Waters (WAT) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	3 Months Ended
	Apr. 04, 2015	1-May-15	Jun. 28, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	WATERS CORP /DE/
Entity Trading Symbol	WAT
Entity Central Index Key	1000697
Document Type	10-Q
Document Fiscal Period Focus	Q1
Document Period End Date	4-Apr-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$8,843,973,000
Entity Common Stock, Shares Outstanding		82,692,719

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Apr. 04, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$440,798	$422,177
Investments	1,668,247	1,633,211
Accounts receivable, less allowances for doubtful accounts and sales returns of $7,002 and $7,179 at April 4, 2015 and December 31, 2014, respectively	394,370	433,616
Inventories	257,530	246,430
Other current assets	115,028	118,302
Total current assets	2,875,973	2,853,736
Property, plant and equipment, net	316,814	321,583
Intangible assets, net	213,108	232,371
Goodwill	350,021	354,838
Other assets	116,810	115,406
Total assets	3,872,726	3,877,934
Current liabilities:
Notes payable and debt	175,316	225,243
Accounts payable	63,954	65,704
Accrued employee compensation	28,950	47,198
Deferred revenue and customer advances	167,343	129,706
Accrued income taxes	19,405	15,143
Accrued warranty	12,871	13,266
Other current liabilities	70,632	85,335
Total current liabilities	538,471	581,595
Long-term liabilities:
Long-term debt	1,310,000	1,240,000
Long-term portion of retirement benefits	84,239	85,230
Long-term income tax liabilities	21,313	20,397
Other long-term liabilities	56,463	56,046
Total long-term liabilities	1,472,015	1,401,673
Total liabilities	2,010,486	1,983,268
Commitments and contingencies (Notes 5, 6 and 9)
Stockholders' equity:
Preferred stock, par value $0.01 per share, 5,000 shares authorized, none issued at April 4, 2015 and December 31, 2014	0	0
Common stock, par value $0.01 per share, 400,000 shares authorized, 157,030 and 156,716 shares issued, 82,701 and 83,147 shares outstanding at April 4, 2015 and December 31, 2014, respectively	1,570	1,567
Additional paid-in capital	1,414,700	1,392,494
Retained earnings	4,490,574	4,394,513
Treasury stock, at cost, 74,329 and 73,569 shares at April 4, 2015 and December 31, 2014, respectively	-3,906,228	-3,815,203
Accumulated other comprehensive loss	-138,376	-78,705
Total stockholders' equity	1,862,240	1,894,666
Total liabilities and stockholders' equity	$3,872,726	$3,877,934

Consolidated_Balance_Sheets_Un1

Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $)	Apr. 04, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowances for doubtful accounts and sales returns	$7,002	$7,179
Preferred stock, par value per share	$0.01	$0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value per share	$0.01	$0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	157,030,000	156,716,000
Common stock, shares outstanding	82,701,000	83,147,000
Treasury stock, shares	74,329,000	73,569,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Income Statement [Abstract]
Product sales	$302,873	$284,795
Service sales	157,531	145,713
Total net sales	460,404	430,508
Cost of product sales	121,953	122,475
Cost of service sales	67,293	65,244
Total cost of sales	189,246	187,719
Gross profit	271,158	242,789
Selling and administrative expenses	119,751	126,635
Research and development expenses	28,951	24,746
Purchased intangibles amortization	2,474	2,647
Operating income	119,982	88,761
Interest expense	-8,975	-7,489
Interest income	2,340	1,458
Income from operations before income taxes	113,347	82,730
Provision for income taxes	17,286	12,428
Net income	$96,061	$70,302
Net income per basic common share	$1.16	$0.83
Weighted-average number of basic common shares	83,025	84,977
Net income per diluted common share	$1.15	$0.82
Weighted-average number of diluted common shares and equivalents	83,752	85,873

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Statement of Comprehensive Income [Abstract]
Net income	$96,061	$70,302
Foreign currency translation	-64,348	26,717
Unrealized gains on investments before income taxes	2,767	142
Income tax (expense) benefit from unrealized gains on investments	-116	2
Unrealized gains on investments, net of tax	2,651	144
Retirement liability adjustment before reclassifications	2,136	-931
Retirement liability amounts reclassified to selling and administrative expenses	921	516
Retirement liability adjustment before income taxes	3,057	-415
Income tax (expense) benefit from retirement liability adjustment	-1,031	132
Retirement liability adjustment, net of tax	2,026	-283
Other comprehensive (loss) income	-59,671	26,578
Comprehensive income	$36,390	$96,880

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Cash flows from operating activities:
Net income	$96,061	$70,302
Adjustments to reconcile net income to net cash provided by operating activities:
Provisions for doubtful accounts on accounts receivable	159	1,059
Provisions on inventory	1,368	1,139
Stock-based compensation	8,455	8,129
Deferred income taxes	2,828	-2,218
Depreciation	11,445	8,819
Amortization of intangibles	11,104	11,523
Change in operating assets and liabilities, net of acquisitions:
Decrease in accounts receivable	24,802	30,147
Increase in inventories	-21,369	-24,163
Increase in other current assets	-1,776	-8,008
Increase in other assets	-4,891	-7,169
Decrease in accounts payable and other current liabilities	-25,518	-11,491
Increase in deferred revenue and customer advances	42,555	34,356
Increase in other liabilities	9,367	3,330
Net cash provided by operating activities	154,590	115,755
Cash flows from investing activities:
Additions to property, plant, equipment and software capitalization	-21,410	-21,395
Business acquisitions, net of cash acquired		-3,615
Purchases of investments	-794,422	-607,028
Maturities of investments	759,386	512,089
Net cash used in investing activities	-56,446	-119,949
Cash flows from financing activities:
Proceeds from debt issuances	120,073	10,053
Payments on debt	-100,000	-1,295
Proceeds from stock plans	11,269	35,322
Purchases of treasury shares	-91,025	-92,572
Excess tax benefit related to stock option plans	2,757	8,507
Payments of derivative contracts	-3,348	-314
Net cash used in financing activities	-60,274	-40,299
Effect of exchange rate changes on cash and cash equivalents	-19,249	-921
Increase (decrease) in cash and cash equivalents	18,621	-45,414
Cash and cash equivalents at beginning of period	422,177	440,796
Cash and cash equivalents at end of period	$440,798	$395,382

