1,730	)		2,019
	State and Foreign		(3,644	)		(1,359	)		1,800
			5,264			(3,089	)		3,819
	Provision for income taxes	$	20,615		$	23,525		$	27,107
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,
		2014			2013
	Deferred tax assets:
	Loss carry-forwards and credits	$	30,523		$	28,138
	Inventory and warranty reserves		15,015			10,890
	Accounts receivable and other accruals		2,726			2,615
	Stock-based compensation		3,255			3,581
	Executive supplemental retirement benefits		3,321			8,026
	Other		—			63
	Total deferred tax assets	$	54,840		$	53,313
	Deferred tax liabilities:
	Acquired intangible assets		(2,833	)		(2,782	)
	Depreciation and amortization		(6,537	)		(5,085	)
	Other		(2,002	)		(1,202	)
	Total deferred tax liabilities		(11,372	)		(9,069	)
	Valuation allowance		(26,763	)		(27,102	)
	Net deferred tax assets	$	16,705		$	17,142
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,
		2014			2013			2012
	Balance at beginning of year	$	47,684		$	40,674		$	36,540
	Decreases for prior years		(13	)		—			—
	Increases for the current year		550			7,308			4,134
	Reductions related to settlements with taxing authorities		(18,235	)		—			—
	Reductions related to expiration of statute of limitations		(10,376	)		(298	)		—
	Balance at end of year	$	19,610		$	47,684		$	40,674

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Activity for RSUs	The following table presents the activity for RSUs under the Plans:
		Year Ended December 31, 2014
		Non-vested RSUs			Weighted
					Average
					Grant  Date
					Fair Value
	Non-vested RSUs — beginning of period		732,034		$	28.08
	Granted		442,836		$	29.44
	Vested		(375,354	)	$	28.53
	Forfeited or expired		(82,802	)	$	28.24
	Non-vested RSUs — end of period		716,714		$	28.67
Summary of Activity for Options	The following table presents the activity for options under the Plans:
		Year Ended December 31, 2014
		Options			Weighted
					Average Exercise
					Price
	Outstanding — beginning of period		135,733		$	20.88
	Exercised		(83,336	)	$	19.26
	Forfeited or expired		(22,173	)	$	28.64
	Outstanding — end of period		30,224		$	19.67
	Exercisable at end of period		30,224		$	19.67
Summary of Information with Respect to Options Outstanding and Exercisable	The following table summarizes information with respect to options outstanding and exercisable under the Plans at December 31, 2014:
	Range of Exercise Prices	Options Outstanding and Exercisable
		Number			Weighted Average			Weighted  Average			Aggregate Intrinsic
		of Shares			Exercise  Price			Remaining			Value
								Contractual Life			(In Thousands)
								(In Years)
	$15.84 – $24.35		30,224		$	19.67			0.85		$	511,728
Effect of Recording Stock-Based Compensation	The following table reflects the effect of recording stock-based compensation for the years 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
	Stock-based compensation expense by type of award:
	Restricted stock units	$	10,203		$	12,982		$	11,836
	Employee stock purchase plan		1,112			1,010			1,195
	Total stock-based compensation		11,315			13,992			13,031
	Tax effect on stock-based compensation		(331	)		(495	)		(1,862	)
	Net effect on net income	$	10,984		$	13,497		$	11,169
	Effect on net earnings per share:
	Basic	$	0.21		$	0.25		$	0.21
	Diluted	$	0.21		$	0.25		$	0.21
Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation	The pre-tax effect within the consolidated statements of operations and comprehensive income of recording stock-based compensation for the years 2014, 2013 and 2012 was as follows:
		Years Ended December 31,
		2014			2013			2012
	Cost of revenues	$	1,960		$	2,038		$	1,867
	Research and development expense		1,659			1,902			2,278
	Selling, general and administrative expense		7,696			10,052			8,886
	Total pre-tax stock-based compensation expense	$	11,315		$	13,992		$	13,031
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,
		2014			2013			2012
	Employee stock purchase plan rights:
	Expected life (years)		0.5			0.5			0.5
	Risk-free interest rate		0.1	%		0.1	%		0.1	%
	Expected volatility		26.4	%		27.7	%		32.2	%
	Expected annual dividends per share	$	0.655		$	0.64		$	0.62

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
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,
		2014		2013		2012
	Numerator:
	Net income	$	115,778	$	35,776	$	48,029
	Denominator:
	Shares used in net income per common share — basic		53,232,000		53,061,000		52,686,000
	Effect of dilutive securities:
	Stock options, restricted stock and employee stock purchase plan		283,000		420,000		548,000
	Shares used in net income per common share — diluted		53,515,000		53,481,000		53,234,000
	Net income per common share:
	Basic	$	2.17	$	0.67	$	0.91
	Diluted	$	2.16	$	0.67	$	0.9

