IDEXX Laboratories (IDXX) 10-K 16 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 06, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Registrant Name	IDEXX LABORATORIES INC /DE
Entity Central Index Key	874,716
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		87,122,794
Entity Public Float			$ 14,011,555,111
Trading Symbol	idxx

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 187,675	$ 154,901
Marketable securities	284,255	236,949
Accounts receivable, net of reserves of $4,576 in 2017 and $4,523 in 2016	234,597	204,494
Inventories	164,318	158,034
Other current assets	101,140	91,206
Total current assets	971,985	845,584
Long-Term Assets:
Property and equipment, net	379,096	357,422
Goodwill	199,873	178,228
Intangible assets, net	43,846	46,155
Other long-term assets	118,616	103,315
Total long-term assets	741,431	685,120
TOTAL ASSETS	1,713,416	1,530,704
Current Liabilities:
Accounts payable	66,968	60,057
Accrued liabilities	253,418	236,131
Line of credit	655,000	611,000
Current portion of deferred revenue	29,181	27,380
Total current liabilities	1,004,567	934,568
Long-Term Liabilities:
Deferred income tax liabilities	25,353	39,287
Long-term debt	606,075	593,110
Long-term deferred revenue, net of current portion	35,545	33,015
Other long-term liabilities	95,718	38,937
Total long-term liabilities	762,691	704,349
Total liabilities	1,767,258	1,638,917
Commitments and Contingencies (Note 14)
Stockholders’ Equity (Deficit):
Common stock, $0.10 par value: Authorized: 120,000 shares; Issued: 104,275 shares in 2017 and 103,341 shares in 2016	10,428	10,334
Additional paid-in capital	1,073,931	1,011,895
Deferred stock units: Outstanding: 229 units in 2017 and 231 units in 2016	5,988	5,514
Retained earnings	803,545	540,401
Accumulated other comprehensive loss	(36,470)	(43,053)
Treasury stock, at cost: 17,171 shares in 2017 and 15,367 shares in 2016	(1,911,528)	(1,633,443)
Total IDEXX Laboratories, Inc. stockholders’ equity (deficit)	(54,106)	(108,352)
Noncontrolling interest	264	139
Total stockholders’ equity (deficit)	(53,842)	(108,213)
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)	$ 1,713,416	$ 1,530,704

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets [Abstract]
Accounts receivable, reserves	$ 4,576	$ 4,523
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	104,275,000	103,341,000
Deferred stock units, outstanding	229,000	231,000
Treasury stock, shares	17,171,000	15,367,000

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Product revenue	$ 1,176,115	$ 1,070,973	$ 974,933
Service revenue	792,943	704,450	626,959
Total revenue	1,969,058	1,775,423	1,601,892
Cost of Revenue:
Cost of product revenue	446,449	416,810	360,208
Cost of service revenue	425,227	383,177	351,414
Total cost of revenue	871,676	799,987	711,622
Gross profit	1,097,382	975,436	890,270
Expenses:
Sales and marketing	354,294	317,058	299,955
General and administrative	220,878	207,017	182,510
Research and development	109,182	101,122	99,681
Impairment charge			8,212
Income from operations	413,028	350,239	299,912
Interest expense	(37,225)	(32,049)	(29,239)
Interest income	5,254	3,656	2,468
Income before provision for income taxes	381,057	321,846	273,141
Provision for income taxes	117,788	99,792	81,006
Net income	263,269	222,054	192,135
Less: Net income attributable to noncontrolling interest	125	9	57
Net income attributable to IDEXX Laboratories, Inc. stockholders	$ 263,144	$ 222,045	$ 192,078
Earnings per Share:
Basic	$ 3	$ 2.47	$ 2.07
Diluted	$ 2.94	$ 2.44	$ 2.05
Weighted Average Shares Outstanding:
Basic	87,769	89,732	92,601
Diluted	89,567	90,884	93,649

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 263,269	$ 222,054	$ 192,135
Other comprehensive income, net of tax:
Foreign currency translation adjustments	25,107	(5,874)	(30,718)
Unrealized gain (loss) on net investment hedge	(8,347)	2,142	1,894
Unrealized gain (loss) on investments, net of tax expense (benefit) of $- in 2017, $113 in 2016 and ($93) in 2015	(42)	245	(226)
Unrealized gain (loss) on derivative instruments:
Unrealized (loss) gain, net of tax (benefit) expense of ($5,304) in 2017, $2,174 in 2016 and $3,736 in 2015	(10,332)	4,950	8,839
Less: reclassification adjustment for losses (gains) included in net income, net of tax expense of $224 in 2017, $949 in 2016 and $5,853 in 2015	197	(2,251)	(13,983)
Unrealized gain (loss) on derivative instruments	(10,135)	2,699	(5,143)
Other comprehensive income (loss), net of tax	6,583	(788)	(34,194)
Comprehensive income	269,852	221,266	157,941
Less: comprehensive income attributable to noncontrolling interest	125	9	57
Comprehensive income attributable to IDEXX Laboratories, Inc.	$ 269,727	$ 221,257	$ 157,884

Consolidated Statements Of Com6

Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements Of Comprehensive Income [Abstract]
Unrealized gain (loss) on investments, tax expense (benefit)		$ 113	$ (93)
Unrealized (loss) gain, net of tax (benefit) expense	$ (5,304)	2,174	3,736
Reclassification adjustment for gains included in net income, tax expense	$ 224	$ 949	$ 5,853

Consolidated Statements Of Stoc

Consolidated Statements Of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Deferred Stock Units [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Total
Balance, value at Dec. 31, 2014	$ 10,195	$ 888,293	$ 5,066	$ 1,675,299	$ (8,071)	$ (2,453,266)	$ 73	$ 117,589
Balance, shares at Dec. 31, 2014	101,947
Net income (loss)				192,078			57	192,135
Other comprehensive loss, net					(34,194)			(34,194)
Repurchases of common stock						(412,172)		(412,172)
Stock split enacted through stock dividend				(1,518,264)		1,518,264
Shares retired, value				(30,757)		30,757
Shares retired, shares	(346)
Common stock issued under stock plans, including excess tax benefit, value	$ 63	32,700						32,763
Common stock issued under stock plans, including excess tax benefit, shares	636
Deferred stock units activity		(258)	258
Share-based compensation cost		19,799	85					19,884
Balance, value at Dec. 31, 2015	$ 10,258	940,534	5,409	318,356	(42,265)	(1,316,417)	130	(83,995)
Balance, shares at Dec. 31, 2015	102,237
Net income (loss)				222,045			9	222,054
Other comprehensive loss, net					(788)			(788)
Repurchases of common stock						(317,026)		(317,026)
Common stock issued under stock plans, including excess tax benefit, value	$ 76	51,904						51,980
Common stock issued under stock plans, including excess tax benefit, shares	1,104
Deferred stock units activity		(343)	14					(329)
Share-based compensation cost		19,800	91					19,891
Balance, value at Dec. 31, 2016	$ 10,334	1,011,895	5,514	540,401	(43,053)	(1,633,443)	139	$ (108,213)
Balance, shares at Dec. 31, 2016	103,341							103,341
Net income (loss)				263,144			125	$ 263,269
Other comprehensive loss, net					6,583			6,583
Repurchases of common stock						(278,085)		(278,085)
Common stock issued under stock plans, including excess tax benefit, value	$ 94	39,005						39,099
Common stock issued under stock plans, including excess tax benefit, shares	934
Deferred stock units activity		(350)	338					(12)
Share-based compensation cost		23,381	136					23,517
Balance, value at Dec. 31, 2017	$ 10,428	$ 1,073,931	$ 5,988	$ 803,545	$ (36,470)	$ (1,911,528)	$ 264	$ (53,842)
Balance, shares at Dec. 31, 2017	104,275							104,275

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income	$ 263,269	$ 222,054	$ 192,135
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	83,140	78,218	68,956
Amortization on marketable securities, net	38	843	1,432
Impairment charge		2,228	8,212
Provision for uncollectible accounts	1,881	1,170	2,200
Provision for deferred income taxes	(7,918)	20,881	5,143
Share-based compensation expense	23,517	19,891	19,884
Other	969	986	(472)
Tax benefit from share-based compensation arrangements		(14,702)	(11,315)
Changes in assets and liabilities:
Accounts receivable	(24,918)	(22,554)	(50,142)
Inventories	(19,062)	7,648	(34,969)
Accounts payable	1,391	2,117	(2,468)
Deferred revenue	3,551	7,672	(319)
Other assets and liabilities	47,418	12,491	23,525
Net cash provided by operating activities	373,276	338,943	221,802
Cash Flows from Investing Activities:
Purchases of property and equipment	(74,384)	(64,787)	(82,921)
Purchases of marketable securities	(334,164)	(227,894)	(271,958)
Proceeds from the sale and maturities of marketable securities	286,759	203,859	56,775
Acquisitions of intangible assets	(2,320)
Acquisitions of a businesses, net of cash acquired	(14,579)	(1,964)	(10,302)
Net cash used by investing activities	(138,688)	(90,786)	(308,406)
Cash Flows from Financing Activities:
Borrowings on revolving credit facilities, net	44,000	38,000	24,000
Issuance of senior notes			250,097
Debt issue costs		(56)	(1,380)
Repurchases of common stock	(282,565)	(304,086)	(401,981)
Proceeds from exercises of stock options and employee stock purchase plans	38,622	38,344	22,397
Payment of acquisition-related contingent consideration		(4,728)
Shares withheld for statutory tax withholding on restricted stock (Note 2)	(8,073)	(4,372)	(5,438)
Tax benefit from share-based compensation arrangements		14,702	11,315
Net cash used by financing activities	(208,016)	(222,196)	(100,990)
Net effect of changes in exchange rates on cash	6,202	(54)	(5,948)
Net increase (decrease) in cash and cash equivalents	32,774	25,907	(193,542)
Cash and cash equivalents at beginning of period	154,901	128,994	322,536
Cash and cash equivalents at end of period	$ 187,675	$ 154,901	$ 128,994

Nature Of Business, Basis Of Pr

Nature Of Business, Basis Of Presentation And Principles Of Consolidation	12 Months Ended
	Dec. 31, 2017
Nature Of Business, Basis Of Presentation And Principles Of Consolidation [Abstract]
Nature Of Business, Basis Of Presentation And Principles Of Consolidation	NOTE 1. NATURE OF BUSINESS, BASIS OF PRESENTATION AND PRINCIPLES OF CONSOLIDATION  The accompanying consolidated financial statements of IDEXX Laboratories, Inc. have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and with the requirements of Regulation S-X.  These statements include the accounts of IDEXX Laboratories, Inc. and our wholly-owned and majority-owned subsidiaries (“IDEXX,” the “Company,” “we” or “our”). We do not have any variable interest entities for which we are the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation.  We have included certain terms and abbreviations used throughout this Annual Report on Form 10-K in the " Glossary of Terms and Selected Abbreviations.”  We develop, manufacture , and distribute products and provide services for the veterinary, bioresearch, water, livestock, poultry , and dairy markets. We also sell a line of portable electrolytes and blood gas analyzers for the human point-of-care medical diagnostics market. Our principal line of business, which we refer to as our Companion Animal Group (“CAG”) operating segment, provides diagnosti c capabilities and information management solutions for the veterinary market as well as biological materials testing and services for the bioresearch market. Our principal markets for these products and services are the United States (“U.S.”), Europe , Japan, and Australia , but we also sell to customers and distributors in many other countries around the world. Ou r Water operating segment provides innovative testing solutions for the quality and safety of water in our principal markets of the U.S. and Europe, but we also sell to customers in many other countries around the world. Our Livestock, Poultry and Dairy (“LPD”) operating segment provides diagnostic tests and related instrumentation and performs services that are used to manage the health status of livestock and poultry, to improve bovine reproductive efficiency, and to ensure the quality and safety of milk and food. Our principal market s for these products and services are Europe, China, and Australia but we also sell to customers in many other countries around the world. We also operate a smaller operating segment that comprises products for the human point-of-care medical diagnostics market (“OPTI Medical”). Financial information about our OPTI Medical operating segment is combined and presented with our pharmaceutical and out-licensing arrangements remaining from our pharmaceutical business in an “Other” category because they do not meet the quantitative or qualitative thresholds for reportable segments. See Note 15 for additional information regarding our reportable operating segments, products and services and geographical areas.  Stock Split  On May 6, 2015, we announced a two -for-one split of our outstanding shares of common stock which was effected through a stock dividend that was paid through the issuance of treasury shares. The stock split entitled each stockholder of record at the close of business on May 18, 2015 to receive one additional share of common stock for each outstanding share of common stock held. The additional shares of our common stock paid pursuant to the stock split were distributed by our transfer agent on June 15, 2015. All share and per share amounts in the consolidated balance sheets, consolidated statement of operations and notes to the consolidated financial statements retroactively reflect the effect of the stock split unless otherwise noted. 

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Summary Of Significant Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	 NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES  (a) Estimates  The preparation of these consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures. On an ongoing basis, we evaluate these estimates, including those related to reserves for accounts receivable; goodwill and other intangible assets; income taxes; inventory valuation; revenue recognition, product returns, customer programs and multiple element arrangements; share-based compensation; warranty reserves; self-insurance reserves; fair value measurements and loss contingencies. We accrue contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates.  ( b ) Cash and Cash Equivalents  We consider all highly liquid investments with original maturities of ninety days or less to be cash equivalents. Cash and cash equivalents consist primarily of demand deposits, money market funds and short duration agency bonds and commercial paper as described above. There is no restricted cash on our consolidated balance sheet for the years ended December 31, 2017 and 2016.  (c) Marketable Securities – See Note 5  (d) Inventories – See Note 6  (e) Property and Equipment – See Note 7  (f) Goodwill and Other Intangible Assets – See Note 9  ( g) Warranty Reserves  We provide a standard twelve-month warranty on all instruments sold. We recognize the cost of instrument warranties in cost of product revenue at the time revenue is recognized based on the estimated cost to repair the instrument over its warranty period. Cost of product revenue reflects not only estimated warranty expense for instruments sold in the current period, but also any changes in estimated warranty expense for the portion of the aggregate installed base that is under warranty. Estimated warranty expense is based on a variety of inputs, including historical instrument performance in the customers’ environment, historical and estimated costs incurred in servicing instruments and projected instrument reliability. Should actual service rates or costs differ from our estimates, revisions to the estimated warranty liability would be required. The liability for warranties is included in accrued liabilities in the accompanying consolidated balance sheets.  ( h ) Income Taxes – See Note 12  (i) Taxes Remitted to Governmental Authorities by IDEXX on Behalf of Customer  We calculate, collect from our customers, and remit to governmental authorities sales, value-added and excise taxes assessed by governmental authorities in connection with revenue-producing transactions with our customers. We report these taxes on a net basis and do not include these tax amounts in revenue or cost of product or service revenue.  (j) Revenue Recognition  We recognize revenue when four criteria are met: (i) persuasive evidence of an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured. Revenue generating transactions generally fall into one of the following categories of revenue recognition:  · We recognize revenue from the sales of consumables, rapid assay test kits and other diagnostic products when the product is delivered to the customer, except as noted below. · We recognize revenue from the sales of instruments, non-cancelable software licenses and hardware systems upon installation and the customer’s acceptance of the instrument or system as we have no significant further obligations after this point in time. · We recognize service revenue at the time the service is performed. · We recognize revenue associated with extended maintenance agreements (“EMAs”) and our software-as-a-service subscriptions over the life of the contracts using the straight-line method, which approximates the expected timing in which applicable services are performed. Amounts collected in advance of revenue recognition are recorded as current or long-term deferred revenue based on the time from the balance sheet date to the future date of revenue recognition. · We recognize revenue on certain instrument systems under rental programs over the life of the rental agreement using the straight-line method. Amounts collected in advance of revenue recognition are recorded as current or long-term deferred revenue based on the time from the balance sheet date to the future date of revenue recognition. · We recognize revenue on practice management systems sales, where the system includes software that is considered more than incidental, either by allocating the revenue to each element of the sale based on relative fair values of the elements, including post-contract support when fair value for all elements is available, or by use of the residual method when only the fair value of the post-contract support is available. We recognize revenue for the system upon installation and customer acceptance and recognize revenue equal to the fair value of the post-contract support over the support period. · Shipping costs reimbursed by the customer are included in revenue. These same costs are also included in cost of product revenue.  Multiple Element Arrangements (“MEAs”) . Arrangements to sell products to customers frequently include multiple deliverables. Our most significant MEAs include the sale of one or more of the instruments from the IDEXX VetLab suite of analyzers, diagnostic imaging systems or practice management software, combined with one or more of the following products: EMAs, consumables, rapid assay kits and reference laboratory diagnostic and consulting services. Practice management software is frequently sold with post-contract customer support and implementation services. Delivery of the various products or performance of services within the arrangement may or may not coincide. Delivery of our IDEXX VetLab instruments, diagnostic imaging systems, and practice management software generally occurs at the onset of the arrangement. EMAs, consumables, rapid assay kits, and reference laboratory diagnostic and consulting services typically are delivered over future periods, generally one to six years . In certain arrangements, revenue recognized is limited to the amount invoiced or received that is not contingent on the delivery of products and services in the future.  W e allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition, as discussed above, have been met for each element. If available, we establish the selling price of each element based on vendor-specific objective evidence (“VSOE”), which represents the price charged for a deliverable when it is sold separately. We use third-party evidence (“TPE”) if VSOE is not available or best estimate of selling price if neither VSOE nor TPE is available. When these arrangements include a separately-priced EMA, we recognize revenue related to the EMA at the stated contractual price on a straight-line basis over the life of the agreement to the extent the separately stated price is substantive. If there is no stated contractual price for an EMA, or the separately stated price is not substantive, we allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition, as discussed above, have been met for each element .  When arrangements within the scope of software revenue recognition guidance include multiple elements, we allocate revenue to each element based on relative fair value, when VSOE exists for all elements, or by using the residual method when there is VSOE for the undelivered elements but no such evidence for the delivered elements. Under the residual method, the fair value of the undelivered elements is deferred and the residual revenue is allocated to the delivered elements. Revenue is recognized on any delivered elements when the four criteria for revenue recognition have been met for each element. If VSOE does not exist for the undelivered element, all revenue from the arrangement is deferred until the earlier of the point at which such sufficient VSOE does exist or all elements of the arrangement have been delivered. We determine fair value based on amounts charged separately for the delivered and undelivered elements to similar customers in standalone sales of the specific elements.  Certain arrangements with customers include discounts on future sales of products and services. We apply judgment in determining whether future discounts are significant and incremental. When the future discount offered is not considered significant and incremental, we do not account for the discount as an element of the original arrangement. If the future discount is significant and incremental, we recognize that discount as an element of the original arrangement and allocate the discount to the other elements of the arrangement based on relative selling price. To determine whether a discount is significant and incremental, we look to the discount provided in comparison to standalone sales of the same product or service to similar customers, the level of discount provided on other elements in the arrangement, and the significance of the discount to the overall arrangement. If the discount in the MEA approximates the discount typically provided in standalone sales, that discount is not considered incremental.  Customer Programs . We record reductions to revenue related to customer marketing and incentive programs, which include end-user rebates and other volume-based incentives. Incentives may be provided in the form of IDEXX Points, credits or cash and are earned by end users upon achieving defined volume purchases or utilization levels or upon entering an agreement to purchase products or services in future periods. These amounts are presented on a net basis when applicable, which accounts for any differences between estimates and actual incentives earned for the relevant customer marketing or incentive program. These differences have been insignificant in all quarterly or annual periods. Our most significant customer programs are categorized as follows:  Customer Loyalty Programs . Our customer loyalty programs offer customers the opportunity to earn incentives on a variety of IDEXX products and services as those products and services are purchased and utilized. Revenue reductions related to customer loyalty programs are recorded based on the actual issuance of incentives, incentives earned but not yet issued and estimates of incentives to be earned in the future.  Up-Front Customer Loyalty Programs . Our up-front loyalty programs provide incentives to customers in the form of cash payments or IDEXX Points upon entering multi-year agreements to purchase annual minimum amounts of future products or services. We predominately offer up-front loyalty incentives in response to competitive offerings. If a customer breaches its agreement, they are required to refund all or a portion of the up-front cash or IDEXX Points, or make other repayments, remedial actions, or both. These incentives are considered to be customer acquisition costs and are capitalized within other current assets and other long-term assets and are subsequently recognized as a reduction to revenue over the term of the customer agreement. If these up-front incentives are subsequently utilized to purchase IDEXX VetLab instruments, diagnostic imaging systems or Cornerstone practice management systems, product revenue and cost is deferred and recognized over the term of the customer agreement as products and services are provided to the customer. We monitor customer purchases over the term of their agreement to assess the realizability of our capitalized customer acquisition costs. For the years ended December 31, 2017, 2016 and 2015, impairments of customer acquisition costs were immaterial.  IDEXX Instrument Marketing Programs . Our instrument marketing programs require the customer to enroll at the time of instrument purchase and offer customers the opportunity to earn incentives in future periods based on the volume of the products they purchase and utilize over the term of the program. These arrangements are considered MEAs in accordance with our revenue recognition policy stated above. Revenue reductions related to instrument marketing programs are recorded based on an estimate of customer purchase and utilization levels and the incentive the customer will earn over the term of the program. Our estimates are based on historical experience and the specific terms and conditions of the marketing program, requiring us to apply judgment to estimate future product purchases and utilization. Differences between our estimates and actual incentives earned are accounted for as a change in estimate. These differences were not material for the years ended December 31, 2017, 2016 and 2015. At December 31, 2017, a 5 percent change in our estimate of future customer utilization would increase or reduce revenue by approximately $0.4 million.  Reagent Rental Programs . Our reagent rental programs provide customers the right to use our instruments in consideration for multi-year agreements to purchase annual minimum amounts of consumables. No instrument revenue is recognized at the time of instrument installation. We recognize a portion of the revenue allocated to the instrument concurrent with the future sale of consumables. We determine the amount of revenue allocated from the consumable to the instrument based on relative selling prices and determine the rate of instrument revenue recognition in proportion to the customer’s minimum volume commitment. The cost of the instrument is capitalized within property and equipment or deferred within other assets, and is charged to cost of product revenue on a straight-line basis over the term of the minimum purchase agreement.  IDEXX Points are considered the same as cash and may be applied against the purchase price of IDEXX products and services or applied to trade receivables due to us. IDEXX Points that have not yet been used by customers are classified as a liability until use or expiration occurs. We estimate the amount of IDEXX Points expected to expire, or breakage, based on historical expirations and we recognize the estimated benefit of breakage in proportion to actual redemptions of IDEXX Points by customers. On November 30 of each year, unused IDEXX Points earned before January 1 of the prior year generally expire and any variance from the breakage estimate is accounted for as a change in estimate. This variance was not material for the years ended December 31, 2017, 2016 and 2015.  Future market conditions and changes in product offerings may cause us to change marketing strategies to increase or decrease customer incentive offerings, possibly resulting in incremental reductions of revenue in future periods as compared to reductions in the current or prior periods. Additionally, certain customer programs require us to estimate, based on historical experience, and apply judgment to predict the number of customers who will actually redeem the incentive. In determining estimated revenue reductions, we utilize data collected directly from end users, which includes the volume of qualifying products purchased and the number of qualifying tests run as reported to us by end users via IDEXX SmartService , a secure internet link that enables us to extract data and provide diagnostic service and support for certain IDEXX VetLab instruments through remote access. Differences between estimated and actual customer participation in programs may impact the amount and timing of revenue recognition.  Doubtful Accounts Receivable . We recognize revenue when collection from the customer is reasonably assured. We maintain allowances for doubtful accounts for potentially uncollectible receivables. We base our estimates on a detailed analysis of specific customer situations and a percentage of our accounts receivable by aging category. Additional allowances may be required if either the financial condition of our customers was to deteriorate or a strengthening U.S. dollar impacts the ability of foreign customers to make payments to us on their U.S. denominated purchases. Account balances are charged off against the allowance when we believe it is probable the receivable will not be recovered. We do not have any off-balance sheet credit exposure related to our customers. We have no significant customers that accounted for greater than 10 percent of our consolidated revenues for the year ended December 31, 2017. Similarly, we have no concentration of credit risk as of December 31, 2017.  (k) Research and Development Costs  Research and development costs, which consist of salaries, employee benefits, materials and external consulting and product development costs, are expensed as incurred. We evaluate our software research and development costs for capitalization after the technological feasibility of software and products containing software has been established. No costs were capitalized during the years ended December 31, 2017, 2016 and 2015.  (l) Advertising Costs  Advertising costs, which are recognized as sales and marketing expense in the period in which they are incurred, were $ 1.7 million, $2.1 million, and $1.2 million for the years ended December 31, 2017, 2016 and 2015, respectively.  (m) Legal Costs  Legal costs are considered period costs and accordingly are expensed in the year services are provided.  (n ) Share-Based Compensation – See Note 4  (o) Self-Insurance Accruals  We self-insure costs associated with health, workers’ compensation, and general welfare claims incurred by our U.S. and Canadian employees up to certain limits. Insurance companies provide insurance for claims above these limits. Claim liabilities are recorded for estimates of the loss that we will ultimately incur on reported claims, as well as estimates of claims that have been incurred but not yet reported. Such liabilities are based on individual coverage, the average time from when a claim is incurred to the time it is paid and judgments about the present and expected levels of claim frequency and severity. Estimated claim liabilities could be significantly affected if future occurrences and claims differ from these assumptions and historical trends. Estimated claim liabilities are included in accrued liabilities in the accompanying consolidated balance sheets.  (p) Leases – See Note 14  ( q ) Earnings per Share – See Note 13  (r) Foreign Currency  The functional currency of all but three of our subsidiaries is their local currency. Assets and liabilities of these foreign subsidiaries are translated to the U.S. dollar using the exchange rate in effect at the balance sheet date. Revenue and expense accounts are translated to the U.S. dollar using the exchange rate at the date which those elements are recognized, and where it is impractical to do so, an average exchange rate in effect during the period is used to translate those elements. Cumulative translation gains and losses are shown in the accompanying consolidated balance sheets as a separate component of accumulated other comprehensive income (“AOCI”) .  Revenues and expenses denominated in a currency other than the respective subsidiary’s functional currency are recorded at the current exchange rate when the transaction is recognized. Monetary assets and liabilities denominated in a currency other than the respective subsidiary’s functional currency are remeasured at each balance sheet date using the exchange rate in effect at each balance sheet date. These foreign currency gains and losses are included in general and administrative expenses. We recognized aggregate foreign currency gains of $1.1 million for the year ended December 31, 2017, losses of $ 1.3 million for the year ended December 31, 2016, and losses of $ 0.2 million for the year ended December 31, 2015.  (s ) Hedging Instruments – See Note 17  (t ) Fair Value Measurements – See Note 16  (u) Comprehensive Income  We report all changes in equity, including net income and transactions or other events and circumstances from non-owner sources during the period in which they are recognized. We have chosen to present comprehensive income, which encompasses net income, foreign currency translation adjustments, gains and losses on our net investment hedge and the difference between the cost and the fair market value of investments in debt and equity securities, forward currency exchange contracts and interest rate swap agreements, in the consolidated statements of comprehensive income. S ee Note 19 for information about the effects on net income of significant amounts reclassified out of each component of AOCI for the years ended December 31, 2017, 2016 and 2015.  (v) Concentrations of Risk  Financial Instruments . Financial instruments that potentially subject us to concentrations of credit risk are principally cash, cash equivalents, accounts receivable and derivatives. To mitigate such risk with respect to cash and cash equivalents, we place our cash with highly-rated financial institutions, in non-interest bearing accounts that are insured by the U.S. government and money market funds invested in government securities. Concentration of credit risk with respect to accounts receivable is limited to certain customers to whom we make substantial sales. To reduce risk, we routinely assess the financial strength of our most significant customers and monitor the amounts owed to us, taking appropriate action when necessary. As a result, we believe that accounts receivable credit risk exposure is limited. We maintain an allowance for doubtful accounts, but historically have not experienced any material losses related to an individual customer or group of customers in any particular industry or geographic area.  To mitigate concentration of credit risk with respect to derivatives we enter into transactions with highly-rated financial institutions, enter into master netting arrangements with counterparties to our derivative transactions and frequently monitor the credit worthiness of our counterparties. Our master netting arrangements reduce our exposure in that they permit outstanding receivables and payables with the counterparties to our derivative transactions to be offset in the event of default. We have not incurred such losses and consider the risk of counterparty default to be minimal.  Inventory . If we are unable to obtain adequate quantities of the inventory we need to sell our products, we could face cost increases or delays or discontinuations in product shipments, which could have a material adverse effect on our results of operations. Many of the third parties that provide us with the instruments we sell and certain components, raw materials and consumables used in or with our products are obtained from sole or single source suppliers. Some of the products that we purchase from these sources are proprietary or complex in nature, and, therefore, cannot be readily or easily replaced by alternative sources.  (w) New Accounting Pronouncements Adopted  Effective January 1, 2017, we adopted the FASB Accounting Standard Update (“ASU”) 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting which simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, recognition of stock compensation award forfeitures, classification of awards as either equity or liabilities, the calculation of diluted shares outstanding and classification on the statement of cash flows.  The following table summarizes the most significant impacts of the new accounting guidance for the years ended December 31, 2017 and 2016, as applicable:      Description of Change: Impact of Change: Adoption Method:  Tax benefits related to share-based payments at settlement are recorded through the income statement instead of equity Decrease in income tax expense by approximately $27.7 million for the year ended December 31, 2017 Prospective (required)   Calculation of diluted shares outstanding under the treasury method will no longer assume that tax benefits related to share-based payments are used to repurchase common stock Increase in the weighted average diluted shares outstanding by approximately 450,000 shares for the year ended December 31, 2017 Prospective (required)   An election can be made to reduce share-based compensation expense for forfeitures as they occur instead of estimating forfeitures that are expected to occur No change to share-based compensation expense, as we have elected to continue to estimate forfeitures that are expected to occur N/A   Tax benefits related to share-based payments at settlement are classified as operating cash flows instead of financing cash flows Increase in cash flow from operating activities and decreases in cash flow from financing activities by approximately $27.7 million for the year ended December 31, 2017 Prospective (elected)   Cash payments to tax authorities for shares withheld to meet employee tax withholding requirements on restricted stock units are classified as financing cash flow instead of operating cash flow Increases in cash flow from operating activities and decreases in cash flow from financing activities for the years ended December 31, 2017 , 2016 and 2015 by approximately $8.1 million, $4.4 million, and $5.4 million, respectively Retrospective (required) Effective July 1, 2017, we adopted ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business , which amended the definition of a business to be an integrated set of activities and assets that is capable of being conducted and managed for the purpose of providing a return in the form of dividends, lower costs, or other economic benefits directly to investors or other owners, members, or participants. In order to be considered a business, the three elements of inputs, processes and outputs must be present. In a business acquisition, if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the integrated set of assets and activities acquired is not considered a business. We began using this guidance in analyzing acquisitions and disposals in the third quarter of 2017. This amendment may impact the allocation of purchase price in future acquisitions that are determined to be asset acquisitions as opposed to business combinations, however during the third and fourth quarters of 2017 there was no material impact on our consolidated financial statements.  (x) New Accounting Pronouncements Not Yet Adopted  In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (the “New Revenue Standard”), which will replace most of the existing revenue recognition guidance within U.S. GAAP. The FASB has also issued several updates to ASU 2014-09. The core principle of ASU 2014-09 is that an entity should recognize revenue for the transfer of goods or services to customers in an amount that it expects to be entitled to receive for those goods or services. In doing so, companies will be required to make certain judgments and estimates, including identifying contract performance obligations, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price among separate performance obligations. Additionally, disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, significant judgments reached in the application of the guidance and assets recognized from the costs to obtain or fulfill a contract will be required. In July 2015, the FASB approved a one-year deferral of the effective date to all annual and interim periods beginning after December 15, 2017. The new guidance permits two methods of adoption: a full retrospective method to each prior reporting period presented or a modified retrospective approach with the cumulative effect of initially applying the guidance recognized at the date of initial application. We will adopt ASU 2014-09, as amended, in the first quarter of 2018 on a modified-retrospective basis.  Since the issuance of ASU 2014-09, we have been preparing for the adoption of the New Revenue Standard. We have been monitoring the activity of the FASB and the Transition Resource Group as it relates to specific industry interpretive guidance and overall interpretations and clarifications. We developed a three-phase adoption plan and have completed Phase I and Phase II. Phase I included activities such as establishing a transition team and assessing significant revenue streams and representative contracts to determine potential changes to existing accounting policies. Phase II of our adoption plan, in which we further determine the impact of adoption, includes activities such as validating and concluding on changes to existing accounting policies, quantifying the effects on our consolidated financial statements, evaluating expanded disclosure requirements and addressing the impact on business processes, systems, and internal controls. Phase III of our adoption plan will complete our adoption and implementation of the New Revenue Standard during the first quarter of 2018 and will include activities such as running parallel reporting for impacted areas under the New Revenue Standard and the current standard, recording the accounting adjustments that were identified in Phase II, evaluating and testing modified and newly implemented internal controls over the New Revenue Standard, and revising our financial statements disclosures.  While ASU 2014-09 will not impact the overall economics of our products and services sold under customer marketing and incentive programs, we expect the New Revenue Standard will require us to accelerate revenue recognition related to certain of our customer programs and to delay revenue recognition for certain other customer programs. We expect to accelerate revenue recognition on instruments and systems placed through programs where customers are committed to purchase future goods and services, including our up-front customer loyalty and volume commitment programs. This change is the result of the New Revenue Standard no longer limiting revenue recognition to the amount of customer consideration received upon placement. Conversely, we expect to defer an increased portion of revenue related to instrument placements under programs that provide rebate incentives on future purchases, including certain of our IDEXX instrument marketing programs. Under the New Revenue Standard, future purchases that are optional and not subject to a customer commitment, are not considered part of the customer arrangement, resulting in the instrument absorbing a higher relative allocation of rebate incentives. We expect this change to result in lower instrument revenue upon placement and higher recurring revenues over the terms of the rebate incentive programs. Additionally, adoption of the New Revenue Standard will result in earlier recognition of consumables, rapid assay test kits and other diagnostic products due to revenue recognition upon shipment, as compared to upon delivery to the customer. Furthermore, the New Revenue Standard requires the deferral of incremental costs to obtain a customer contract over the term of the customer arrangement, such as sales commissions. We are in the process of converting our financial statements in accordance with ASU 2014-09 and expect to record a charge to retained earnings of less than $10 million in the first quarter of 2018.  In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , to increase transparency and comparability among organizations’ leasing arrangements. The FASB has also issued updates to ASU 2016-02. The principal difference from previous guidance is tha