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Apr. 04, 2015
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	1  Basis of Presentation and Summary of Significant Accounting Policies
	Waters Corporation (“Waters®” or the “Company”) is an analytical instrument manufacturer that primarily designs, manufactures, sells and services, through its Waters Division, high performance liquid chromatography (“HPLC”), ultra performance liquid chromatography (“UPLC®” and together with HPLC, referred to as “LC”) and mass spectrometry (“MS”) technology systems and support products, including chromatography columns, other consumable products and comprehensive post-warranty service plans. These systems are complementary products that are frequently employed together (“LC-MS”) and sold as integrated instrument systems using a common software platform. LC is a standard technique and is utilized in a broad range of industries to detect, identify, monitor and measure the chemical, physical and biological composition of materials, and to purify a full range of compounds. MS instruments are used in drug discovery and development, including clinical trial testing, the analysis of proteins in disease processes (known as “proteomics”), nutritional safety analysis and environmental testing. LC-MS instruments combine a liquid phase sample introduction and separation system with mass spectrometric compound identification and quantification. Through its TA Division (“TA®”), the Company primarily designs, manufactures, sells and services thermal analysis, rheometry and calorimetry instruments, which are used in predicting the suitability and stability of fine chemicals, pharmaceuticals, water, polymers and viscous liquids for various industrial, consumer goods and healthcare products, as well as for life science research. The Company is also a developer and supplier of software-based products that interface with the Company's instruments, as well as other suppliers' instruments, and are typically purchased by customers as part of the instrument system.
	The Company's interim fiscal quarter typically ends on the thirteenth Saturday of each quarter. Since the Company's fiscal year end is December 31, the first and fourth fiscal quarters may have more or less than thirteen complete weeks. The Company's first fiscal quarters for 2015 and 2014 ended on April 4, 2015 and March 29, 2014, respectively.
	The accompanying unaudited interim consolidated financial statements have been prepared in accordance with the instructions to the Quarterly Report on Form 10-Q and do not include all of the information and note disclosures required by generally accepted accounting principles (“GAAP”) in the United States of America. The consolidated financial statements include the accounts of the Company and its subsidiaries, most of which are wholly owned. All material inter-company balances and transactions have been eliminated.
	The preparation of consolidated financial statements in conformity with 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 at the dates of the financial statements. Actual amounts may differ from these estimates under different assumptions or conditions.
	It is management's opinion that the accompanying interim consolidated financial statements reflect all adjustments (which are normal and recurring) that are necessary for a fair statement of the results for the interim periods. The interim consolidated financial statements should be read in conjunction with the consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014, as filed with the U.S. Securities and Exchange Commission on February 27, 2015.
	Cash, Cash Equivalents and Investments
	Cash equivalents represent highly liquid investments, with original maturities of 90 days or less, while investments with longer maturities are classified as investments. The Company maintains cash balances in various operating accounts in excess of federally insured limits, and in foreign subsidiary accounts in currencies other than U.S. dollars. As of April 4, 2015 and December 31, 2014, $2,067 million out of $2,109 million and $1,971 million out of $2,055 million, respectively, of the Company's total cash, cash equivalents and investments were held by foreign subsidiaries and may be subject to material tax effects on distribution to U.S. legal entities.
	Fair 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 April 4, 2015 and December 31, 2014. 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.
	The following table represents the Company's assets and liabilities measured at fair value on a recurring basis at April 4, 2015 (in thousands):
								Quoted Prices
								in Active			Significant
								Markets			Other			Significant
								for Identical			Observable			Unobservable
					Total at			Assets			Inputs			Inputs
					4-Apr-15			(Level 1)			(Level 2)			(Level 3)
	Assets:
		U.S. Treasury securities			$	641,693		$	-		$	641,693		$	-
		Foreign government securities				24,994			-			24,994			-
		Corporate debt securities				1,067,736			-			1,067,736			-
		Time deposits				64,265			-			64,265			-
		Equity securities				147			-			147			-
		Other cash equivalents				29,000			-			29,000			-
		Waters 401(k) Restoration Plan assets				35,678			-			35,678			-
		Foreign currency exchange contracts				445			-			445			-
			Total		$	1,863,958		$	-		$	1,863,958		$	-
	Liabilities:
		Contingent consideration			$	3,780		$	-		$	-		$	3,780
		Foreign currency exchange contracts				631			-			631			-
			Total		$	4,411		$	-		$	631		$	3,780
	The following table represents the Company's assets and liabilities measured at fair value on a recurring basis at December 31, 2014 (in thousands):
								Quoted Prices
								in Active			Significant
								Markets			Other			Significant
					Total at			for Identical			Observable			Unobservable
					December 31,			Assets			Inputs			Inputs
					2014			(Level 1)			(Level 2)			(Level 3)
	Assets:
		U.S. Treasury securities			$	626,772		$	-		$	626,772		$	-
		Foreign government securities				24,998			-			24,998			-
		Corporate debt securities				984,105			-			984,105			-
		Time deposits				64,240			-			64,240			-
		Equity securities				147			-			147			-
		Other cash equivalents				29,000			-			29,000			-
		Waters 401(k) Restoration Plan assets				33,935			-			33,935			-
		Foreign currency exchange contracts				123			-			123			-
			Total		$	1,763,320		$	-		$	1,763,320		$	-
	Liabilities:
		Contingent consideration			$	3,612		$	-		$	-		$	3,612
		Foreign currency exchange contracts				651			-			651			-
			Total		$	4,263		$	-		$	651		$	3,612
	The fair values of the Company's cash equivalents, investments, 401(k) restoration plan assets and foreign currency exchange contracts are determined through market and observable sources and have been classified as Level 2. These assets and liabilities have been initially valued at the transaction price and subsequently valued, typically utilizing third-party pricing services. The pricing services use many inputs to determine value, including reportable trades, benchmark yields, credit spreads, broker/dealer quotes, current spot rates and other industry and economic events. The Company validates the prices provided by third-party pricing services by reviewing their pricing methods and obtaining market values from other pricing sources. After completing these validation procedures, the Company did not adjust or override any fair value measurements provided by third-party pricing services as of April 4, 2015 and December 31, 2014.
	Fair Value of Contingent Consideration
	The fair value of the Company's liability for contingent consideration related to the July 2014 acquisition of Medimass Research, Development and Service Kft. is determined using a probability-weighted discounted cash flow model, which uses significant unobservable inputs, and has been classified as Level 3. Subsequent changes in the fair value of the contingent consideration liability are recorded in the results of operations. The fair value of the contingent consideration liability associated with future earnout payments is based on several factors, including the development of future products, estimated sales of those products and a discount rate reflective of the Company's creditworthiness. A change in any of these unobservable inputs can significantly change the fair value of the contingent consideration. Although there is no contractual limit, the fair value of future contingent consideration payments was estimated to be $4 million at both April 4, 2015 and December 31, 2014, based on the Company's best estimate, as the earnout is based on future sales of certain products through 2034. There have been no changes in significant assumptions since December 31, 2014 and the change in fair value since then is primarily due to change in time value of money.
	Fair Value of Other Financial Instruments
	The Company's cash, accounts receivable, accounts payable and variable interest rate debt are recorded at cost, which approximates fair value. The carrying value of the Company's fixed interest rate debt was $500 million and $600 million at April 4, 2015 and December 31, 2014, respectively. The fair value of the Company's fixed interest rate debt was estimated using discounted cash flow models, based on estimated current rates offered for similar debt under current market conditions for the Company. The fair value of the Company's fixed interest rate debt was estimated to be $515 million and $608 million at April 4, 2015 and December 31, 2014, respectively, using Level 2 inputs.
	Derivative Transactions
	The Company enters into foreign currency exchange contracts to manage exposures to changes in foreign currency exchange rates on certain inter-company balances and short-term assets and liabilities. Principal hedged currencies include the Euro, Japanese yen, British pound and Brazilian real. At April 4, 2015 and December 31, 2014, the Company held forward foreign exchange contracts with notional amounts totaling $109 million and $110 million, respectively.
	The Company's foreign currency exchange contracts included in the consolidated balance sheets are classified as follows (in thousands):
				4-Apr-15			31-Dec-14
	Other current assets			$	445		$	123
	Other current liabilities			$	631		$	651
	The following is a summary of the activity in cost of sales in the statements of operations related to the forward foreign exchange contracts (in thousands):
		Three Months Ended
		4-Apr-15			29-Mar-14
Realized losses on closed contracts		$	-3,348		$	-314
Unrealized gains (losses) on open contracts			342			-881
Cumulative net pre-tax losses		$	-3,006		$	-1,195
Stockholders' Equity
In May 2014, the Company's Board of Directors authorized the Company to repurchase up to $750 million of its outstanding common stock over a three-year period and authorized the extension of the May 2012 program until May 2015. During the three months ended April 4, 2015 and March 29, 2014, the Company repurchased 0.7 million and 0.8 million shares of the Company's outstanding common stock at a cost of $85 million and $86 million, respectively, under the May 2012 and May 2014 authorizations. As of April 4, 2015, the Company repurchased an aggregate of 7.6 million shares at a cost of $750 million under the May 2012 repurchase program, which is now completed. The Company has a total of $684 million authorized for future repurchases under the May 2014 plan. In addition, the Company repurchased $6 million and $7 million of common stock related to the vesting of restricted stock units during the three months ended April 4, 2015 and March 29, 2014, respectively. The Company believes that it has the financial flexibility to fund these share repurchases given current cash levels and debt borrowing capacity, as well as to invest in research, technology and business acquisitions to further grow the Company's sales and profits.
Product 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 suppliers, 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.
The following is a summary of the activity of the Company's accrued warranty liability for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
		Balance at									Balance at
		Beginning			Accruals for			Settlements			End of
		of Period			Warranties			Made			Period
Accrued warranty liability:
4-Apr-15		$	13,266		$	1,762		$	-2,157		$	12,871
29-Mar-14		$	12,962		$	1,752		$	-1,919		$	12,795
Subsequent Events
The Company did not have any material subsequent events, except for the amendment of the Company's credit agreement discussed in Note 5, “Debt”.

Marketable_Securities

Marketable Securities	3 Months Ended
	Apr. 04, 2015
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash, Cash Equivalents and Short-term Investments	2 Marketable Securities
	The Company's marketable securities within cash equivalents and investments included in the consolidated balance sheets are detailed as follows (in thousands):
			4-Apr-15
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gain		Loss		Value
	U.S. Treasury securities		$	640,441	$	1,270	$	-18	$	641,693
	Foreign government securities			24,994		-		-		24,994
	Corporate debt securities			1,066,695		1,171		-130		1,067,736
	Time deposits			64,265		-		-		64,265
	Equity securities			77		70		-		147
		Total	$	1,796,472	$	2,511	$	-148	$	1,798,835
	Amounts included in:
		Cash equivalents	$	130,588	$	-	$	-	$	130,588
		Investments		1,665,884		2,511		-148		1,668,247
		Total	$	1,796,472	$	2,511	$	-148	$	1,798,835
			31-Dec-14
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gain		Loss		Value
	U.S. Treasury securities		$	626,683	$	246	$	-157	$	626,772
	Foreign government securities			24,998		-		-		24,998
	Corporate debt securities			984,668		125		-688		984,105
	Time deposits			64,240		-		-		64,240
	Equity securities			77		70		-		147
		Total	$	1,700,666	$	441	$	-845	$	1,700,262
	Amounts included in:
		Cash equivalents	$	67,051	$	-	$	-	$	67,051
		Investments		1,633,615		441		-845		1,633,211
		Total	$	1,700,666	$	441	$	-845	$	1,700,262
	The estimated fair value of marketable debt securities by maturity date is as follows (in thousands):
			4-Apr-15		31-Dec-14
	Due in one year or less		$	897,303	$	872,872
	Due after one year through three years			837,120		763,003
		Total	$	1,734,423	$	1,635,875

Inventories

Inventories	3 Months Ended
	Apr. 04, 2015
Inventory Items, Net Of Reserves Alternative [Abstract]
Inventories Disclosure	3  Inventories
	Inventories are classified as follows (in thousands):
			4-Apr-15		31-Dec-14
	Raw materials		$	85,943	$	84,952
	Work in progress			19,513		16,749
	Finished goods			152,074		144,729
		Total inventories	$	257,530	$	246,430

Goodwill_and_Other_Intangibles

Goodwill and Other Intangibles	3 Months Ended
	Apr. 04, 2015
Goodwill and Other Intangibles [Abstract]
Goodwill and Other Intangibles	4  Goodwill and Other Intangibles
	The carrying amount of goodwill was $350 million and $355 million at April 4, 2015 and December 31, 2014, respectively. During the three months ended April 4, 2015, the effect of foreign currency translation decreased goodwill by $5 million.
	The Company's intangible assets included in the consolidated balance sheets are detailed as follows (in thousands):
			4-Apr-15						31-Dec-14
							Weighted-						Weighted-
			Gross				Average		Gross				Average
			Carrying		Accumulated		Amortization		Carrying		Accumulated		Amortization
			Amount		Amortization		Period		Amount		Amortization		Period
	Capitalized software			308,213		183,036	7	years		334,280		196,477	7	years
	Purchased intangibles		$	158,050	$	111,965	11	years	$	163,855	$	112,279	11	years
	Trademarks and IPR&D			13,857		-	-			14,095		-	-
	Licenses			5,390		3,620	6	years		5,371		3,634	6	years
	Patents and other
		intangibles		55,897		29,678	8	years		56,513		29,353	8	years
		Total	$	541,407	$	328,299	8	years	$	574,114	$	341,743	8	years
	During the three months ended April 4, 2015, the effect of foreign currency translation decreased the gross carrying value of intangible assets and accumulated amortization for intangible assets by $42 million and $24 million, respectively. Amortization expense for intangible assets was $11 million and $12 million for the three months ended April 4, 2015 and March 29, 2014, respectively. Amortization expense for intangible assets is estimated to be approximately $44 million per year for each of the next five years.