Business_Segment_Geographic_Ar1

Business Segment, Geographic Area, Product and Significant Customer Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Net Revenues by Reportable Segment	The following is net revenues by reportable segment:
			Years Ended December 31,
			2014			2013			2012
	Advanced Manufacturing Capital Equipment		$	639,623		$	526,027		$	479,751
	Analytical Solutions Group			61,161			56,324			62,765
	Europe Region Sales & Service (1)			55,115			48,518			51,440
	Asia Region Sales & Service (1)			240,772			218,048			229,731
	Corporate, Eliminations and Other			(215,802	)		(179,497	)		(180,179	)
			$	780,869		$	669,420		$	643,508
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,
			2014			2013			2012
	Gross profit by reportable segment:
	Advanced Manufacturing Capital Equipment			260,669			187,685			171,308
	Analytical Solutions Group			30,787			29,431			32,741
	Europe Region Sales & Service (1)			15,467			13,600			15,156
	Asia Region Sales & Service (1)			40,717			42,948			36,962
	Corporate, Eliminations and Other			(9,874	)		(7,090	)		13,312
	Total gross profit by reportable segment			337,766			266,574			269,479
	Operating expenses:
	Research and development			62,888			63,570			60,118
	Selling, general and administrative			131,828			142,014			127,185
	Litigation			—			—			5,316
	Insurance reimbursement			—			(1,071	)		—
	Acquisition costs			499			171			1,258
	Restructuring			2,464			1,364			343
	Amortization of intangible assets			4,945			2,139			1,036
	Income from operations			135,142			58,387			74,223
	Net interest income			1,251			914			913
	Income before income taxes			136,393			59,301			75,136
	Provision for income taxes			20,615			23,525			27,107
	Net income		$	115,778		$	35,776		$	48,029
	-1	The Europe and Asia sales and service operations do not represent total geographical Europe and Asia financial information. These sales and service operations only represent the sales from the resale and service of Advanced Manufacturing Capital Equipment and Analytical Solutions Group products in their respective regions. The Advanced Manufacturing Capital Equipment and Analytical Solutions Group segments both have sales in each region. Accordingly, total geographical sales include sales from multiple reportable segments.
Schedule of Capital Expenditures, Depreciation and Amortization Expense and Segment Assets by Reportable Segment	The following is capital expenditures by reportable segment for the years ended December 31, 2014, 2013 and 2012:
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2014:
	Capital expenditures		$	8,634		$	1,763		$	183		$	690	$	1,913		$	13,183
	December 31, 2013:
	Capital expenditures		$	8,729		$	513		$	250		$	857	$	2,061		$	12,410
	December 31, 2012:
	Capital expenditures		$	11,817		$	1,228		$	132		$	886	$	3,642		$	17,705
	The following is depreciation and amortization expense by reportable segment for the years ended December 31, 2014, 2013 and 2012:
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2014:
	Depreciation and amortization		$	15,119		$	1,101		$	488		$	1,241	$	2,565		$	20,514
	December 31, 2013:
	Depreciation and amortization		$	11,836		$	1,252		$	348		$	1,177	$	2,489		$	17,102
	December 31, 2012:
	Depreciation and amortization		$	9,594		$	1,176		$	326		$	1,711	$	1,635		$	14,442
	Total income tax expense is impracticable to present by reportable segment because the necessary information is not available or used by the CODM.
	The following is segment assets by reportable segment:
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2014:
	Segment assets:
	Accounts receivable		$	15,296		$	5,335		$	6,503		$	39,046	$	40,182		$	106,362
	Inventory			128,345			3,915			3,241			24,619		(4,951	)		155,169
	Total segment assets		$	143,641		$	9,250		$	9,744		$	63,665	$	35,231		$	261,531
			Product Groups						Foreign Sales & Service
									Operations
			Advanced			Analytical			Europe			Asia		Corporate,			Total
			Manufacturing			Solutions								Eliminations
			Capital			Group								and Other
			Equipment
	December 31, 2013:
	Segment assets:
	Accounts receivable		$	20,767		$	5,603		$	6,538		$	44,207	$	39,629		$	116,744
	Inventory			117,822			4,391			4,254			25,094		(8,834	)		142,727
	Total segment assets		$	138,589		$	9,994		$	10,792		$	69,301	$	30,795		$	259,471
Reconciliation of Segment Assets to Consolidated Total Assets	A reconciliation of segment assets to consolidated total assets is as follows:
			Years Ended December 31,
			2014			2013
	Total segment assets		$	261,531		$	259,471
	Cash and cash equivalents and investments			592,232			650,022
	Other current assets			41,529			30,143
	Property, plant and equipment, net			72,776			77,536
	Goodwill and intangible assets, net			238,770			163,999
	Other assets			17,206			31,847
	Consolidated total assets		$	1,224,044		$	1,213,018
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,
			2014			2013			2012
	Net revenues:
	United States		$	448,452		$	363,948		$	326,894
	Korea			97,323			75,401			64,541
	Japan			61,092			56,978			81,883
	Europe			80,659			77,910			85,362
	Asia (excluding Korea and Japan)			93,343			95,183			84,828
			$	780,869		$	669,420		$	643,508
			Years Ended December 31,
			2014			2013
	Long-lived assets:(1)
	United States		$	57,701		$	60,700
	Europe			6,099			5,484
	Asia			10,887			13,475
			$	74,687		$	79,659
	-1	Long-lived assets include property, plant and equipment, net and certain other assets, excluding long-term income tax receivable in the U.S.
Worldwide Net Revenue for Each Group of Products	Worldwide net revenue for each group of products is as follows:
			Years Ended December 31,
			2014			2013			2012
	Instruments, Control and Vacuum Products		$	383,863		$	341,375		$	324,939
	Power and Reactive Gas Products			335,271			273,357			251,669
	Analytical Solutions Group Products			61,735			54,688			66,900
			$	780,869		$	669,420		$	643,508
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,
			2014			2013			2012
	Applied Materials, Inc.			19.1	%		17	%		14.5	%
	Lam Research Corporation			12.9	%		12.3	%		10.1	%

Restructurings_Tables

Restructurings (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Schedule of Company's Restructuring Activity	The activity related to the Company’s restructuring accrual is shown below:
		2014
	Balance at January 1	$	—
	Charged to expense		2,464
	Payments		(2,372	)
	Balance at December 31	$	92

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Minimum Lease Payments under Operating Lease	Minimum lease payments under operating leases are as follows:
		Operating Leases
	Year ending December 31,
	2015	$	6,197
	2016		4,935
	2017		4,102
	2018		3,111
	2019		2,170
	Thereafter		2,201
	Total minimum lease payments	$	22,716

Supplemental_Financial_Data_Ta

Supplemental Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
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)
	2014
	Statement of Operations Data
	Net revenues	$	206,353	$	184,697	$	186,798	$	203,021
	Gross profit		89,372		79,635		79,325		89,434
	Income from operations		37,778		30,660		28,150		38,554
	Net income	$	31,245	$	21,224	$	29,117	$	34,192
	Net income per share:
	Basic	$	0.58	$	0.4	$	0.55	$	0.64
	Diluted	$	0.58	$	0.4	$	0.55	$	0.64
	Cash dividends paid per common share	$	0.16	$	0.165	$	0.165	$	0.165
	2013
	Statement of Operations Data
	Net revenues	$	141,645	$	156,928	$	166,453	$	204,394
	Gross profit		54,702		61,958		62,234		87,680
	Income from operations		4,676		10,427		12,332		30,952
	Net income	$	5,761	$	7,320	$	2,458	$	20,237
	Net income per share:
	Basic	$	0.11	$	0.14	$	0.05	$	0.38
	Diluted	$	0.11	$	0.14	$	0.05	$	0.38
	Cash dividends paid per common share	$	0.16	$	0.16	$	0.16	$	0.16

Business_Description_Additiona

Business Description - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Segment
	Product
Number Of Product Groups And Reportable Segments [Abstract]
Number of product groups	3
Number of reportable segments	4

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Significant Accounting Policies [Line Items]
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 months
Amortization period of leasehold improvements	shorter of the lease term or the estimated useful life of the leased asset
Increase (decrease) in valuation allowance on state tax credit carryforwards	($339)	($395)	$1,022
Valuation allowance	26,763	27,102	27,497
Minimum percentage of recognition of tax benefits from uncertain tax positions	50.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Schedule Of Significant Accounting Policies [Line Items]
Number of customers comprising of Accounts Receivable	2
Customer Concentration Risk [Member] | Customer A [Member] | Sales Revenue, Net [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	19.10%	17.00%	14.50%
Customer Concentration Risk [Member] | Customer B [Member] | Sales Revenue, Net [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	12.90%	12.30%	10.10%
Customer Concentration Risk [Member] | Semiconductor Products [Member] | Sales [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	70.00%	68.00%	62.00%
Selling, General and Administrative Expenses [Member]
Schedule Of Significant Accounting Policies [Line Items]
Net foreign exchange gains and losses from re-measurement	$314	$1,937	$301
Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Intangible assets amortized period	2 years
Minimum [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	10.00%
Minimum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	20 years
Minimum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Office Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Intangible assets amortized period	10 years
Maximum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	31 years 6 months
Maximum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Furniture and Fixtures [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Office Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years