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Acquisitions [Abstract]
Acquisitions	 NOTE 3. ACQUISITIONS  We believe that our acquisitions of businesses and other assets enhance our existing businesses by either ex panding our geographic range and customer base or expanding our existing product lines.  On July 1, 2017, we adopted ASU 2017-01, which amended the definition of a business. During the third and fourth quarters of 2017, we acquired four reference laboratory customer lists in the United States for approximately $2.3 million and recorded these transactions as asset acquisitions, with a majority of the acquisition price valued as intangible assets. The results of operations for these reference laboratories have been included in our CAG segment since the acquisition dates. In addition to the amount paid at time of purchase, these agreements include contingent payments of up to $0.4 million, that will be recorded upon payment.  During the second quarter of 2017, we acquired the assets of two software companies that expand our suite of technology applications for the veterinary profession, specifically related to patient referral management and other connectivity needs between practices and other parties. The combined purchase price of $15 million consists of $12 million paid at closing and a $3 million contingent payment to be paid within 36 months if certain commercial goals are achieved. We finalized the valuation of the acquired assets in the third quarter of 2017. The fair value estimate of the assets acquired consists of $13.3 million of goodwill, representing synergies within our broader CAG portfolio, $1.0 million of customer relationship intangibles and $0.6 million of technology intangible assets. Goodwill related to these acquisitions is expected to be deductible for income tax purposes. The amount of net tangible assets acquired was immaterial. Pro forma information has not been presented for these acquisitions because such information is not material to our financial statements. The results of operations have been included in our CAG segment since the acquisition date.  During the first quarter of 2017, we acquired a reference laboratory in Austria for approximately €1.3 million, with the majority of the acquisition price valued as an intangible asset. The results of operations of this reference laboratory have been included in our CAG segment since the acquisition date.  During the year ended December 31, 2016, we paid an aggregate of $3.5 million in cash and amounts payable to acquire the assets of a veterinary reference laboratory testing business. We allocated the purchase price and recognized customer related amortizable intangible assets and goodwill. The fair value of the fixed assets acquired was immaterial. Goodwill is calculated as the consideration in excess of net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized. The goodwill recorded from the business acquisition is deductible for income tax purposes. The results of operations have been included in our CAG segment since the acquisition date. Pro forma information has not been presented for this business acquisition because such information is not material to the financial statements.  During the year ended December 31, 2015, we paid an aggregate of $7.5 million in cash and recorded contingent consideration of $3.2 million to acquire the assets of two reference laboratories , each accounted for as a separate business combination. As part of these business acquisitions, we recognized $5.2 million in customer list amortizable intangible assets, $5.0 million in goodwill, $1.1 million in working capital, $0.3 million in fixed assets and a deferred tax liability of $0.9 million. The customer lists were each assigned useful lives of 15 years. Goodwill is calculated as the consideration in excess of net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized. The goodwill recorded from these business acquisitions is not deductible for income tax purposes. The results of operations have been included in our CAG segment since the acquisition date. The results of operations of these acquired businesses have been included since the acquisition date. Pro forma information has not been presented for these business acquisitions because such information is not material to the financial statements. 

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Share-Based Compensation [Abstract]
Share-Based Compensation	NOTE 4. SHARE-BASED COMPENSATION  We provide for various forms of share-based compensation awards to our employees and non-employee directors. Our share-based compensation plans allow for the issuance of a mix of stock options, restricted stock, stock appreciation rights, employee stock purchase rights and other stock unit awards. With the exception of stock options, the fair value of our awards is equal to the closing stock price of IDEXX common stock on the date of grant. We calculate the fair value of our stock option awards using the Black-Scholes-Merton option-pricing model. For stock options, restricted stock units (“RSUs”), and “deferred stock units (DSUs”), s hare-based compensation expense is recognized net of estimated forfeitures, on a straight-line basis over the requisite service period of the award for stock options . For performance-based restricted stock units (PBRSUs”), s hare-based compensation expense is recognized net of estimated forfeitures, on a grade-vesting methodology over the requisite service period .  Stock options permit a holder to buy IDEXX stock upon vesting at the stock’s price on the date the option was granted. An RSU is an agreement to issue shares of IDEXX stock at the time of vesting. A PBRSUs is an agreement to issues shares of IDEXX stock at the time of vesting upon successful completion of certain performance goals. DSUs are granted under our Executive Deferred Compensation Plan (the “Executive Plan”) and non-employee Director Deferred Compensation Plan (the “Director Plan”) . DSUs may or may not have vesting conditions depending on the plan under w hich they are issued. We did no t issue any restricted stock or stock appreciation rights during the years ended December 31, 201 7, 2016 and 201 5, no r were any restricted stock or stock appreciation rights outstanding as of those years ended. There were no material modifications to the terms of outstanding options, RSUs , PBRSUs, or DSUs during the years ended December 31, 2017, 2016 or 2015.  We primarily issue shares of common stock to satisfy stock option exercises and employee stock purchase rights and to settle RSUs , PBRSUs, and DSUs. We issue shares of treasury stock to settle certain RSUs and upon the exercise of certain stock options, which were not material for the years ended December 31, 2017, 2016 and 2015. The number of shares of common stock and treasury stock issued are equivalent to the number of awards exercised or settled.  With the exception of employee stock purchase rights, equity awards are issued to employees and non-employee directors under the 2009 Stock Incentive Pla n (the “2009 Stock Plan”). Our Board of Directors has authorized the issuance of 19.9 million shares of our common stock under this share-based incentive plan. Any shares that are subject to awards of stock options or stock appreciation rights will be counted against the share limit as one share for every share granted. Any shares that are issued other than stock options and stock appreciation rights will be counted against the share limit as two shares for every share granted. If any shares issued under our prior plans are forfeited, settled for cash , or expire, these shares, to the extent of such forfeiture, cash settlement or expiration, will again be available for issuance under the 2009 Stock Plan. As of December 31, 2017, there were approximately 11 .4 million remaining shares available for issuance under the 2009 Stock Plan.  Share-Based Compensation  Share-based compensation costs are classified in our consolidated financial statements consistent with the classification of cash compensation paid to the employees receiving such share-based compensation. The following is a summary of share-based compensation costs and related tax benefits recorded in our consolidated statements of income for t he years ended December 31, 2017, 2016 and 2015 (in thousands) :      For the Years Ended December 31,  2017 2016 2015   Share-based compensation expense included in cost of revenue $ 2,675 $ 2,305 $ 2,138  Share-based compensation expense included in operating expenses 20,842 17,586 17,746  Total share-based compensation expense included in consolidated statements of income 23,517 19,891 19,884  Income tax benefit resulting from share-based compensation expense (6,810) (6,143) (6,229)  Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards 16,707 13,748 13,655  Income tax benefit resulting from settlement of share-based awards (1) (27,743) - -  Net (benefit) expense related to share-based compensation arrangements included in consolidated statements of income $ (11,036) $ 13,748 $ 13,655  (1) See Note 1(w) for more information regarding the adoption of ASU 2016-09.  Share-based compensation expense is reduced for an estimate of the number of awards that are expected to be forfeited. We use historical data and other factors to estimate expected employee terminations and to evaluate whether particular groups of employees have significantl y different forfeiture expectations .  The total unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards at December 31, 201 7, was $ 45. 2 million, which will be recognized over a weighted average period of approximately 1.6 years.  Stock Options  Option awards are granted with an exercise price equal to the closing market price of our common stock on the date of grant. Options granted to employees primarily vest ratably over five years on each anniversary of the date of grant and options granted to non-employee directors vest fully on the first anniversary of the date of grant. Vesting of option awards issued is conditional based on continuous service. Options granted after May 8, 2013 have a contractual term of ten years, options granted between January 1, 2006 and May 8, 2013 have contractual terms of seven years and options grant ed prior to January 1, 2006 had contractual terms of ten years. Upon any change in control of the company, 25 percent of the unvested stock options then outstanding will vest and become exercisable. However, if the acquiring entity does not assume outstanding options, then all options will vest immediately prior to the change in control.  We use the Black-Scholes-Merton option-pricing model to determine the fair value of options granted. Option-pricing models require the input of highly subjective assumptions, particularly for the expected stock price volatility and the expected term of options. Changes in the subjective input assumptions can materially affect the fair value estimate. Our expected stock price volatility assumptions are based on the historical volatility of our stock over periods that are similar to the expected terms of grants and other relevant factors. We derive the expected term based on historical experience and other relevant factors concerning expected employee behavior with regard to option exercise. The risk-free interest rate is based on U.S. Treasury yields for a maturity approximating the expected term calculated at the date of grant. We have never paid any cash dividends on our common stock and we have no intention to pay a dividend at this time; therefore, we assume that no dividends will be paid over the expected terms of option awards.  We determine the assumptions used in the valuation of option awards as of the date of grant. Differences in the expected stock price volatility, expected term or risk-free interest rate may necessitate distinct valuation assumptions at those grant dates. As such, we may use different assumptions for options granted throughout the year. The weighted averages of the valuation assumptions used to determine the fair value of each option award on the date of grant and the weighted average estimated fair values were as follows:     For the Years Ended December 31,  2017 2016 2015   Share price at grant $ 142.89 $ 69.07 $ 78.08  Expected stock price volatility 26 % 25 % 23 %  Expected term, in years 5.8 5.7 5.6  Risk-free interest rate 2.0 % 1.2 % 1.5 %   Weighted average fair value of options granted $ 40.83 $ 17.87 $ 19.72  A summary o f the status of options granted under our share-based compensation plans at December 31, 201 7 , and changes during the year then ended, are presented in the table below:    Number of Options (000) Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value ($000)   Outstanding as of December 31, 2016 3,176 $ 57.31  Granted 384 142.89  Exercised (716) 42.66  Forfeited (117) 68.41  Outstanding as of December 31, 2017 2,727 $ 72.72 6.0 $ 228,243   Fully vested as of December 31, 2017 1,327 $ 56.06 4.2 $ 133,115   Fully vested and expected to vest as of December 31, 2017 2,649 $ 72.45 5.9 $ 222,422 The total fair value of options vested was $9.2 million , $9.3 million , and $8.7 million during the year s ended December 31, 201 7, 2016 and 2015, respectively . Intrinsic value of stock options exercised represents the amount by which the market price of the common stock exceeded the exercise price, before applicable income taxes. The total intrinsic value of stock options exercised was $78.3 million, $51.0 million, and $ 35. 1 million during the year s ended December 31, 201 7, 2016 and 2015, respectively .  Restricted Stock Units  The majority of RSUs, including our PBRSUs, granted to employees vest ratably over five years on each ann iversary of the date of grant. PBRSUs granted to employees vest based on meeting performance goals in the year of grant. RSUs granted to non-employee directors vest fully on the first anniversary of the date of grant. Vesting as it relates to RSUs and PBRSUs issued is conditional based on continuous service . Upon any change in control of the company, 25 percent of the unvested RSUs and PBRSUs then outstanding will vest, provided, however, that if the acquiring entity does not assume the RSUs and PBRSUs , then all such units will vest immediately prior to the change in control. At time of grant, we assume all PBRSUs will meet performance goals to vest.  A summary of the status of RSUs and PBRSUs granted under our share-based compensation plans at December 31, 2017, and changes during the period then ended, are presented in the table below:     Number of Units (000) Weighted Average Grant-Date Fair Value   Nonvested as of December 31, 2016 468 $ 64.88  Granted 97 142.27  Vested (155) 59.63  Forfeited (27) 76.56  Nonvested as of December 31, 2017 383 $ 85.74   Expected to vest as of December 31, 2017 357 $ 85.23  The total fair value of RSUs and PBRSUs vested was $ 22.1 million, $ 12. 4 million, and $ 15. 3 million during the year s ended December 31 , 201 7, 2016 and 2015, respectively . The aggregate intrinsic value of nonvested RSUs and PBRSUs as of December 31, 201 7 , is equal to the fair value of IDEXX’s common stock as of December 31, 201 7 , multiplied by the number of nonvest ed units as of December 31, 2017 . Deferred Stock Units  Under our Director Plan, non-employee directors may defer a portion of their cash fees in the form of vested DSUs. Prior to 2014, certain members of our management could elect to defer a portion of their cash compensation in the form of vested deferred stock units under our Executive Plan. Each DSU represents the right to receive one unissued share of our common stock. These recipients receive a number of DSUs equal to the amount of cash fees or compensation deferred divided by the closing sale price of the common stock on the date of deferral. Also under the Director Plan, non-employee directors are awarded annual grants of DSUs that vest fully on the first anniversary of the date of grant. Vesting for these annual DSU grants is conditional based on continuous service. DSUs are exchanged for a fixed number of shares of common stock, upon vesting if vesting criteria apply, subject to the limitations of the Director and Executive Plans and applicable law.  There were approximately 229,000 and 231,000 vested DSUs outstanding under our share-based compensation plans as of December 31, 201 7 and 201 6 , respectively. Unvested DSUs as of December 31, 2017 and 2016, were not material.  Employee Stock Purchase Rights  Employee stock purchase rights are issued under the 1997 Employee Stock Purchase Plan, under which we reserved and may issue up to an aggregate of 4.7 million shares of common stock in periodic offerings. Under this plan, stock is sold to employees at a 15 percent discount off the closing price of the stock on the last day of each quarter. The dollar value of t his discount is equal to the fair value of purchase rights recognized as share-based compensatio n. We issued approximately 61,000, 85,000 , a nd 105,000 shares of common stock in connection with the Employee Stock Purchase Plan during the years ended December 31, 201 7 , 201 6 and 201 5 , respectively. As of December 31, 201 7 , there wer e approximately 1.2 million re maining shares available for issuance under the 1997 Employee Stock Purchase Plan.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2017
Marketable Securities [Abstract]
Marketable Securities	NOTE 5 . MARKETABLE SECURITIES  During the year ended December 31, 2017, we purchased marketable debt securities, which are classified as available-for-sale and carried at fair value in the accompanying consolidated balance sheets on a trade date basis. We have classified our investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Unrealized holding gains and losses are deferred within accumulated other comprehensive income (“AOCI”), net of applicable taxes, except when an impairment is determined to be other-than-temporary or the security is divested prior to maturity. Within the accompanying consolidated statements of operations, interest earned and amortization of premiums or discounts on marketable securities are included in interest income, and realized gains and losses on the sale of our marketable securities are included in other income.  The amortized cost and fair value of marketable securities were as follows ( in thousands ):     As of December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value   Corporate bonds $ 140,969 $ 96 $ (179) $ 140,886  Certificates of deposit 58,510 - - 58,510  Commercial paper 29,171 - - 29,171  Asset backed securities 22,206 4 (43) 22,167  U.S. government bonds 15,619 11 (19) 15,611  Agency bonds 10,990 9 (52) 10,947  Treasury bills 6,964 - (1) 6,963  Total marketable securities $ 284,429 $ 120 $ (294) $ 284,255   As of December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value   Corporate bonds $ 130,833 $ 40 $ (102) $ 130,771  Certificates of deposit 40,400 - - 40,400  Asset backed securities 27,290 25 - 27,315  Commercial paper 20,228 - - 20,228  U.S. government bonds 12,244 1 (14) 12,231  Agency bonds 4,600 4 - 4,604  Municipal bonds 1,400 - - 1,400  Total marketable securities $ 236,995 $ 70 $ (116) $ 236,949  As of December 31, 2017, unrealized losses on marketable securities that have been in a continuous loss position for more than twelve months were not material. Our portfolio of marketable securities had an average AA- credit rating as of December 31, 2017 . There were no marketable securities that we consider to be other-than-temporarily impaired as of December 31, 2017. Our investment strategy is to buy short-duration marketable securities with a high credit rating. Some of our marketable securities have call features that can effectively shorten the lifespan from the contractual maturity date. We use effective maturity date to measure the duration of the marketable securities.  Remaining effective maturities of marketable securities were as follows ( in thousands ):    As of December 31, 2017 Amortized Cost Fair Value   Due in one year or less $ 175,849 $ 175,780  Due after one through three years 108,580 108,475  $ 284,429 $ 284,255 