Debt

Debt	3 Months Ended
	Apr. 04, 2015
Debt [Abstract]
Debt Disclosure	5  Debt
	In June 2013, the Company entered into a credit agreement (the “2013 Credit Agreement”) that provides for a $1.1 billion revolving facility and a $300 million term loan facility. The revolving facility and term loan facility both mature on June 25, 2018 and require no scheduled prepayments before that date.
	The interest rates applicable to the 2013 Credit Agreement are, at the Company's option, equal to either the alternate base rate calculated daily (which is a rate per annum equal to the greatest of (a) the prime rate in effect on such day, (b) the federal funds effective rate in effect on such day plus 1/2% per annum, or (c) the adjusted LIBO rate on such day (or if such day is not a business day, the immediately preceding business day) for a deposit in U.S. dollars with a maturity of one month plus 1% per annum) or the applicable 1, 2, 3 or 6 month adjusted LIBO rate, in each case, plus an interest rate margin based upon the Company's leverage ratio, which can range between 0 to 12.5 basis points for alternate base rate loans and between 75 basis points and 112.5 basis points for adjusted LIBO rate loans. The facility fee on the 2013 Credit Agreement ranges between 12.5 basis points and 25 basis points. The 2013 Credit Agreement requires that the Company comply with an interest coverage ratio test of not less than 3.50:1 as of the end of any fiscal quarter for any period of four consecutive fiscal quarters and a leverage ratio test of not more than 3.50:1 as of the end of any fiscal quarter. In addition, the 2013 Credit Agreement includes negative covenants, affirmative covenants, representations and warranties and events of default that are customary for investment grade credit facilities.
	As of April 4, 2015, $125 million of the outstanding portion of the revolving facility were classified as short-term liabilities in the consolidated balance sheet due to the fact that the Company expects to repay this portion of the borrowing under the revolving line of credit within the next twelve months. The remaining $560 million of the outstanding portion of the revolving facility were classified as long-term liabilities in the consolidated balance sheet, as this portion is not expected to be repaid within the next twelve months.
	As of April 4, 2015 and December 31, 2014, the Company had a total of $500 million and $600 million of outstanding senior unsecured notes, respectively. Interest on the fixed rate senior unsecured notes is payable semi-annually each year. Interest on the floating rate senior unsecured notes is payable quarterly. The Company may prepay all or some of the senior unsecured notes at any time in an amount not less than 10% of the aggregate principal amount outstanding, plus the applicable make-whole amount or prepayment premium for Series H senior unsecured notes. In the event of a change in control of the Company (as defined in the note purchase agreement), the Company may be required to prepay the senior unsecured notes at a price equal to 100% of the principal amount thereof, plus accrued and unpaid interest. These senior unsecured notes require that the Company comply with an interest coverage ratio test of not less than 3.50:1 for any period of four consecutive fiscal quarters and a leverage ratio test of not more than 3.50:1 as of the end of any fiscal quarter. In addition, these senior unsecured notes include customary negative covenants, affirmative covenants, representations and warranties and events of default.
	The Company had the following outstanding debt at April 4, 2015 and December 31, 2014 (in thousands):
			4-Apr-15		31-Dec-14
	Foreign subsidiary lines of credit		$	316	$	243
	Senior unsecured notes - Series A - 3.75%, due February 2015			-		100,000
	Senior unsecured notes - Series C - 2.50%, due March 2016			50,000		-
	2013 Credit Agreement			125,000		125,000
		Total notes payable and debt		175,316		225,243
	Senior unsecured notes - Series B - 5.00%, due February 2020			100,000		100,000
	Senior unsecured notes - Series C - 2.50%, due March 2016			-		50,000
	Senior unsecured notes - Series D - 3.22%, due March 2018			100,000		100,000
	Senior unsecured notes - Series E - 3.97%, due March 2021			50,000		50,000
	Senior unsecured notes - Series F - 3.40%, due June 2021			100,000		100,000
	Senior unsecured notes - Series G - 3.92%, due June 2024			50,000		50,000
	Senior unsecured notes - Series H - floating rate*, due June 2024			50,000		50,000
	2013 Credit Agreement			860,000		740,000
		Total long-term debt		1,310,000		1,240,000
	Total debt		$	1,485,316	$	1,465,243
	* Series H senior unsecured notes bear interest at 3 month LIBOR for that floating rate interest period plus 1.25%.
	As of April 4, 2015 and December 31, 2014, the Company had a total amount available to borrow of $413 million and $533 million, respectively, after outstanding letters of credit, under the 2013 Credit Agreement. The weighted-average interest rates applicable to the senior unsecured notes and 2013 Credit Agreement borrowings collectively were 2.09% and 2.31% at April 4, 2015 and December 31, 2014, respectively. As of April 4, 2015, the Company was in compliance with all debt covenants.
	The Company and its foreign subsidiaries also had available short-term lines of credit totaling $87 million and $88 million at April 4, 2015 and December 31, 2014, respectively, for the purpose of short-term borrowing and issuance of commercial guarantees. At April 4, 2015 and December 31, 2014, the weighted-average interest rates applicable to these short-term borrowings were 1.12% and 1.48%, respectively.
	On April 23, 2015, Waters entered into an amendment to the 2013 Credit Agreement. The amended credit agreement provides for an increase of the revolving commitments from $1.1 billion to $1.3 billion and extends the maturity of the original credit agreement from June 25, 2018 until April 23, 2020. The Company plans to use future proceeds from the revolving facility for general corporate purposes.