Investments_Fair_Value_of_Shor

Investments - Fair Value of Short-Term Available-for-Sale and Trading Investments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	$129,594	$299,715
Fair value of short-term securities	129,594	300,715
Time Deposits and Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	20,900	64,989
Bankers Acceptance Drafts [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	82	491
Commercial Paper [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments		53,434
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	24,020	18,351
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	2,099
U.S. Agency Obligations [Member]
Schedule of Investments [Line Items]
Fair value of short-term available-for-sale investments	82,493	162,450
Mutual Funds [Member]
Schedule of Investments [Line Items]
Fair value of short-term securities		$1,000

Investments_Fair_Value_of_Long

Investments - Fair Value of Long-Term Available-for-Sale Investments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	$157,201	$60,405
Time Deposits and Certificates of Deposit [Member]
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	48	54
Asset Backed Securities [Member]
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	75,674
Corporate Obligations [Member]
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	64,669
Municipal Bonds [Member]
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	1,254
U.S. Agency Obligations [Member]
Schedule Of Available For Sale And Trading Securities [Line Items]
Fair value of long-term available-for-sale investments	$15,556	$60,351

Investments_Gross_Unrealized_G

Investments - Gross Unrealized Gains and (Losses) Aggregated by Investment Category Short-Term and Long-Term Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Short-term investments, Estimated Fair Value	$129,594	$299,715
Long-term investments, Estimated Fair Value	157,201	60,405
Short Term [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	129,600	299,693
Investments, Gross Unrealized Gains	16	37
Investments, Gross Unrealized (Losses)	-22	-15
Short-term investments, Estimated Fair Value	129,594	299,715
Short Term [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	20,901	64,983
Investments, Gross Unrealized Gains		10
Investments, Gross Unrealized (Losses)	-1	-4
Short-term investments, Estimated Fair Value	20,900	64,989
Short Term [Member] | Bankers Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	82	491
Short-term investments, Estimated Fair Value	82	491
Short Term [Member] | Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	24,029	18,360
Investments, Gross Unrealized Gains	2
Investments, Gross Unrealized (Losses)	-11	-9
Short-term investments, Estimated Fair Value	24,020	18,351
Short Term [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	2,100
Investments, Gross Unrealized (Losses)	-1
Short-term investments, Estimated Fair Value	2,099
Short Term [Member] | U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	82,488	162,430
Investments, Gross Unrealized Gains	14	22
Investments, Gross Unrealized (Losses)	-9	-2
Short-term investments, Estimated Fair Value	82,493	162,450
Short Term [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost		53,429
Investments, Gross Unrealized Gains		5
Short-term investments, Estimated Fair Value		53,434
Long Term [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	157,489	60,428
Investments, Gross Unrealized Gains	8	9
Investments, Gross Unrealized (Losses)	-296	-32
Long-term investments, Estimated Fair Value	157,201	60,405
Long Term [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost		54
Long-term investments, Estimated Fair Value		54
Long Term [Member] | Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	64,842
Investments, Gross Unrealized Gains	1
Investments, Gross Unrealized (Losses)	-174
Long-term investments, Estimated Fair Value	64,669
Long Term [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	1,258
Investments, Gross Unrealized (Losses)	-4
Long-term investments, Estimated Fair Value	1,254
Long Term [Member] | U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	15,563	60,374
Investments, Gross Unrealized Gains	2	9
Investments, Gross Unrealized (Losses)	-9	-32
Long-term investments, Estimated Fair Value	15,556	60,351
Long Term [Member] | Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	48
Long-term investments, Estimated Fair Value	48
Long Term [Member] | Asset Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	75,778
Investments, Gross Unrealized Gains	5
Investments, Gross Unrealized (Losses)	-109
Long-term investments, Estimated Fair Value	$75,674

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts	$1,966	$920
Derivatives - currency forward contracts		656
Cash and cash equivalents	167,517	234,675
Short-term investments	129,594	300,715
Available-for-sale securities	129,594	299,715
Other current assets	1,966	920
Long-term investments	157,201	60,405
Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - currency forward contracts	2,110	920
Total assets	418,828	410,638
Derivatives - currency forward contracts		656
Cash and cash equivalents	129,923	48,598
Short-term investments	129,594	300,715
Other current assets	2,110	920
Total current assets	261,627	350,233
Long-term investments	157,201	60,405
Other current liabilities		656
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	129,092	39,166
Cash and cash equivalents	129,092	38,166
Short-term investments		1,000
Total current assets	129,092	39,166
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]
Derivatives - currency forward contracts	2,110	920
Total assets	289,736	371,472
Derivatives - currency forward contracts		656
Cash and cash equivalents	831	10,432
Short-term investments	129,594	299,715
Other current assets	2,110	920
Total current assets	132,535	311,067
Long-term investments	157,201	60,405
Other current liabilities		656
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	129,092	38,166
Money Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	129,092	38,166
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		7,050
Available-for-sale securities	20,948	65,043
Time Deposits and Certificates of Deposit [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		7,050
Available-for-sale securities	20,948	65,043
Bankers Acceptance Drafts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	131	32
Available-for-sale securities	82	491
Bankers Acceptance Drafts [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	131	32
Available-for-sale securities	82	491
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		3,350
Available-for-sale securities		53,434
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		3,350
Available-for-sale securities		53,434
Mutual Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds		1,000
Mutual Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds		1,000
Corporate Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	700
Available-for-sale securities		18,351
Available-for-sale securities	88,689
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]
Cash and cash equivalents	700
Available-for-sale securities		18,351
Available-for-sale securities	88,689
U.S. Agency Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	98,049	222,801
U.S. Agency 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 securities	98,049	222,801
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 securities	75,674
Asset Backed Securities [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 securities	75,674
Municipal Bonds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,353
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 securities	$3,353

Fair_Value_Measurements_Schedu1

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Parenthetical) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Not included in cash and cash equivalent amount	$167,517	$234,675
Non Negotiable Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Not included in cash and cash equivalent amount	$7,997	$5,629

Derivatives_Additional_Informa

Derivatives - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
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	$28,650	$21,018
Other comprehensive income realization period	12 months