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Inventories [Abstract]
Inventories	NOTE 6 . INVENTORIES  Inventories are stated at the lower of cost (first-in, first-out) or net realizable value . Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We write down the carrying value of inventory for estimated obsolescence by an amount equal to the difference between the cost of inventory and the estimated market value when warranted based on assumptions of future demand, market conditions, remaining shelf life, or product functionality. If actual market conditions or results of estimated functionality are less favorable than those we estimated, additional inventory write-downs may be required, which would have a negative effect on results of operations.  Unpaid inventory reflected within accounts payable in our consolidated balance sheets was $37.2 million , $32.7 million , and $30.1 million at December 31, 201 7, 2016 and 2015, respectively.  The components of inventories are as follows (in thousands) :     December 31, December 31,  2017 2016   Raw materials $ 32,994 $ 27,561  Work-in-process 17,786 14,998  Finished goods 113,538 115,475  Total inventories $ 164,318 $ 158,034 

Property And Equipment, Net

Property And Equipment, Net	12 Months Ended
	Dec. 31, 2017
Property And Equipment, Net [Abstract]
Property And Equipment, Net	NOTE 7 . PROPERTY AND EQUIPMENT, NET  Property and equipment are stated at cost, net of accumulated depreciation and amortization. The costs of additions and improvements are capitalized, while maintenance and repairs are charged to expense as incurred. When an item is sold or retired, the cost and related accumulated depreciation is relieved, and the resulting gain or loss, if any, is recognized in the consolidated statements of income. We evaluate our property and equipment for impairment periodically or as changes in circumstances or the occurrence of events suggest the remaining value is not recoverable from future cash flows. If the carrying value of our property and equipment is impaired, an impairment charge is recorded for the amount by which the carrying value of the property and equipment exceeds its fair value. We provide for depreciation and amortization primarily using the straight-line method by charges to income in amounts that allocate the cost of property and equipment over their estimated useful lives as follows:  Asset Classification Estimated Useful Life  Land improvements 15 to 20 years Buildings and improvements 10 to 40 years Leasehold improvements Shorter of remaining lease term or useful life of improvements Machinery and equipment 3 to 8 years Office furniture and equipment 3 to 7 years Computer hardware and software 3 to 7 years  We capitalize interest on the acquisition and construction of significant assets that require a substantial period of time to be made ready for use. The capitalized interest is included in the cost of the completed asset and depreciated over the asset’s estimated useful life. The amount of interest capitalized during the years ended December 31, 2017 and 2016, was not material.  We capitalize certain costs incurred in connection with developing or obtaining software designated for internal use based on three distinct stages of development. Qualifying costs incurred during the application development stage, which consist primarily of internal payroll and direct fringe benefits and external direct project costs, including labor and travel, are capitalized and amortized on a straight-line basis over the estimated useful life of the asset. Costs incurred during the preliminary project and post-implementation and operation phases are expensed as incurred. These costs are general and administrative in nature and relate primarily to the determination of performance requirements, data conversion and training. Software developed to deliver hosted services to our customers has been designated as internal use.  Property and equipment, net, consisted of the following ( in thousands ) :     December 31, December 31,  2017 2016   Land and improvements $ 7,323 $ 7,255  Buildings and improvements 180,185 171,455  Leasehold improvements 52,227 44,568  Machinery and equipment 284,375 262,718  Office furniture and equipment 47,476 42,124  Computer hardware and software 206,580 189,327  Construction in progress 33,470 25,145  811,636 742,592  Less accumulated depreciation and amortization 432,540 385,170  Total property and equipment, net $ 379,096 $ 357,422  Be l ow are the amounts of depreciation and amortization of property and equipment, capitalized computer software for internal use and unpaid property and equipment reflected in account payable and accrued expenses :     December 31, December 31, December 31,  2017 2016 2015   Depreciation and amortization expense $ 73,797 $ 63,537 $ 57,029  Capitalized computer software developed for internal use 16,131 15,590 19,081  Unpaid property and equipment, reflected in accounts payable and accrued liabilities 11,744 10,601 8,534  We recorded an $8.2 million impairment charge related to internally-developed software not yet placed into service within Unallocated Amounts operating expenses during the year ended December 31, 2015 as a result of a strategic shift to refocus our development efforts within our information management business .

Other Current and Noncurrent As

Other Current and Noncurrent Assets	12 Months Ended
	Dec. 31, 2017
Other Current and Noncurrent Assets [Abstract]
Other Current and Noncurrent Assets	NOTE 8 . OTHER CURRENT AND NONCURRENT ASSETS  Other current assets consisted of the following (in thousands) :     December 31, December 31,  2017 2016   Prepaid expenses $ 28,967 $ 25,746  Taxes receivable 35,475 27,672  Customer acquisition costs, net 23,520 18,085  Other assets 13,178 19,703  Total other current assets $ 101,140 $ 91,206  Other noncurrent assets consisted of the following (in thousands) :     December 31, December 31,  2017 2016   Investment in long-term product supply arrangements $ 9,949 $ 10,978  Customer acquisition costs, net 64,670 50,309  Deferred income taxes 7,698 5,707  Other assets 36,299 36,321  Total other long-term assets $ 118,616 $ 103,315 

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets, Net [Abstract]
Goodwill And Intangible Assets, Net	 NOTE 9 . GOODWILL AND INTANGIBLE ASSETS, NET  A significant portion of the purchase price for acquired businesses is generally assigned to intangible assets. Intangible assets other than goodwill are initially valued at fair value. If a quoted price in an active market for the identical asset is not readily available at the measurement date, the fair value of the intangible asset is estimated based on discounted cash flows using market participant assumptions, which are assumptions that are not specific to IDEXX. The selection of appropriate valuation methodologies and the estimation of discounted cash flows require significant assumptions about the timing and amounts of future cash flows, risks, appropriate discount rates, and the useful lives of intangible assets. When material, we utilize independent valuation experts to advise and assist us in determining the fair values of the identified intangible assets acquired in connection with a business acquisition and in determining appropriate amortization methods and periods for those intangible assets. Goodwill is initially valued based on the excess of the purchase price of a business combination over the fair value of acquired net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized.  Our business combinations regularly include contingent consideration arrangements that require additional consideration to be paid based on the achievement of established objectives, most commonly related to the retention or growth of the customer base during the post-combination period. We assess contingent consideration to determine if it is part of the business combination or if it should be accounted for separately from the business combination in the post-combination period. Contingent consideration is recognized at its fair value on the acquisition date. A liability resulting from contingent consideration is remeasured to fair value at each reporting date until the contingency is resolved, with changes in fair value recognized in earnings. Changes in fair value of contingent consideration and differences arising upon settlement were not material during the years ended December 31, 2017, 2016 and 2015. See Note 3 for additional information regarding contingent consideration arising from recent business acquisitions.  We assess goodwill for impairment annually, at the reporting unit level, in the fourth quarter and whenever events or circumstances indicate impairment may exist. In evaluating goodwill for impairment, we have the option to first assess the qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill i mpairment test. The more likely than not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events or circumstances, we determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, we would then perform step one of the two-step impairment test; otherwise, no further impairment test would be required. In contrast, we can opt to bypass the qualitative assessment for any reporting unit in any period and proceed directly to step one of the two-step impairment test. Doing so does not preclude us from performing the qualitative assessment in any subsequent period.  In the fourth quarter of 2017, we elected to bypass the qualitative approach and instead proceeded directly to step one of the two-step impairment test to assess the fair value of all of our reporting units. As part of step one of the two-step impairment test, we estimate the fair values of applicable reporting units using an income approach based on discounted forecasted cash flows. We make significant assumptions about the extent and timing of future cash flows, growth rates and discount rates. Model assumptions are based on our projections and best estimates, using appropriate and customary market participant assumptions. In addition, we make certain assumptions in allocating shared assets and liabilities to individual reporting units in determining the carrying value of each reporting unit. Changes in forecasted cash flows or the discount rate would affect the estimated fair values of our reporting units and could result in a goodwill impairment charge in a future period.  No goodwill impairments were identified during the years ended December 31, 2017, 2016 or 2015.  We assess the realizability of intangible assets other than goodwill whenever events or changes in circumstances indicate that the carrying value may not be recoverable. If an impairment review is triggered, we evaluate the carrying value of intangible assets based on estimated undiscounted future cash flows over the remaining useful life of the primary asset of the asset group and compare that value to the carrying value of the asset group. The cash flows that are used contain our best estimates, using appropriate and customary assumptions and projections at the time. If the net carrying value of an intangible asset exceeds the related estimated undiscounted future cash flows, an impairment to adjust the intangible asset to its fair value would be reported as a non-cash charge to earnings. If necessary, we would calculate the fair value of an intangible asset using the present value of the estimated future cash flows to be generated by the intangible asset, and applying a risk-adjusted discount rate. We had no impairments of our intangible assets during the year ended December 31, 2017.  During the first half of 2016, management reviewed the OPTI Medical product offerings. As a result of this review, we discontinued certain development activities in the human point-of-care medical diagnostics market during March 2016 that was devoted to a new platform and focused our efforts in this market on supporting our current generation OPTI CCA-TS2 Blood Gas and Electrolyte analyzer. Non-cash intangible asset impairments of $2.2 million were recorded within our condensed consolidated statement of operations , within general and administrative expenses , within our unallocated segment, during 2016. The intangibles associated with our OPTI Medical human point-of-care medical diagnostics market are fully written off. Impairments of our intangible assets during the year ended December 31, 2015, were not material.  We provide for amortization primarily using the straight-line method by charges to income in amounts that allocate the intangible assets over their estimated useful lives as follows:   Asset Classification Estimated Useful Life  Patents 13 years Product rights (1) 5 to 15 years Customer-related intangible assets (2) 5 to 17 years Noncompete agreements 3 to 5 years (1) Product rights comprise certain technologies, intellectual property, licenses , and trade names acquired from third parties. (2) Customer-related intangible assets are comprise d of customer lists and customer relationships acquired from third parties.  Intangible assets other than goodwill consisted of the following (in thousands) :     December 31, 2017 December 31, 2016  Cost Accumulated Amortization Net Cost Accumulated Amortization Net  Patents $ - $ - $ - $ 2,192 $ 2,075 $ 117  Product rights (1) 32,558 25,251 7,307 29,748 20,877 8,871  Customer-related intangible assets (2) 80,398 44,382 36,016 74,922 38,190 36,732  Noncompete agreements 1,271 748 523 1,111 676 435  $ 114,227 $ 70,381 $ 43,846 $ 107,973 $ 61,818 $ 46,155 The above table excludes fully amortized intangible assets for the periods presented. (1) Product rights comprise certain technologies, licenses and trade names acquired from third parties. (2) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties.  Amortization expense of intangible assets other than goodwill was $9.0 mi llion, $ 9.5 million , and $ 10.4 million for the years ended December 31, 201 7, 2016 and 2015, respectively .  At December 31, 2017, the aggregate amortization expense associated with intangible assets is estimated to be as follows for each of the next five years and thereafter ( in thousands ):    Amortization Expense   2018 $ 8,142  2019 7,283  2020 5,857  2021 5,053  2022 4,027  Thereafter 13,484  $ 43,846  The increase in goodwill during the twelve months ended December 31, 2017, resulted from changes in foreign currency exchange rates, and additional goodwill recognized in connection with the acquisition of businesses. The decrease in goodwill during the twelve months ended December 31, 201 6 , resulted from changes in foreign currency exchange rates, partly offset by goodwill recognized in connection with the acquisition of businesses. See Note 3 for information regarding goodwill and other intangible assets recognized in connection with the acquisition of businesses and other assets during the years ended December 31, 201 7 , 201 6 and 201 5 .  The changes in the carrying amount of goodwill for t he years ended December 31, 2017, 2016 and 2015, were as follows ( in thousands ):      CAG Water LPD Other Consolidated Total  Balance as of December 31, 2014 $ 148,151 $ 13,689 $ 16,079 $ 6,531 $ 184,450  Business combinations 5,047 - - - 5,047  Impact of changes in foreign currency exchange rates (8,007) (651) (1,905) - (10,563)  Balance as of December 31, 2015 $ 145,191 $ 13,038 $ 14,174 $ 6,531 $ 178,934  Business combinations 1,720 - - - 1,720  Impact of changes in foreign currency exchange rates (717) (2,148) 439 - (2,426)  Balance as of December 31, 2016 $ 146,194 $ 10,890 $ 14,613 $ 6,531 $ 178,228  Business combinations 13,541 - - - 13,541  Impact of changes in foreign currency exchange rates 6,501 1,061 542 - 8,104  Balance as of December 31, 2017 $ 166,236 $ 11,951 $ 15,155 $ 6,531 $ 199,873 

Accrued Liabilities And Other L

Accrued Liabilities And Other Long Term Liabilities	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities And Other Long Term Liabilities [Abstract]
Accrued Liabilities And Other Long Term Liabilities	NOTE 10 . ACCRUED LIABILITIES AND OTHER LONG-TERM LIABILITIES  Accrued liabilities consisted of the following ( in thousands ):     December 31, December 31,  2017 2016   Accrued expenses $ 64,430 $ 71,984  Accrued employee compensation and related expenses 102,944 91,113  Accrued taxes 29,389 23,973  Accrued customer programs 56,655 49,061  Total accrued liabilities $ 253,418 $ 236,131    Other long-term liabilities consisted of the following ( in thousands ):       December 31, December 31,  2017 2016   Accrued taxes $ 66,506 $ 18,798  Accrued customer programs 12,956 10,371  Other accrued long-term expenses 16,256 9,768  Total other long-term liabilities $ 95,718 $ 38,937 

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt [Abstract]
Debt	NOTE 1 1 . DEBT  Effective January 1, 2016, we adopted FASB amendments that require debt issuance costs related to a recognized debt liability be presented within the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This reclassification of the presentation of deferred financing costs did not have a material impact on other long-term assets or long-term debt amounts reported in our condensed consolidated balance sheet and additionally would not have a material impact on such amounts reported in a prior period. These amendments have been reflected prospectively from the date of inception; prior period amounts have not been revised for the effects of this amendment. For line-of-credit arrangements, borrowers have the option of presenting debt issuance costs as an asset which is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any related outstanding borrowings. As such, we continue to present deferred financing costs associated with our unsecured revolving credit facility within other long-term assets in the accompanying condensed consolidated balance sheets.  Credit Facility  In December 201 5 , we refinanced our existing $ 700 million unsecured revolving credit facility by entering into a second amended and restated credit agreement relating to a five -year unsecured revolving credit facility in the principal amount of $ 850 million with a syndicate of multinational banks, which matures on December 4, 2020 (the new credit facility and the prior credit facility are referred to collectively as the “Credit Facility”) and requires no scheduled prepayments before that date. Alt hough the Credit Facility does not mature until December 4 , 20 20 , all individual borrowings under the terms of the Credit Facility have a stated term between 30 and 180 days. At the end of each term, the obligation is either repaid or rolled over into a new borrowing. The Credit Facility contains a subjective material adverse event clause, which allows the debt holders to call the loans under the Credit Facility if we fail to provide prompt written notice to the syndicate of such an event. Based on the stated term and the existence of the subjective material adverse event clause, this Credit Facility is reflected in the current liabilities section of our consolidated balance sheets. At December 31, 201 7, we had $ 655.0 million outstanding under our Credit Facility with a weighted average effective interest rate of 2.81 percent. At December 31, 2016, we had $ 611.0 million outstanding under our Credit Facility with a weighted average effective interest rate 1.95 percent . The funds available under the Credit Facility at December 31, 201 7, and December 31, 201 6, reflect a further reduction due to the issuance of a letter of credit for $ 1.0 million , which was issued in connection with our workers’ compensation policy.  Applicable interest rates on borrowings under the Credit Facility generally range from 0.875 to 1.375 percentage points (“Credit Spread”) above the London interbank offered rate, based on our leverage ratio, or the prevailing prime rate plus a maximum spread of up to 0.375 percent, based on our leverage ratio. We pr eviously entered into forward fixed interest rate swap agreements to manage the economic effect of the first $ 80 million of variable interest rate borrowings. We designate d the interest rate swaps as cash flow hedges. See Note 17 for a discussion of our derivative instruments and hedging activities. Under the Credit Facility, we pay quarterly commitment fees of 0.075 percent to 0.25 percent , based on our leverage ratio, on any unused commitment.  Th e obligations under the Credit Facility may be accelerated upon the occurrence of an event of default under the Credit Facility, which includes customary events of default including payment defaults, defaults in the performance of the affirmative, negative and financial covenants, the inaccuracy of representations or warranties, bankruptcy and insolvency related defaults, defaults relating to judgments, certain events related to employee pension benefit plans under the Employee Retirement Income Security Act of 1974, the failure to pay specified indebtedness, cross-acceleration to specified indebtedness and a change of control default. The Credit Facility contains affirmative, negative , and financial covenants customary for financings of this type. The negative covenants include restrictions on liens, indebtedness of subsidiaries of the Company, fundamental changes, investments, transactions with affiliates and certain restrictive agreements. The sole financial covenant is a consolidated leverage ratio test that requires our ratio of debt to earnings before interest, taxes, depreciation, amortization , and share-based compensation defined as the consolidated leverage ratio under the terms of the Credit Facility, not to exceed 3.5 -to-1 . At December 31, 2017, we were in compliance with the covenants of the Credit Facility.  Senior Notes  In December 2013, we issued and sold through a private placement an aggregate principal amount of $ 150 million of unsecured senior notes consisting of $75 million of 3.94% Series A Senior Notes due December 11, 2023 (the “2023 Notes”) and $75 million of 4.04% Series B Senior Notes due December 11, 2025 (the “2025 Series B Notes” and together with the 2023 Notes, the “December Notes”) under a Note Purchase Agreement among the Company , New York Life Insurance Company and the accredited institutional purch asers named therein (the “December 2013 Note Agreement”).  In July 2014, we issued and sold through a private placement an aggregate principal amount of $125 million of unsecured senior notes consisting of $75 million of 3.76% Series B Senior Notes due July 21, 2024 (the “2024 Notes”) and $50 million of 3.32% Series A Senior Notes due July 21, 2021 (the “2021 Notes” and together with the 2024 Notes, the “Prudential Notes”) under a Note Purchase and Private Shelf Agreement among the Company, Prudential Investment Management, Inc. (“Prudential”) and the accredited institutional purchasers named therein (the “July 2014 Note Agreement”).  In September 2014, we issued and sold through a private placement an aggregate principal amount of $75 million of unsecured 3.72% senior notes due September 4, 2026 (the “2026 Notes”) under a Note Purchase Agreement dated as of July 22, 2014, among the Company, New York Life Insurance Company and the accredited institutional purchasers named therein (the “September 2014 Note Agreement”).  In December 2014, we entered into a Multi -C urrency Note Purchase and Private Shelf Agreement among the Company, Metropolitan Life Insurance Company (“MetLife”) , and the accredited institutional purchasers named therein pursuant to which we agreed to issue and sell $75 million of its unsecured 3.25% Series A Senior Notes having a seven -year term , and $75 million of its unsecured 3.72% Series B Senior Notes having a twelve -year term. The issuance, sale and purchase of the se notes occurred in February 2015 (the “MetLife Notes”) . The agreement (the “December 2014 Note Agreement”) also provides for an uncommitted shelf facility by which we may request that MetLife purchase, over the subsequent three years, up to $50 million of additional senior promissory notes of the Company at a fixed interest rate to be determined at the time of purchase and with a maturity date not to exceed fifteen years.  In June 2015, we entered into an Amended and Restated Multi-Currency Note Purchase and Private Shelf Agreement (the “2015 Amended Agreement”), among the Company, Prudential Investment Management, Inc., and the accredited institutional purchasers named therein, which amends and restates the Note Purchase and Private Shelf Agreement dated July 21, 2014. We refer to the 2015 Amended Agreement together with the December 2013 Note Agreement, September 2014 Note Agreement, and December 2014 Note Agreement collectively as the “Senior Note Agreements.”)  Pursuant to the 2015 Amended Agreement, we issued and sold through a private placement a principal amount of €88 .9 million of unsecured 1.785% Series C Senior Notes due June 18, 2025 (the “2025 Series C Notes”). We refer to the 2025 Series C Notes together with the Prudential Notes, December Notes, MetLife Notes and the 2026 Notes, collectively, as the “Senior Notes”) . We used the net proceeds from this issuance and sale of the 2025 Notes for general corporate purposes, including repaying amounts outstanding under our Credit Facility. The 2015 Amended Agreement also provides for an uncommitted shelf facility by which we may request that Prudential purchase, over the next three years, up to $75 million (or the foreign currency equivalent) of additional senior promissory notes of the Company at a fixed interest rate and with a maturity date not to exceed twelve years (the “Shelf Notes”). Prudential is under no obligation to purchase any of the Shelf Notes. The interest rate of any series of Shelf Notes will be determined at the time of purchase. The proceeds of any series of Shelf Notes are able to be used for general corporate purposes.  The Senior Note Agreement s contain affirmative, negative , and financial covenants customary for agreements of this type. The negative covenants include restrictions on liens, indebtedness of our subsidiaries, priority indebtedness, fundamental changes, investments, transactions with affiliates, certain restrictive agreements , and violations of laws and regulations. The sole financial covenant is a consolidated leverage ratio test that requires our ratio of debt to earnings before i nterest, taxes, depreciation, amortization , and share-based compensation , as defined in the Senior Note Agreement s , not to exceed 3.5 -to-1. At December 31, 2017, we were in compliance with the covenants of the Senior Note Agreements.  Should we elect to prepay the Senior Notes, such aggregate prepayment will include the applicable make-whole amount(s), as defined within the applicable Senior Note Agreements. Additionally, in the event of a change in control of the Company or upon the disposition of certain assets of the Company the proceeds of which are not reinvested (as defined in the Senior Note Agreements), we may be required to prepay all or a portion of the Senior Notes. The obligations under the Senior Notes may be accelerated upon the occurrence of an event of default under the applicable Senior Note Agreement, each of which includes customary events of default including payment defaults, defaults in the performance of the affirmative, negative and financial covenants, the inaccuracy of representations or warranties, bankruptcy and insolvency related defaults, defaults relating to judgments, certain events related to employee pension benefit plans under the Employee Retirement Income Security Act of 1974, the failure to pay specified indebtedness and cross-acceleration to specified indebtedness.  Interest paid for the periods ended December 31, 2017, 2016 and 2015, was $37.6 million , $31.8 million, and $27.2 million, respectively.  A nnual principal payments on long-term debt at December 31, 201 7, are as follows (in thousands ):      Years Ending December 31, Amount   2018 -  2019 -  2020 -  2021 50,000  2022 75,000  Thereafter 481,567  $ 606,567 