Income_Taxes

Income Taxes	3 Months Ended
	Apr. 04, 2015
Income Taxes [Abstract]
Income Taxes	6  Income Taxes
	The Company's effective tax rate was 15.3% and 15.0% for the three months ended April 4, 2015 and March 29, 2014, respectively. The Company accounts for its uncertain tax return reporting positions in accordance with the accounting standards for income taxes, which require financial statement reporting of the expected future tax consequences of uncertain tax reporting positions on the presumption that all concerned tax authorities possess full knowledge of those reporting positions, as well as all of the pertinent facts and circumstances, but prohibit any discounting of unrecognized tax benefits associated with those reporting positions for the time value of money.
	The following is a summary of the activity of the Company's unrecognized tax benefits for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
			4-Apr-15		29-Mar-14
	Balance at the beginning of the period		$	19,596	$	24,716
		Net changes in uncertain tax benefits		933		-812
	Balance at the end of the period		$	20,529	$	23,904
	With limited exceptions, the Company is no longer subject to tax audit examinations in significant jurisdictions for the years ended on or before December 31, 2007. However, carryforward attributes that were generated in years beginning on or before January 1, 2010 may still be adjusted upon examination by tax authorities if the attributes are utilized. The Company continuously monitors the lapsing of statutes of limitations on potential tax assessments for related changes in the measurement of unrecognized tax benefits, related net interest and penalties, and deferred tax assets and liabilities. As of April 4, 2015, the Company expects to record additional reductions in the measurement of its unrecognized tax benefits and related net interest and penalties of approximately $5 million within the next twelve months due to the lapsing of statutes of limitations on potential tax assessments. The Company does not expect to record any other material reductions in the measurement of its unrecognized tax benefits within the next twelve months.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Apr. 04, 2015
Stock-Based Compensation [Abstract]
Stock-Based Compensation	7  Stock-Based Compensation
	The Company maintains various shareholder-approved, stock-based compensation plans which allow for the issuance of incentive or non-qualified stock options, stock appreciation rights, restricted stock or other types of awards (e.g. restricted stock units).
	The Company accounts for stock-based compensation costs in accordance with the accounting standards for stock-based compensation, which require that all share-based payments to employees be recognized in the statements of operations based on their fair values. The Company recognizes the expense using the straight-line attribution method. The stock-based compensation expense recognized in the consolidated statements of operations is based on awards that ultimately are expected to vest; therefore, the amount of expense has been reduced for estimated forfeitures. The stock-based compensation accounting standards require forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures were estimated based on historical experience. If actual results differ significantly from these estimates, stock-based compensation expense and the Company's results of operations could be materially impacted. In addition, if the Company employs different assumptions in the application of these standards, the compensation expense that the Company records in the future periods may differ significantly from what the Company has recorded in the current period.
	The consolidated statements of operations for the three months ended April 4, 2015 and March 29, 2014 include the following stock-based compensation expense related to stock option awards, restricted stock, restricted stock unit awards and the employee stock purchase plan (in thousands):
				Three Months Ended
				4-Apr-15			29-Mar-14
	Cost of sales			$	674		$	756
	Selling and administrative expenses				6,634			6,435
	Research and development expenses				1,147			938
		Total stock-based compensation		$	8,455		$	8,129
	Stock Options
	In determining the fair value of the stock options, the Company makes a variety of assumptions and estimates, including volatility measures, expected yields and expected stock option lives. The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model. The Company uses implied volatility on its publicly-traded options as the basis for its estimate of expected volatility. The Company believes that implied volatility is the most appropriate indicator of expected volatility because it is generally reflective of historical volatility and expectations of how future volatility will differ from historical volatility. The expected life assumption for grants is based on historical experience for the population of non-qualified stock optionees. The risk-free interest rate is the yield currently available on U.S. Treasury zero-coupon issues with a remaining term approximating the expected term used as the input to the Black-Scholes model. The relevant data used to determine the value of the stock options granted during the three months ended April 4, 2015 and March 29, 2014 are as follows:
	Options Issued and Significant Assumptions Used to Estimate Option Fair Values		4-Apr-15		29-Mar-14
	Options issued in thousands		32		32
	Risk-free interest rate		1.60%		1.90%
	Expected life in years		4		4
	Expected volatility		0.267		0.245
	Expected dividends		-		-
	Weighted-Average Exercise Price and Fair Value of Options on the Date of Grant		4-Apr-15			29-Mar-14
	Exercise price		$	113.88		$	99.22
	Fair value		$	26.94		$	22.38
	The following table summarizes stock option activity for the plans for the three months ended April 4, 2015 (in thousands, except per share data):
					Number of Shares		Price per Share					Weighted-Average Exercise Price
	Outstanding at December 31, 2014				3,280		$	37.84	to	$	113.36	$	82.85
		Granted			32			$	113.88			$	113.88
		Exercised			-135		$	37.84	to	$	98.21	$	75.5
		Canceled			-72		$	79.05	to	$	87.06	$	83.25
	Outstanding at April 4, 2015				3,105		$	38.09	to	$	113.88	$	83.48
	Restricted Stock
	During the three months ended April 4, 2015, the Company granted ten thousand shares of restricted stock. The fair value of these awards on the grant date was $113.88 per share.
	Restricted Stock Units
	The following table summarizes the unvested restricted stock unit award activity for the three months ended April 4, 2015 (in thousands, except for per share amounts):
				Shares		Weighted-Average Price
	Unvested at December 31, 2014			533		$	94.38
		Granted		129		$	118.75
		Vested		-143		$	85.34
		Forfeited		-2		$	92.09
	Unvested at April 4, 2015			517		$	102.97
	Restricted stock units are generally granted annually in February and vest in equal annual installments over a five-year period.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Apr. 04, 2015
Earnings Per Share [Abstract]
Earnings Per Share	8  Earnings Per Share
	Basic and diluted earnings per share (“EPS”) calculations are detailed as follows (in thousands, except per share data):
			Three Months Ended April 4, 2015
			Net Income		Weighted-Average Shares	Per Share
			(Numerator)		(Denominator)	Amount
	Net income per basic common share		$	96,061	83,025	$	1.16
	Effect of dilutive stock option, restricted
		stock and restricted stock unit securities			727
	Net income per diluted common share		$	96,061	83,752	$	1.15
			Three Months Ended March 29, 2014
			Net Income		Weighted-Average Shares	Per Share
			(Numerator)		(Denominator)	Amount
	Net income per basic common share		$	70,302	84,977	$	0.83
	Effect of dilutive stock option, restricted
		stock and restricted stock unit securities			896
	Net income per diluted common share		$	70,302	85,873	$	0.82
	For both the three months ended April 4, 2015 and March 29, 2014, the Company had 0.6 million stock options that were antidilutive due to having higher exercise prices than the Company's average stock price during the period. These securities were not included in the computation of diluted EPS. The effect of dilutive securities was calculated using the treasury stock method.

Retirement_Plans

Retirement Plans	3 Months Ended
	Apr. 04, 2015
Retirement Plans [Abstract]
Retirement Plans	9  Retirement Plans
	The Company sponsors various retirement plans. The summary of the components of net periodic pension costs for the plans for the three months ended April 4, 2015 and March 29, 2014 is as follows (in thousands):
			Three Months Ended
			4-Apr-15						29-Mar-14
			U.S.		U.S. Retiree		Non-U.S.		U.S.		U.S. Retiree		Non-U.S.
			Pension		Healthcare		Pension		Pension		Healthcare		Pension
			Plans		Plan		Plans		Plans		Plan		Plans
	Service cost		$	-	$	262	$	1,337	$	-	$	199	$	1,212
	Interest cost			1,513		118		402		1,595		118		592
	Expected return on plan
		assets		-2,318		-122		-410		-2,308		-107		-392
	Net amortization:
		Prior service cost (credit)		-		-		14		-		-13		-47
		Net actuarial loss (gain)		679		-		273		485		-4		97
	Net periodic pension
		(benefit) cost	$	-126	$	258	$	1,616	$	-228	$	193	$	1,462
	During fiscal year 2015, the Company expects to contribute a total of approximately $4 million to $11 million to the Company's defined benefit plans.

Business_Segment_Information

Business Segment Information	3 Months Ended
	Apr. 04, 2015
Business Segment Information [Abstract]
Business Segment Information	10  Business Segment Information
	The Company's business activities, for which discrete financial information is available, are regularly reviewed and evaluated by the chief operating decision maker. As a result of this evaluation, the Company determined that it has two operating segments: Waters Division and TA Division.
	Waters Division is primarily in the business of designing, manufacturing, distributing and servicing LC and MS instruments, columns and other chemistry consumables that can be integrated and used along with other analytical instruments. TA Division is primarily in the business of designing, manufacturing, distributing and servicing thermal analysis, rheometry and calorimetry instruments. The Company's two divisions are its operating segments and each has similar economic characteristics; product processes; products and services; types and classes of customers; methods of distribution and regulatory environments. Because of these similarities, the two segments have been aggregated into one reporting segment for financial statement purposes. Please refer to the consolidated financial statements for financial information regarding the one reportable segment of the Company.
	Net sales for the Company's products and services are as follows for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
				Three Months Ended
				4-Apr-15		29-Mar-14
	Product net sales:
		Waters instrument systems		$	188,504	$	176,364
		Chemistry			78,183		75,203
		TA instrument systems			36,186		33,228
			Total product sales		302,873		284,795
	Service net sales:
		Waters service			142,981		132,042
		TA service			14,550		13,671
			Total service sales		157,531		145,713
	Total net sales			$	460,404	$	430,508

Recent_Accounting_Standard_Cha

Recent Accounting Standard Changes and Developments	3 Months Ended
	Apr. 04, 2015
Recent Accounting Standard Changes and Developments [Abstract]
Recent Accounting Standard Changes and Developments	11 Recent Accounting Standard Changes and Developments
	Recently Issued Accounting Standards
	In May 2014, amended accounting guidance was issued regarding the recognition of revenue from contracts with customers. The objective of this guidance is to significantly enhance comparability and clarify principles of revenue recognition practices across entities, industries, jurisdictions and capital markets. This guidance is effective for annual and interim reporting periods beginning after December 15, 2016; however, there is currently a proposal to delay the effective period by one year. Adoption prior to December 15, 2016 is not permitted. The Company is currently evaluating the potential impact that the adoption of this standard will have on the Company's financial position, results of operations or cash flows.
	In April 2015, accounting guidance was issued which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability. This guidance is effective for annual and interim reporting periods beginning after December 15, 2015 and early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of this standard will have on the Company's financial position, results of operations or cash flows.

