2.2.0.25falsefalse20200 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies)truefalsefalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010 USD ($) USD ($) / shares $FROM_Jan01_2010_TO_Dec31_2010http://www.sec.gov/CIK0001000697duration2010-01-01T00:00:002010-12-31T00:00:00SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170EPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2true0wat_BasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPoliciesAbstractwatfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseBasis of Presentation and Summary of Significant Accounting Policies (Policies) [Abstract]3false0wat_UseOfEstimatesAndJudgmentsTextBlockwatfalsenadurationProvides an entity's explanation that the preparation of financial statements in conformity with generally accepted...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Use of Estimates The preparation of consolidated financial statements in conformity with generally accepted accounting principles (“GAAP”) requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent liabilities. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition, product returns and allowances, bad debts, inventory valuation, equity investments, goodwill and intangible assets, warranty and installation provisions, income taxes, contingencies, litigation, retirement plan obligations and stock-based compensation. The Company bases its estimates on historical experience and on various other assumptions 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 amounts may differ from these estimates under different assumptions or conditions.Use of Estimates The preparation of consolidated financial statements in conformity with generally accepted accounting principles (“GAAP”)falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringProvides an entity's explanation that the preparation of financial statements in conformity with generally accepted accounting principles requires the use of management estimates. Estimates used in the determination of carrying amounts of assets or liabilities, or in disclosure of gain or loss contingencies should be disclosed if known information available prior to issuance of the financial statements indicates that both of these criteria are met: (1) It is at least reasonably possible that the estimate of the effect on the financial statements of a condition, situation, or set of circumstances that existed at the date of the financial statements will change in the near term (less than one year from the date of issuance) due to one or more future confirming events, and (2) The effect of the change would be material to the financial statements. The disclosure should indicate the nature of the uncertainty and include an indication that it is at least reasonably possible that a change in the estimate will occur in the near term. Disclosure of the factors that cause the estimate to be sensitive to change also is encouraged. Entities also may identify those areas that are subject to significant estimates.No authoritative reference available.falsefalseUse of Estimates4false0wat_ConsolidationsPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for its subsidiaries or other investments that are consolidated, including the...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries, most of which are wholly owned. The Company consolidates entities in which it owns or controls fifty percent or more of the voting shares. All material inter-company balances and transactions have been eliminated.Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries, most of which are whollyfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for its subsidiaries or other investments that are consolidated, including the accounting treatment for intercompany accounts or transactions and any noncontrolling interest.No authoritative reference available.falsefalsePrinciples of Consolidation5false0us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Translation of Foreign Currencies For most of the Company's foreign operations, assets and liabilities are translated into U.S. dollars at exchange rates prevailing on the balance sheet date, while revenues and expenses are translated at average exchange rates prevailing during the period. Any resulting translation gains or losses are included in accumulated other comprehensive income in the consolidated balance sheets.Translation of Foreign Currencies For most of the Company's foreign operations, assets and liabilities are translated into U.S. dollars at exchangefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes a reporting enterprise's accounting policy for (1) transactions denominated in a currency other than the reporting enterprise's functional currency, (2) translating foreign currency financial statements that are incorporated into the financial statements of the reporting enterprise by consolidation, combination, or the equity method of accounting, and (3) remeasurement of the financial statements of a foreign reporting enterprise in a hyperinflationary economy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 5, 7-20, 80 falsefalseTranslation of Foreign Currencies6false0us-gaap_CashAndCashEquivalentsPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Cash and Cash Equivalents Cash equivalents primarily represent highly liquid investments, with original maturities of 90 days or less, primarily in bank deposits, and AAA rated U.S. treasury and European government bond money market funds, which are convertible to a known amount of cash and carry an insignificant risk of change in market value. Investments with longer maturities are classified as short-term investments, and are held primarily in bank deposits and U.S., German, French and Dutch government treasury bills. The Company maintains balances in various operating accounts in excess of federally insured limits, and in foreign subsidiary accounts in currencies other than U.S. dollars.Cash and Cash Equivalents Cash equivalents primarily represent highly liquid investments, with original maturities of 90 days or less, primarily infalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringA description of a company's cash and cash equivalents accounting policy. An entity shall disclose its policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value. Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. In addition, cash equivalents include short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. For a bank, may include explanation and amount of requirement to maintain reserves against deposits.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Financial Reporting Release (FRR) -Number 203 -Paragraph 02-03 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 8, 9, 10 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Technical Practice Aid (TPA) -Number 2110 -Paragraph 6 falsefalseCash And Cash Equivalents7false0wat_ShortTermInvestmentsPolicyTextBlockwatfalsenadurationThis element describes an entity's accounting policy for investments in debt and equity securities that are classified as...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Short-Term Investments Short-term investments are classified as available-for-sale in accordance with the accounting standard for investments in debt and equity securities. All available-for-sale securities are recorded at fair market value and any unrealized holding gains and losses, to the extent deemed temporary, are included in accumulated other comprehensive income in stockholders' equity, net of the related tax effects. Realized gains and losses are determined on the specific identification method and are included in other income (expense) net. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other than temporary” and marks the investment to market through a charge to the statement of operations. The Company classifies its investments as short-term investments exclusive of those categorized as cash equivalents.Short-Term Investments Short-term investments are classified as available-for-sale in accordance with the accounting standard for investments in debt andfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis element describes an entity's accounting policy for investments in debt and equity securities that are classified as available-for-sale. These policies also may describe the entity's accounting treatment for transfers between investment categories, how the entity determines whether impairments of available-for-sale securities are other than temporary, and how the fair values of such securities are determined.No authoritative reference available.falsefalseShort-Term Investments8false0wat_AccountsReceivableAndAllowanceForDoubtfulAccountsPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for trade and other accounts receivables. This disclosure may include the basis at...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the best estimate of the amount of probable credit losses in the existing accounts receivable. The allowance is based on a number of factors, including historical experience and the customer's credit-worthiness. The allowance for doubtful accounts is reviewed on at least a quarterly basis. Past due balances over 90 days and over a specified amount are reviewed individually for collectibility. Account balances are charged against the allowance when the Company feels it is probable that the receivable will not be recovered. The Company does not have any off-balance sheet credit exposure related to its customers.Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. ThefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for trade and other accounts receivables. This disclosure may include the basis at which such receivables are carried in the entity's statements of financial position (for example, net realizable value), how the entity determines the level of its allowance for doubtful accounts, when impairments, charge-offs or recoveries are recognized, and the entity's income recognition policies for such receivables, including its treatment of related fees and costs, its treatment of premiums, discounts or unearned income, when accrual of interest is discontinued, how the entity records payments received on nonaccrual receivables and its policy for resuming accrual of interest on such receivables. If the enterprise holds a large number of similar loans, disclosure may include the accounting policy for the anticipation of prepayments and significant assumptions underlying prepayment estimates for amortization of premiums, discounts, and nonrefundable fees and costs.No authoritative reference available.falsefalseAccounts Receivable and Allowance for Doubtful Accounts9false0us-gaap_InventoryPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Inventory The Company values all of its inventories at the lower of cost or market on a first-in, first-out basis (“FIFO”).Inventory The Company values all of its inventories at the lower of cost or market on a first-in, first-out basis (“FIFO”).falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policies covering its major classes of inventories, bases of stating inventories (for example lower of cost or market), methods by which amounts are added and removed from inventory classes (for example FIFO, LIFO, or average cost), loss recognition on impairment of inventories, and situations in which inventories are stated above cost. If inventory is carried at cost, this description includes the nature of the cost elements included in inventory.