Derivatives_Summary_of_Primary

Derivatives - Summary of Primary Net Hedging Positions and Corresponding Fair Values (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	$28,650	$21,018
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	1,966	264
Forward Exchange Contracts [Member] | U.S. Dollar/Japanese Yen [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	8,035	7,191
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	1,107	920
Forward Exchange Contracts [Member] | U.S. Dollar/South Korean Won [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	12,512	9,254
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	372	-521
Forward Exchange Contracts [Member] | U.S. Dollar/Euro [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	2,060	2,806
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	185	-85
Forward Exchange Contracts [Member] | U.S. Dollar/U.K. Pound Sterling [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	1,308	1,767
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	70	-50
Forward Exchange Contracts [Member] | U.S. Dollar/Taiwan Dollar [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	4,735
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	$232

Derivatives_Summary_of_Fair_Va

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Forward exchange contracts, assets	$1,966	$920
Forward exchange contracts, liabilities		-656
Total net derivative asset designated as hedging instruments	1,966	264
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Forward exchange contracts, assets	1,966	920
Forward exchange contracts, liabilities		-656
Total net derivative asset designated as hedging instruments	$1,966	$264

Derivatives_Summary_of_Fair_Va1

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Parenthetical) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative asset classified in other current assets	$1,966	$920
Derivative liability classified in other current liabilities		($656)

Derivatives_Summary_of_Losses_

Derivatives - Summary of (Losses) Gains on Derivatives Designated as Hedging Instruments (Detail) (Forward Exchange Contracts [Member], Cash Flow Hedging [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Forward Exchange Contracts [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net (loss) gain recognized in OCI	($984)	($48)	$936
Net (loss) gain reclassified from OCI into income	($160)	$1,086	($930)

Derivatives_Summary_of_Gains_L

Derivatives - Summary of Gains (Losses) on Derivatives Not Designated as Hedging Instruments (Detail) (Derivatives Not Designated as Hedging Instruments [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivatives Not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) Not Designated as Hedging Instruments [Line Items]
Net gain (loss) recognized in income	$101	($215)	($1,606)

Inventories_Summary_of_Invento

Inventories - Summary of Inventories (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$81,121	$75,687
Work-in-process	26,604	24,304
Finished goods	47,444	42,736
Inventories	$155,169	$142,727

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Inventory related excess and obsolete charges	$12,131	$21,671	$15,028
Special charges for obsolete inventory		$6,423

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$283,227	$277,629
Less: accumulated depreciation	210,451	200,093
Property, plant and equipment, net	72,776	77,536
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	8,650	9,225
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	66,885	68,569
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	122,720	116,475
Furniture and Fixtures, Office Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	59,972	59,068
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	21,353	20,590
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$3,647	$3,702

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property Plant And Equipment Capitalized Interest Costs [Abstract]
Depreciation of property, plant and equipment	$15,569	$14,964	$13,406

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 12, 2013	Jun. 30, 2013	Aug. 29, 2012	Dec. 31, 2012	30-May-14
Business Acquisition [Line Items]
Total cash paid, net of cash acquired	$86,950	$2,326	$22,607
Alter S.r.l [Member]
Business Acquisition [Line Items]
Business combination consideration price				2,447
Acquisition purchase price, net of cash acquired				2,426
Acquisition date	12-Mar-13
Total cash paid, net of cash acquired				2,426	2,058
Cash acquired from acquisition	21
Remaining cash to be paid	368
Holdback provisions paid	123
Plasmart, Inc. [Member]
Business Acquisition [Line Items]
Business combination consideration price						22,700
Acquisition purchase price, net of cash acquired						22,607
Acquisition date	29-Aug-12
Total cash paid, net of cash acquired						22,607
Acquisition related costs						1,258
Working capital adjustments							1,778
Step-up inventory						303
Granville-Phillips [Member]
Business Acquisition [Line Items]
Business combination consideration price, cash								86,950
Business combination contingent consideration								50
Business combination consideration price								$87,000

Acquisitions_Summary_of_Estima

Acquisitions - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 12, 2013	Jun. 30, 2013	Aug. 29, 2012	Jun. 30, 2014	30-May-14
Business Acquisition [Line Items]
Goodwill	$192,381	$150,909	$150,733
Total purchase price, net of cash acquired	86,950	2,326	22,607
Granville-Phillips [Member]
Business Acquisition [Line Items]
Inventory								6,223
Property and equipment								299
Intangible assets								38,850
Goodwill							41,612	41,612
Other assets								191
Warranty liability								-175
Total purchase price								87,000
Alter S.r.l [Member]
Business Acquisition [Line Items]
Current assets				1,053
Property and equipment				211
Intangible assets				2,806
Goodwill				381
Other assets				67
Total assets acquired				4,518
Debt (Note 15)				770
Deferred taxes and other liabilities				1,301
Total liabilities assumed				2,071
Total purchase price				2,447
Cash acquired				-21
Total purchase price, net of cash acquired				2,426	2,058
Plasmart, Inc. [Member]
Business Acquisition [Line Items]
Current assets						5,536
Property and equipment						3,565
Intangible assets						10,745
Goodwill						9,989
Other assets						554
Total assets acquired						30,389
Debt (Note 15)						4,561
Deferred taxes and other liabilities						3,128
Total liabilities assumed						7,689
Total purchase price						22,700
Cash acquired						-93
Total purchase price, net of cash acquired						$22,607

Acquisitions_Allocation_of_Acq

Acquisitions - Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives (Detail) (USD $)	12 Months Ended	0 Months Ended		12 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	30-May-14	Mar. 12, 2013	Dec. 31, 2013	Aug. 29, 2012	31-May-13
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets	2 years
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets	10 years
Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	38,850	$38,850
Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			2,806	268
Plasmart, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price					10,745
Customer Relationships [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	21,250	21,250
Estimated useful life of finite lived intangible assets		7 years
Customer Relationships [Member] | Plasmart, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price					5,381
Estimated useful life of finite lived intangible assets					10 years
Trademark and Trade Names [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	1,900	1,900
Estimated useful life of finite lived intangible assets		12 years
Trademark and Trade Names [Member] | Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			598
Estimated useful life of finite lived intangible assets						3 years
Developed Technology [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price		15,700
Developed Technology [Member] | Granville-Phillips [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets		9 years
Developed Technology [Member] | Granville-Phillips [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets		12 years
Developed Technology [Member] | Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			2,208
Estimated useful life of finite lived intangible assets						9 years
Developed Technology [Member] | Plasmart, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price					5,029
Developed Technology [Member] | Plasmart, Inc. [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets					7 years 6 months
Developed Technology [Member] | Plasmart, Inc. [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets					9 years 6 months
Trade Mark and Trade Names [Member] | Plasmart, Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price					$335
Estimated useful life of finite lived intangible assets					7 years