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Apr. 04, 2015
Basis of Presentation and Summary of Significant Accounting Policies (Policies) [Abstract]
Nature of Operations	Waters Corporation (“Waters®” or the “Company”) is an analytical instrument manufacturer that primarily designs, manufactures, sells and services, through its Waters Division, high performance liquid chromatography (“HPLC”), ultra performance liquid chromatography (“UPLC®” and together with HPLC, referred to as “LC”) and mass spectrometry (“MS”) technology systems and support products, including chromatography columns, other consumable products and comprehensive post-warranty service plans. These systems are complementary products that are frequently employed together (“LC-MS”) and sold as integrated instrument systems using a common software platform. LC is a standard technique and is utilized in a broad range of industries to detect, identify, monitor and measure the chemical, physical and biological composition of materials, and to purify a full range of compounds. MS instruments are used in drug discovery and development, including clinical trial testing, the analysis of proteins in disease processes (known as “proteomics”), nutritional safety analysis and environmental testing. LC-MS instruments combine a liquid phase sample introduction and separation system with mass spectrometric compound identification and quantification. Through its TA Division (“TA®”), the Company primarily designs, manufactures, sells and services thermal analysis, rheometry and calorimetry instruments, which are used in predicting the suitability and stability of fine chemicals, pharmaceuticals, water, polymers and viscous liquids for various industrial, consumer goods and healthcare products, as well as for life science research. The Company is also a developer and supplier of software-based products that interface with the Company's instruments, as well as other suppliers' instruments, and are typically purchased by customers as part of the instrument system.
Fiscal Period Description	The Company's interim fiscal quarter typically ends on the thirteenth Saturday of each quarter. Since the Company's fiscal year end is December 31, the first and fourth fiscal quarters may have more or less than thirteen complete weeks. The Company's first fiscal quarters for 2015 and 2014 ended on April 4, 2015 and March 29, 2014, respectively.
Basis of Accounting	The accompanying unaudited interim consolidated financial statements have been prepared in accordance with the instructions to the Quarterly Report on Form 10-Q and do not include all of the information and note disclosures required by generally accepted accounting principles (“GAAP”) in the United States of America.
	It is management's opinion that the accompanying interim consolidated financial statements reflect all adjustments (which are normal and recurring) that are necessary for a fair statement of the results for the interim periods. The interim consolidated financial statements should be read in conjunction with the consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2014, as filed with the U.S. Securities and Exchange Commission on February 27, 2015.
Consolidation Policy	The consolidated financial statements include the accounts of the Company and its subsidiaries, most of which are wholly owned. All material inter-company balances and transactions have been eliminated.
Use of Estimates	The preparation of consolidated financial statements in conformity with 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 at the dates of the financial statements. Actual amounts may differ from these estimates under different assumptions or conditions.
Cash, Cash Equivalents and Investments Policy	Cash equivalents represent highly liquid investments, with original maturities of 90 days or less, while investments with longer maturities are classified as investments.
Fair Value Measurements Policy	Fair 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 April 4, 2015 and December 31, 2014. 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.
	Fair Value of Other Financial Instruments
	The Company's cash, accounts receivable, accounts payable and variable interest rate debt are recorded at cost, which approximates fair value.
Product Warranty Policy	Product 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 suppliers, 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.

Income_Taxes_Policies

Income Taxes (Policies)	3 Months Ended
	Apr. 04, 2015
Income Taxes [Abstract]
Uncertain Income Tax Reporting Positions Policy	The Company accounts for its uncertain tax return reporting positions in accordance with the accounting standards for income taxes, which require financial statement reporting of the expected future tax consequences of uncertain tax reporting positions on the presumption that all concerned tax authorities possess full knowledge of those reporting positions, as well as all of the pertinent facts and circumstances, but prohibit any discounting of unrecognized tax benefits associated with those reporting positions for the time value of money.

StockBased_Compensation_Polici

Stock-Based Compensation (Policies)	3 Months Ended
	Apr. 04, 2015
Stock-Based Compensation [Abstract]
Stock-Based Compensation Policy	The Company accounts for stock-based compensation costs in accordance with the accounting standards for stock-based compensation, which require that all share-based payments to employees be recognized in the statements of operations based on their fair values. The Company recognizes the expense using the straight-line attribution method. The stock-based compensation expense recognized in the consolidated statements of operations is based on awards that ultimately are expected to vest; therefore, the amount of expense has been reduced for estimated forfeitures. The stock-based compensation accounting standards require forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures were estimated based on historical experience. If actual results differ significantly from these estimates, stock-based compensation expense and the Company's results of operations could be materially impacted. In addition, if the Company employs different assumptions in the application of these standards, the compensation expense that the Company records in the future periods may differ significantly from what the Company has recorded in the current period.
	Stock Options
	In determining the fair value of the stock options, the Company makes a variety of assumptions and estimates, including volatility measures, expected yields and expected stock option lives. The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model. The Company uses implied volatility on its publicly-traded options as the basis for its estimate of expected volatility. The Company believes that implied volatility is the most appropriate indicator of expected volatility because it is generally reflective of historical volatility and expectations of how future volatility will differ from historical volatility. The expected life assumption for grants is based on historical experience for the population of non-qualified stock optionees. The risk-free interest rate is the yield currently available on U.S. Treasury zero-coupon issues with a remaining term approximating the expected term used as the input to the Black-Scholes model.

Earnings_Per_Share_Policies

Earnings Per Share (Policies)	3 Months Ended
	Apr. 04, 2015
Earnings Per Share [Abstract]
Earnings Per Share Policy	The effect of dilutive securities was calculated using the treasury stock method.

Recent_Accounting_Standard_Cha1

Recent Accounting Standard Changes and Developments (Policies)	3 Months Ended
	Apr. 04, 2015
Recent Accounting Standard Changes and Developments [Abstract]
New Accounting Pronouncements	11 Recent Accounting Standard Changes and Developments
	Recently Issued Accounting Standards
	In May 2014, amended accounting guidance was issued regarding the recognition of revenue from contracts with customers. The objective of this guidance is to significantly enhance comparability and clarify principles of revenue recognition practices across entities, industries, jurisdictions and capital markets. This guidance is effective for annual and interim reporting periods beginning after December 15, 2016; however, there is currently a proposal to delay the effective period by one year. Adoption prior to December 15, 2016 is not permitted. The Company is currently evaluating the potential impact that the adoption of this standard will have on the Company's financial position, results of operations or cash flows.
	In April 2015, accounting guidance was issued which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability. This guidance is effective for annual and interim reporting periods beginning after December 15, 2015 and early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of this standard will have on the Company's financial position, results of operations or cash flows.

Basis_of_Presentation_and_Sign

Basis of Presentation and Significant Accounting Policies (Tables)	3 Months Ended
	Apr. 04, 2015
Fair Value of Assets and Liabilities Measured on a Recurring Basis [Abstract]
Fair Value of Assets and Liabilities Measured on a Recurring Basis	The following table represents the Company's assets and liabilities measured at fair value on a recurring basis at April 4, 2015 (in thousands):
								Quoted Prices
								in Active			Significant
								Markets			Other			Significant
								for Identical			Observable			Unobservable
					Total at			Assets			Inputs			Inputs
					4-Apr-15			(Level 1)			(Level 2)			(Level 3)
	Assets:
		U.S. Treasury securities			$	641,693		$	-		$	641,693		$	-
		Foreign government securities				24,994			-			24,994			-
		Corporate debt securities				1,067,736			-			1,067,736			-
		Time deposits				64,265			-			64,265			-
		Equity securities				147			-			147			-
		Other cash equivalents				29,000			-			29,000			-
		Waters 401(k) Restoration Plan assets				35,678			-			35,678			-
		Foreign currency exchange contracts				445			-			445			-
			Total		$	1,863,958		$	-		$	1,863,958		$	-
	Liabilities:
		Contingent consideration			$	3,780		$	-		$	-		$	3,780
		Foreign currency exchange contracts				631			-			631			-
			Total		$	4,411		$	-		$	631		$	3,780
	The following table represents the Company's assets and liabilities measured at fair value on a recurring basis at December 31, 2014 (in thousands):
								Quoted Prices
								in Active			Significant
								Markets			Other			Significant
					Total at			for Identical			Observable			Unobservable
					December 31,			Assets			Inputs			Inputs
					2014			(Level 1)			(Level 2)			(Level 3)
	Assets:
		U.S. Treasury securities			$	626,772		$	-		$	626,772		$	-
		Foreign government securities				24,998			-			24,998			-
		Corporate debt securities				984,105			-			984,105			-
		Time deposits				64,240			-			64,240			-
		Equity securities				147			-			147			-
		Other cash equivalents				29,000			-			29,000			-
		Waters 401(k) Restoration Plan assets				33,935			-			33,935			-
		Foreign currency exchange contracts				123			-			123			-
			Total		$	1,763,320		$	-		$	1,763,320		$	-
	Liabilities:
		Contingent consideration			$	3,612		$	-		$	-		$	3,612
		Foreign currency exchange contracts				651			-			651			-
			Total		$	4,263		$	-		$	651		$	3,612
Summary of Derivative Instruments by Risk Exposure [Abstract]
Gains (Losses) on Foreign Currency Exchange Contracts	The following is a summary of the activity in cost of sales in the statements of operations related to the forward foreign exchange contracts (in thousands):
			Three Months Ended
			4-Apr-15			29-Mar-14
	Realized losses on closed contracts		$	-3,348		$	-314
	Unrealized gains (losses) on open contracts			342			-881
	Cumulative net pre-tax losses		$	-3,006		$	-1,195
Fair Value of Forward Foreign Exchange Contracts	The Company's foreign currency exchange contracts included in the consolidated balance sheets are classified as follows (in thousands):
				4-Apr-15			31-Dec-14
	Other current assets			$	445		$	123
	Other current liabilities			$	631		$	651
Warranty Accrual Roll Forward [Abstract]
Warranty Accrual Roll Forward	The following is a summary of the activity of the Company's accrued warranty liability for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
			Balance at									Balance at
			Beginning			Accruals for			Settlements			End of
			of Period			Warranties			Made			Period
	Accrued warranty liability:
	4-Apr-15		$	13,266		$	1,762		$	-2,157		$	12,871
	29-Mar-14		$	12,962		$	1,752		$	-1,919		$	12,795