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	NOTE 1 2 . INCOME TAXES  The Tax Cuts and Jobs Act (the “Tax Act”) was enacted on December 22, 2017, and includes significant changes to the U.S. corporate tax system. Effective January 1, 2018, the Tax Act reduced the U.S. federal corporate tax rate from 35 percent to 21 percent, and transitioned the U.S. federal tax system from a worldwide tax system to a territorial tax system, and eliminated or reduced certain domestic deductions among other changes. In converting to the new territorial tax system, a deemed repatriation tax on previously tax-deferred earnings of certain foreign subsidiaries was required to be recognized as of December 31, 2017, and will be payable over eight years.  On December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”) that provides additional guidance allowing companies to apply a measurement period of up to twelve months to account for the impacts of the Tax Act in their financial statements.  As of December 31, 2017, w e have accounted for the impacts of the Tax Act to the extent a re asonable estimate could be made and we recognized provisional amount s related to the deemed repatriation tax, offset by the re measurement of our deferred tax assets and liabilities , and other adjustments . The provisional amount s are included as a component of income tax expense from continuing operations as a reasonable estimate of the effects of the Tax Act on our U.S. federal and state tax obligations. We will continue to refine our estimates throughout the measurement period or until the ac counting is complete as allowed under SAB 118 .  As a result of the Tax Act we are no longer asserting indefinite reversal under ASC 740-30-25 for undistributed earnings of non-U.S. subsidiaries as of December 31, 2017. We have recorded a provisional amount of $48.8 million for the deemed repatriation tax liability related to these earnings.  The provision for income taxes is determined using the asset and liability approach of accounting for income taxes. Under this approach, deferred taxes represent the estimated future tax effects of temporary differences between book and tax treatment of assets and liabilities and carryforwards to the extent they are realizable. We record a valuation allowance to reduce our deferred tax assets to the amount that is more likely than not to be realized. While we consider future taxable income and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance, in the event we determine that we would be able to realize our deferred tax assets in the future in excess of the net recorded amount, a reduction of the valuation allowance would increase income in the period such determination was made. Likewise, should we determine that we would not be able to realize all or part of our net deferred tax asset in the future, a reduction to the deferred tax asset would be charged to income in the period such determination was made.  We record a liability for uncertain tax positions that do not meet the more likely than not standard as prescribed by the authoritative guidance for income tax accounting. We record tax benefits for only those positions that we believe will more likely than not be sustained. Unrecognized tax benefits are the differences between tax positions taken, or expected to be taken, in tax returns, and the benefits recognized for accounting purposes. We classify uncertain tax positions as long-term liabilities.  Significant judgment is required in determining our worldwide provision for income taxes and our income tax filings are regularly under audit by tax authorities. Any audit result differing from amounts recorded would increase or decrease income in the period that we determine such adjustment is likely. Interest expense and penalties associated with the underpayment of income taxes are included in income tax expense. Earnings before income taxes were as follows ( in thousands ):    For the Years Ended December 31,  2017 2016 2015   Domestic $ 268,714 $ 227,875 $ 187,200  International 112,343 93,971 85,941  $ 381,057 $ 321,846 $ 273,141  The provision (benefit) for income taxes comprised the following ( in thousands ):    For the Years Ended December 31,  2017 2016 2015  Current  Federal $ 92,453 $ 53,285 $ 52,966  State 9,258 6,608 5,353  International 23,993 19,291 17,681  125,704 79,184 76,000  Deferred  Federal (1,201) 20,305 5,762  State (4,102) 1,196 526  International (2,613) (893) (1,282)  (7,916) 20,608 5,006  $ 117,788 $ 99,792 $ 81,006  The provision for income taxes differs from the amounts computed by applying the statutory federal income tax rate as follows:    For the Years Ended December 31,  2017 2016 2015   U.S. federal statutory rate 35.0 % 35.0 % 35.0 %  State income tax, net of federal tax benefit 1.9 1.8 1.6  International income taxes (5.5) (4.8) (5.3)  Shares-based compensation from settlements (1) (6.7) - -  Domestic manufacturing exclusions (1.1) (1.0) (1.5)  Research and development credit (0.9) (0.8) (1.2)  Impact of the Tax Cuts and Jobs Act 9.4 - -  State income tax carryforwards (1.4) - -  Other, net 0.2 0.8 1.1  Effective tax rate 30.9 % 31.0 % 29.7 % (1) See Note 2(w) for the impact of the adoption of ASU 2016-09.  Our effective income tax rate was 30.9 percent for the year ended December 31, 2017, and 31.0 percent for the year ended December 31, 2016. Our effective income tax rate for the year ended December 31, 2017, was lower as a result of the adoption of ASU 2016-09 related to share-based compensation, which decreased our effective tax rate by approximately 7 percent (s ee Note 2 for more information regarding the adoption of ASU 2016-09) and the utilization of foreign tax credits, which reduced our effective tax rate by approximately 1 percent . These decreases were offset by the following non-recurring items: A deemed repatriation tax, net of the remeasurement of our deferred tax assets and liabilities resulting from the Tax Act and a tax benefit related to state tax credit carryforwards, which combined, increased our tax rate by approximately 8 percent.  Our effective income tax rate was 31.0 percent for the year ended December 31, 2016, and 29.7 percent for the year ended December 31, 2015. The increase in our effective income tax rate for the year ended December 31, 2016, as compared to the year ended December 31, 2015, was primarily related to a change in earnings mix in 2016, with relatively higher earnings subject to domestic tax rates as opposed to lower international tax rates including the impact of foreign currency exchange rates.  Income taxes paid for the periods ended December 31, 2017, 2016 and 2015 was $81.2 million, $74.7 million, and $54.9 million, respectively.  We have business operations in Switzerland and the Netherlands and have been granted tax rulings by each jurisdiction. Our Netherlands ruling is set to expire on December 31, 2022, and our Switzerland ruling remains in effect as long as our business operations comply with the ruling requirements during the period or until Switzerland adopts new international tax rules. As a result of the tax rulings, our net income was higher by $8.9 million , $7.8 million, and $8.5 million for the years ended December 31, 2017, 2016 and 2 01 5, respectively. The benefit from these tax rulings is reflected within the overall benefit received from international income taxes in the table above.  The components of the net deferred tax assets (liabilities) included in the accompanying consolidated balance sheets are as follows ( in thousands ):     December 31, 2017 December 31, 2016   Assets  Accrued expenses $ 13,843 $ 22,145  Accounts receivable reserves 2,624 2,715  Deferred revenue 10,618 13,400  Inventory basis differences 3,039 3,959  Property-based differences 1,324 1,382  Share-based compensation 9,035 13,021  Other 918 678  Net operating loss carryforwards 3,350 4,182  Tax credit carryforwards 8,096 -  Unrealized losses on foreign currency exchange contracts, interest rate swaps and investments 2,355 148  Total assets 55,202 61,630  Valuation allowance (6,211) (4,891)  Total assets, net of valuation allowance 48,991 56,739   Liabilities  Deferred instrument costs (20,399) (24,142)  Property-based differences (31,859) (43,159)  Intangible asset basis differences (13,574) (17,672)  Other (656) (771)  Unrealized gains on foreign currency exchange contracts, interest rate swaps and investments (158) (4,575)  Total liabilities (66,646) (90,319)  Net deferred tax assets (liabilities) $ (17,655) $ (33,580)  The passage of the Tax Act, which reduced the U.S. federal income tax rate from 35 percent to 21 percent, resulted in a decrease to our net deferred tax liabilities by approximately $17 million.  As of December 31, 2017, we have recorded a valuation allowance of $6.2 million against certain deferred tax assets related to temporary differences including net operating loss (“NOL”) and tax credit carryforwards, as it is more likely than not that they will not be realized or utilized within the carryforward period. The increase in the valuation allowance from the prior period primarily relates to recording a deferred tax asset for certain state tax credits that we do not believe will be utilized due to insufficient taxable income in that jurisdiction. There was no impact to income tax expense.  As of December 31, 2017, we have NOL’s in certain state and international jurisdictions of approximately $13.1 million available to offset future taxable income. Most of these NOL’s will expire at various dates between 2021 and 2026 and the remainder have indefinite lives. The following table summarizes the changes in unrecognized tax benefits during the years ended December 31, 201 7 , 201 6 and 201 5 ( in thousands ):     For the Years Ended December 31,  2017 2016 2015   Total amounts of unrecognized tax benefits, beginning of period $ 18,463 $ 7,204 $ 5,942  Gross increases in unrecognized tax benefits as a result of tax positions taken during a prior period 74 75 47  Gross increases in unrecognized tax benefits as a result of tax positions taken in the current period 4,681 12,657 1,569  Decreases in unrecognized tax benefits relating to settlements with taxing authorities (713) (1,326) -  Decreases in unrecognized tax benefits as a result of a lapse of the applicable statutes of limitations (1,088) (147) (354)  Total amounts of unrecognized tax benefits, end of period $ 21,417 $ 18,463 $ 7,204  The total amount of unrecognized tax b enefits at December 31, 2017 and December 31, 2016, was $ 21. 4 million and $ 18. 5 million, respectively. Of the total unrecognized tax benefits at December 31, 2017 and 2016, $ 9.1 million and $ 5.9 million, respectively, comprise unrecognized tax positions that would, if recognized, affect our effective tax rate. The increase in net liability primarily relates to an uncertain tax position taken during the year related to the deemed repatriation tax provided in the Tax Act .  During the years ended December 31, 2017, 2016 and 2015, we recorded interest expense and penalties of $0.9 million , $0.3 million, and $ 0.3 million , respectively, as income tax expense in our consolidated statement of income. At December 31, 2017 and 2016, we had $ 1.0 million and $ 0.6 million, respectively, of estimated interest expense and penalties accrued in our consolidated balance sheets.  In the ordinary course of our business, our income tax filings are regularly under audit by tax authorities. While we believe we have appropriately provided for all uncertain tax positions, amounts asserted by taxing authorities could be greater or less than our accrued position. Accordingly, additional provisions on income tax matters, or reductions of previously accrued provisions, could be recorded in the future as we revise our estimates due to changing facts and circumstances or the underlying matters are settled or otherwise resolved. We are currently under tax examinations by various state and international tax authorities. We anticipate that these examinations will be concluded within the next year. With few exceptions, we are no longer subject to income tax examinations in any state and local, or international jurisdictions in which we conduct significant taxable activities for years before 20 13 .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 13 . EARNINGS PER SHARE  Basic earnings per share is computed by dividing net income attributable to IDEXX Laboratories, Inc. stockholders by the weighted average number of shares of common stock and vested deferred stock units outstanding during the year. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and assumed issuance of unvested restricted stock units and unvested deferred stock units using the treasury stock method unless the effect is anti-dilutive. The treasury stock method assumes that proceeds, including cash received from the exercise of employee stock options, the total unrecognized compensation expense for unvested share-based compensation awards and, prior to the adoption of new accounting guidance related to share-based compensation on January 1, 2017, the tax benefits resulting from share-based compensation tax deductions in excess of the related expense recognized for financial reporting purposes, would be used to purchase our common stock at the average market price during the period. For further discussion regarding the impact of the new accounting guidance related to share-based compensation, see Note 2. Vested deferred stock units outstanding are included in shares outstanding for basic and diluted earnings per share because the associated shares of our common stock are issuable for no cash consideration, the number of shares of our common stock to be issued is fixed and issuance is not contingent. See Note 4 for additional information regarding deferred stock units.  The following is a reconciliation of shares outstanding for basic and diluted earnings per share for the years ended December 31, 2017, 2016 and 2015 ( in thousands ):     For the Years Ended December 31,  2017 2016 2015   Shares outstanding for basic earnings per share: 87,769 89,732 92,601   Shares outstanding for diluted earnings per share:  Shares outstanding for basic earnings per share 87,769 89,732 92,601  Dilutive effect of share-based payment awards 1,798 1,152 1,048  89,567 90,884 93,649  C ertain options to acquire shares have been excluded from the calculation of shares outstanding for dilutive earnings per share because they were anti-dilutive. The following table presents information concerning those anti-dilutive options for the years ended December 31, 2017, 2016 and 2015 (in thousands ):     For the Years Ended December 31,  2017 2016 2015   Weighted average number of shares underlying anti-dilutive options 327 88 644  

Commitments, Contingencies And

Commitments, Contingencies And Guarantees	12 Months Ended
	Dec. 31, 2017
Commitments, Contingencies And Guarantees [Abstract]
Commitments, Contingencies And Guarantees	NOTE 14 . COMMITMENTS, CONTINGENCIES AND GUARANTEES  Lease s  The m ajority of our facilities are occupied under operating lease arrangements with various expiration dates through 20 30 . W e are responsible for the real estate taxes and operating expenses related to these facilities. Additional ly , we enter into operating leases for certain vehicles and office equipment in the normal course of business . We determine the expected term of any executed agreements using the non-cancelable lease term plus any renewal options by which the failure to renew imposes a penalty in such amount that renewal is reasonably assured. The derived expected term is then used in the determination of a capital or operating lease and in the calculation of straight-line rent expense. Rent escalations are considered in the calculation of minimum lease payments in our capital lease tests and in determining straight-line rent expense for operating leases.  Commitments  Rent expense charged to operations under operating leases was approximate ly $ 23.0 million, $ 22.7 mi llion , and $ 20.5 million for the year s ended December 31, 201 7, 2016 and 2015, respectively .  Minimum annual rental payments under these agreements are estimated as follows ( in thousands ):     Years Ending December 31, Amount   2018 $ 19,233  2019 15,687  2020 11,974  2021 9,461  2022 7,139  Thereafter 32,435  $ 95,929  We have various minimum royalty payments due through 2035 of $ 1.7 million. If these obligations are not satisfied, the related license arrangements may be terminated, resulting in either a loss in ex clusivity or the right to use the technology.  We are required to annually purchase a minimum amount of inventory from certain suppliers. Through 2025, we have a total of $ 11.8 million in minimum purchase commitments under these arrangements.  Contingencies  Although we are not currently party to any material contingencies of which we are aware or have recorded a reserve for, w e are subject to claims that may arise in the ordinary course of business, including with respect to actual and threatened litigation and other matters. We accrue for loss contingencies when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. However, our actual losses with respect to these contingencies could exceed our accruals.  Under our current employee healthcare insurance policy for U.S. employees, we retain claims liability risk per incident up to $1 million per year in 2017, $ 0.45 million per year in 2016, and $0.43 million p er year in 201 5 . We recognized employee healthcare claim expense of $ 47.2 million for the year ended December 31, 201 7 , $ 40.4 million for the year ended December 31, 201 6 and $ 34.6 million during the year ended December 31, 201 5 , which represents actual claims paid and an estimate of our liability for the uninsured portion of employee healthcare obligations that have been incurred but not paid. Should employee health insurance claims exceed our estimated liability, we would have further obligations. Our estimated liability for healthcare claims that have been incurred but not paid as of December 31, 2017 and 2016, was $ 4.2 million and $ 4.0 million , respectively .  Under our workers’ compensation insurance policies for U.S. employees, we have retained the first $0.3 million for the years ended December 31, 2017, 2016 and 2015, in claim liability per incident with aggregate maximum claim liabilities per year of $2.5 million, $2.6 million , and $3.5 million for the years ended December 31, 2017, 2016 and 2015, respectively. Workers’ compensation expense recognized during the years ended December 31, 2017, 2016 and 2015 and our respective liability for such claims as of December 31, 2017, 2016 and 2015 was not material. Claims incurred during the years ended December 31, 2017 and 2016 are relatively undeveloped as of December 31, 2017. Therefore , it is possible that we could incur additional healthcare and wage indemnification costs beyond those previously recognized up to our aggregate liability for each of the respective claim years. For the years ended on or prior to December 31, 201 5 , based on our retained claim liability per incident and our aggregate claim liability per year, our maximum liability in excess of the amounts deemed probable and previously recognized is not material as of December 31, 201 7 . As of December 31, 201 7 , we had outstanding letters of credit totaling $ 1.0 million to the insurance companies as security for these claims in connection with these policies.  We have entered into an employment agreement with our chief executive officer whereby payment may be required if we terminate his employment without cause other than following a change in control. The amount payable is based upon the executive’s salary at the time of termination and the cost to us of continuing to provide certain benefits. Had this officer been terminated without cause at December 31, 201 7 , other than following a change in control, we would have had an obligation for salaries and benefits of approximately $ 1.6 million under such agreement. In addition, the agreement provides for continued vesting of his outstanding equity awards for a period of two years .  We have entered into employment agreements with each of our officers that require us to make certain payments in the event the officer’s employment is terminated under certain circumstances within a certain period following a change in control. The amount payable by us under each of these agreements is based on the officer’s salary and bonus history at the time of termination and the cost to us of continuing to provide certain benefits. Had all of our officers been terminated in qualifying terminations following a change in control at December 31, 201 7 , we would have had aggregate obligations of approximately $ 29.4 million under these agreements. These agreements also provide for the acceleration of the vesting of all stock options and restricted stock units upon any qualifying termination following a change in control. At this time, we believe the likelihood of terminations as a result of the scenarios described is remote, and therefore, we have not accrued for such loss contingencies.  We have total acquisition-related contingent consideration liabilities outstanding of $ 3.0 million , primarily related to the achievement of certain revenue milestones , recorded at December 31, 2017, and $0.9 million recorded at December 31, 2016 .  From time to time, we have received notices alleging that our products infringe third-party proprietary rights, although we are not aware of any pending litigation with respect to such claims. Patent litigation frequently is complex and expensive, and the outcome of patent litigation can be difficult to predict. There can be no assurance that we will prevail in any infringement proceedings that may be commenced against us. If we lose any such litigation, we may be stopped from selling certain products and/or we may be required to pay damages as a result of the litigation.  Guarantees  We enter into agreements with third parties in the ordinary course of business under which we are obligated to indemnify such third parties for and against various risks and losses. The precise terms of such indemnities vary with the nature of the agreement. In many cases, we limit the maximum amount of our indemnification obligations, but in some cases those obligations may be theoretically unlimited. We have not incurred material expenses in discharging any of these indemnification obligations, and based on our analysis of the nature of the risks involved, we believe that the fair value of these agreements is minimal. Accordingly, we have recorded no liabilities for these obligations at December 31, 201 7 and 201 6 .  When acquiri ng a business, we sometimes assume liability for certain events or occurrences that took place pr ior to the date of acquisition. As of December 31, 2017 and 2016, we do not have any material pre-acquisition liabilities recorded.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting	NOTE 15 . SEGMENT REPORTING  We operate primarily through three business segments: diagnostic and information technology-based products and services for the veterinary market, which we refer to as CAG; water quality products (“Water”); and diagnostic products and services for livestock and poultry health and to ensure the quality and safety of milk and food, which we refer to as LPD. Our Other operating segment combines and presents products for the human point-of-care medical diagnostics market with our pharmaceutical intellectual property and our out-licensing arrangements because they do not meet the quantitative or qualitative thresholds for reportable segments.  Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources and in assessing performance. Our chief operating decision-maker is our Chief Executive Officer. Our reportable segments include: CAG, Water, LPD, and Other. Assets are not allocated to segments for internal reporting purposes.  CAG develops, designs, manufactures and distributes products and performs services for veterinarians and the bioresearch market, primarily related to diagnostics and information management. Water develops, designs, manufactures and distributes a range of products used in the detection of various microbiological parameters in water. LPD develops, designs, manufactures and distributes diagnostic tests and related instrumentation and performs services that are used to manage the health status of livestock and poultry, to improve bovine reproductive efficiency, and to ensure the quality and safety of milk and food . OPTI Medical develops, designs, manufactures and distributes point-of-care electrolyte and blood gas analyzers and related consumable products for the human medical diagnostics market. The accounting policies of our segments are the same as those described in the summary of significant accounting policies in Note 2 except for inventories, as discussed below. Intersegment revenues, which are not included in the table below, were not material for the years ended December 31, 201 7 , 201 6 and 201 5 .  Certain costs are not allocated to our reportable segments and are instead reported under the caption “Unallocated Amounts”. These costs include costs that do not align with one of our existing operating segments or are cost prohibitive to allocate, which primarily consist of our R&D function, regional or country expenses, certain foreign currency revaluation gains and losses on monetary balances in currencies other than our subsidiaries’ functional currency and unusual items. Corporate support function costs (such as information technology, facilities, human resources, finance and legal), health benefits and incentive compensation are charged to our business segments at pre-determined budgeted amounts or rates. Differences from these pre-determined budgeted amounts or rates are captured within Unallocated Amounts.  Effective January 1, 2016, we modified our management reporting to the Chief Operating Decision Maker to provide a more comprehensive view of the performance of our operating segments by including the capitalization and subsequent recognition of variances between standard and actual manufacturing costs, which adjusts the timing of cost recognition from when the variance is created to the period in which the related inventory is sold. Prior to January 1, 2016, the capitalization and subsequent recognition of these variances were not allocated to our operating segments and were instead reported under the caption “Unallocated Amounts”.  Below is our segment information ( in thousand s):    For the Years Ended December 31,  CAG Water LPD Other Unallocated Amounts Consolidated Total  2017  Revenue $ 1,703,377 $ 114,395 $ 128,481 $ 22,805 $ - $ 1,969,058   Income (loss) from operations $ 363,557 $ 50,616 $ 16,464 $ 4,837 $ (22,446) $ 413,028  Interest expense, net (31,971)  Income before provision for income taxes 381,057  Provision for income taxes 117,788  Net income 263,269  Less: Net income attributable to noncontrolling interest 125  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 263,144   Depreciation and amortization $ 71,835 $ 2,856 $ 5,052 $ 3,397 $ - $ 83,140  Expenditures for long-lived assets (1) $ 64,759 $ 2,573 $ 3,021 $ 4,031 $ - $ 74,384   2016  Revenue $ 1,522,689 $ 103,579 $ 126,491 $ 22,664 $ - $ 1,775,423   Income (loss) from operations $ 301,342 $ 45,702 $ 18,914 $ 884 $ (16,603) $ 350,239  Interest expense, net (28,393)  Income before provision for income taxes 321,846  Provision for income taxes 99,792  Net income 222,054  Less: Net income attributable to noncontrolling interest 9  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 222,045   Depreciation and amortization $ 64,878 $ 3,098 $ 5,543 $ 4,699 $ - $ 78,218  Expenditures for long-lived assets (1) $ 56,329 $ 2,102 $ 4,824 $ 1,532 $ - $ 64,787   2015  Revenue $ 1,356,287 $ 96,884 $ 127,143 $ 21,578 $ - $ 1,601,892   Income (loss) from operations $ 233,319 $ 44,752 $ 27,157 $ (137) $ (5,179) $ 299,912  Interest expense, net (26,771)  Income before provision for income taxes 273,141  Provision for income taxes 81,006  Net income 192,135  Less: Net loss attributable to noncontrolling interest 57  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 192,078   Depreciation and amortization $ 60,715 $ 3,188 $ 4,367 $ 686 $ - $ 68,956  Expenditures for long-lived assets (1) $ 69,371 $ 2,781 $ 9,110 $ 1,659 $ - $ 82,921 __________ (1) Expenditures for long-lived assets exclude expenditures for intangible assets. See Note 3 for information regarding acquisitions of intangible assets during the years ended December 31, 201 7 , 201 6 and 2015 .  Revenue by product and service categories was as follows ( in thousands ):     For the Years Ended December 31,  2017 2016 2015  CAG segment revenue:  CAG Diagnostics recurring revenue: $ 1,451,701 $ 1,281,262 $ 1,147,026  IDEXX VetLab consumables 518,774 451,456 396,526  Rapid assay products 205,309 189,122 182,670  Reference laboratory diagnostic and consulting services 660,142 581,067 512,155  CAG Diagnostics service and accessories 67,476 59,617 55,675  CAG Diagnostics capital - instruments 119,963 121,191 98,502  Veterinary software, services and diagnostic imaging systems 131,713 120,236 110,759  CAG segment revenue 1,703,377 1,522,689 1,356,287   Water segment revenue 114,395 103,579 96,884  LPD segment revenue 128,481 126,491 127,143  Other segment revenue 22,805 22,664 21,578   Total revenue $ 1,969,058 $ 1,775,423 $ 1,601,892 Revenue by principal geographic area, based on customers’ domiciles, was as follows ( in thousands ):     For the Years Ended December 31,  2017 2016 2015  Americas  United States $ 1,203,547 $ 1,089,595 $ 980,281  Canada 83,818 74,923 69,303  Latin America 46,893 38,872 34,725  1,334,258 1,203,390 1,084,309   Europe, the Middle East and Africa  Germany 88,328 80,156 73,395  United Kingdom 80,149 77,671 74,879  France 55,993 51,204 46,972  Italy 31,889 28,907 25,903  Spain 28,866 24,268 19,998  Switzerland 17,913 16,361 15,631  Netherlands 15,877 14,049 11,645  Other 100,409 83,147 79,910  419,424 375,763 348,333  Asia Pacific Region  Australia 56,994 52,871 49,274  China 55,810 48,257 40,619  Japan 53,344 51,544 43,171  Other 49,228 43,598 36,186  215,376 196,270 169,250  Total $ 1,969,058 $ 1,775,423 $ 1,601,892  Net long-lived assets, consisting of net property and equipment, are subject to geographic risks because they are generally difficult to move and to effectively utilize in another geographic area in a reasonable time period and because they are relatively illiquid. Net long-lived assets by principal geographic areas were as follows (in thousands) :    December 31, December 31,  2017 2016  Americas  United States $ 310,696 $ 298,944  Brazil 17,030 17,910  Canada 2,238 1,977  329,964 318,831  Europe, the Middle East and Africa  United Kingdom 11,528 9,127  Germany 7,522 5,040  Netherlands 8,225 5,948  France 2,305 2,428  Switzerland 1,755 2,450  Other 3,838 3,490  35,173 28,483  Asia Pacific Region  Japan 4,065 2,469  Australia 4,426 4,185  Other 5,468 3,454  13,959 10,108  Total $ 379,096 $ 357,422 