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Financial Reporting Release (FRR) -Number 206 -Chapter 2 -Paragraph b -Subparagraph i, ii Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 4 -Paragraph 3, 5-10, 15, 16, 17 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 6 -Subparagraph a -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 9 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 81-1 -Paragraph 69-75 falsefalseInventory Policy10false0us-gaap_IncomeTaxPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Income Taxes  Deferred income taxes are recognized for temporary differences between the financial statement and income tax basis of assets and liabilities using tax rates in effect for the years in which the differences are expected to reverse. A valuation allowance is provided to offset any net deferred tax assets if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. A liability has also been recorded to recognize uncertain tax return reporting positions.Income Taxes  Deferred income taxes are recognized for temporary differences between the financial statement and income tax basis of assets andfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 4 -Paragraph 11 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 48 -Paragraph 20 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 6-34, 43, 47, 49 falsefalseIncome Tax Policy11false0us-gaap_PropertyPlantAndEquipmentPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Property, Plant and Equipment Property, plant and equipment are recorded at cost. Expenditures for maintenance and repairs are charged to expense, while the costs of significant improvements are capitalized. Depreciation is provided using the straight-line method over the following estimated useful lives: buildings — fifteen to thirty years; building improvements — five to ten years; leasehold improvements — the shorter of the economic useful life or life of lease; and production and other equipment — three to ten years. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are eliminated from the consolidated balance sheets and related gains or losses are reflected in the consolidated statements of operations.Asset Impairments The Company reviews its long-lived assets for impairment in accordance with the accounting standard for property, plant and equipment. Whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable, the Company evaluates the fair value of the asset, relying on a number of factors, including, but not limited to, operating results, business plans, economic projections and anticipated future cash flows. Any change in the carrying amount of an asset as a result of the Company's evaluation is separately identified in the consolidated statements of operations.Property, Plant and Equipment Property, plant and equipment are recorded at cost. Expenditures for maintenance and repairs are charged to expense, whilefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for property, plant and equipment which may include the basis of such assets, depreciation methods used and estimated useful lives, the entity's capitalization policy, including its accounting treatment for costs incurred for repairs and maintenance activities, whether such asset balances include capitalized interest and the method by which such is calculated, how disposals of such assets are accounted for and how impairment of such assets is assessed and recognized.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 9 -Section C -Paragraph 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 22 -Paragraph 12, 13 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 8, 9 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph a -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 -Subparagraph d falsefalseProperty, Plant and Equipment Policy12false0wat_GoodwillPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for goodwill. This accounting policy also may address how an entity assesses and...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00The Company tests for goodwill impairment using a fair-value approach at the reporting unit level annually, or earlier, if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Additionally, the Company performs an annual goodwill impairment assessment for its reporting units as of January 1 each year. The goodwill and other intangible assets accounting standard defines a reporting unit as an operating segment, or one level below an operating segment, if discrete financial information is prepared and reviewed by management. For goodwill impairment review purposes, the Company has two reporting units, the Waters Division and TA. Goodwill is allocated to the reporting units at the time of acquisition. Under the impairment test, if a reporting unit's carrying amount exceeds its estimated fair value, goodwill impairment is recognized to the extent that the carrying amount of goodwill exceeds the implied fair value of the goodwill. The fair value of reporting units was estimated using a discounted cash flows technique, which includes certain management assumptions, such as estimated future cash flows, estimated growth rates and discount rates.The Company tests for goodwill impairment using a fair-value approach at the reporting unit level annually, or earlier, if an event occurs or circumstancesfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for goodwill. This accounting policy also may address how an entity assesses and measures impairment of goodwill, how reporting units are determined, how goodwill is allocated to such units, and how the fair values of the reporting units are determined.No authoritative reference available.falsefalseGoodwill Policy13false0wat_OtherIntangibleAssetsPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for intangible assets. This accounting policy may address both intangible assets...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Purchased intangibles are recorded at their fair market values as of the acquisition date and amortized over their estimated useful lives, ranging from one to fifteen years. Other intangibles are amortized over a period ranging from one to thirteen years. Debt issuance costs are amortized over the life of the related debt. Acquired IPR&D is amortized from the date of completion over its estimated useful life. In addition, acquired IPR&D will be tested for impairment until completion of the acquired programs.Purchased intangibles are recorded at their fair market values as of the acquisition date and amortized over their estimated useful lives, ranging from one tofalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for intangible assets. This accounting policy may address both intangible assets subject to amortization and those that are not. The following also may be disclosed: (1) a description of intangible assets (2) the estimated useful lives of those assets (3) the amortization method used (4) how the entity assesses and measures impairment of such assets (5) how future cash flows are estimated (6) how the fair values of such asset are determined.No authoritative reference available.falsefalseOther Intangible Assets Policy14false0wat_SoftwareDevelopmentCostsForSoftwareToBeSoldPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for costs incurred to (1) establish the technological feasibility of a computer...