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Apr. 04, 2015
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Schedule of Cash, Cash Equivalents and Short-term Investments	The Company's marketable securities within cash equivalents and investments included in the consolidated balance sheets are detailed as follows (in thousands):
			4-Apr-15
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gain		Loss		Value
	U.S. Treasury securities		$	640,441	$	1,270	$	-18	$	641,693
	Foreign government securities			24,994		-		-		24,994
	Corporate debt securities			1,066,695		1,171		-130		1,067,736
	Time deposits			64,265		-		-		64,265
	Equity securities			77		70		-		147
		Total	$	1,796,472	$	2,511	$	-148	$	1,798,835
	Amounts included in:
		Cash equivalents	$	130,588	$	-	$	-	$	130,588
		Investments		1,665,884		2,511		-148		1,668,247
		Total	$	1,796,472	$	2,511	$	-148	$	1,798,835
			31-Dec-14
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gain		Loss		Value
	U.S. Treasury securities		$	626,683	$	246	$	-157	$	626,772
	Foreign government securities			24,998		-		-		24,998
	Corporate debt securities			984,668		125		-688		984,105
	Time deposits			64,240		-		-		64,240
	Equity securities			77		70		-		147
		Total	$	1,700,666	$	441	$	-845	$	1,700,262
	Amounts included in:
		Cash equivalents	$	67,051	$	-	$	-	$	67,051
		Investments		1,633,615		441		-845		1,633,211
		Total	$	1,700,666	$	441	$	-845	$	1,700,262
Investments Classified by Contractual Maturity Date	The estimated fair value of marketable debt securities by maturity date is as follows (in thousands):
			4-Apr-15		31-Dec-14
	Due in one year or less		$	897,303	$	872,872
	Due after one year through three years			837,120		763,003
		Total	$	1,734,423	$	1,635,875

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Apr. 04, 2015
Inventory Items, Net Of Reserves Alternative [Abstract]
Inventory, Net of Reserves	Inventories are classified as follows (in thousands):
			4-Apr-15		31-Dec-14
	Raw materials		$	85,943	$	84,952
	Work in progress			19,513		16,749
	Finished goods			152,074		144,729
		Total inventories	$	257,530	$	246,430

Goodwill_and_Other_Intangibles1

Goodwill and Other Intangibles (Tables)	3 Months Ended
	Apr. 04, 2015
Goodwill and Other Intangibles [Abstract]
Schedule of Intangible Assets by Major Class	The Company's intangible assets included in the consolidated balance sheets are detailed as follows (in thousands):
			4-Apr-15						31-Dec-14
							Weighted-						Weighted-
			Gross				Average		Gross				Average
			Carrying		Accumulated		Amortization		Carrying		Accumulated		Amortization
			Amount		Amortization		Period		Amount		Amortization		Period
	Capitalized software			308,213		183,036	7	years		334,280		196,477	7	years
	Purchased intangibles		$	158,050	$	111,965	11	years	$	163,855	$	112,279	11	years
	Trademarks and IPR&D			13,857		-	-			14,095		-	-
	Licenses			5,390		3,620	6	years		5,371		3,634	6	years
	Patents and other
		intangibles		55,897		29,678	8	years		56,513		29,353	8	years
		Total	$	541,407	$	328,299	8	years	$	574,114	$	341,743	8	years

Debt_Tables

Debt (Tables)	3 Months Ended
	Apr. 04, 2015
Debt [Abstract]
Schedule of Outstanding Debt	The Company had the following outstanding debt at April 4, 2015 and December 31, 2014 (in thousands):
			4-Apr-15		31-Dec-14
	Foreign subsidiary lines of credit		$	316	$	243
	Senior unsecured notes - Series A - 3.75%, due February 2015			-		100,000
	Senior unsecured notes - Series C - 2.50%, due March 2016			50,000		-
	2013 Credit Agreement			125,000		125,000
		Total notes payable and debt		175,316		225,243
	Senior unsecured notes - Series B - 5.00%, due February 2020			100,000		100,000
	Senior unsecured notes - Series C - 2.50%, due March 2016			-		50,000
	Senior unsecured notes - Series D - 3.22%, due March 2018			100,000		100,000
	Senior unsecured notes - Series E - 3.97%, due March 2021			50,000		50,000
	Senior unsecured notes - Series F - 3.40%, due June 2021			100,000		100,000
	Senior unsecured notes - Series G - 3.92%, due June 2024			50,000		50,000
	Senior unsecured notes - Series H - floating rate*, due June 2024			50,000		50,000
	2013 Credit Agreement			860,000		740,000
		Total long-term debt		1,310,000		1,240,000
	Total debt		$	1,485,316	$	1,465,243
	* Series H senior unsecured notes bear interest at 3 month LIBOR for that floating rate interest period plus 1.25%.

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Apr. 04, 2015
Income Taxes [Abstract]
Unrecognized Tax Benefits Roll Forward	The following is a summary of the activity of the Company's unrecognized tax benefits for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
			4-Apr-15		29-Mar-14
	Balance at the beginning of the period		$	19,596	$	24,716
		Net changes in uncertain tax benefits		933		-812
	Balance at the end of the period		$	20,529	$	23,904

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Apr. 04, 2015
Stock-Based Compensation [Abstract]
Schedule of Stock-Based Compensation Expense	The consolidated statements of operations for the three months ended April 4, 2015 and March 29, 2014 include the following stock-based compensation expense related to stock option awards, restricted stock, restricted stock unit awards and the employee stock purchase plan (in thousands):
				Three Months Ended
				4-Apr-15			29-Mar-14
	Cost of sales			$	674		$	756
	Selling and administrative expenses				6,634			6,435
	Research and development expenses				1,147			938
		Total stock-based compensation		$	8,455		$	8,129
Relevant Data Used to Determine the Value of Stock Options Granted During the Period	The relevant data used to determine the value of the stock options granted during the three months ended April 4, 2015 and March 29, 2014 are as follows:
	Options Issued and Significant Assumptions Used to Estimate Option Fair Values		4-Apr-15		29-Mar-14
	Options issued in thousands		32		32
	Risk-free interest rate		1.60%		1.90%
	Expected life in years		4		4
	Expected volatility		0.267		0.245
	Expected dividends		-		-
	Weighted-Average Exercise Price and Fair Value of Options on the Date of Grant		4-Apr-15			29-Mar-14
	Exercise price		$	113.88		$	99.22
	Fair value		$	26.94		$	22.38
Stock Options Outstanding Roll Forward	The following table summarizes stock option activity for the plans for the three months ended April 4, 2015 (in thousands, except per share data):
					Number of Shares		Price per Share					Weighted-Average Exercise Price
	Outstanding at December 31, 2014				3,280		$	37.84	to	$	113.36	$	82.85
		Granted			32			$	113.88			$	113.88
		Exercised			-135		$	37.84	to	$	98.21	$	75.5
		Canceled			-72		$	79.05	to	$	87.06	$	83.25
	Outstanding at April 4, 2015				3,105		$	38.09	to	$	113.88	$	83.48
Restricted Stock Units Unvested Roll Forward	The following table summarizes the unvested restricted stock unit award activity for the three months ended April 4, 2015 (in thousands, except for per share amounts):
				Shares		Weighted-Average Price
	Unvested at December 31, 2014			533		$	94.38
		Granted		129		$	118.75
		Vested		-143		$	85.34
		Forfeited		-2		$	92.09
	Unvested at April 4, 2015			517		$	102.97

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Apr. 04, 2015
Earnings Per Share Reconciliation [Abstract]
Earnings Per Share Reconciliation	Basic and diluted earnings per share (“EPS”) calculations are detailed as follows (in thousands, except per share data):
			Three Months Ended April 4, 2015
			Net Income		Weighted-Average Shares	Per Share
			(Numerator)		(Denominator)	Amount
	Net income per basic common share		$	96,061	83,025	$	1.16
	Effect of dilutive stock option, restricted
		stock and restricted stock unit securities			727
	Net income per diluted common share		$	96,061	83,752	$	1.15
			Three Months Ended March 29, 2014
			Net Income		Weighted-Average Shares	Per Share
			(Numerator)		(Denominator)	Amount
	Net income per basic common share		$	70,302	84,977	$	0.83
	Effect of dilutive stock option, restricted
		stock and restricted stock unit securities			896
	Net income per diluted common share		$	70,302	85,873	$	0.82

Retirement_Plans_Tables

Retirement Plans (Tables)	3 Months Ended
	Apr. 04, 2015
Retirement Plans [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost	The summary of the components of net periodic pension costs for the plans for the three months ended April 4, 2015 and March 29, 2014 is as follows (in thousands):
			Three Months Ended
			4-Apr-15						29-Mar-14
			U.S.		U.S. Retiree		Non-U.S.		U.S.		U.S. Retiree		Non-U.S.
			Pension		Healthcare		Pension		Pension		Healthcare		Pension
			Plans		Plan		Plans		Plans		Plan		Plans
	Service cost		$	-	$	262	$	1,337	$	-	$	199	$	1,212
	Interest cost			1,513		118		402		1,595		118		592
	Expected return on plan
		assets		-2,318		-122		-410		-2,308		-107		-392
	Net amortization:
		Prior service cost (credit)		-		-		14		-		-13		-47
		Net actuarial loss (gain)		679		-		273		485		-4		97
	Net periodic pension
		(benefit) cost	$	-126	$	258	$	1,616	$	-228	$	193	$	1,462

Business_Segment_Information_T

Business Segment Information (Tables)	3 Months Ended
	Apr. 04, 2015
Business Segment Information [Abstract]
Revenue from External Customers by Products and Services	Net sales for the Company's products and services are as follows for the three months ended April 4, 2015 and March 29, 2014 (in thousands):
				Three Months Ended
				4-Apr-15		29-Mar-14
	Product net sales:
		Waters instrument systems		$	188,504	$	176,364
		Chemistry			78,183		75,203
		TA instrument systems			36,186		33,228
			Total product sales		302,873		284,795
	Service net sales:
		Waters service			142,981		132,042
		TA service			14,550		13,671
			Total service sales		157,531		145,713
	Total net sales			$	460,404	$	430,508