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements [Abstract]
Fair Value Measurements	NOTE 16 . FAIR VALUE MEASUREMENTS  U.S. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. U.S. GAAP requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value.  We have certain financial assets and liabilities that are measured at fair value on a recurring basis, certain nonfinancial assets and liabilities that may be measured at fair value on a non-recurring basis and certain financial assets and liabilities that are not measured at fair value in our consolidated balance sheets but for which we disclose the fair value. The fair value disclosures of these assets and liabilities are based on a three-level hierarchy, which is defined as follows: Level 1 Quoted prices in active markets for identical assets or liabilities that the entity can access at the measurement date. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.  Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.  Our marketable debt securities are initially valued at the transaction price and are subsequently remeasured to fair value as of the balance sheet date utilizing third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches and observable market inputs to determine value. Observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers and other industry and economic events. We validate the prices provided by our third-party pricing services by obtaining independent market values from other pricing sources and analyzing pricing data in certain instances .  Our foreign currency exchange contracts are measured at fair value on a recurring basis in our accompanying consolidated balance sheets. We measure the fair value of our foreign currency exchange contracts classified as derivative instruments using an income approach, based on prevailing market forward rates less the contract rate multiplied by the notional amount. The product of this calculation is then adjusted for counterparty risk.  Our interest rate swap agreement in prior years were measured at fair value on a recurring basis in our accompanying consolidated balance sheets. These interest rate swaps were classified as derivative instruments using an income approach, utilizing a discounted cash flow analysis based on the terms of the contract and the interest rate curve adjusted for counterparty risk.  The amount outstanding under our unsecured revolving credit facility and long-term debt are measured at carrying value in our accompanying consolidated balance sheets though we disclose the fair value of these financial instruments. We determine the fair value of the amount outstanding under our credit facility and long-term debt using an income approach, utilizing a discounted cash flow analysis based on current market interest rates for debt issues with similar remaining years to maturity, adjusted for applicable credit risk. Our credit facility and long-term debt are valued using Level 2 inputs. The estimated fair value of our credit facility approximates its carrying value. At December 31, 201 7 , the estimated fair value and carrying value of our long-term debt were $632.0 million and $ 606.6 million , respectively. At December 31, 201 6 , the estimated fair value and carrying value of our long-term debt were $609.5 million and $593.7 million, respectively.  The following table sets forth our assets and liabilities that were measured at fair value on a recurring basis at December 31, 201 7, and at December 31, 2016, by level within the fair value hierarchy ( in thousands ):    Quoted Prices Significant  in Active Other Significant  Markets for Observable Unobservable  Identical Assets Inputs Inputs Balance at  As of December 31, 2017 (Level 1) (Level 2) (Level 3) December 31, 2017   Assets  Money market funds (1) $ 32,962 $ - $ - $ 32,962  Certificates of deposit (1) $ - $ 1,250 $ - $ 1,250   Marketable securities  Corporate bonds $ - $ 140,886 $ - $ 140,886  Certificates of deposit - 58,510 - 58,510  Commercial paper - 29,171 - 29,171  Asset backed securities - 22,167 - 22,167  U.S. government bonds - 15,611 - 15,611  Agency bonds - 10,947 - 10,947  Treasury bills - 6,963 - 6,963  Total marketable securities $ - $ 284,255 $ - $ 284,255   Equity mutual funds (2) $ 2,162 $ - $ - $ 2,162  Foreign currency exchange contracts (3) $ - $ 477 $ - $ 477  Liabilities  Foreign currency exchange contracts (3) $ - $ 6,468 $ - $ 6,468  Deferred compensation (4) $ 2,162 $ - $ - $ 2,162     Quoted Prices Significant  in Active Other Significant  Markets for Observable Unobservable  Identical Assets Inputs Inputs Balance at  As of December 31, 2016 (Level 1) (Level 2) (Level 3) December 31, 2016   Assets  Money market funds (1) $ 34,208 $ - $ - $ 34,208  Certificates of deposit (1) $ - $ 1,500 $ - $ 1,500  Commercial paper (1) $ - $ 898 $ - $ 898   Marketable securities  Corporate bonds $ - $ 130,771 $ - $ 130,771  Certificates of deposit - 40,400 - 40,400  Asset backed securities - 27,315 - 27,315  Commercial paper - 20,228 - 20,228  U.S. government bonds - 12,231 - 12,231  Agency bonds - 4,604 - 4,604  Municipal bonds - 1,400 - 1,400  Total marketable securities $ - $ 236,949 $ - $ 236,949   Equity mutual funds (2) $ 2,182 $ - $ - $ 2,182  Foreign currency exchange contracts (3) $ - $ 8,926 $ - $ 8,926  Liabilities  Foreign currency exchange contracts (3) $ - $ 1,081 $ - $ 1,081  Deferred compensation (4) $ 2,182 $ - $ - $ 2,182 __________ (1) Money market funds, certificates of deposit and commercial paper with an original maturity of less than ninety days are included within cash and cash equivalents. The remaining balance of cash and cash equivalents as of December 31, 201 7, and December 31, 201 6, consisted of demand deposits. Commercial paper and certificates of deposit with an original maturity of over ninety days are included within marketable securities. (2) Equity mutual funds relate to a deferred compensation plan that was assumed as part of a previous business combination. This amount is include d within other long-term assets . See number (4) below for a discussion of the related deferred compensation liability. (3) Foreign currency exchange contracts are included within other current assets; other long-term assets; accrued liabilities; or other long-term liabilities depending on the gain (loss) position an d anticipated settlement date. (4) A deferred compensation plan assumed as part of a previous business combination is included within accrued liabilities and other long-term liabilities. The fair value of our deferred compensation plan is indexed to the performance of the underlying equity mutual funds discussed in number (2) above.  We did not have any transfers between Level 1 and Level 2 or transfers in or out of Level 3 of the fair value hierarchy during the years ended December 31, 2017 and 2016.  The estimated fair value of certain financial instruments, including cash and cash equivalents, accounts receivable and accounts payable, approximate carrying value due to their short maturity.

Hedging Instruments

Hedging Instruments	12 Months Ended
	Dec. 31, 2017
Hedging Instruments [Abstract]
Hedging Instruments	Note 17 . HEDGING Instruments  We recognize all derivative and non-derivative instruments (collectively “hedging instruments”) on the balance sheet at fair value at the balance sheet date. Instruments that do not qualify for hedge accounting treatment must be recorded at fair value through earnings. To qualify for hedge accounting treatment, cash flow and net investment hedges must be highly effective in offsetting changes to expected future cash flows or fair value on hedged transactions. If the instrument qualifies for hedge accounting, c hanges in the fair value of the hedging instrument from the effective portion of the hedge are deferred in AOCI, net of tax, and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. We immediately record in earnings the extent to which a hedging instrument is not effective in achieving offsetting changes in fair value. We de-designate hedging instruments from hedge accounting when the likelihood of the hedged transaction occurring becomes less than probable. For de-designated instruments, the gain or loss from the time of de-designation through maturity of the instrument is recognized in earnings. Any gain or loss in AOCI at the time of de-designation is reclassified into earnings in the same period or periods during which the hedged transaction affects earnings.  We enter into master netting arrangements with the counterparties to our derivative transactions which permit certain outstanding receivables and payables to be offset in the event of default. Our derivative contracts do not require either party to post cash collateral. We elect to present our derivative assets and liabilitie s in the accompanying consolidated balance sheets on a gross basis. All cash flows related to our foreign currency exchange contracts and interest rate swaps are classified as operating cash flows, which is consistent with the cash flow treatment of the underlying items being hedged.  Disclosure within this footnote is presented to provide transparency about how and w hy we use derivative and non-derivative instruments (collectively “hedging instruments”) and how the hedging instruments and related hedged items affect our financial position, results of operations, and cash flows. See Note 16 for additional information regarding the fair value of our derivative instruments and Note 19 for additional information regarding the effect of derivative instruments designated as cash flow hedges on the consolidated statement of operations.  We are exposed to certain risks related to our ongoing business operations. The primary risks th at we manage by using hedging instruments are foreign currency exchange risk and interest rate risk. Our subsidiaries enter into foreign currency exchange contracts to manage the exchange risk associated with their forecasted intercompany inventory purchases and sales for the next year. From time to time, we may also enter into other foreign currency exchange contracts or foreign-denominated debt issuances to minimize the impact of foreign currency fluctuations associated with specific balance sheet exposures, including net investments in certain foreign subsidiaries. We may also enter into interest rate swaps to minimize the impact of interest rate fluctuations associated with borrowings under our variable-rate Credit Facility .  The primary purpose of our foreign currency hedging activities is to protect against the volatility associated with foreign currency transactions, includi ng transactions denominated in e uro, British pound, Japanese yen, Canadian dollar, Australian dollar , and Swiss franc. We also utilize natural hedges to mitigate our transaction and commitment exposures. Our corporate policy prescribes the range of allowable hedging activity. We enter into foreign currency exchange contracts with well-capitalized multinational financial institutions , and we do not hold or engage in t ransactions involving hedging instruments for purposes other than risk management. Our accounting policies for these contracts are based on our designation of such instruments as hedging transactions.  Cash Flow Hedges  We have designated our foreign currency exchange contracts and variable-to-fixed interest rate swaps as cash flow hedges as these derivative instruments mitigate the exposure to variability in the cash flows of forecasted transactions attributable to foreign currency exchange and interest rates. Unless noted otherwise, we have also designated our derivative instruments as qualifying for hedge accounting treatment.  We did not de-designate any instruments from hedge accounting treatment during the years ended December 31, 2017, 2016 and 2015. Gains or losses related to hedge ineffectiveness recognized in earnings during the years ended December 31, 2017, 2016 and 2015 were not material . At December 31, 201 7 , the estimated amount of net losse s, net of income tax expense, which are expected to be reclassified out of AOCI and into earnings within the next twelve months is $ 5.2 million if exchange and interest rates do not fluctuate from the levels at December 31, 201 7 .  We hedge approximately 85 percent of the estimated exposure from intercompany product purchases and sales denominated in the euro, British pound, Canadian dollar, Japanese yen, Australian dollar , and Swiss franc. We have additional unhedged foreign currency exposures related to foreign services and emerging markets where it is not practical to hedge. We primarily utilize foreign currency exchange contracts with durations of less than 24 months . Quarterly, we enter into contracts to hedge incremental portions of anticipated foreign currency transactions for the current and following year. As a result, our risk with respect to foreign currency exchange rate fluctuations and the notional value of foreign currency exchange contracts may vary throughout the year. The U.S. dollar is the currency purchased or sold in all of our foreign currency exchange contracts. The notional amount of foreign currency exchange contracts to hedge forecasted intercompany inventory purch ases and sales totaled $ 176.5 million , and $1 75.9 million at December 31, 201 7 and 2016, respectively .  We previously entered into forward fixed interest rate swap agreements to manage the economic effect of variable interest obligations on amounts borrowed under the terms of our Credit Facility. Beginning on March 30, 2012, the variable interest rate associated with $ 40 million of borrowings outstanding under the Credit Facility became effectively fixed at 1.36 percent plus the range of applicable interest rate fixed credit spreads (“ Credit Spread ”) through June 30, 2016. Beginning on March 28, 2013, the variable interest rate associated with an additional $ 40 million of borrowings outstanding under the Credit Facility became effectively fixed at 1.64 percent plus the Credit Spread through June 30, 2016. Beginning July 1, 2016, we no longer have outstanding interest rate swap agreements.  Net Investment Hedge  In June 2015, we issued and sold our 2025 Series C Notes through a private placement an aggregate principal amount of €88.9 million. We have designated these euro-denominated notes as a hedge of our euro net investment in certain foreign subsidiaries to reduce the volatility in stockholders’ equity caused by changes in foreign currency exchange rates in the euro relative to the U.S. dollar. As a result of this designation, gains and losses from the change in translated U.S. dollar value of these euro-denominated notes are recorded in AOCI rather than to earnings. We recorded an $8.3 million loss , net of income tax, within AOCI as a result of this net investment hedge for the year ended December 31, 2017. This unrealized loss recorded at December 31, 2017, will not be reclassified in earnings until the complete or substantially complete liquidation of the net investment i n the hedged foreign operations or all or a portion of the hedge no longer qualifies for hedge accounting treatmen t. See Note 11 to the consolidated financial statements included in this Annual Report on Form 10-K for further information regarding the issuance of these 2025 Series C Notes .  Fair Values of Hedging Instruments Designated as Hedges in Consolidated Balance Sheets  The fair values of hedging instruments, and their respective classification on the consolidated balance sheets and amounts subject to offset under master netting arrangements consisted of the following (in thousands) :     Hedging Assets  December 31, December 31,  2017 2016   Derivatives designated as hedging instruments Balance Sheet Classification  Foreign currency exchange contracts Other current assets $ 477 $ 8,926  Total derivative instruments presented as cash flow hedges on the balance sheet 477 8,926  Gross amounts subject to master netting arrangements not offset on the balance sheet 477 679  Net amount $ - $ 8,247     Hedging Liabilities  December 31, December 31,  2017 2016   Derivatives designated as hedging instruments Balance Sheet Classification  Foreign currency exchange contracts Accrued liabilities $ 6,468 $ 1,081  Total derivative instruments presented as cash flow hedges on the balance sheet 6,468 1,081  Foreign currency borrowings designated as net investment hedge on the balance sheet Long-term debt 106,567 93,664  Total hedging instruments presented on the balance sheet 113,035 94,745  Gross amounts subject to master netting arrangements not offset on the balance sheet 477 679  Net amount $ 112,558 $ 94,066  The effect of derivative instruments designated as cash flow hedges on the consolidated balance sheets for the years ended December 31, 201 7 , 201 6 and 201 5 consisted of the following (in thousands) :     Gain (Loss) Recognized in AOCI on Derivative Instruments (Effective Portion)  For Year Ended December 31,  Derivative instruments 2017 2016 2015   Foreign currency exchange contracts, net of tax $ (10,135) $ 2,457 $ (5,604)  Interest rate swaps, net of tax - 242 461  Total derivative instruments, net of tax $ (10,135) $ 2,699 $ (5,143) 

Repurchases Of Common Stock

Repurchases Of Common Stock	12 Months Ended
	Dec. 31, 2017
Repurchases Of Common Stock [Abstract]
Repurchases Of Common Stock	NOTE 18 . REPURCHASES OF COMMON STOCK  Our Board of D irectors has authorized the repurchase of up to 68.0 million shares of our common stock in the open market or in negotiated transactions pursuant to the Company’s share repurchase program. We believe that the repurchase of our common stock is a favorable means of returning value to our shareholders, and we also repurchase to offset the dilutive effect of our share-based compensation programs. Repurchases of our common stock may vary d epending upon the level of other investing activities and the shar e price. As of December 31, 2017 , there are approximately 5.0 million r emaining shares available for repurchase under this authorization.  We primarily acquire shares by means of repurchases in the open market. However, we also acquire shares that are sur rendered by employees in payment for the minimum required withholding taxes due on the vesting of restricted stock units and the settlement of deferred stock units, otherwise referred to herein as employee surrenders.  The following is a summary of our open market common stock repurchases and shares acquired through employee surrender for the years ended December 31, 2017 , 201 6 and 201 5 ( in thousands, except per share amounts ):     For the Years Ended December 31,  2017 2016 2015   Share repurchases during the period (1) 1,749 3,071 5,659  Shares acquired through employee surrender (1) 57 60 69  Total shares repurchased (1) 1,806 3,131 5,728   Cost of share repurchases during the period $ 270,297 $ 313,072 $ 406,430  Cost of employee surrenders 8,074 4,372 5,457  Total cost of shares repurchased $ 278,371 $ 317,444 $ 411,887   Average cost per share - open market repurchase $ 154.51 $ 101.96 $ 71.82  Average cost per share - employee surrenders $ 142.55 $ 73.04 $ 72.55  Average cost per share - total $ 154.13 $ 101.40 $ 71.90  (1) Shares repurchased and acquired through employee surrender for payment of minimum required withholding taxes on and before June 15, 2015 and the associated average cost per share have been adjusted to reflect the June 2015 two-for-one stock split. Actual shares repurchased were approximately 4.3 million for the year ended December 31, 2015. 

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income	 NOTE 1 9 . ACCUMULATED OTHER COMPREHENSIVE INCOME  The changes in a ccumulated other comprehensive income , net of tax, for the years ended December 31, 2017 and 2016 consisted of the following (in thousands) :     Unrealized Gain (Loss) on Investments, Net of Tax Unrealized Gain (Loss) on Derivatives Instruments, Net of Tax Unrealized Gain on Net Investment Hedge, Net of Tax Cumulative Translation Adjustment Total   Balance as of December 31, 2015 $ (225) $ 2,217 $ 1,894 $ (46,151) $ (42,265)  Other comprehensive income (loss) before reclassifications 245 4,950 2,142 (5,874) 1,463  Gains reclassified from accumulated other comprehensive income - (2,251) - - (2,251)  Balance as of December 31, 2016 20 4,916 4,036 (52,025) (43,053)  Other comprehensive income (loss) before reclassifications (42) (10,332) (8,347) 25,107 6,386  Gains reclassified from accumulated other comprehensive income - 197 - - 197  Balance as of December 31, 2017 $ (22) $ (5,219) $ (4,311) $ (26,918) $ (36,470)  The following is a summary of reclassifications out of accumulated other comprehensive income for the years ended December 31, 2017, 2016 and 2015 ( in thousands ):    Amounts Reclassified from Accumulated Other  Affected Line Item in the Comprehensive Income  Details about Accumulated Other Statement Where For the Years Ended December 31,  Comprehensive Income Components Net Income is Presented 2017 2016 2015   Gains (losses) on derivative instruments included in net income:  Foreign currency exchange contracts Cost of revenue $ 27 $ 3,621 $ 20,878  Interest rate swaps Interest expense - (421) (1,042)  Total gains before tax 27 3,200 19,836  Tax expense 224 949 5,853  Gains, net of tax $ (197) $ 2,251 $ 13,983 

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2017
Preferred Stock [Abstract]
Preferred Stock	NOTE 20 . PREFERRED STOCK  Our Board of D irectors is authorized, subject to any limitations prescribed by law, without further stockholder approval, to issue from time to time up to 500,000 shares of Preferred Stock, $ 1.00 par value per share (“Preferred Stock”), in one or more series. Each such series of Preferred Stock shall have such number of shares, designations, preferences, voting powers, qualifications and special or relative rights or privileges as shall be determined by the Board of D irectors, which may include, among others, dividend rights, voting rights, redemption and sinking fund provisions, liquidation preferences, conversion rights and preemptive rights. There are no shares of Preferred Stock outstanding as of December 31, 2017 .

IDEXX Retirement And Incentive

IDEXX Retirement And Incentive Savings Plan	12 Months Ended
	Dec. 31, 2017
IDEXX Retirement And Incentive Savings Plan [Abstract]
IDEXX Retirement And Incentive Savings Plan	NOTE 21 . IDEXX RETIREMENT AND INCENTIVE SAVINGS PLAN  We have established the IDEXX Retirement and Incentive Savings Plan (the “401(k) Plan”). U.S. e mployees eligible to participate in the 401(k) Plan may contribute specified percentages of their salaries. We match a portion of these contributions, not to exceed 4 percent of participants’ eligible compensation . We matched $ 13.8 million, $ 12.5 million , and $ 11.5 million for the year s ended December 31, 2017, 2016 and 2015, respectively . In addition, we may make contributions to the 401(k) Plan at the discretion of the Board of D irectors. There were no discretionary contributions in 201 7 , 201 6 or 201 5 .  We also have established defined contribution plans for regional employees in Europe and in Canada. With respect to these plans, our contributions over the past three years have not been material.

Summary Of Quarterly Data

Summary Of Quarterly Data	12 Months Ended
	Dec. 31, 2017
Summary Of Quarterly Data [Abstract]
Summary Of Quarterly Data	 NOTE 22 . SUMMARY OF QUARTERLY DATA (UNAUDITED)  A summary of quarterly data (1) follows ( in thousands, except per share data ):     For the Three Months Ended  March 31, June 30, September 30, December 31,   2017  Revenue $ 462,021 $ 508,940 $ 491,976 $ 506,121  Gross profit 258,191 292,715 274,002 272,474  Operating income 92,243 122,564 100,413 97,808  Net income attributable to IDEXX Laboratories, Inc. stockholders 69,019 85,357 70,511 38,257  Earnings per share:  Basic $ 0.78 $ 0.97 $ 0.81 $ 0.44  Diluted $ 0.77 $ 0.95 $ 0.79 $ 0.43   2016  Revenue $ 417,550 $ 466,569 $ 448,308 $ 442,996  Gross profit 227,537 260,543 246,730 240,626  Operating income 73,793 104,162 88,459 83,825  Net income attributable to IDEXX Laboratories, Inc. stockholders 46,019 67,202 56,455 52,369  Earnings per share:  Basic $ 0.51 $ 0.75 $ 0.63 $ 0.59  Diluted $ 0.51 $ 0.74 $ 0.62 $ 0.58  (1) Amounts presented may not recalculate to full-year totals due to rounding.