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00The Company capitalizes software development costs for products offered for sale in accordance with the accounting standard for the costs of software to be sold, leased, or otherwise marketed. Capitalized costs are amortized to cost of sales over the period of economic benefit, which approximates a straight-line basis over the estimated useful lives of the related software products, generally three to five years.The Company capitalizes software development costs for products offered for sale in accordance with the accounting standard for the costs of software to befalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for costs incurred to (1) establish the technological feasibility of a computer software product to be sold, leased, or otherwise marketed; and (2) produce product masters after establishing technological feasibility. This accounting policy also may apply to purchased computer software. This policy also may address the entity's amortization policy for its capitalized computer software costs and how it evaluates such capitalized costs for impairment.No authoritative reference available.falsefalseSoftware Development Costs for Software to be Sold15false0wat_InternalUseSoftwarePolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for costs incurred when both (1) the software is acquired, internally developed, or...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00The Company capitalizes internal software development costs in accordance with the accounting standard for goodwill and other intangible assets. Capitalized internal software development costs are amortized over the period of economic benefit which approximates a straight-line basis over ten years.The Company capitalizes internal software development costs in accordance with the accounting standard for goodwill and other intangible assets. CapitalizedfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for costs incurred when both (1) the software is acquired, internally developed, or modified solely to meet the entity's internal needs, and (2) during the software's development or modification, no substantive plan exists or is being developed to market the software externally.No authoritative reference available.falsefalseInternal Use Software Policy16false0wat_EquityAndCostMethodInvestmentsPolicyTextBlockwatfalsenadurationThis element describes an entity's application of the equity method of accounting to investments in common stock or other...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Investments The Company accounts for its investments that represent less than twenty percent ownership, and for which the Company does not have significant influence, using the accounting standard for investments in debt and equity securities. Investments for which the Company does not have the ability to exercise significant influence, and for which there is not a readily determinable market value, are accounted for under the cost method of accounting. The Company periodically evaluates the carrying value of its investments accounted for under the cost method of accounting and carries them at the lower of cost or estimated net realizable value. For investments in which the Company owns or controls between twenty and forty-nine percent of the voting shares, or over which it exerts significant influence over operating and financial policies, the equity method of accounting is used.Investments The Company accounts for its investments that represent less than twenty percent ownership, and for which the Company does not havefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis element describes an entity's application of the equity method of accounting to investments in common stock or other interests including unconsolidated domestic subsidiaries, corporate joint ventures, noncontrolling interests in real estate ventures, limited partnerships, and limited liability companies. Additionally, this element describes the entity's application of the cost method to equity investments or other interests that are not consolidated or accounted for under the equity method of accounting. The description provided may include a description of how equity method or cost investments are assessed for impairment.No authoritative reference available.falsefalseEquity and Cost Method Investments17false0wat_FairValueMeasurementsPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for determining the fair value of its assets and liabilities.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Fair Value Measurements In accordance with the accounting standards for fair value measurements and disclosures, certain of the Company's assets and liabilities are measured at fair value on a recurring basis as of December 31, 2010 and 2009. Fair values determined by Level 1 inputs utilize observable data, such as quoted prices in active markets. Fair values determined by Level 2 inputs utilize data points other than quoted prices in active markets that are observable either directly or indirectly. Fair values determined by Level 3 inputs utilize unobservable data points for which there is little or no market data, which require the reporting entity to develop its own assumptions.In January 2009, the Company implemented the accounting and disclosure requirements related to non-financial assets and liabilities that are remeasured at fair value on a non-recurring basis. The adoption of this accounting and disclosure requirement did not have a significant impact on the Company's financial statements.Fair Value of Other Financial Instruments The Company's cash, accounts receivable, accounts payable and debt are recorded at cost, which approximates fair value.Fair Value Measurements In accordance with the accounting standards for fair