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		1 Months Ended	35 Months Ended
Share data in Millions, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014	31-May-14	Apr. 04, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional amount of foreign exchange contracts	$109,000,000			$109,000,000	$110,000,000
Cumulative net pre-tax losses on foreign exchange contracts	-3,006,000	-1,195,000
Realized losses on foreign exchange contracts	-3,348,000	-314,000
Unrealized gains (losses) on foreign exchange contracts	342,000	-881,000
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	1,798,835,000			1,798,835,000	1,700,262,000
Other cash equivalents	29,000,000			29,000,000	29,000,000
Waters 401(k) Restoration Plan assets	35,678,000			35,678,000	33,935,000
Forward foreign exchange contract assets	445,000			445,000	123,000
Fair value of total assets measured on a recurring basis	1,863,958,000			1,863,958,000	1,763,320,000
Contingent consideration	3,780,000			3,780,000	3,612,000
Forward foreign exchange contract liabilities	631,000			631,000	651,000
Fair value of total liabilities measured on a recurring basis	4,411,000			4,411,000	4,263,000
Cash Equivalents and Investments [Line Items]
Cash equivalents description	Cash equivalents represent highly liquid investments, with original maturities of 90 days or less, while investments with longer maturities are classified as investments.
Cash, cash equivalents and investments	2,109,000,000			2,109,000,000	2,055,000,000
Debt [Line Items]
Long-term debt	1,310,000,000			1,310,000,000	1,240,000,000
Warranty Accrual Roll Forward [Abstract]
Accrued warranty liability, balance at beginning of period	13,266,000	12,962,000
Accruals for warranties	1,762,000	1,752,000
Settlements made	-2,157,000	-1,919,000
Accrued warranty liability, balance at end of period	12,871,000	12,795,000		12,871,000
Programs authorized by Board of Directors [Member]
Stock Repurchase Program [Line Items]
Treasury stock shares acquired	0.7	0.8
Treasury stock	85,000,000	86,000,000
Stock repurchase program remaining amount authorized for future purchases	684,000,000			684,000,000
Related To Vesting Of Restricted Stock Units [Member]
Stock Repurchase Program [Line Items]
Treasury stock	6,000,000	7,000,000
May 2014 Program [Member]
Stock Repurchase Program [Line Items]
Stock repurchase program authorization amount			750,000,000
Stock repurchase program period, in years			3 years
May 2012 Program [Member]
Stock Repurchase Program [Line Items]
Treasury stock shares acquired				7.6
Treasury stock				750,000,000
Unsecured debt [Member]
Debt [Line Items]
Long-term debt	500,000,000			500,000,000	600,000,000
Fair value of debt instruments	515,000,000			515,000,000	608,000,000
Held by foreign subsidiaries [Member]
Cash Equivalents and Investments [Line Items]
Cash, cash equivalents and investments	2,067,000,000			2,067,000,000	1,971,000,000
US Treasury Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	641,693,000			641,693,000	626,772,000
Foreign Government Debt Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	24,994,000			24,994,000	24,998,000
Corporate Debt Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	1,067,736,000			1,067,736,000	984,105,000
Time Deposits
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	64,265,000			64,265,000	64,240,000
Equity Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	147,000			147,000	147,000
Significant Other Observable Inputs (Level 2)
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Other cash equivalents	29,000,000			29,000,000	29,000,000
Waters 401(k) Restoration Plan assets	35,678,000			35,678,000	33,935,000
Forward foreign exchange contract assets	445,000			445,000	123,000
Fair value of total assets measured on a recurring basis	1,863,958,000			1,863,958,000	1,763,320,000
Forward foreign exchange contract liabilities	631,000			631,000	651,000
Fair value of total liabilities measured on a recurring basis	631,000			631,000	651,000
Significant Other Observable Inputs (Level 2) | US Treasury Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	641,693,000			641,693,000	626,772,000
Significant Other Observable Inputs (Level 2) | Foreign Government Debt Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	24,994,000			24,994,000	24,998,000
Significant Other Observable Inputs (Level 2) | Corporate Debt Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	1,067,736,000			1,067,736,000	984,105,000
Significant Other Observable Inputs (Level 2) | Time Deposits
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	64,265,000			64,265,000	64,240,000
Significant Other Observable Inputs (Level 2) | Equity Securities
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents and Investments, Fair Value	147,000			147,000	147,000
Significant Unobservable Inputs (Level 3)
Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	3,780,000			3,780,000	3,612,000
Fair value of total liabilities measured on a recurring basis	$3,780,000			$3,780,000	$3,612,000

Marketable_Securities_Details

Marketable Securities (Details) (USD $)	Apr. 04, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Cash Equivalents and Investments [Line Items]
Amortized Cost	$1,796,472	$1,700,666
Unrealized Gain	2,511	441
Unrealized Loss	-148	-845
Fair Value	1,798,835	1,700,262
Debt securities due in one year or less	897,303	872,872
Debt securities due after one year through three years	837,120	763,003
Total debt securities	1,734,423	1,635,875
Cash Equivalents [Member]
Cash Equivalents and Investments [Line Items]
Amortized Cost	130,588	67,051
Fair Value	130,588	67,051
Investments [Member]
Cash Equivalents and Investments [Line Items]
Amortized Cost	1,665,884	1,633,615
Unrealized Gain	2,511	441
Unrealized Loss	-148	-845
Fair Value	1,668,247	1,633,211
US Treasury Securities
Cash Equivalents and Investments [Line Items]
Amortized Cost	640,441	626,683
Unrealized Gain	1,270	246
Unrealized Loss	-18	-157
Fair Value	641,693	626,772
Foreign Government Debt Securities
Cash Equivalents and Investments [Line Items]
Amortized Cost	24,994	24,998
Fair Value	24,994	24,998
Corporate Debt Securities
Cash Equivalents and Investments [Line Items]
Amortized Cost	1,066,695	984,668
Unrealized Gain	1,171	125
Unrealized Loss	-130	-688
Fair Value	1,067,736	984,105
Time Deposits
Cash Equivalents and Investments [Line Items]
Amortized Cost	64,265	64,240
Fair Value	64,265	64,240
Equity Securities
Cash Equivalents and Investments [Line Items]
Amortized Cost	77	77
Unrealized Gain	70	70
Fair Value	$147	$147

Inventories_Details

Inventories (Details) (USD $)	Apr. 04, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Inventory Items, Net Of Reserves Alternative [Abstract]
Raw materials	$85,943	$84,952
Work in progress	19,513	16,749
Finished goods	152,074	144,729
Total inventories	$257,530	$246,430

Goodwill_and_Other_Intangibles2

Goodwill and Other Intangibles (Details) (USD $)	3 Months Ended		12 Months Ended
	Apr. 04, 2015	Mar. 29, 2014	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$350,021,000		$354,838,000
Goodwill foreign currency translation adjustments	-5,000,000
Intangible Assets [Line Items]
Intangible assets, gross	541,407,000		574,114,000
Intangible assets, accumulated amortization	328,299,000		341,743,000
Weighted-average useful life of acquired intangible assets	8 years		8 years
Intangible assets, gross foreign currency translation adjustments	-42,000,000
Intangible assets, accumulated amortization foreign currency translation adjustments	-24,000,000
Amortization expense	11,000,000	12,000,000
Future amortization expense, year 1	44,000,000
Future amortization expense, year 2	44,000,000
Future amortization expense, year 3	44,000,000
Future amortization expense, year 4	44,000,000
Future amortization expense, year 5	44,000,000
Capitalized software [Member]
Intangible Assets [Line Items]
Intangible assets, gross	308,213,000		334,280,000
Intangible assets, accumulated amortization	183,036,000		196,477,000
Weighted-average useful life of acquired intangible assets	7 years		7 years
Purchased intangibles [Member]
Intangible Assets [Line Items]
Intangible assets, gross	158,050,000		163,855,000
Intangible assets, accumulated amortization	111,965,000		112,279,000
Weighted-average useful life of acquired intangible assets	11 years		11 years
Trademarks and IPR&D[Member]
Intangible Assets [Line Items]
Intangible assets, gross	13,857,000		14,095,000
Licenses [Member]
Intangible Assets [Line Items]
Intangible assets, gross	5,390,000		5,371,000
Intangible assets, accumulated amortization	3,620,000		3,634,000
Weighted-average useful life of acquired intangible assets	6 years		6 years
Patents and other intangibles [Member]
Intangible Assets [Line Items]
Intangible assets, gross	55,897,000		56,513,000
Intangible assets, accumulated amortization	$29,678,000		$29,353,000
Weighted-average useful life of acquired intangible assets	8 years		8 years