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Goodwill (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance, Goodwill Gross Carrying Amount	$290,323	$290,147
Acquired goodwill, Gross Carrying Amount	41,993
Foreign currency translation, Gross Carrying Amount	-521	176
Ending balance, Goodwill Gross Carrying Amount	331,795	290,323
Beginning balance, Accumulated Impairment (Loss)	-139,414	-139,414
Acquired goodwill, Accumulated Impairment (Loss)	0	0
Foreign currency translation, Accumulated Impairment (Loss)	0	0
Ending balance, Accumulated Impairment (Loss)	-139,414	-139,414
Beginning balance, Goodwill Net	150,909	150,733
Acquired goodwill, Net	41,993
Foreign currency translation, Net	-521	176
Ending balance, Goodwill Net	$192,381	$150,909

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Goodwill (Parenthetical) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014	30-May-14	Mar. 12, 2013
Goodwill [Line Items]
Goodwill		$192,381	$150,909	$150,733
Granville-Phillips [Member]
Goodwill [Line Items]
Goodwill					41,612	41,612
Alter S.r.l [Member]
Goodwill [Line Items]
Goodwill							381
Acquisition purchase price adjustment	$381

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Goodwill Associated with Reportable Segments (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]
Goodwill	$192,381	$150,909	$150,733
Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Goodwill	184,234	142,065
Analytical Solutions Group [Member]
Segment Reporting Information [Line Items]
Goodwill	8,668	8,668
Foreign Currency Translation [Member]
Segment Reporting Information [Line Items]
Goodwill	($521)	$176

Goodwill_and_Intangible_Assets5

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Intangible Liability Disclosure [Abstract]
Impairment charges	$0	$0	$0
Aggregate amortization expense related to acquired intangibles	$4,945,000	$2,139,000	$1,036,000

Goodwill_and_Intangible_Assets6

Goodwill and Intangible Assets - Intangible Assets (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$163,737	$124,887
Accumulated Amortization	-117,799	-112,854
Foreign Currency Translation	451	1,057
Intangible assets, net	46,389	13,090
Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	100,380	84,680
Accumulated Amortization	-79,875	-78,072
Foreign Currency Translation	135	519
Intangible assets, net	20,640	7,127
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	35,821	14,571
Accumulated Amortization	-12,634	-9,831
Foreign Currency Translation	280	454
Intangible assets, net	23,467	5,194
Patents, Trademarks, Trade Names and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	27,536	25,636
Accumulated Amortization	-25,290	-24,951
Foreign Currency Translation	36	84
Intangible assets, net	$2,282	$769

Goodwill_and_Intangible_Assets7

Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Detail) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 12, 2013	Jun. 30, 2013	30-May-14
Finite-Lived Intangible Assets [Line Items]
Acquisition purchase price	$86,950	$2,326	$22,607
Alter S.r.l [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets		268		2,806
Acquisition purchase price				2,426	2,058
Alter S.r.l [Member] | Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets		388		2,208
Alter S.r.l [Member] | Trademark and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets				598
Granville-Phillips [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	38,850					38,850
Granville-Phillips [Member] | Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	15,700
Granville-Phillips [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	21,250					21,250
Granville-Phillips [Member] | Trademark and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$1,900					$1,900

Goodwill_and_Intangible_Assets8

Goodwill and Intangible Assets - Estimated Amortization Expense (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$6,451
2016	6,226
2017	6,173
2018	6,164
2019	6,121
Thereafter	$15,254

Other_Assets_Schedule_of_Other

Other Assets - Schedule of Other Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Current Assets:
Income tax receivable	$10,322	$39
Other	17,190	16,676
Total other current assets	27,512	16,715
Other Assets:
Deferred tax assets, net	7,202	9,208
Long-term income tax receivable	8,092	20,516
Other	1,912	2,123
Total other assets	$17,206	$31,847

Other_Liabilities_Schedule_of_

Other Liabilities - Schedule of Other Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Current Liabilities:
Product warranties	$6,266	$6,956	$8,266
Deferred revenue	8,283	5,556
Other	21,240	21,730
Total other current liabilities	35,789	34,242
Other Liabilities:
Long-term income tax payable	20,203	46,745
Accrued compensation	12,068	9,646
Other	6,324	6,682
Total other liabilities	$38,595	$63,073

Product_Warranties_Product_War

Product Warranties - Product Warranty Activities (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Guarantees [Abstract]
Beginning of period	$6,956	$8,266
Provision for product warranties	2,713	2,755
Direct charges to warranty liability	-3,271	-3,987
Foreign currency translation	-132	-78
End of period	$6,266	$6,956

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	Institution
Japan [Member]
Debt Instrument [Line Items]
Number of financial institutions for available lines of credit and borrowing arrangements	2
Aggregate borrowings expire and renewed	3 month intervals
Total available line of credit	$19,250,000
Total borrowings outstanding	0	0
Alter S.r.l [Member]
Debt Instrument [Line Items]
Total borrowings outstanding	$0

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Company's Effective Tax Rate to U.S. Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. Federal income tax statutory rate	35.00%	35.00%	35.00%
Federal tax credits	-1.00%	-1.80%
State income taxes, net of federal benefit	2.00%	1.30%	1.30%
Effect of foreign operations taxed at various rates	-7.30%	0.30%	-2.60%
Qualified production activity tax benefit	-1.80%	-1.40%	-0.50%
Deferred tax asset valuation allowance	-0.50%	-0.70%	1.40%
Release of income tax reserves (including interest)	-10.70%
Foreign tax credits in excess of taxes on foreign dividends	-1.00%
Income tax charges on accumulated foreign earnings		10.90%
Tax benefit related to reinstatement of tax incentives		-4.00%
Other	0.40%	0.10%	1.50%
Total	15.10%	39.70%	36.10%

Income_Taxes_Components_of_Inc

Income Taxes - Components of Income from Continuing Operations Before Income Taxes and Related Provision for Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income from continuing operations before income taxes:
United States	$86,015	$29,546	$28,652
Foreign	50,378	29,755	46,484
Income before income taxes	136,393	59,301	75,136
Current taxes:
United States	8,361	11,338	14,745
State	1,124	1,159	783
Foreign	5,866	14,117	7,760
Current taxes, Total	15,351	26,614	23,288
Deferred taxes:
United States	8,908	-1,730	2,019
State and Foreign	-3,644	-1,359	1,800
Deferred taxes, Total	5,264	-3,089	3,819
Provision for income taxes	$20,615	$23,525	$27,107