Valuation And Qualifying Accoun

Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation and Qualifying Accounts [Abstract]
Valuation And Qualifying Accounts	SCHEDULE II IDEXX LABORATORIES, INC. AND SUBSIDIARIES  VALUATION AND QUALIFYING ACCOUNTS ( in thousands )      Balance at Beginning of Year Charges to Costs and Expenses Write-Offs/Cash Payments Foreign Currency Translation Balance at End of Year   Reserves for doubtful accounts receivable:  December 31, 2015 $ 4,306 $ 2,200 $ (817) $ (561) $ 5,128  December 31, 2016 5,128 822 (531) (896) 4,523  December 31, 2017 4,523 591 (1,660) 1,122 4,576   Valuation allowance for deferred tax assets:  December 31, 2015 $ 4,678 $ 634 $ (468) $ (398) $ 4,446  December 31, 2016 4,446 885 (816) 376 4,891  December 31, 2017 4,891 1,789 (679) 210 6,211   

Summary Of Significant Accoun32

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2017
Summary Of Significant Accounting Policies [Abstract]
Estimates	(a) Estimates  The preparation of these consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures. On an ongoing basis, we evaluate these estimates, including those related to reserves for accounts receivable; goodwill and other intangible assets; income taxes; inventory valuation; revenue recognition, product returns, customer programs and multiple element arrangements; share-based compensation; warranty reserves; self-insurance reserves; fair value measurements and loss contingencies. We accrue contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates.
Cash And Cash Equivalents	( b ) Cash and Cash Equivalents  We consider all highly liquid investments with original maturities of ninety days or less to be cash equivalents. Cash and cash equivalents consist primarily of demand deposits, money market funds and short duration agency bonds and commercial paper as described above. There is no restricted cash on our consolidated balance sheet for the years ended December 31, 2017 and 2016.
Warranty Reserves	(g) Warranty Reserves  We provide a standard twelve-month warranty on all instruments sold. We recognize the cost of instrument warranties in cost of product revenue at the time revenue is recognized based on the estimated cost to repair the instrument over its warranty period. Cost of product revenue reflects not only estimated warranty expense for instruments sold in the current period, but also any changes in estimated warranty expense for the portion of the aggregate installed base that is under warranty. Estimated warranty expense is based on a variety of inputs, including historical instrument performance in the customers’ environment, historical and estimated costs incurred in servicing instruments and projected instrument reliability. Should actual service rates or costs differ from our estimates, revisions to the estimated warranty liability would be required. The liability for warranties is included in accrued liabilities in the accompanying consolidated balance sheets.
Taxes Remitted To Governmental Authorities By IDEXX On Behalf Of Customer	(i) Taxes Remitted to Governmental Authorities by IDEXX on Behalf of Customer  We calculate, collect from our customers, and remit to governmental authorities sales, value-added and excise taxes assessed by governmental authorities in connection with revenue-producing transactions with our customers. We report these taxes on a net basis and do not include these tax amounts in revenue or cost of product or service revenue.
Revenue Recognition	 (j) Revenue Recognition  We recognize revenue when four criteria are met: (i) persuasive evidence of an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured. Revenue generating transactions generally fall into one of the following categories of revenue recognition:  · We recognize revenue from the sales of consumables, rapid assay test kits and other diagnostic products when the product is delivered to the customer, except as noted below. · We recognize revenue from the sales of instruments, non-cancelable software licenses and hardware systems upon installation and the customer’s acceptance of the instrument or system as we have no significant further obligations after this point in time. · We recognize service revenue at the time the service is performed. · We recognize revenue associated with extended maintenance agreements (“EMAs”) and our software-as-a-service subscriptions over the life of the contracts using the straight-line method, which approximates the expected timing in which applicable services are performed. Amounts collected in advance of revenue recognition are recorded as current or long-term deferred revenue based on the time from the balance sheet date to the future date of revenue recognition. · We recognize revenue on certain instrument systems under rental programs over the life of the rental agreement using the straight-line method. Amounts collected in advance of revenue recognition are recorded as current or long-term deferred revenue based on the time from the balance sheet date to the future date of revenue recognition. · We recognize revenue on practice management systems sales, where the system includes software that is considered more than incidental, either by allocating the revenue to each element of the sale based on relative fair values of the elements, including post-contract support when fair value for all elements is available, or by use of the residual method when only the fair value of the post-contract support is available. We recognize revenue for the system upon installation and customer acceptance and recognize revenue equal to the fair value of the post-contract support over the support period. · Shipping costs reimbursed by the customer are included in revenue. These same costs are also included in cost of product revenue.  Multiple Element Arrangements (“MEAs”) . Arrangements to sell products to customers frequently include multiple deliverables. Our most significant MEAs include the sale of one or more of the instruments from the IDEXX VetLab suite of analyzers, diagnostic imaging systems or practice management software, combined with one or more of the following products: EMAs, consumables, rapid assay kits and reference laboratory diagnostic and consulting services. Practice management software is frequently sold with post-contract customer support and implementation services. Delivery of the various products or performance of services within the arrangement may or may not coincide. Delivery of our IDEXX VetLab instruments, diagnostic imaging systems, and practice management software generally occurs at the onset of the arrangement. EMAs, consumables, rapid assay kits, and reference laboratory diagnostic and consulting services typically are delivered over future periods, generally one to six years . In certain arrangements, revenue recognized is limited to the amount invoiced or received that is not contingent on the delivery of products and services in the future.  W e allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition, as discussed above, have been met for each element. If available, we establish the selling price of each element based on vendor-specific objective evidence (“VSOE”), which represents the price charged for a deliverable when it is sold separately. We use third-party evidence (“TPE”) if VSOE is not available or best estimate of selling price if neither VSOE nor TPE is available. When these arrangements include a separately-priced EMA, we recognize revenue related to the EMA at the stated contractual price on a straight-line basis over the life of the agreement to the extent the separately stated price is substantive. If there is no stated contractual price for an EMA, or the separately stated price is not substantive, we allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition, as discussed above, have been met for each element .  When arrangements within the scope of software revenue recognition guidance include multiple elements, we allocate revenue to each element based on relative fair value, when VSOE exists for all elements, or by using the residual method when there is VSOE for the undelivered elements but no such evidence for the delivered elements. Under the residual method, the fair value of the undelivered elements is deferred and the residual revenue is allocated to the delivered elements. Revenue is recognized on any delivered elements when the four criteria for revenue recognition have been met for each element. If VSOE does not exist for the undelivered element, all revenue from the arrangement is deferred until the earlier of the point at which such sufficient VSOE does exist or all elements of the arrangement have been delivered. We determine fair value based on amounts charged separately for the delivered and undelivered elements to similar customers in standalone sales of the specific elements.  Certain arrangements with customers include discounts on future sales of products and services. We apply judgment in determining whether future discounts are significant and incremental. When the future discount offered is not considered significant and incremental, we do not account for the discount as an element of the original arrangement. If the future discount is significant and incremental, we recognize that discount as an element of the original arrangement and allocate the discount to the other elements of the arrangement based on relative selling price. To determine whether a discount is significant and incremental, we look to the discount provided in comparison to standalone sales of the same product or service to similar customers, the level of discount provided on other elements in the arrangement, and the significance of the discount to the overall arrangement. If the discount in the MEA approximates the discount typically provided in standalone sales, that discount is not considered incremental.  Customer Programs . We record reductions to revenue related to customer marketing and incentive programs, which include end-user rebates and other volume-based incentives. Incentives may be provided in the form of IDEXX Points, credits or cash and are earned by end users upon achieving defined volume purchases or utilization levels or upon entering an agreement to purchase products or services in future periods. These amounts are presented on a net basis when applicable, which accounts for any differences between estimates and actual incentives earned for the relevant customer marketing or incentive program. These differences have been insignificant in all quarterly or annual periods. Our most significant customer programs are categorized as follows:  Customer Loyalty Programs . Our customer loyalty programs offer customers the opportunity to earn incentives on a variety of IDEXX products and services as those products and services are purchased and utilized. Revenue reductions related to customer loyalty programs are recorded based on the actual issuance of incentives, incentives earned but not yet issued and estimates of incentives to be earned in the future.  Up-Front Customer Loyalty Programs . Our up-front loyalty programs provide incentives to customers in the form of cash payments or IDEXX Points upon entering multi-year agreements to purchase annual minimum amounts of future products or services. We predominately offer up-front loyalty incentives in response to competitive offerings. If a customer breaches its agreement, they are required to refund all or a portion of the up-front cash or IDEXX Points, or make other repayments, remedial actions, or both. These incentives are considered to be customer acquisition costs and are capitalized within other current assets and other long-term assets and are subsequently recognized as a reduction to revenue over the term of the customer agreement. If these up-front incentives are subsequently utilized to purchase IDEXX VetLab instruments, diagnostic imaging systems or Cornerstone practice management systems, product revenue and cost is deferred and recognized over the term of the customer agreement as products and services are provided to the customer. We monitor customer purchases over the term of their agreement to assess the realizability of our capitalized customer acquisition costs. For the years ended December 31, 2017, 2016 and 2015, impairments of customer acquisition costs were immaterial.  IDEXX Instrument Marketing Programs . Our instrument marketing programs require the customer to enroll at the time of instrument purchase and offer customers the opportunity to earn incentives in future periods based on the volume of the products they purchase and utilize over the term of the program. These arrangements are considered MEAs in accordance with our revenue recognition policy stated above. Revenue reductions related to instrument marketing programs are recorded based on an estimate of customer purchase and utilization levels and the incentive the customer will earn over the term of the program. Our estimates are based on historical experience and the specific terms and conditions of the marketing program, requiring us to apply judgment to estimate future product purchases and utilization. Differences between our estimates and actual incentives earned are accounted for as a change in estimate. These differences were not material for the years ended December 31, 2017, 2016 and 2015. At December 31, 2017, a 5 percent change in our estimate of future customer utilization would increase or reduce revenue by approximately $0.4 million.  Reagent Rental Programs . Our reagent rental programs provide customers the right to use our instruments in consideration for multi-year agreements to purchase annual minimum amounts of consumables. No instrument revenue is recognized at the time of instrument installation. We recognize a portion of the revenue allocated to the instrument concurrent with the future sale of consumables. We determine the amount of revenue allocated from the consumable to the instrument based on relative selling prices and determine the rate of instrument revenue recognition in proportion to the customer’s minimum volume commitment. The cost of the instrument is capitalized within property and equipment or deferred within other assets, and is charged to cost of product revenue on a straight-line basis over the term of the minimum purchase agreement.  IDEXX Points are considered the same as cash and may be applied against the purchase price of IDEXX products and services or applied to trade receivables due to us. IDEXX Points that have not yet been used by customers are classified as a liability until use or expiration occurs. We estimate the amount of IDEXX Points expected to expire, or breakage, based on historical expirations and we recognize the estimated benefit of breakage in proportion to actual redemptions of IDEXX Points by customers. On November 30 of each year, unused IDEXX Points earned before January 1 of the prior year generally expire and any variance from the breakage estimate is accounted for as a change in estimate. This variance was not material for the years ended December 31, 2017, 2016 and 2015.  Future market conditions and changes in product offerings may cause us to change marketing strategies to increase or decrease customer incentive offerings, possibly resulting in incremental reductions of revenue in future periods as compared to reductions in the current or prior periods. Additionally, certain customer programs require us to estimate, based on historical experience, and apply judgment to predict the number of customers who will actually redeem the incentive. In determining estimated revenue reductions, we utilize data collected directly from end users, which includes the volume of qualifying products purchased and the number of qualifying tests run as reported to us by end users via IDEXX SmartService , a secure internet link that enables us to extract data and provide diagnostic service and support for certain IDEXX VetLab instruments through remote access. Differences between estimated and actual customer participation in programs may impact the amount and timing of revenue recognition.  Doubtful Accounts Receivable . We recognize revenue when collection from the customer is reasonably assured. We maintain allowances for doubtful accounts for potentially uncollectible receivables. We base our estimates on a detailed analysis of specific customer situations and a percentage of our accounts receivable by aging category. Additional allowances may be required if either the financial condition of our customers was to deteriorate or a strengthening U.S. dollar impacts the ability of foreign customers to make payments to us on their U.S. denominated purchases. Account balances are charged off against the allowance when we believe it is probable the receivable will not be recovered. We do not have any off-balance sheet credit exposure related to our customers. We have no significant customers that accounted for greater than 10 percent of our consolidated revenues for the year ended December 31, 2017. Similarly, we have no concentration of credit risk as of December 31, 2017.
Research And Development Costs	(k) Research and Development Costs  Research and development costs, which consist of salaries, employee benefits, materials and external consulting and product development costs, are expensed as incurred. We evaluate our software research and development costs for capitalization after the technological feasibility of software and products containing software has been established. No costs were capitalized during the years ended December 31, 2017, 2016 and 2015.
Advertising Costs	 (l) Advertising Costs  Advertising costs, which are recognized as sales and marketing expense in the period in which they are incurred, were $ 1.7 million, $2.1 million, and $1.2 million for the years ended December 31, 2017, 2016 and 2015, respectively.
Legal Costs	(m) Legal Costs  Legal costs are considered period costs and accordingly are expensed in the year services are provided.
Self-Insurnace Accruals	 (o) Self-Insurance Accruals  We self-insure costs associated with health, workers’ compensation, and general welfare claims incurred by our U.S. and Canadian employees up to certain limits. Insurance companies provide insurance for claims above these limits. Claim liabilities are recorded for estimates of the loss that we will ultimately incur on reported claims, as well as estimates of claims that have been incurred but not yet reported. Such liabilities are based on individual coverage, the average time from when a claim is incurred to the time it is paid and judgments about the present and expected levels of claim frequency and severity. Estimated claim liabilities could be significantly affected if future occurrences and claims differ from these assumptions and historical trends. Estimated claim liabilities are included in accrued liabilities in the accompanying consolidated balance sheets.
Foreign Currency	(r) Foreign Currency  The functional currency of all but three of our subsidiaries is their local currency. Assets and liabilities of these foreign subsidiaries are translated to the U.S. dollar using the exchange rate in effect at the balance sheet date. Revenue and expense accounts are translated to the U.S. dollar using the exchange rate at the date which those elements are recognized, and where it is impractical to do so, an average exchange rate in effect during the period is used to translate those elements. Cumulative translation gains and losses are shown in the accompanying consolidated balance sheets as a separate component of accumulated other comprehensive income (“AOCI”) .  Revenues and expenses denominated in a currency other than the respective subsidiary’s functional currency are recorded at the current exchange rate when the transaction is recognized. Monetary assets and liabilities denominated in a currency other than the respective subsidiary’s functional currency are remeasured at each balance sheet date using the exchange rate in effect at each balance sheet date. These foreign currency gains and losses are included in general and administrative expenses. We recognized aggregate foreign currency gains of $1.1 million for the year ended December 31, 2017, losses of $ 1.3 million for the year ended December 31, 2016, and losses of $ 0.2 million for the year ended December 31, 2015.
Comprehensive Income	(u) Comprehensive Income  We report all changes in equity, including net income and transactions or other events and circumstances from non-owner sources during the period in which they are recognized. We have chosen to present comprehensive income, which encompasses net income, foreign currency translation adjustments, gains and losses on our net investment hedge and the difference between the cost and the fair market value of investments in debt and equity securities, forward currency exchange contracts and interest rate swap agreements, in the consolidated statements of comprehensive income. S ee Note 19 for information about the effects on net income of significant amounts reclassified out of each component of AOCI for the years ended December 31, 2017, 2016 and 2015.
Concentrations Of Risk	(v) Concentrations of Risk  Financial Instruments . Financial instruments that potentially subject us to concentrations of credit risk are principally cash, cash equivalents, accounts receivable and derivatives. To mitigate such risk with respect to cash and cash equivalents, we place our cash with highly-rated financial institutions, in non-interest bearing accounts that are insured by the U.S. government and money market funds invested in government securities. Concentration of credit risk with respect to accounts receivable is limited to certain customers to whom we make substantial sales. To reduce risk, we routinely assess the financial strength of our most significant customers and monitor the amounts owed to us, taking appropriate action when necessary. As a result, we believe that accounts receivable credit risk exposure is limited. We maintain an allowance for doubtful accounts, but historically have not experienced any material losses related to an individual customer or group of customers in any particular industry or geographic area.  To mitigate concentration of credit risk with respect to derivatives we enter into transactions with highly-rated financial institutions, enter into master netting arrangements with counterparties to our derivative transactions and frequently monitor the credit worthiness of our counterparties. Our master netting arrangements reduce our exposure in that they permit outstanding receivables and payables with the counterparties to our derivative transactions to be offset in the event of default. We have not incurred such losses and consider the risk of counterparty default to be minimal.  Inventory . If we are unable to obtain adequate quantities of the inventory we need to sell our products, we could face cost increases or delays or discontinuations in product shipments, which could have a material adverse effect on our results of operations. Many of the third parties that provide us with the instruments we sell and certain components, raw materials and consumables used in or with our products are obtained from sole or single source suppliers. Some of the products that we purchase from these sources are proprietary or complex in nature, and, therefore, cannot be readily or easily replaced by alternative sources.
New Accounting Pronouncements Adopted	(w) New Accounting Pronouncements Adopted  Effective January 1, 2017, we adopted the FASB Accounting Standard Update (“ASU”) 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting which simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, recognition of stock compensation award forfeitures, classification of awards as either equity or liabilities, the calculation of diluted shares outstanding and classification on the statement of cash flows.  The following table summarizes the most significant impacts of the new accounting guidance for the years ended December 31, 2017 and 2016, as applicable:      Description of Change: Impact of Change: Adoption Method:  Tax benefits related to share-based payments at settlement are recorded through the income statement instead of equity Decrease in income tax expense by approximately $27.7 million for the year ended December 31, 2017 Prospective (required)   Calculation of diluted shares outstanding under the treasury method will no longer assume that tax benefits related to share-based payments are used to repurchase common stock Increase in the weighted average diluted shares outstanding by approximately 450,000 shares for the year ended December 31, 2017 Prospective (required)   An election can be made to reduce share-based compensation expense for forfeitures as they occur instead of estimating forfeitures that are expected to occur No change to share-based compensation expense, as we have elected to continue to estimate forfeitures that are expected to occur N/A   Tax benefits related to share-based payments at settlement are classified as operating cash flows instead of financing cash flows Increase in cash flow from operating activities and decreases in cash flow from financing activities by approximately $27.7 million for the year ended December 31, 2017 Prospective (elected)   Cash payments to tax authorities for shares withheld to meet employee tax withholding requirements on restricted stock units are classified as financing cash flow instead of operating cash flow Increases in cash flow from operating activities and decreases in cash flow from financing activities for the years ended December 31, 2017 , 2016 and 2015 by approximately $8.1 million, $4.4 million, and $5.4 million, respectively Retrospective (required) Effective July 1, 2017, we adopted ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business , which amended the definition of a business to be an integrated set of activities and assets that is capable of being conducted and managed for the purpose of providing a return in the form of dividends, lower costs, or other economic benefits directly to investors or other owners, members, or participants. In order to be considered a business, the three elements of inputs, processes and outputs must be present. In a business acquisition, if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the integrated set of assets and activities acquired is not considered a business. We began using this guidance in analyzing acquisitions and disposals in the third quarter of 2017. This amendment may impact the allocation of purchase price in future acquisitions that are determined to be asset acquisitions as opposed to business combinations, however during the third and fourth quarters of 2017 there was no material impact on our consolidated financial statements.
New Accounting Pronouncements Not Yet Adopted	(x) New Accounting Pronouncements Not Yet Adopted  In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (the “New Revenue Standard”), which will replace most of the existing revenue recognition guidance within U.S. GAAP. The FASB has also issued several updates to ASU 2014-09. The core principle of ASU 2014-09 is that an entity should recognize revenue for the transfer of goods or services to customers in an amount that it expects to be entitled to receive for those goods or services. In doing so, companies will be required to make certain judgments and estimates, including identifying contract performance obligations, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price among separate performance obligations. Additionally, disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, significant judgments reached in the application of the guidance and assets recognized from the costs to obtain or fulfill a contract will be required. In July 2015, the FASB approved a one-year deferral of the effective date to all annual and interim periods beginning after December 15, 2017. The new guidance permits two methods of adoption: a full retrospective method to each prior reporting period presented or a modified retrospective approach with the cumulative effect of initially applying the guidance recognized at the date of initial application. We will adopt ASU 2014-09, as amended, in the first quarter of 2018 on a modified-retrospective basis.  Since the issuance of ASU 2014-09, we have been preparing for the adoption of the New Revenue Standard. We have been monitoring the activity of the FASB and the Transition Resource Group as it relates to specific industry interpretive guidance and overall interpretations and clarifications. We developed a three-phase adoption plan and have completed Phase I and Phase II. Phase I included activities such as establishing a transition team and assessing significant revenue streams and representative contracts to determine potential changes to existing accounting policies. Phase II of our adoption plan, in which we further determine the impact of adoption, includes activities such as validating and concluding on changes to existing accounting policies, quantifying the effects on our consolidated financial statements, evaluating expanded disclosure requirements and addressing the impact on business processes, systems, and internal controls. Phase III of our adoption plan will complete our adoption and implementation of the New Revenue Standard during the first quarter of 2018 and will include activities such as running parallel reporting for impacted areas under the New Revenue Standard and the current standard, recording the accounting adjustments that were identified in Phase II, evaluating and testing modified and newly implemented internal controls over the New Revenue Standard, and revising our financial statements disclosures.  While ASU 2014-09 will not impact the overall economics of our products and services sold under customer marketing and incentive programs, we expect the New Revenue Standard will require us to accelerate revenue recognition related to certain of our customer programs and to delay revenue recognition for certain other customer programs. We expect to accelerate revenue recognition on instruments and systems placed through programs where customers are committed to purchase future goods and services, including our up-front customer loyalty and volume commitment programs. This change is the result of the New Revenue Standard no longer limiting revenue recognition to the amount of customer consideration received upon placement. Conversely, we expect to defer an increased portion of revenue related to instrument placements under programs that provide rebate incentives on future purchases, including certain of our IDEXX instrument marketing programs. Under the New Revenue Standard, future purchases that are optional and not subject to a customer commitment, are not considered part of the customer arrangement, resulting in the instrument absorbing a higher relative allocation of rebate incentives. We expect this change to result in lower instrument revenue upon placement and higher recurring revenues over the terms of the rebate incentive programs. Additionally, adoption of the New Revenue Standard will result in earlier recognition of consumables, rapid assay test kits and other diagnostic products due to revenue recognition upon shipment, as compared to upon delivery to the customer. Furthermore, the New Revenue Standard requires the deferral of incremental costs to obtain a customer contract over the term of the customer arrangement, such as sales commissions. We are in the process of converting our financial statements in accordance with ASU 2014-09 and expect to record a charge to retained earnings of less than $10 million in the first quarter of 2018.  In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , to increase transparency and comparability among organizations’ leasing arrangements. The FASB has also issued updates to ASU 2016-02. The principal difference from previous guidance is that effect ive upon adoption, the lease assets and lease liabilities arising from operating leases will be recognized in the balance sheet. For public business entities, the amendments in this update are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. In transition, we are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach, including the option to utilize a number of practical expedients. We are in process of evaluating our lessee and lessor arrangements to determine the impact of this amendment on the consolidated financial statements. This evaluation includes an extensive review of revenue through leasing arrangements as well as lease expenses, which are primarily through operating lease arrangements for most of our facilities. We currently expect that most of our operating lease commitments will be subject to the new standard and recognized as operating lease liabilities and right-of-use assets upon our adoption, which will increase our total assets and total liabilities that we report relative to such amounts prior to adoption.  In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) , which require that financial assets measured at amortized cost be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net carrying value at the amount expected to be collected. The income statement reflects the measurement of credit losses for newly recognized financial assets, as well as the increases or decreases of expected credit losses that have taken place during the period. The measurement of expected credit losses is based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down to the security. Credit losses on available-for-sale securities will be required when the amortized cost is below the fair market value. During 2017, the amortized cost of our available-for-sale securities was within $0.2 million of the fair value. The amendments in this update are effective for fiscal years beginning after December 15, 2019 and interim periods within those annual periods. Early adoption for fiscal year beginning after December 15, 2018 is permitted. During 2018, with the passage of the Tax Act in the fourth quarter of 2017, we intend to liquidate our marketable securities which would result in no impact from t his amendment on our financial statements.  In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230) : Classification of Certain Cash Receipts and Cash Payments , which provide guidance on the statement of cash flows presentation of certain transactions where diversity in practice exists on the classification of certain cash receipts and payments. The effective date will be the first quarter of an entity’s fiscal year 2018. The amendment should be adopted using a retrospective transition approach, but may be applied prospectively if retrospective application would be impracticable. This amendment is not expected to have a material impact on our financial statements.  In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740) : Intra-Ent it y Transfers of Assets Other Than Inventory , that requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. The amendments are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. These amendments should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings at the beginning of the period adopted. We will adopt ASU 2016-16 in the first quarter of 2018 and estimate the cumulative-effect adjustment charge to retained earnings will be approximately $8 million.  In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash , to add guidance on the classification and presentation of restricted cash. These amendments require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We do not expect the adoption of the amendments to have a material impact on our consolidated financial statements.  In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other (Topic 350) , to simplify the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Instead, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill. The amendments are effective for annual or any interim goodwill impairment test in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We will be early adopting ASU 2017-04 during the first quarter of 2018. We do not expect the adoption to have a material impact on our consolidated financial statements .  In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting , which provides clarification on accounting for modifications in share-based payment awards. ASU 2017-09 is effective for fiscal years beginning after December 15, 2017, with early adoption permitted. The adoption of this guidance is not expected to have an impact on our consolidated financial statements or related disclosures unless there are modifications to our share-based payment awards.  In August 2017, the FASB issued ASU 2017- 12, Derivatives and Hedging (Topic 815) . The new standard amends the hedge accounting recognition and presentation requirements. The ASU also simplifies the application of the hedge accounting guidance. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The adoption of this guidance is not expected to have an impact on our consolidated financial statements or related disclosures.