Debt_Details

Debt (Details) (USD $)	3 Months Ended
	Apr. 04, 2015	Apr. 23, 2015	Dec. 31, 2014	Jun. 30, 2013
Debt [Line Items]
Face value of debt		$1,300,000,000
Notes payable and debt	175,316,000		225,243,000
Long-term debt	1,310,000,000		1,240,000,000
Total debt	1,485,316,000		1,465,243,000
Senior unsecured notes - Series A [Member]
Debt [Line Items]
Stated interest rate on debt instrument	3.75%
Notes payable and debt			100,000,000
Senior unsecured notes - Series B [Member]
Debt [Line Items]
Stated interest rate on debt instrument	5.00%
Long-term debt	100,000,000		100,000,000
Senior unsecured notes - Series C [Member]
Debt [Line Items]
Stated interest rate on debt instrument	2.50%
Notes payable and debt	50,000,000
Long-term debt			50,000,000
Senior unsecured notes - Series D [Member]
Debt [Line Items]
Stated interest rate on debt instrument	3.22%
Long-term debt	100,000,000		100,000,000
Senior unsecured notes - Series E [Member]
Debt [Line Items]
Stated interest rate on debt instrument	3.97%
Long-term debt	50,000,000		50,000,000
Senior unsecured notes - Series F [Member]
Debt [Line Items]
Stated interest rate on debt instrument	3.40%
Long-term debt	100,000,000		100,000,000
Senior Unsecured Notes - Series G [Member]
Debt [Line Items]
Stated interest rate on debt instrument	3.92%
Long-term debt	50,000,000		50,000,000
Senior Unsecured Note - Series H [Member]
Debt [Line Items]
Interest rate terms on debt	* Series H senior unsecured notes bear interest at 3 month LIBOR for that floating rate interest period plus 1.25%.
Long-term debt	50,000,000		50,000,000
Foreign subsidiary lines of credit [Member]
Debt [Line Items]
Notes payable and debt	316,000		243,000
Weighted-average interest rate	1.12%		1.48%
Line of credit maximum borrowing capacity	87,000,000		88,000,000
Unsecured debt [Member]
Debt [Line Items]
Call feature on debt instrument	The Company may prepay all or some of the senior unsecured notes at any time in an amount not less than 10% of the aggregate principal amount outstanding, plus the applicable make-whole amount or prepayment premium for Series H senior unsecured notes. In the event of a change in control of the Company (as defined in the note purchase agreement), the Company may be required to prepay the senior unsecured notes at a price equal to 100% of the principal amount thereof, plus accrued and unpaid interest.
Debt covenant description	These senior unsecured notes require that the Company comply with an interest coverage ratio test of not less than 3.50:1 for any period of four consecutive fiscal quarters and a leverage ratio test of not more than 3.50:1 as of the end of any fiscal quarter.
Long-term debt	500,000,000		600,000,000
Credit Agreement dated June 2013 [Member]
Debt [Line Items]
Interest rate terms on debt	The interest rates applicable to the 2013 Credit Agreement are, at the Company’s option, equal to either the alternate base rate calculated daily (which is a rate per annum equal to the greatest of (a) the prime rate in effect on such day, (b) the federal funds effective rate in effect on such day plus 1/2% per annum, or (c) the adjusted LIBO rate on such day (or if such day is not a business day, the immediately preceding business day) for a deposit in U.S. dollars with a maturity of one month plus 1% per annum) or the applicable 1, 2, 3 or 6 month adjusted LIBO rate, in each case, plus an interest rate margin based upon the Company’s leverage ratio, which can range between 0 to 12.5 basis points for alternate base rate loans and between 75 basis points and 112.5 basis points for adjusted LIBO rate loans.
Debt facility fee	The facility fee on the 2013 Credit Agreement ranges between 12.5 basis points and 25 basis points.
Debt covenant description	The 2013 Credit Agreement requires that the Company comply with an interest coverage ratio test of not less than 3.50:1 as of the end of any fiscal quarter for any period of four consecutive fiscal quarters and a leverage ratio test of not more than 3.50:1 as of the end of any fiscal quarter.
Notes payable and debt	125,000,000		125,000,000
Long-term debt	860,000,000		740,000,000
Unused borrowing capacity	413,000,000		533,000,000
Credit Agreement dated June 2013 [Member] | Term loan facility [Member]
Debt [Line Items]
Face value of debt				300,000,000
Credit Agreement dated June 2013 [Member] | Revolving facilities [Member]
Debt [Line Items]
Face value of debt				1,100,000,000
Notes payable and debt	125,000,000
Long-term debt	$560,000,000
Credit Agreement dated July 2013 and unsecured debt [Member]
Debt [Line Items]
Weighted-average interest rate	2.09%		2.31%

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
	Apr. 04, 2015	Mar. 29, 2014
Income Tax Contingency [Line Items]
Unrecognized tax benefits, balance at the beginning of the period	$19,596,000	$24,716,000
Other changes in uncertain tax benefits	933,000	-812,000
Unrecognized tax benefits, balance at the end of the period	20,529,000	23,904,000
Expected change in unrecognized tax benefits in the next twelve months	($5,000,000)
Income Taxes [Line Items]
Effective income tax rate	15.30%	15.00%

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	3 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Stock-Based Compensation Allocation of Recognized Period Expense [Line Items]
Allocated stock-based compensation expense	$8,455,000	$8,129,000
Stock Options Outstanding Roll Forward [Line Items]
Options outstanding at beginning of period	3,280
Options granted	32	32
Options exercised	-135
Options canceled	-72
Options outstanding at end of period	3,105
Weighted-average exercise price of options outstanding at beginning of period	$82.85
Weighted-average exercise price of options granted	$113.88	$99.22
Weighted-average exercise price of options exercised	$75.50
Weighted average exercise price of options canceled	$83.25
Weighted-average exercise price of options outstanding at end of period	$83.48
Stock Option Fair Value Assumptions and Methodology [Abstract]
Stock option fair value assumptions, risk free interest rate	1.60%	1.90%
Stock option fair value assumptions, expected life in years	4 years	4 years
Stock option fair value assumptions, expected volatility	26.70%	24.50%
Stock option fair value assumptions, expected dividends	0	0
Weighted-average grant date fair value of options granted	$26.94	$22.38
Minimum
Stock Options Outstanding Roll Forward [Line Items]
Weighted-average exercise price of options outstanding at beginning of period	$37.84
Weighted-average exercise price of options exercised	$37.84
Weighted average exercise price of options canceled	$79.05
Weighted-average exercise price of options outstanding at end of period	$38.09
Maximum
Stock Options Outstanding Roll Forward [Line Items]
Weighted-average exercise price of options outstanding at beginning of period	$113.36
Weighted-average exercise price of options exercised	$98.21
Weighted average exercise price of options canceled	$87.06
Weighted-average exercise price of options outstanding at end of period	$113.88
Restricted Stock Plan [Member]
Stock-Based Compensation by Award [Line Items]
Shares granted	10
Weighted-average grant date fair value of shares granted	$113.88
Restricted Stock Unit Plan [Member]
Stock-Based Compensation by Award [Line Items]
Unvested shares at beginning of period	533
Shares granted	129
Shares vested	-143
Shares forfeited	-2
Unvested shares at end of period	517
Weighted-average grant date fair value of shares unvested at beginning of period	$94.38
Weighted-average grant date fair value of shares granted	$118.75
Weighted-average grant date fair value of shares vested	$85.34
Weighted-average grant date fair value of shares forfeited	$92.09
Weighted-average grant date fair value of shares unvested at end of period	$102.97
Award vesting period	5 years
Cost of sales [Member]
Stock-Based Compensation Allocation of Recognized Period Expense [Line Items]
Allocated stock-based compensation expense	674,000	756,000
Selling and administrative expenses [Member]
Stock-Based Compensation Allocation of Recognized Period Expense [Line Items]
Allocated stock-based compensation expense	6,634,000	6,435,000
Research and development expenses [Member]
Stock-Based Compensation Allocation of Recognized Period Expense [Line Items]
Allocated stock-based compensation expense	$1,147,000	$938,000

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	600,000	600,000
Earnings Per Share Reconciliation [Abstract]
Net income	$96,061	$70,302
Net income per basic common share	$1.16	$0.83
Net income per diluted common share	$1.15	$0.82
Weighted-average number of basic common shares	83,025,000	84,977,000
Effect of dilutive stock option, restricted stock and restricted stock unit securities	727,000	896,000
Weighted-average number of diluted common shares and equivalents	83,752,000	85,873,000

Retirement_Plans_Details

Retirement Plans (Details) (USD $)	3 Months Ended
	Apr. 04, 2015	Mar. 29, 2014
Minimum
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions to defined benefit plans in current fiscal year	$4,000,000
Maximum
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions to defined benefit plans in current fiscal year	11,000,000
U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1,513,000	1,595,000
Expected return on plan assets	-2,318,000	-2,308,000
Net amortization: Net actuarial loss (gain)	679,000	485,000
Net periodic pension (benefit) cost	-126,000	-228,000
U.S. Retiree Healthcare Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	262,000	199,000
Interest cost	118,000	118,000
Expected return on plan assets	-122,000	-107,000
Net amortization: Prior service cost (credit)		-13,000
Net amortization: Net actuarial loss (gain)		-4,000
Net periodic pension (benefit) cost	258,000	193,000
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,337,000	1,212,000
Interest cost	402,000	592,000
Expected return on plan assets	-410,000	-392,000
Net amortization: Prior service cost (credit)	14,000	-47,000
Net amortization: Net actuarial loss (gain)	273,000	97,000
Net periodic pension (benefit) cost	$1,616,000	$1,462,000

Business_Segment_Information_D

Business Segment Information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Apr. 04, 2015	Mar. 29, 2014
Entity-Wide Revenue from External Customers [Line Items]
Number of operating segments	2
Number of reportable segments	1
Product sales	$302,873	$284,795
Service sales	157,531	145,713
Total net sales	460,404	430,508
Waters instrument systems [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	188,504	176,364
Chemistry [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	78,183	75,203
TA instrument systems [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	36,186	33,228
Waters service [Member]
Entity-Wide Revenue from External Customers [Line Items]
Service sales	142,981	132,042
TA service [Member]
Entity-Wide Revenue from External Customers [Line Items]
Service sales	$14,550	$13,671