Income_Taxes_Significant_Compo

Income Taxes - Significant Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets:
Loss carry-forwards and credits	$30,523	$28,138
Inventory and warranty reserves	15,015	10,890
Accounts receivable and other accruals	2,726	2,615
Stock-based compensation	3,255	3,581
Executive supplemental retirement benefits	3,321	8,026
Other		63
Total deferred tax assets	54,840	53,313
Deferred tax liabilities:
Acquired intangible assets	-2,833	-2,782
Depreciation and amortization	-6,537	-5,085
Other	-2,002	-1,202
Total deferred tax liabilities	-11,372	-9,069
Valuation allowance	-26,763	-27,102	-27,497
Net deferred tax assets	$16,705	$17,142

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Gross Massachusetts tax research other tax credit carryforwards	$8,762
Tax credit expiration period	2028
Gross unrecognized tax benefits excluding interest and penalties	19,610	47,684	40,674	36,540
Net unrecognized tax benefit excluding interest and penalties that would impact effective tax rate	11,533
Net benefit to income tax expense, excluding interest and penalties, due to discrete reserve releases	13,380
Accrued interest on unrecognized tax benefits	578	2,159	1,571
Unrecognized tax benefits related to various U.S. federal, state and foreign tax positions	134
Income tax examination, description	The Company is subject to examination by U.S. federal, state and foreign tax authorities. The United States Internal Revenue Service commenced an examination of the Company's U.S. federal tax filings for open tax years 2007 through 2009 during the quarter ended June 30, 2012.
Change in valuation allowance	-339	-395	1,022
Undistributed earnings in foreign subsidiaries	471,155
Income tax holiday tax rate	9.00%	7.00%	10.00%
Other Operations [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	16.00%
Earliest Tax Year [Member]
Income Taxes [Line Items]
Income tax examination period	2007
Open tax year	2011
Latest Tax Year [Member]
Income Taxes [Line Items]
Income tax examination period	2009
Open tax year	2013
2015 [Member]
Income Taxes [Line Items]
U.S. Federal capital loss carryforwards	59,275
Net operating Loss	$9,869

Income_Taxes_Reconciliation_of1

Income Taxes - Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Balance at beginning of year	$47,684	$40,674	$36,540
Decreases for prior years	-13
Increases for the current year	550	7,308	4,134
Reductions related to settlements with taxing authorities	-18,235
Reductions related to expiration of statute of limitations	-10,376	-298
Balance at end of year	$19,610	$47,684	$40,674

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended				12 Months Ended			0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 09, 2015	Jul. 25, 2011
Stockholders Equity [Line Items]
Common stock, value of shares authorized to repurchase									$200,000,000
Stock repurchase, shares					727,912	107,000
Value of shares repurchased					20,809,000	2,875,000	11,501,000
Average price of repurchased shares					$28.59	$26.87
Cash dividend paid	$0.17	$0.17	$0.17	$0.16
Dividend payment to common shareholders					$34,851,000	$33,975,000	$32,686,000
Dividend declared date					9-Feb-15
Dividend to be paid date					13-Mar-15
Dividend declared, shareholders of record date					2-Mar-15
Subsequent Event [Member]
Stockholders Equity [Line Items]
Cash dividend to be paid								$0.17

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares issued	53,154,666	53,363,450
Vesting period	3 years
Weighted average remaining contractual life of options exercisable	10 months 6 days
Closing stock price per share	$36.60
Number of in-the-money options exercisable	30,224
Tax effect from stock-based plans	$331,000	$495,000	$1,862,000
Capitalization of share based payment costs	471,000	471,000
Options granted	0	0	0
Total intrinsic value of options exercised	958,000	684,000	1,228,000
Weighted average fair value per share of employee stock purchase plan rights, granted	$6.37	$5.76	$7.24
Total intrinsic value of options exercised and fair value of options vested	12,106,000	19,221,000	16,498,000
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 an acquisition.
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per share of employee stock purchase plan rights, granted	$29.44
Unrecognized compensation cost	11,618,000
Estimated weighted average amortization period	1 year 3 months 7 days
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] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 day
Employee Stock Purchase Plan - Third Amended and Restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	1,950,000
Percentage of payroll deduction to compensation	Up to 10%
Percentage of Common Stock through payroll deductions	10.00%
Percentage of closing price of the Common Stock	85.00%
Common Stock, shares issued	69,474	138,674
Employee Stock Purchase Plan - Third Amended and Restated [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock	85.00%
Employee Stock Purchase Plan - Third Amended and Restated [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of payroll deduction	21,250
Common stock, exercise price	$24.52	$20.42
Employee Stock Purchase Plan - Third Amended and Restated [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price		$23.96
Employee Stock Purchase Plan - Second Amended and Restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	400,000
Percentage of Common Stock through payroll deductions	10.00%
Percentage of closing price of the Common Stock	85.00%
Common Stock, shares issued	20,053	33,929
Employee Stock Purchase Plan - Second Amended and Restated [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock	85.00%
Employee Stock Purchase Plan - Second Amended and Restated [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of payroll deduction	21,250
Common stock, exercise price	$24.52
Employee Stock Purchase Plan - Second Amended and Restated [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price	$20.42	$23.96
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	21,250
Percentage of closing price of the Common Stock	85.00%
Common Stock, shares issued	82,481
Common stock, exercise price	$24.33
Shares reserved for future issuance	2,417,519
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	85.00%
Stock Incentive Plan 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance	17,876,234
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
Stock Incentive Plans 2001 and After [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of exercise price fair value option grant in period	100.00%
Stock options granted to employees under plans prior to 2001, vested after one year	25.00%
Stock options granted to employees under plans prior to 2001, vested per quarter thereafter	6.25%
Stock options expired	10 years
1997 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description	Options granted to directors generally vested at the earliest of (1)B one day prior to the next annual meeting, (2)B 13 months from date of grant, or (3)B the effective date of an acquisition.
1997 Director Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	13 months
1997 Director Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 day
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted to employees under plans prior to 2001, vested after one year	33.30%	33.30%
Stock options expired	3 years
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 combined years of age plus Years of Service (as defined in the applicable RSU agreement) equal to 70 years or more are expensed immediately.
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received from employees as a result of employee stock option exercises	1,605,000	1,869,000
Tax effect from stock-based plans	$175,000	$94,000

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Activity for RSUs (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, Granted	$6.37	$5.76	$7.24
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested RSUs - beginning of period	732,034
Granted	442,836
Vested	-375,354
Forfeited or expired	-82,802
Non-vested RSUs - end of period	716,714
Weighted Average Grant Date Fair Value, Beginning of period	$28.08
Weighted Average Grant Date Fair Value, Granted	$29.44
Weighted Average Grant Date Fair Value, Vested	$28.53
Weighted Average Grant Date Fair Value, Forfeited or expired	$28.24
Weighted Average Grant Date Fair Value, end of period	$28.67