value measurements and disclosures, certain of the Company's assets andfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for determining the fair value of its assets and liabilities.No authoritative reference available.falsefalseFair Value Measurements18false0us-gaap_DerivativesPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Company records its hedge transactions in accordance with the accounting standards for derivative instruments and hedging activities, which establishes the accounting and reporting standards for derivative instruments, including certain derivative instruments embedded in other contracts, and for hedging activities. All derivatives, whether designated in hedging relationships or not, are required to be recorded on the consolidated balance sheets at fair value as either assets or liabilities. If the derivative is designated as a fair-value hedge, the changes in the fair value of the derivative and of the hedged item attributable to the hedged risk are recognized in earnings. If the derivative is designated as a cash flow hedge, the effective portions of changes in the fair value of the derivative are recorded in other comprehensive income and are recognized in earnings when the hedged item affects earnings; ineffective portions of changes in fair value are recognized in earnings. In addition, disclosures required for derivative instruments and hedging activities include the Company's objectives for using derivative instruments, the level of derivative activity the Company engages in, as well as how derivative instruments and related hedged items affect the Company's financial position and performance.The Company records its hedge transactions in accordance with the accounting standards for derivative instruments and hedging activities, which establishes thefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policies for its derivative instruments and hedging activities. Disclosure may include: (1) Each method used to account for derivative financial instruments and derivative commodity instruments ("derivatives"); (2) the types of derivatives accounted for under each method; (3) the criteria required to be met for each accounting method used, including a discussion of the criteria required to be met for hedge or deferral accounting and accrual or settlement accounting (for example: whether and how risk reduction, correlation, designation, and effectiveness tests are applied); (4) the accounting method used if the criteria specified for hedge accounting are not met; (5) the method used to account for termination of derivatives designated as hedges or derivatives used to affect directly or indirectly the terms, fair values, or cash flows of a designated item; (6) the method used to account for derivatives when the designated item matures, is sold, is extinguished, or is terminated. In addition, the method used to account for derivatives designated to an anticipated transaction, when the anticipated transaction is no longer likely to occur; and (7) where and when derivatives, and their related gains (losses) are reported in the statement of financial position, cash flows, and results of operations and (8) an accounting policy decision to offset fair value amounts with counterparties. An entity should also consider describing its embedded derivatives, and the method(s) used to determine the fair values of derivatives and any significant assumptions used in such valuations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph n -Article 4 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 39 -Paragraph 10 falsefalseDerivatives Policy19false0us-gaap_RevenueRecognitionPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Revenue Recognition Sales of products and services are generally recorded based on product shipment and performance of service, respectively. The Company's deferred revenue on the consolidated balance sheets consists of the obligation on instrument service contracts and customer payments received in advance prior to shipment of the instrument. Revenue is recognized when all of the following revenue recognition criteria are met: persuasive evidence of an arrangement exists; delivery has occurred; the vendor's fee is fixed or determinable; collectibility is reasonably assured and, if applicable, upon acceptance when acceptance criteria with contractual cash holdback are specified. Shipping and handling costs are included in cost of sales net of amounts invoiced to the customer per the order.  Product shipments, including those for demonstration or evaluation, and service contracts are not recorded as revenues until a valid purchase order or master agreement is received specifying fixed terms and prices. The Company recognizes product revenue when legal title has transferred and risk of loss passes to the customer. The Company structures its sales arrangements as FOB shipping point or international equivalent and, accordingly, recognizes revenue upon shipment. In some cases, FOB destination based shipping terms are included in sales arrangements, in which cases revenue is recognized when the products arrive at the customer site. The Company's method of revenue recognition for certain products requiring installation is in accordance with the multiple element revenue recognition accounting standards. With respect to the installation obligations, the larger of the contractual cash holdback or the fair value of the installation service is deferred when the product is shipped and revenue is recognized as a multiple-element arrangement when installation is complete. The Company determines the fair value of installation based upon a number of factors, including hourly service billing rates, estimated installation hours and comparisons of amounts charged by third parties.  