Share-Based Compensation (Polic

Share-Based Compensation (Policy)	12 Months Ended
	Dec. 31, 2017
Share-Based Compensation [Abstract]
Share-Based Compensation Policy	We provide for various forms of share-based compensation awards to our employees and non-employee directors. Our share-based compensation plans allow for the issuance of a mix of stock options, restricted stock, stock appreciation rights, employee stock purchase rights and other stock unit awards. With the exception of stock options, the fair value of our awards is equal to the closing stock price of IDEXX common stock on the date of grant. We calculate the fair value of our stock option awards using the Black-Scholes-Merton option-pricing model. For stock options, restricted stock units (“RSUs”), and “deferred stock units (DSUs”), s hare-based compensation expense is recognized net of estimated forfeitures, on a straight-line basis over the requisite service period of the award for stock options . For performance-based restricted stock units (PBRSUs”), s

Marketable Securities (Policy)

Marketable Securities (Policy)	12 Months Ended
	Dec. 31, 2017
Marketable Securities [Abstract]
Marketable Securities	During the year ended December 31, 2017, we purchased marketable debt securities, which are classified as available-for-sale and carried at fair value in the accompanying consolidated balance sheets on a trade date basis. We have classified our investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Unrealized holding gains and losses are deferred within accumulated other comprehensive income (“AOCI”), net of applicable taxes, except when an impairment is determined to be other-than-temporary or the security is divested prior to maturity. Within the accompanying consolidated statements of operations, interest earned and amortization of premiums or discounts on marketable securities are included in interest income, and realized gains and losses on the sale of our marketable securities are included in other income. 

Inventories (Policy)

Inventories (Policy)	12 Months Ended
	Dec. 31, 2017
Inventories [Abstract]
Inventories	Inventories are stated at the lower of cost (first-in, first-out) or net realizable value . Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We write down the carrying value of inventory for estimated obsolescence by an amount equal to the difference between the cost of inventory and the estimated market value when warranted based on assumptions of future demand, market conditions, remaining shelf life, or product functionality. If actual market conditions or results of estimated functionality are less favorable than those we estimated, additional inventory write-downs may be required, which would have a negative effect on results of operations.

Property And Equipment, Net (Po

Property And Equipment, Net (Policy)	12 Months Ended
	Dec. 31, 2017
Property And Equipment, Net [Abstract]
Property And Equipment	Property and equipment are stated at cost, net of accumulated depreciation and amortization. The costs of additions and improvements are capitalized, while maintenance and repairs are charged to expense as incurred. When an item is sold or retired, the cost and related accumulated depreciation is relieved, and the resulting gain or loss, if any, is recognized in the consolidated statements of income. We evaluate our property and equipment for impairment periodically or as changes in circumstances or the occurrence of events suggest the remaining value is not recoverable from future cash flows. If the carrying value of our property and equipment is impaired, an impairment charge is recorded for the amount by which the carrying value of the property and equipment exceeds its fair value. We provide for depreciation and amortization primarily using the straight-line method by charges to income in amounts that allocate the cost of property and equipment over their estimated useful lives as follows:  Asset Classification Estimated Useful Life  Land improvements 15 to 20 years Buildings and improvements 10 to 40 years Leasehold improvements Shorter of remaining lease term or useful life of improvements Machinery and equipment 3 to 8 years Office furniture and equipment 3 to 7 years Computer hardware and software 3 to 7 years  We capitalize interest on the acquisition and construction of significant assets that require a substantial period of time to be made ready for use. The capitalized interest is included in the cost of the completed asset and depreciated over the asset’s estimated useful life. The amount of interest capitalized during the years ended December 31, 2017 and 2016, was not material.  We capitalize certain costs incurred in connection with developing or obtaining software designated for internal use based on three distinct stages of development. Qualifying costs incurred during the application development stage, which consist primarily of internal payroll and direct fringe benefits and external direct project costs, including labor and travel, are capitalized and amortized on a straight-line basis over the estimated useful life of the asset. Costs incurred during the preliminary project and post-implementation and operation phases are expensed as incurred. These costs are general and administrative in nature and relate primarily to the determination of performance requirements, data conversion and training. Software developed to deliver hosted services to our customers has been designated as internal use.

Goodwill and Intangible Asset37

Goodwill and Intangible Assets, Net (Policy)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets, Net [Abstract]
Goodwill And Other Intangible Assets	A significant portion of the purchase price for acquired businesses is generally assigned to intangible assets. Intangible assets other than goodwill are initially valued at fair value. If a quoted price in an active market for the identical asset is not readily available at the measurement date, the fair value of the intangible asset is estimated based on discounted cash flows using market participant assumptions, which are assumptions that are not specific to IDEXX. The selection of appropriate valuation methodologies and the estimation of discounted cash flows require significant assumptions about the timing and amounts of future cash flows, risks, appropriate discount rates, and the useful lives of intangible assets. When material, we utilize independent valuation experts to advise and assist us in determining the fair values of the identified intangible assets acquired in connection with a business acquisition and in determining appropriate amortization methods and periods for those intangible assets. Goodwill is initially valued based on the excess of the purchase price of a business combination over the fair value of acquired net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized.  Our business combinations regularly include contingent consideration arrangements that require additional consideration to be paid based on the achievement of established objectives, most commonly related to the retention or growth of the customer base during the post-combination period. We assess contingent consideration to determine if it is part of the business combination or if it should be accounted for separately from the business combination in the post-combination period. Contingent consideration is recognized at its fair value on the acquisition date. A liability resulting from contingent consideration is remeasured to fair value at each reporting date until the contingency is resolved, with changes in fair value recognized in earnings. Changes in fair value of contingent consideration and differences arising upon settlement were not material during the years ended December 31, 2017, 2016 and 2015. See Note 3 for additional information regarding contingent consideration arising from recent business acquisitions.  We assess goodwill for impairment annually, at the reporting unit level, in the fourth quarter and whenever events or circumstances indicate impairment may exist. In evaluating goodwill for impairment, we have the option to first assess the qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill i mpairment test. The more likely than not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events or circumstances, we determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, we would then perform step one of the two-step impairment test; otherwise, no further impairment test would be required. In contrast, we can opt to bypass the qualitative assessment for any reporting unit in any period and proceed directly to step one of the two-step impairment test. Doing so does not preclude us from performing the qualitative assessment in any subsequent period.  In the fourth quarter of 2017, we elected to bypass the qualitative approach and instead proceeded directly to step one of the two-step impairment test to assess the fair value of all of our reporting units. As part of step one of the two-step impairment test, we estimate the fair values of applicable reporting units using an income approach based on discounted forecasted cash flows. We make significant assumptions about the extent and timing of future cash flows, growth rates and discount rates. Model assumptions are based on our projections and best estimates, using appropriate and customary market participant assumptions. In addition, we make certain assumptions in allocating shared assets and liabilities to individual reporting units in determining the carrying value of each reporting unit. Changes in forecasted cash flows or the discount rate would affect the estimated fair values of our reporting units and could result in a goodwill impairment charge in a future period.  No goodwill impairments were identified during the years ended December 31, 2017, 2016 or 2015.  We assess the realizability of intangible assets other than goodwill whenever events or changes in circumstances indicate that the carrying value may not be recoverable. If an impairment review is triggered, we evaluate the carrying value of intangible assets based on estimated undiscounted future cash flows over the remaining useful life of the primary asset of the asset group and compare that value to the carrying value of the asset group. The cash flows that are used contain our best estimates, using appropriate and customary assumptions and projections at the time. If the net carrying value of an intangible asset exceeds the related estimated undiscounted future cash flows, an impairment to adjust the intangible asset to its fair value would be reported as a non-cash charge to earnings. If necessary, we would calculate the fair value of an intangible asset using the present value of the estimated future cash flows to be generated by the intangible asset, and applying a risk-adjusted discount rate. We had no impairments of our intangible assets during the year ended December 31, 2017.  During the first half of 2016, management reviewed the OPTI Medical product offerings. As a result of this review, we discontinued certain development activities in the human point-of-care medical diagnostics market during March 2016 that was devoted to a new platform and focused our efforts in this market on supporting our current generation OPTI CCA-TS2 Blood Gas and Electrolyte analyzer. Non-cash intangible asset impairments of $2.2 million were recorded within our condensed consolidated statement of operations , within general and administrative expenses , within our unallocated segment, during 2016. The intangibles associated with our OPTI Medical human point-of-care medical diagnostics market are fully written off. Impairments of our intangible assets during the year ended December 31, 2015, were not material.  We provide for amortization primarily using the straight-line method by charges to income in amounts that allocate the intangible assets over their estimated useful lives as follows:   Asset Classification Estimated Useful Life  Patents 13 years Product rights (1) 5 to 15 years Customer-related intangible assets (2) 5 to 17 years Noncompete agreements 3 to 5 years (1) Product rights comprise certain technologies, intellectual property, licenses , and trade names acquired from third parties. (2) Customer-related intangible assets are comprise d of customer lists and customer relationships acquired from third parties.

Income Taxes (Policy)

Income Taxes (Policy)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	The Tax Cuts and Jobs Act (the “Tax Act”) was enacted on December 22, 2017, and includes significant changes to the U.S. corporate tax system. Effective January 1, 2018, the Tax Act reduced the U.S. federal corporate tax rate from 35 percent to 21 percent, and transitioned the U.S. federal tax system from a worldwide tax system to a territorial tax system, and eliminated or reduced certain domestic deductions among other changes. In converting to the new territorial tax system, a deemed repatriation tax on previously tax-deferred earnings of certain foreign subsidiaries was required to be recognized as of December 31, 2017, and will be payable over eight years.  On December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”) that provides additional guidance allowing companies to apply a measurement period of up to twelve months to account for the impacts of the Tax Act in their financial statements.  As of December 31, 2017, w e have accounted for the impacts of the Tax Act to the extent a re asonable estimate could be made and we recognized provisional amount s related to the deemed repatriation tax, offset by the re measurement of our deferred tax assets and liabilities , and other adjustments . The provisional amount s are included as a component of income tax expense from continuing operations as a reasonable estimate of the effects of the Tax Act on our U.S. federal and state tax obligations. We will continue to refine our estimates throughout the measurement period or until the ac counting is complete as allowed under SAB 118 .  As a result of the Tax Act we are no longer asserting indefinite reversal under ASC 740-30-25 for undistributed earnings of non-U.S. subsidiaries as of December 31, 2017. We have recorded a provisional amount of $48.8 million for the deemed repatriation tax liability related to these earnings.  The provision for income taxes is determined using the asset and liability approach of accounting for income taxes. Under this approach, deferred taxes represent the estimated future tax effects of temporary differences between book and tax treatment of assets and liabilities and carryforwards to the extent they are realizable. We record a valuation allowance to reduce our deferred tax assets to the amount that is more likely than not to be realized. While we consider future taxable income and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance, in the event we determine that we would be able to realize our deferred tax assets in the future in excess of the net recorded amount, a reduction of the valuation allowance would increase income in the period such determination was made. Likewise, should we determine that we would not be able to realize all or part of our net deferred tax asset in the future, a reduction to the deferred tax asset would be charged to income in the period such determination was made. 

Earnings Per Share (Policy)

Earnings Per Share (Policy)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share Policy	Basic earnings per share is computed by dividing net income attributable to IDEXX Laboratories, Inc. stockholders by the weighted average number of shares of common stock and vested deferred stock units outstanding during the year. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and assumed issuance of unvested restricted stock units and unvested deferred stock units using the treasury stock method unless the effect is anti-dilutive. The treasury stock method assumes that proceeds, including cash received from the exercise of employee stock options, the total unrecognized compensation expense for unvested share-based compensation awards and, prior to the adoption of new accounting guidance related to share-based compensation on January 1, 2017, the tax benefits resulting from share-based compensation tax deductions in excess of the related expense recognized for financial reporting purposes, would be used to purchase our common stock at the average market price during the period. For further discussion regarding the impact of the new accounting guidance related to share-based compensation, see Note 2. Vested deferred stock units outstanding are included in shares outstanding for basic and diluted earnings per share because the associated shares of our common stock are issuable for no cash consideration, the number of shares of our common stock to be issued is fixed and issuance is not contingent. See Note 4 for additional information regarding deferred stock units.

Commitments, Contingencies An40

Commitments, Contingencies And Guarantees (Policy)	12 Months Ended
	Dec. 31, 2017
Commitments, Contingencies And Guarantees [Abstract]
Leases	The m ajority of our facilities are occupied under operating lease arrangements with various expiration dates through 20 30 . W e are responsible for the real estate taxes and operating expenses related to these facilities. Additional ly , we enter into operating leases for certain vehicles and office equipment in the normal course of business . We determine the expected term of any executed agreements using the non-cancelable lease term plus any renewal options by which the failure to renew imposes a penalty in such amount that renewal is reasonably assured. The derived expected term is then used in the determination of a capital or operating lease and in the calculation of straight-line rent expense. Rent escalations are considered in the calculation of minimum lease payments in our capital lease tests and in determining straight-line rent expense for operating leases.

Fair Value Measurements (Policy

Fair Value Measurements (Policy)	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements [Abstract]
Fair Value Measurements Policy	U.S. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. U.S. GAAP requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value.  We have certain financial assets and liabilities that are measured at fair value on a recurring basis, certain nonfinancial assets and liabilities that may be measured at fair value on a non-recurring basis and certain financial assets and liabilities that are not measured at fair value in our consolidated balance sheets but for which we disclose the fair value. The fair value disclosures of these assets and liabilities are based on a three-level hierarchy, which is defined as follows: Level 1 Quoted prices in active markets for identical assets or liabilities that the entity can access at the measurement date. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.  Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.  Our marketable debt securities are initially valued at the transaction price and are subsequently remeasured to fair value as of the balance sheet date utilizing third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches and observable market inputs to determine value. Observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers and other industry and economic events. We validate the prices provided by our third-party pricing services by obtaining independent market values from other pricing sources and analyzing pricing data in certain instances .  Our foreign currency exchange contracts are measured at fair value on a recurring basis in our accompanying consolidated balance sheets. We measure the fair value of our foreign currency exchange contracts classified as derivative instruments using an income approach, based on prevailing market forward rates less the contract rate multiplied by the notional amount. The product of this calculation is then adjusted for counterparty risk.  Our interest rate swap agreement in prior years were measured at fair value on a recurring basis in our accompanying consolidated balance sheets. These interest rate swaps were classified as derivative instruments using an income approach, utilizing a discounted cash flow analysis based on the terms of the contract and the interest rate curve adjusted for counterparty risk.  The amount outstanding under our unsecured revolving credit facility and long-term debt are measured at carrying value in our accompanying consolidated balance sheets though we disclose the fair value of these financial instruments. We determine the fair value of the amount outstanding under our credit facility and long-term debt using an income approach, utilizing a discounted cash flow analysis based on current market interest rates for debt issues with similar remaining years to maturity, adjusted for applicable credit risk. Our credit facility and long-term debt are valued using Level 2 inputs. The estimated fair value of our credit facility approximates its carrying value. At December 31, 201 7 , the estimated fair value and carrying value of our long-term debt were $632.0 million and $ 606.6 million , respectively. At December 31, 201 6 , the estimated fair value and carrying value of our long-term debt were $609.5 million and $593.7 million, respectively.

Derivative Instruments And Hedg

Derivative Instruments And Hedging (Policy)	12 Months Ended
	Dec. 31, 2017
Hedging Instruments [Abstract]
Derivatives Policy	We recognize all derivative and non-derivative instruments (collectively “hedging instruments”) on the balance sheet at fair value at the balance sheet date. Instruments that do not qualify for hedge accounting treatment must be recorded at fair value through earnings. To qualify for hedge accounting treatment, cash flow and net investment hedges must be highly effective in offsetting changes to expected future cash flows or fair value on hedged transactions. If the instrument qualifies for hedge accounting, c hanges in the fair value of the hedging instrument from the effective portion of the hedge are deferred in AOCI, net of tax, and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. We immediately record in earnings the extent to which a hedging instrument is not effective in achieving offsetting changes in fair value. We de-designate hedging instruments from hedge accounting when the likelihood of the hedged transaction occurring becomes less than probable. For de-designated instruments, the gain or loss from the time of de-designation through maturity of the instrument is recognized in earnings. Any gain or loss in AOCI at the time of de-designation is reclassified into earnings in the same period or periods during which the hedged transaction affects earnings.  We enter into master netting arrangements with the counterparties to our derivative transactions which permit certain outstanding receivables and payables to be offset in the event of default. Our derivative contracts do not require either party to post cash collateral. We elect to present our derivative assets and liabilitie s in the accompanying consolidated balance sheets on a gross basis. All cash flows related to our foreign currency exchange contracts and interest rate swaps are classified as operating cash flows, which is consistent with the cash flow treatment of the underlying items being hedged.

Summary Of Significant Accoun43

Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Summary Of Significant Accounting Policies [Abstract]
Summary Of The Most Significant Impacts Of The New Accounting Guidance	  Description of Change: Impact of Change: Adoption Method:  Tax benefits related to share-based payments at settlement are recorded through the income statement instead of equity Decrease in income tax expense by approximately $27.7 million for the year ended December 31, 2017 Prospective (required)   Calculation of diluted shares outstanding under the treasury method will no longer assume that tax benefits related to share-based payments are used to repurchase common stock Increase in the weighted average diluted shares outstanding by approximately 450,000 shares for the year ended December 31, 2017 Prospective (required)   An election can be made to reduce share-based compensation expense for forfeitures as they occur instead of estimating forfeitures that are expected to occur No change to share-based compensation expense, as we have elected to continue to estimate forfeitures that are expected to occur N/A   Tax benefits related to share-based payments at settlement are classified as operating cash flows instead of financing cash flows Increase in cash flow from operating activities and decreases in cash flow from financing activities by approximately $27.7 million for the year ended December 31, 2017 Prospective (elected)   Cash payments to tax authorities for shares withheld to meet employee tax withholding requirements on restricted stock units are classified as financing cash flow instead of operating cash flow Increases in cash flow from operating activities and decreases in cash flow from financing activities for the years ended December 31, 2017 , 2016 and 2015 by approximately $8.1 million, $4.4 million, and $5.4 million, respectively Retrospective (required) 

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Share-Based Compensation [Abstract]
Schedule Of Selected Financial Impact Of Share-Based Compensation	   For the Years Ended December 31,  2017 2016 2015   Share-based compensation expense included in cost of revenue $ 2,675 $ 2,305 $ 2,138  Share-based compensation expense included in operating expenses 20,842 17,586 17,746  Total share-based compensation expense included in consolidated statements of income 23,517 19,891 19,884  Income tax benefit resulting from share-based compensation expense (6,810) (6,143) (6,229)  Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards 16,707 13,748 13,655  Income tax benefit resulting from settlement of share-based awards (1) (27,743) - -  Net (benefit) expense related to share-based compensation arrangements included in consolidated statements of income $ (11,036) $ 13,748 $ 13,655  (1) See Note 1(w) for more information regarding the adoption of ASU 2016-09.
Schedule Of Weighted Averages Of The Assumptions Used In Estimating The Fair Value Of Stock Option Awards	   For the Years Ended December 31,  2017 2016 2015   Share price at grant $ 142.89 $ 69.07 $ 78.08  Expected stock price volatility 26 % 25 % 23 %  Expected term, in years 5.8 5.7 5.6  Risk-free interest rate 2.0 % 1.2 % 1.5 %   Weighted average fair value of options granted $ 40.83 $ 17.87 $ 19.72 
Schedule Of Stock Option Activity	   Number of Options (000) Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value ($000)   Outstanding as of December 31, 2016 3,176 $ 57.31  Granted 384 142.89  Exercised (716) 42.66  Forfeited (117) 68.41  Outstanding as of December 31, 2017 2,727 $ 72.72 6.0 $ 228,243   Fully vested as of December 31, 2017 1,327 $ 56.06 4.2 $ 133,115   Fully vested and expected to vest as of December 31, 2017 2,649 $ 72.45 5.9 $ 222,422 
Schedule Of Restricted Stock Unit Activity	   Number of Units (000) Weighted Average Grant-Date Fair Value   Nonvested as of December 31, 2016 468 $ 64.88  Granted 97 142.27  Vested (155) 59.63  Forfeited (27) 76.56  Nonvested as of December 31, 2017 383 $ 85.74   Expected to vest as of December 31, 2017 357 $ 85.23 

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Marketable Securities [Abstract]
Amortized Cost And Fair Value Of Marketable Securities	  As of December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value   Corporate bonds $ 140,969 $ 96 $ (179) $ 140,886  Certificates of deposit 58,510 - - 58,510  Commercial paper 29,171 - - 29,171  Asset backed securities 22,206 4 (43) 22,167  U.S. government bonds 15,619 11 (19) 15,611  Agency bonds 10,990 9 (52) 10,947  Treasury bills 6,964 - (1) 6,963  Total marketable securities $ 284,429 $ 120 $ (294) $ 284,255   As of December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value   Corporate bonds $ 130,833 $ 40 $ (102) $ 130,771  Certificates of deposit 40,400 - - 40,400  Asset backed securities 27,290 25 - 27,315  Commercial paper 20,228 - - 20,228  U.S. government bonds 12,244 1 (14) 12,231  Agency bonds 4,600 4 - 4,604  Municipal bonds 1,400 - - 1,400  Total marketable securities $ 236,995 $ 70 $ (116) $ 236,949 
Contractual Maturities Of Marketable Securities	  As of December 31, 2017 Amortized Cost Fair Value   Due in one year or less $ 175,849 $ 175,780  Due after one through three years 108,580 108,475  $ 284,429 $ 284,255 

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2017
Inventories [Abstract]
Schedule Of Components Of Inventories	   December 31, December 31,  2017 2016   Raw materials $ 32,994 $ 27,561  Work-in-process 17,786 14,998  Finished goods 113,538 115,475  Total inventories $ 164,318 $ 158,034 

Property And Equipment, Net (Ta

Property And Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property And Equipment, Net [Abstract]
Schedule Of Estimated Useful Lives For Property And Equipment	 Asset Classification Estimated Useful Life  Land improvements 15 to 20 years Buildings and improvements 10 to 40 years Leasehold improvements Shorter of remaining lease term or useful life of improvements Machinery and equipment 3 to 8 years Office furniture and equipment 3 to 7 years Computer hardware and software 3 to 7 years 
Schedule Of Property And Equipment	  December 31, December 31,  2017 2016   Land and improvements $ 7,323 $ 7,255  Buildings and improvements 180,185 171,455  Leasehold improvements 52,227 44,568  Machinery and equipment 284,375 262,718  Office furniture and equipment 47,476 42,124  Computer hardware and software 206,580 189,327  Construction in progress 33,470 25,145  811,636 742,592  Less accumulated depreciation and amortization 432,540 385,170  Total property and equipment, net $ 379,096 $ 357,422 
Summary Of Depreciation And Amortization, Capitalized Computer Software For Internal Use And Unpaid Property Equipment Reflected In Account Payable And Accrued Expenses	  December 31, December 31, December 31,  2017 2016 2015   Depreciation and amortization expense $ 73,797 $ 63,537 $ 57,029  Capitalized computer software developed for internal use 16,131 15,590 19,081  Unpaid property and equipment, reflected in accounts payable and accrued liabilities 11,744 10,601 8,534 