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Activity for Options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, Outstanding - beginning of period	135,733
Options, Exercised	-83,336
Options, Forfeited or expired	-22,173
Options, Outstanding - end of period	30,224
Options, Exercisable at end of period	30,224
Weighted Average Exercise Price, Outstanding - beginning of period	$20.88
Weighted Average Exercise Price, Exercised	$19.26
Weighted Average Exercise Price, Forfeited or expired	$28.64
Weighted Average Exercise Price, Outstanding - end of period	$19.67
Weighted Average Exercise Price, Exercisable at end of period	$19.67

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Information with Respect to Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Options Outstanding	30,224	135,733
Weighted Average Exercise Price	$19.67
Exercisable Weighted Average Remaining Contractual Life (In Years)	10 months 6 days
Aggregate Intrinsic Value (In Thousands)	$511,728
Minimum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range	$15.84
Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range	$24.35

StockBased_Compensation_Effect

Stock-Based Compensation - Effect of Recording Stock-Based Compensation (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$11,315	$13,992	$13,031
Tax effect on stock-based compensation	-331	-495	-1,862
Net effect on net income	10,984	13,497	11,169
Basic	$0.21	$0.25	$0.21
Diluted	$0.21	$0.25	$0.21
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	10,203	12,982	11,836
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$1,112	$1,010	$1,195

StockBased_Compensation_PreTax

Stock-Based Compensation - Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$11,315	$13,992	$13,031
Cost of revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	1,960	2,038	1,867
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	1,659	1,902	2,278
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	$7,696	$10,052	$8,886

StockBased_Compensation_Fair_V

Stock-Based Compensation - Fair Value of Employees' Purchase Rights Estimated Using Black-Scholes Option-Pricing Model (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected life (years)									6 months	6 months	6 months
Risk-free interest rate									0.10%	0.10%	0.10%
Expected volatility									26.40%	27.70%	32.20%
Expected annual dividends per share	$0.17	$0.17	$0.17	$0.16	$0.16	$0.16	$0.16	$0.16	$0.66	$0.64	$0.62

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
	Plan
	Age
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
Employers contribution percentage limit	50.00%
Employees maximum contribution as a percentage of salary	6.00%
Company's contributions	$2,484	$2,334	$2,245
Foreign defined benefit plan	1
Bonus expense	14,434	16,006	8,855
Supplemental retirement benefits cost	2,258	4,988	3,454
Accumulated benefit obligation	8,941	21,403
Chief Executive Officer [Member]
Defined Benefit Plan Disclosure [Line Items]
Payment related to accrued supplemental retirement benefits				13,921
Other Current Liabilities [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		14,517
Other Noncurrent Liabilities [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		$6,886

Net_Income_Per_Share_Reconcili

Net Income Per Share - Reconciliation of Basic and Diluted Net Income Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income	$34,192	$29,117	$21,224	$31,245	$20,237	$2,458	$7,320	$5,761	$115,778	$35,776	$48,029
Denominator:
Shares used in net income per common share - basic									53,232,000	53,061,000	52,686,000
Effect of dilutive securities:
Stock options, restricted stock and employee stock purchase plan									283,000	420,000	548,000
Shares used in net income per common share - diluted									53,515,000	53,481,000	53,234,000
Net income per common share:
Basic	$0.64	$0.55	$0.40	$0.58	$0.38	$0.05	$0.14	$0.11	$2.17	$0.67	$0.91
Diluted	$0.64	$0.55	$0.40	$0.58	$0.38	$0.05	$0.14	$0.11	$2.16	$0.67	$0.90

Net_Income_Per_Share_Additiona

Net Income Per Share - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Stock options and restricted stock units outstanding	747,000	868,000	1,198,000
Number of shares excluded from computation of diluted earnings per share	600	83,000	204,000

Business_Segment_Geographic_Ar2

Business Segment, Geographic Area, Product and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Customer
	Segment
	Product
Segment Reporting [Abstract]
Number of reportable segments	4
Number of operating segments	9
Number of product groups	3
Number of customers with net revenues greater than 10% of total net revenues	2
Entity wide net revenue major customer percentage minimum	10.00%

Business_Segment_Geographic_Ar3

Business Segment, Geographic Area, Product and Significant Customer Information - Net Revenues by Reportable Segment (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net revenues	$203,021	$186,798	$184,697	$206,353	$204,394	$166,453	$156,928	$141,645	$780,869	$669,420	$643,508
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Total net revenues									639,623	526,027	479,751
Operating Segments [Member] | Analytical Solutions Group [Member]
Segment Reporting Information [Line Items]
Total net revenues									61,161	56,324	62,765
Operating Segments [Member] | Europe Region Sales & Service [Member]
Segment Reporting Information [Line Items]
Total net revenues									55,115	48,518	51,440
Operating Segments [Member] | Asia Region Sales & Service Operations [Member]
Segment Reporting Information [Line Items]
Total net revenues									240,772	218,048	229,731
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Total net revenues									($215,802)	($179,497)	($180,179)

Business_Segment_Geographic_Ar4

Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Gross Profit to Consolidated Net Income (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Gross profit	$89,434	$79,325	$79,635	$89,372	$87,680	$62,234	$61,958	$54,702	$337,766	$266,574	$269,479
Research and development									62,888	63,570	60,118
Selling, general and administrative									131,828	142,014	127,185
Litigation											5,316
Insurance reimbursement										-1,071
Acquisition costs									499	171	1,258
Restructuring									2,464	1,364	343
Amortization of intangible assets									4,945	2,139	1,036
Income from operations	38,554	28,150	30,660	37,778	30,952	12,332	10,427	4,676	135,142	58,387	74,223
Net interest income									1,323	999	1,059
Income before income taxes									136,393	59,301	75,136
Provision for income taxes									20,615	23,525	27,107
Net income	34,192	29,117	21,224	31,245	20,237	2,458	7,320	5,761	115,778	35,776	48,029
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Gross profit									260,669	187,685	171,308
Operating Segments [Member] | Analytical Solutions Group [Member]
Segment Reporting Information [Line Items]
Gross profit									30,787	29,431	32,741
Operating Segments [Member] | Europe Region Sales & Service [Member]
Segment Reporting Information [Line Items]
Gross profit									15,467	13,600	15,156
Operating Segments [Member] | Asia Region Sales & Service Operations [Member]
Segment Reporting Information [Line Items]
Gross profit									40,717	42,948	36,962
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Gross profit									($9,874)	($7,090)	$13,312