Instrument service contracts are typically billed at the beginning of the maintenance period. The amount of the service contract is amortized ratably to revenue over the instrument maintenance period. There are no deferred costs associated with the service contract as the cost of the service is recorded when the service is performed. No revenue is recognized until all revenue recognition criteria have been met. Sales of software are accounted for in accordance with the accounting standards for software revenue recognition. The Company's software arrangements typically include software licenses and maintenance contracts. Software license revenue is recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, collection is probable, and there are no significant post-delivery obligations remaining. The revenue associated with the software maintenance contract is recognized ratably over the maintenance term. Unspecified rights to software upgrades are typically sold as part of the maintenance contract on a when-and-if-available basis. The Company uses the residual method to allocate software revenue when a transaction includes multiple elements and vendor specific objective evidence of the fair value of undelivered elements exists. Under the residual method, the fair value of the undelivered element (maintenance) is deferred and the remaining portion of the arrangement fee is allocated to the delivered element (software license) and recognized as revenue.  Returns and customer credits are infrequent and are recorded as a reduction to sales. Rights of return are not included in sales arrangements. Revenue associated with products that contain specific customer acceptance criteria is not recognized before the customer acceptance criteria are satisfied. Discounts from list prices are recorded as a reduction to sales.Revenue Recognition Sales of products and services are generally recorded based on product shipment and performance of service, respectively. ThefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction should be disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section B -Paragraph Question 1 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 22 -Paragraph 8, 12, 13 falsefalseRevenue Recognition20false0wat_ProductWarrantyPolicyTextBlockwatfalsenadurationDescription for the guarantor's accounting for standard warranties including the methodology for measuring the liability.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Product Warranty Costs The Company accrues estimated product warranty costs at the time of sale, which are included in cost of sales in the consolidated statements of operations. While the Company engages in extensive product quality programs and processes, including actively monitoring and evaluating the quality of its component supplies, the Company's warranty obligation is affected by product failure rates, material usage and service delivery costs incurred in correcting a product failure. The amount of the accrued warranty liability is based on historical information, such as past experience, product failure rates, number of units repaired and estimated costs of material and labor. The liability is reviewed for reasonableness at least quarterly.Product Warranty Costs The Company accrues estimated product warranty costs at the time of sale, which are included in cost of sales in the consolidatedfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescription for the guarantor's accounting for standard warranties including the methodology for measuring the liability.No authoritative reference available.falsefalseProduct Warranty Costs21false0us-gaap_AdvertisingCostsPolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Advertising Costs All advertising costs are expensed as incurred and are included in selling and administrative expenses in the consolidated statements of operations.Advertising Costs All advertising costs are expensed as incurred and are included in selling and administrative expenses in the consolidated statements offalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for advertising costs. For those costs that cannot be capitalized, discloses whether such costs are expensed as incurred or the first period in which the advertising takes place. For direct response advertising costs that are capitalized, describes those assets and the accounting policy used, including a description of the qualifying activity, the types of costs capitalized and the related amortization period. An entity also may disclose its accounting policy for cooperative advertising arrangements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 93-7 -Paragraph 49 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 02-16 -Paragraph 6 falsefalseAdvertising Costs22false0wat_ResearchAndDevelopmentExpensesPolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for costs it has incurred (1) in a planned search or critical investigation aimed at...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Research and Development Expenses Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, overhead costs, contract services and other outside costs. Research and development expenses are expensed as incurred.Research and Development Expenses Research and development expenses are comprised of costs incurred in performing research and development activities,falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for costs it has incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process.No authoritative reference available.falsefalseResearch and Development Expenses23false0us-gaap_EarningsPerSharePolicyTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00Earnings Per Share In accordance with the earnings per share accounting standard, the Company presents two earnings per share (“EPS”) amounts. Income per basic common share is based on income available to common shareholders and the weighted-average number of common shares outstanding during the periods presented. Income per diluted common share includes additional dilution from potential common stock, such as stock issuable pursuant to the exercise of stock options outstanding.The effect of dilutive securities was calculated using the treasury stock method.Earnings Per Share In accordance with the earnings per share accounting standard, the Company presents two earnings per share (“EPS”) amounts.falsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDiscloses the methodology and assumptions used to compute basic and diluted earnings (loss) per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 6, 8-16, 60 falsefalseEarnings Per Share Policy24false0wat_ComprehensiveIncomePolicyTextBlockwatfalsenadurationDescribes an entity's accounting policy for presentation of comprehensive income.