Business_Segment_Geographic_Ar5

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Capital Expenditures, Depreciation and Amortization Expense and Segment Assets by Reportable Segment (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Capital expenditures	$13,183	$12,410	$17,705
Depreciation and amortization	20,514	17,102	14,442
Accounts receivable	106,362	116,744
Inventory	155,169	142,727
Total segment assets	261,531	259,471
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	8,634	8,729	11,817
Depreciation and amortization	15,119	11,836	9,594
Accounts receivable	15,296	20,767
Inventory	128,345	117,822
Total segment assets	143,641	138,589
Operating Segments [Member] | Analytical Solutions Group [Member]
Segment Reporting Information [Line Items]
Capital expenditures	1,763	513	1,228
Depreciation and amortization	1,101	1,252	1,176
Accounts receivable	5,335	5,603
Inventory	3,915	4,391
Total segment assets	9,250	9,994
Operating Segments [Member] | Europe Region Sales & Service [Member]
Segment Reporting Information [Line Items]
Capital expenditures	183	250	132
Depreciation and amortization	488	348	326
Accounts receivable	6,503	6,538
Inventory	3,241	4,254
Total segment assets	9,744	10,792
Operating Segments [Member] | Asia Region Sales & Service Operations [Member]
Segment Reporting Information [Line Items]
Capital expenditures	690	857	886
Depreciation and amortization	1,241	1,177	1,711
Accounts receivable	39,046	44,207
Inventory	24,619	25,094
Total segment assets	63,665	69,301
Corporate, Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Capital expenditures	1,913	2,061	3,642
Depreciation and amortization	2,565	2,489	1,635
Accounts receivable	40,182	39,629
Inventory	-4,951	-8,834
Total segment assets	$35,231	$30,795

Business_Segment_Geographic_Ar6

Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Assets to Consolidated Total Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]
Total assets	$1,224,044	$1,213,018
Other current assets	27,512	16,715
Property, plant and equipment, net	72,776	77,536
Other assets	17,206	31,847
Reconciliation of Segment Assets to Consolidated Assets [Member]
Segment Reporting Information [Line Items]
Total assets	261,531	259,471
Cash and cash equivalents and investments	592,232	650,022
Other current assets	41,529	30,143
Property, plant and equipment, net	72,776	77,536
Goodwill and intangible assets, net	238,770	163,999
Other assets	$17,206	$31,847

Business_Segment_Geographic_Ar7

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Net Revenues and Long-Lived Assets by Geographic Regions (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$203,021	$186,798	$184,697	$206,353	$204,394	$166,453	$156,928	$141,645	$780,869	$669,420	$643,508
Long-lived assets	74,687				79,659				74,687	79,659
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									448,452	363,948	326,894
Long-lived assets	57,701				60,700				57,701	60,700
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									97,323	75,401	64,541
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									61,092	56,978	81,883
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									80,659	77,910	85,362
Long-lived assets	6,099				5,484				6,099	5,484
Asia (Excluding Korea and Japan) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									93,343	95,183	84,828
Long-lived assets	$10,887				$13,475				$10,887	$13,475

Business_Segment_Geographic_Ar8

Business Segment, Geographic Area, Product and Significant Customer Information - Worldwide Net Revenue for Each Group of Products (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Net sales from product groups	$203,021	$186,798	$184,697	$206,353	$204,394	$166,453	$156,928	$141,645	$780,869	$669,420	$643,508
Instruments, Control and Vacuum Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									383,863	341,375	324,939
Power and Reactive Gas Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									335,271	273,357	251,669
Analytical Solutions Group Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									$61,735	$54,688	$66,900

Business_Segment_Geographic_Ar9

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, 2014	Dec. 31, 2013	Dec. 31, 2012
Applied Materials Inc [Member]
Revenue, Major Customer [Line Items]
Applied Materials, Inc.	19.10%	17.00%	14.50%
Lam Research Corporation [Member]
Revenue, Major Customer [Line Items]
Applied Materials, Inc.	12.90%	12.30%	10.10%

Restructurings_Additional_Info

Restructurings - Additional Information (Detail) (USD $)	12 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014
	People		People
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$2,464	$1,364	$343
Approximate number of workforce reduction from the company's headcount	131		84
COLORADO
Restructuring Cost and Reserve [Line Items]
Number of facilities closing	1
Proceeds from sale of building, net of commissions				$1,316

Restructuring_Schedule_of_Comp

Restructuring - Schedule of Company's Restructuring Activity (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring and Related Activities [Abstract]
Charged to expense	$2,464	$1,364	$343
Payments	-2,372
Balance at December 31	$92

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Litigation settlement with shareholders of former subsidiary			$5,316
Insurance reimbursement for litigation settlement		1,071
Lease expiration date	2022
Rental expenses under operating leases	6,909	7,896	8,219
Purchase commitments covered by aggregate value	$137,683
Purchase commitments	Less than one year

Commitments_and_Contingencies_2

Commitments and Contingencies - Minimum Lease Payments under Operating Leases (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$6,197
2016	4,935
2017	4,102
2018	3,111
2019	2,170
Thereafter	2,201
Total minimum lease payments	$22,716

Supplemental_Financial_Data_De

Supplemental Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Operations Data
Net revenues	$203,021	$186,798	$184,697	$206,353	$204,394	$166,453	$156,928	$141,645	$780,869	$669,420	$643,508
Gross profit	89,434	79,325	79,635	89,372	87,680	62,234	61,958	54,702	337,766	266,574	269,479
Income from operations	38,554	28,150	30,660	37,778	30,952	12,332	10,427	4,676	135,142	58,387	74,223
Net income	$34,192	$29,117	$21,224	$31,245	$20,237	$2,458	$7,320	$5,761	$115,778	$35,776	$48,029
Net income per share:
Basic	$0.64	$0.55	$0.40	$0.58	$0.38	$0.05	$0.14	$0.11	$2.17	$0.67	$0.91
Diluted	$0.64	$0.55	$0.40	$0.58	$0.38	$0.05	$0.14	$0.11	$2.16	$0.67	$0.90
Cash dividends paid per common share	$0.17	$0.17	$0.17	$0.16	$0.16	$0.16	$0.16	$0.16	$0.66	$0.64	$0.62

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$1,924	$2,078	$1,349
Additions Charged to Costs and Expenses	668	631	888
Additions Charged to Other Accounts	12	-62
Deductions & Write-offs	-354	-723	-159
Balance at End of Year	2,250	1,924	2,078
Valuation Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	827	801	1,167
Additions Charged to Costs and Expenses	2,223	1,933	2,564
Additions Charged to Other Accounts		-36
Deductions & Write-offs	-2,320	-1,871	-2,930
Balance at End of Year	730	827	801
Valuation Allowance on Deferred Tax Asset [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	27,102	27,497	26,475
Additions Charged to Costs and Expenses			-44
Additions Charged to Other Accounts			1,066
Deductions & Write-offs	-339	-395
Balance at End of Year	$26,763	$27,102	$27,497