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Comprehensive Income The Company accounts for comprehensive income in accordance with the accounting standards for comprehensive income, which establish the accounting rules for reporting and displaying comprehensive income. The standard requires that all components of comprehensive income be reported in a financial statement that is displayed with the same prominence as other financial statements.Comprehensive Income The Company accounts for comprehensive income in accordance with the accounting standards for comprehensive income, which establishfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringDescribes an entity's accounting policy for presentation of comprehensive income.No authoritative reference available.falsefalseComprehensive Income Policy25false0wat_RecentlyAdoptedAccountingStandardsTextBlockwatfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Recently Adopted Accounting Standards In June 2009, a new accounting standard was issued relating to the consolidation of variable interest entities. This statement addresses (1) the effects on certain provisions of existing accounting standards as a result of the elimination of the qualifying special-purpose entity concept and (2) constituent concerns about the application of certain key provisions of existing accounting standards, including those in which the accounting and disclosures under existing accounting standards do not always provide timely and useful information about an enterprise's involvement in a variable interest entity. This standard is effective for periods beginning after November 15, 2009. The adoption of this standard did not have a material effect on the Company's financial position, results of operations or cash flows. In January 2010, the Company adopted a newly issued accounting standard which requires additional disclosure about the amounts of and reasons for significant transfers in and out of Level 1 and Level 2 fair-value measurements. This standard also clarifies existing disclosure requirements related to the level of disaggregation of fair value measurements for each class of assets and liabilities and disclosure about inputs and valuation techniques used to measure fair value for both recurring and nonrecurring Level 2 and Level 3 measurements. As this newly issued accounting standard only requires enhanced disclosure, the adoption of this standard did not impact the Company's financial position or results of operations. In addition, effective for interim and annual periods beginning after December 15, 2010, this standard will require additional disclosure and require an entity to present disaggregated information about activity in Level 3 fair-value measurements on a gross basis, rather than as one net amount.Recently Adopted Accounting Standards In June 2009, a new accounting standard was issued relating to the consolidation of variable interest entities. ThisfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringNo definition available.No authoritative reference available.falsefalseRecently Adopted Accounting Standards26false0wat_RecentlyIssuedAccountingStandardsTextBlockwatfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00Recently Issued Accounting Standards In October 2009, a new accounting consensus was issued for multiple-deliverable revenue arrangements. This consensus amends existing revenue recognition accounting standards. This consensus provides accounting principles and application guidance on whether multiple deliverables exist, how the arrangement should be separated and the consideration allocated. This guidance eliminates the requirement to establish the fair value of undelivered products and services and instead provides for separate revenue recognition based upon management's estimate of the selling price for an undelivered item when there is no other means to determine the fair value of that undelivered item. Previously, the existing accounting consensus required that the fair value of the undelivered item be the price of the item either sold in a separate transaction between unrelated third parties or the price charged for each item when the item is sold separately by the vendor. Under the existing accounting consensus, if the fair value of all of the elements in the arrangement was not determinable, then revenue was deferred until all of the items were delivered or fair value was determined. This new approach is effective prospectively for revenue arrangements entered into or materially modified in fiscal years beginning on or after June 15, 2010. The adoption of this standard will not have a material effect on the Company's financial position, results of operations or cash flows. Also in October 2009, a new accounting consensus was issued for certain revenue arrangements that include software elements. This consensus amends the existing accounting guidance for revenue arrangements that contain tangible products and software. This consensus requires that tangible products which contain software components and non-software components that function together to deliver the tangible products essential functionality are no longer within the scope of the software revenue guidance. This new approach is effective prospectively for revenue arrangements entered into or materially modified in fiscal years beginning on or after June 15, 2010. The adoption of this standard will not have a material effect on the Company's financial position, results of operations or cash flows.Recently Issued Accounting Standards In October 2009, a new accounting consensus was issued for multiple-deliverable revenue arrangements. This consensusfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringNo definition available.No authoritative reference available.falsefalseRecently Issued Accounting Standards125Basis of Presentation and Summary of Significant Accounting Policies (Policies)UnKnownUnKnownUnKnownUnKnownfalsetrue