Other Current and Noncurrent 48

Other Current and Noncurrent Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Other Current and Noncurrent Assets [Abstract]
Schedule Of Other Current Assets	   December 31, December 31,  2017 2016   Prepaid expenses $ 28,967 $ 25,746  Taxes receivable 35,475 27,672  Customer acquisition costs, net 23,520 18,085  Other assets 13,178 19,703  Total other current assets $ 101,140 $ 91,206 
Schedule Of Other Noncurrent Assets	  December 31, December 31,  2017 2016   Investment in long-term product supply arrangements $ 9,949 $ 10,978  Customer acquisition costs, net 64,670 50,309  Deferred income taxes 7,698 5,707  Other assets 36,299 36,321  Total other long-term assets $ 118,616 $ 103,315 

Goodwill And Intangible Asset49

Goodwill And Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets, Net [Abstract]
Schedule Of Estimated Useful Lives For Intangible Assets	  Asset Classification Estimated Useful Life  Patents 13 years Product rights (1) 5 to 15 years Customer-related intangible assets (2) 5 to 17 years Noncompete agreements 3 to 5 years (1) Product rights comprise certain technologies, intellectual property, licenses , and trade names acquired from third parties. (2) Customer-related intangible assets are comprise d of customer lists and customer relationships acquired from third parties.
Schedule Of Intangible Assets Other Than Goodwill	    December 31, 2017 December 31, 2016  Cost Accumulated Amortization Net Cost Accumulated Amortization Net  Patents $ - $ - $ - $ 2,192 $ 2,075 $ 117  Product rights (1) 32,558 25,251 7,307 29,748 20,877 8,871  Customer-related intangible assets (2) 80,398 44,382 36,016 74,922 38,190 36,732  Noncompete agreements 1,271 748 523 1,111 676 435  $ 114,227 $ 70,381 $ 43,846 $ 107,973 $ 61,818 $ 46,155 The above table excludes fully amortized intangible assets for the periods presented. (1) Product rights comprise certain technologies, licenses and trade names acquired from third parties. (2) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties.
Schedule Of Expected Amortization Expense	  Amortization Expense   2018 $ 8,142  2019 7,283  2020 5,857  2021 5,053  2022 4,027  Thereafter 13,484  $ 43,846 
Schedule Of Goodwill	  CAG Water LPD Other Consolidated Total  Balance as of December 31, 2014 $ 148,151 $ 13,689 $ 16,079 $ 6,531 $ 184,450  Business combinations 5,047 - - - 5,047  Impact of changes in foreign currency exchange rates (8,007) (651) (1,905) - (10,563)  Balance as of December 31, 2015 $ 145,191 $ 13,038 $ 14,174 $ 6,531 $ 178,934  Business combinations 1,720 - - - 1,720  Impact of changes in foreign currency exchange rates (717) (2,148) 439 - (2,426)  Balance as of December 31, 2016 $ 146,194 $ 10,890 $ 14,613 $ 6,531 $ 178,228  Business combinations 13,541 - - - 13,541  Impact of changes in foreign currency exchange rates 6,501 1,061 542 - 8,104  Balance as of December 31, 2017 $ 166,236 $ 11,951 $ 15,155 $ 6,531 $ 199,873 

Accrued Liabilities And Other50

Accrued Liabilities And Other Long Term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities And Other Long Term Liabilities [Abstract]
Schedule Of Accrued Liabilities	  December 31, December 31,  2017 2016   Accrued expenses $ 64,430 $ 71,984  Accrued employee compensation and related expenses 102,944 91,113  Accrued taxes 29,389 23,973  Accrued customer programs 56,655 49,061  Total accrued liabilities $ 253,418 $ 236,131 
Schedule of Other Long-term Liabilities	  December 31, December 31,  2017 2016   Accrued taxes $ 66,506 $ 18,798  Accrued customer programs 12,956 10,371  Other accrued long-term expenses 16,256 9,768  Total other long-term liabilities $ 95,718 $ 38,937 

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt [Abstract]
Schedule Of Annual Principal Payments On Long-Term Debt	   Years Ending December 31, Amount   2018 -  2019 -  2020 -  2021 50,000  2022 75,000  Thereafter 481,567  $ 606,567 

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Schedule Of Earnings Before Income Taxes	  For the Years Ended December 31,  2017 2016 2015   Domestic $ 268,714 $ 227,875 $ 187,200  International 112,343 93,971 85,941  $ 381,057 $ 321,846 $ 273,141 
Schedule Of Components Of Provision (Benefit) For Income Taxes	   For the Years Ended December 31,  2017 2016 2015  Current  Federal $ 92,453 $ 53,285 $ 52,966  State 9,258 6,608 5,353  International 23,993 19,291 17,681  125,704 79,184 76,000  Deferred  Federal (1,201) 20,305 5,762  State (4,102) 1,196 526  International (2,613) (893) (1,282)  (7,916) 20,608 5,006  $ 117,788 $ 99,792 $ 81,006 
Schedule Of Effective Income Tax Rate Reconciliation	 For the Years Ended December 31,  2017 2016 2015   U.S. federal statutory rate 35.0 % 35.0 % 35.0 %  State income tax, net of federal tax benefit 1.9 1.8 1.6  International income taxes (5.5) (4.8) (5.3)  Shares-based compensation from settlements (1) (6.7) - -  Domestic manufacturing exclusions (1.1) (1.0) (1.5)  Research and development credit (0.9) (0.8) (1.2)  Impact of the Tax Cuts and Jobs Act 9.4 - -  State income tax carryforwards (1.4) - -  Other, net 0.2 0.8 1.1  Effective tax rate 30.9 % 31.0 % 29.7 % (1) See Note 2(w) for the impact of the adoption of ASU 2016-09.
Schedule Of Components Of Net Deferred Tax Assets And Liabilities	   December 31, 2017 December 31, 2016   Assets  Accrued expenses $ 13,843 $ 22,145  Accounts receivable reserves 2,624 2,715  Deferred revenue 10,618 13,400  Inventory basis differences 3,039 3,959  Property-based differences 1,324 1,382  Share-based compensation 9,035 13,021  Other 918 678  Net operating loss carryforwards 3,350 4,182  Tax credit carryforwards 8,096 -  Unrealized losses on foreign currency exchange contracts, interest rate swaps and investments 2,355 148  Total assets 55,202 61,630  Valuation allowance (6,211) (4,891)  Total assets, net of valuation allowance 48,991 56,739   Liabilities  Deferred instrument costs (20,399) (24,142)  Property-based differences (31,859) (43,159)  Intangible asset basis differences (13,574) (17,672)  Other (656) (771)  Unrealized gains on foreign currency exchange contracts, interest rate swaps and investments (158) (4,575)  Total liabilities (66,646) (90,319)  Net deferred tax assets (liabilities) $ (17,655) $ (33,580) 
Schedule Of Changes In Unrecognized Tax Benefits	   For the Years Ended December 31,  2017 2016 2015   Total amounts of unrecognized tax benefits, beginning of period $ 18,463 $ 7,204 $ 5,942  Gross increases in unrecognized tax benefits as a result of tax positions taken during a prior period 74 75 47  Gross increases in unrecognized tax benefits as a result of tax positions taken in the current period 4,681 12,657 1,569  Decreases in unrecognized tax benefits relating to settlements with taxing authorities (713) (1,326) -  Decreases in unrecognized tax benefits as a result of a lapse of the applicable statutes of limitations (1,088) (147) (354)  Total amounts of unrecognized tax benefits, end of period $ 21,417 $ 18,463 $ 7,204 

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule Of Reconciliation Of Shares Outstanding For Basic And Diluted Earnings Per Share	  For the Years Ended December 31,  2017 2016 2015   Shares outstanding for basic earnings per share: 87,769 89,732 92,601   Shares outstanding for diluted earnings per share:  Shares outstanding for basic earnings per share 87,769 89,732 92,601  Dilutive effect of share-based payment awards 1,798 1,152 1,048  89,567 90,884 93,649 
Schedule Of Number Of Anti-Dilutive Stock Options	  For the Years Ended December 31,  2017 2016 2015   Weighted average number of shares underlying anti-dilutive options 327 88 644  

Commitments, Contingencies An54

Commitments, Contingencies And Guarantees (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments, Contingencies And Guarantees [Abstract]
Schedule Of Minimum Annual Rental Payments	   Years Ending December 31, Amount   2018 $ 19,233  2019 15,687  2020 11,974  2021 9,461  2022 7,139  Thereafter 32,435  $ 95,929 

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summary Of Segment Performance	   For the Years Ended December 31,  CAG Water LPD Other Unallocated Amounts Consolidated Total  2017  Revenue $ 1,703,377 $ 114,395 $ 128,481 $ 22,805 $ - $ 1,969,058   Income (loss) from operations $ 363,557 $ 50,616 $ 16,464 $ 4,837 $ (22,446) $ 413,028  Interest expense, net (31,971)  Income before provision for income taxes 381,057  Provision for income taxes 117,788  Net income 263,269  Less: Net income attributable to noncontrolling interest 125  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 263,144   Depreciation and amortization $ 71,835 $ 2,856 $ 5,052 $ 3,397 $ - $ 83,140  Expenditures for long-lived assets (1) $ 64,759 $ 2,573 $ 3,021 $ 4,031 $ - $ 74,384   2016  Revenue $ 1,522,689 $ 103,579 $ 126,491 $ 22,664 $ - $ 1,775,423   Income (loss) from operations $ 301,342 $ 45,702 $ 18,914 $ 884 $ (16,603) $ 350,239  Interest expense, net (28,393)  Income before provision for income taxes 321,846  Provision for income taxes 99,792  Net income 222,054  Less: Net income attributable to noncontrolling interest 9  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 222,045   Depreciation and amortization $ 64,878 $ 3,098 $ 5,543 $ 4,699 $ - $ 78,218  Expenditures for long-lived assets (1) $ 56,329 $ 2,102 $ 4,824 $ 1,532 $ - $ 64,787   2015  Revenue $ 1,356,287 $ 96,884 $ 127,143 $ 21,578 $ - $ 1,601,892   Income (loss) from operations $ 233,319 $ 44,752 $ 27,157 $ (137) $ (5,179) $ 299,912  Interest expense, net (26,771)  Income before provision for income taxes 273,141  Provision for income taxes 81,006  Net income 192,135  Less: Net loss attributable to noncontrolling interest 57  Net income attributable to IDEXX Laboratories, Inc. stockholders $ 192,078   Depreciation and amortization $ 60,715 $ 3,188 $ 4,367 $ 686 $ - $ 68,956  Expenditures for long-lived assets (1) $ 69,371 $ 2,781 $ 9,110 $ 1,659 $ - $ 82,921 __________ (1) Expenditures for long-lived assets exclude expenditures for intangible assets. See Note 3 for information regarding acquisitions of intangible assets during the years ended December 31, 201 7 , 201 6 and 2015 .
Summary Of Revenue By Product And Service Category	   For the Years Ended December 31,  2017 2016 2015  CAG segment revenue:  CAG Diagnostics recurring revenue: $ 1,451,701 $ 1,281,262 $ 1,147,026  IDEXX VetLab consumables 518,774 451,456 396,526  Rapid assay products 205,309 189,122 182,670  Reference laboratory diagnostic and consulting services 660,142 581,067 512,155  CAG Diagnostics service and accessories 67,476 59,617 55,675  CAG Diagnostics capital - instruments 119,963 121,191 98,502  Veterinary software, services and diagnostic imaging systems 131,713 120,236 110,759  CAG segment revenue 1,703,377 1,522,689 1,356,287   Water segment revenue 114,395 103,579 96,884  LPD segment revenue 128,481 126,491 127,143  Other segment revenue 22,805 22,664 21,578   Total revenue $ 1,969,058 $ 1,775,423 $ 1,601,892 
Schedule Of Revenue By Principal Geographic Area	   For the Years Ended December 31,  2017 2016 2015  Americas  United States $ 1,203,547 $ 1,089,595 $ 980,281  Canada 83,818 74,923 69,303  Latin America 46,893 38,872 34,725  1,334,258 1,203,390 1,084,309   Europe, the Middle East and Africa  Germany 88,328 80,156 73,395  United Kingdom 80,149 77,671 74,879  France 55,993 51,204 46,972  Italy 31,889 28,907 25,903  Spain 28,866 24,268 19,998  Switzerland 17,913 16,361 15,631  Netherlands 15,877 14,049 11,645  Other 100,409 83,147 79,910  419,424 375,763 348,333  Asia Pacific Region  Australia 56,994 52,871 49,274  China 55,810 48,257 40,619  Japan 53,344 51,544 43,171  Other 49,228 43,598 36,186  215,376 196,270 169,250  Total $ 1,969,058 $ 1,775,423 $ 1,601,892 
Schedule Of Net Long-Lived Assets By Principal Geographic Areas	  December 31, December 31,  2017 2016  Americas  United States $ 310,696 $ 298,944  Brazil 17,030 17,910  Canada 2,238 1,977  329,964 318,831  Europe, the Middle East and Africa  United Kingdom 11,528 9,127  Germany 7,522 5,040  Netherlands 8,225 5,948  France 2,305 2,428  Switzerland 1,755 2,450  Other 3,838 3,490  35,173 28,483  Asia Pacific Region  Japan 4,065 2,469  Australia 4,426 4,185  Other 5,468 3,454  13,959 10,108  Total $ 379,096 $ 357,422 

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements [Abstract]
Schedule Of Fair Value Of Assets And Liabilities Measured On Recurring Basis	  Quoted Prices Significant  in Active Other Significant  Markets for Observable Unobservable  Identical Assets Inputs Inputs Balance at  As of December 31, 2017 (Level 1) (Level 2) (Level 3) December 31, 2017   Assets  Money market funds (1) $ 32,962 $ - $ - $ 32,962  Certificates of deposit (1) $ - $ 1,250 $ - $ 1,250   Marketable securities  Corporate bonds $ - $ 140,886 $ - $ 140,886  Certificates of deposit - 58,510 - 58,510  Commercial paper - 29,171 - 29,171  Asset backed securities - 22,167 - 22,167  U.S. government bonds - 15,611 - 15,611  Agency bonds - 10,947 - 10,947  Treasury bills - 6,963 - 6,963  Total marketable securities $ - $ 284,255 $ - $ 284,255   Equity mutual funds (2) $ 2,162 $ - $ - $ 2,162  Foreign currency exchange contracts (3) $ - $ 477 $ - $ 477  Liabilities  Foreign currency exchange contracts (3) $ - $ 6,468 $ - $ 6,468  Deferred compensation (4) $ 2,162 $ - $ - $ 2,162     Quoted Prices Significant  in Active Other Significant  Markets for Observable Unobservable  Identical Assets Inputs Inputs Balance at  As of December 31, 2016 (Level 1) (Level 2) (Level 3) December 31, 2016   Assets  Money market funds (1) $ 34,208 $ - $ - $ 34,208  Certificates of deposit (1) $ - $ 1,500 $ - $ 1,500  Commercial paper (1) $ - $ 898 $ - $ 898   Marketable securities  Corporate bonds $ - $ 130,771 $ - $ 130,771  Certificates of deposit - 40,400 - 40,400  Asset backed securities - 27,315 - 27,315  Commercial paper - 20,228 - 20,228  U.S. government bonds - 12,231 - 12,231  Agency bonds - 4,604 - 4,604  Municipal bonds - 1,400 - 1,400  Total marketable securities $ - $ 236,949 $ - $ 236,949   Equity mutual funds (2) $ 2,182 $ - $ - $ 2,182  Foreign currency exchange contracts (3) $ - $ 8,926 $ - $ 8,926  Liabilities  Foreign currency exchange contracts (3) $ - $ 1,081 $ - $ 1,081  Deferred compensation (4) $ 2,182 $ - $ - $ 2,182 __________ (1) Money market funds, certificates of deposit and commercial paper with an original maturity of less than ninety days are included within cash and cash equivalents. The remaining balance of cash and cash equivalents as of December 31, 201 7, and December 31, 201 6, consisted of demand deposits. Commercial paper and certificates of deposit with an original maturity of over ninety days are included within marketable securities. (2) Equity mutual funds relate to a deferred compensation plan that was assumed as part of a previous business combination. This amount is include d within other long-term assets . See number (4) below for a discussion of the related deferred compensation liability. (3) Foreign currency exchange contracts are included within other current assets; other long-term assets; accrued liabilities; or other long-term liabilities depending on the gain (loss) position an d anticipated settlement date. (4) A deferred compensation plan assumed as part of a previous business combination is included within accrued liabilities and other long-term liabilities. The fair value of our deferred compensation plan is indexed to the performance of the underlying equity mutual funds discussed in number (2) above.

Hedging Instruments (Tables)

Hedging Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative [Line Items]
Gain/(Loss) Recognized In Other Comprehensive Income On Derivative Instruments (Effective Portion)	  Gain (Loss) Recognized in AOCI on Derivative Instruments (Effective Portion)  For Year Ended December 31,  Derivative instruments 2017 2016 2015   Foreign currency exchange contracts, net of tax $ (10,135) $ 2,457 $ (5,604)  Interest rate swaps, net of tax - 242 461  Total derivative instruments, net of tax $ (10,135) $ 2,699 $ (5,143) 
Assets [Member]
Derivative [Line Items]
Schedule Of Fair Values And Balance Sheet Classifications Of Derivatives Designated As Hedging Instruments	  Hedging Assets  December 31, December 31,  2017 2016   Derivatives designated as hedging instruments Balance Sheet Classification  Foreign currency exchange contracts Other current assets $ 477 $ 8,926  Total derivative instruments presented as cash flow hedges on the balance sheet 477 8,926  Gross amounts subject to master netting arrangements not offset on the balance sheet 477 679  Net amount $ - $ 8,247 
Liabilities [Member]
Derivative [Line Items]
Schedule Of Fair Values And Balance Sheet Classifications Of Derivatives Designated As Hedging Instruments	  Hedging Liabilities  December 31, December 31,  2017 2016   Derivatives designated as hedging instruments Balance Sheet Classification  Foreign currency exchange contracts Accrued liabilities $ 6,468 $ 1,081  Total derivative instruments presented as cash flow hedges on the balance sheet 6,468 1,081  Foreign currency borrowings designated as net investment hedge on the balance sheet Long-term debt 106,567 93,664  Total hedging instruments presented on the balance sheet 113,035 94,745  Gross amounts subject to master netting arrangements not offset on the balance sheet 477 679  Net amount $ 112,558 $ 94,066  

Repurchases Of Common Stock (Ta

Repurchases Of Common Stock (Tables)	12 Months Ended
	Dec. 31, 2017
Repurchases Of Common Stock [Abstract]
Schedule Of Common Stock Repurchases	   For the Years Ended December 31,  2017 2016 2015   Share repurchases during the period (1) 1,749 3,071 5,659  Shares acquired through employee surrender (1) 57 60 69  Total shares repurchased (1) 1,806 3,131 5,728   Cost of share repurchases during the period $ 270,297 $ 313,072 $ 406,430  Cost of employee surrenders 8,074 4,372 5,457  Total cost of shares repurchased $ 278,371 $ 317,444 $ 411,887   Average cost per share - open market repurchase $ 154.51 $ 101.96 $ 71.82  Average cost per share - employee surrenders $ 142.55 $ 73.04 $ 72.55  Average cost per share - total $ 154.13 $ 101.40 $ 71.90  (1) Shares repurchased and acquired through employee surrender for payment of minimum required withholding taxes on and before June 15, 2015 and the associated average cost per share have been adjusted to reflect the June 2015 two-for-one stock split. Actual shares repurchased were approximately 4.3 million for the year ended December 31, 2015.

Accumulated Other Comprehensi59

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income [Abstract]
Schedule Of Accumulated Other Comprehensive Income	  Unrealized Gain (Loss) on Investments, Net of Tax Unrealized Gain (Loss) on Derivatives Instruments, Net of Tax Unrealized Gain on Net Investment Hedge, Net of Tax Cumulative Translation Adjustment Total   Balance as of December 31, 2015 $ (225) $ 2,217 $ 1,894 $ (46,151) $ (42,265)  Other comprehensive income (loss) before reclassifications 245 4,950 2,142 (5,874) 1,463  Gains reclassified from accumulated other comprehensive income - (2,251) - - (2,251)  Balance as of December 31, 2016 20 4,916 4,036 (52,025) (43,053)  Other comprehensive income (loss) before reclassifications (42) (10,332) (8,347) 25,107 6,386  Gains reclassified from accumulated other comprehensive income - 197 - - 197  Balance as of December 31, 2017 $ (22) $ (5,219) $ (4,311) $ (26,918) $ (36,470) 
Summary Of Reclassifications Out Of Accumulated Other Comprehensive Income	  Amounts Reclassified from Accumulated Other  Affected Line Item in the Comprehensive Income  Details about Accumulated Other Statement Where For the Years Ended December 31,  Comprehensive Income Components Net Income is Presented 2017 2016 2015   Gains (losses) on derivative instruments included in net income:  Foreign currency exchange contracts Cost of revenue $ 27 $ 3,621 $ 20,878  Interest rate swaps Interest expense - (421) (1,042)  Total gains before tax 27 3,200 19,836  Tax expense 224 949 5,853  Gains, net of tax $ (197) $ 2,251 $ 13,983 

Summary Of Quarterly Data (Tabl

Summary Of Quarterly Data (Tables)	12 Months Ended
	Dec. 31, 2017
Summary Of Quarterly Data [Abstract]
Schedule Of Quarterly Data	  For the Three Months Ended  March 31, June 30, September 30, December 31,   2017  Revenue $ 462,021 $ 508,940 $ 491,976 $ 506,121  Gross profit 258,191 292,715 274,002 272,474  Operating income 92,243 122,564 100,413 97,808  Net income attributable to IDEXX Laboratories, Inc. stockholders 69,019 85,357 70,511 38,257  Earnings per share:  Basic $ 0.78 $ 0.97 $ 0.81 $ 0.44  Diluted $ 0.77 $ 0.95 $ 0.79 $ 0.43   2016  Revenue $ 417,550 $ 466,569 $ 448,308 $ 442,996  Gross profit 227,537 260,543 246,730 240,626  Operating income 73,793 104,162 88,459 83,825  Net income attributable to IDEXX Laboratories, Inc. stockholders 46,019 67,202 56,455 52,369  Earnings per share:  Basic $ 0.51 $ 0.75 $ 0.63 $ 0.59  Diluted $ 0.51 $ 0.74 $ 0.62 $ 0.58  (1) Amounts presented may not recalculate to full-year totals due to rounding.

Nature Of Business, Basis Of 61

Nature Of Business, Basis Of Presentation And Principles Of Consolidation (Details)	12 Months Ended
	Dec. 31, 2015
Nature Of Business, Basis Of Presentation And Principles Of Consolidation [Abstract]
Stock split	2

Summary Of Significant Accoun62

Summary Of Significant Accounting Policies (Narrative) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)customer	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Summary Of Significant Accounting Policies [Line Items]
Restricted cash		$ 0	$ 0
Research And Development Costs, Capitalized		0	0	$ 0
Advertising costs		1,700,000	2,100,000	1,200,000
Foreign currency transaction losses		1,100,000	$ (1,300,000)	$ (200,000)
Available-for-sale Securities Valuation, Difference Between Fair Value And Amortized Cost		$ 200,000
Sales Revenue, Net [Member]
Summary Of Significant Accounting Policies [Line Items]
Number Of Significant Customers | customer		0
Concentration Risk, Percentage		0.00%
Percentage of IDEXX consolidated total		0.00%
Future Customer Utilization [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Estimate, Percent		5.00%
Change in Accounting Estimate, Increase (Decrease) Revenue		$ 400,000
Scenario, Forecast [Member] | Accounting Standards Update 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ 10,000,000
Scenario, Forecast [Member] | Accounting Standards Update 2016-16 [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ 8,000,000
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue Recognition, Multiple Element Arrangements, Delivery Term, Years		6 years
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue Recognition, Multiple Element Arrangements, Delivery Term, Years		1 year

Summary Of Significant Accoun63

Summary Of Significant Accounting Policies (Summary Of The Most Significant Impacts Of The New Accounting Guidance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Increase in operating activities	$ 373,276	$ 338,943	$ 221,802
Decrease in financing activities	208,016	222,196	100,990
Accounting Standards Update 2016-09 [Member]
Effective Income Tax Rate Reconciliation, Deduction, Amount	$ 27,700
Weighted Average Number Diluted Shares Outstanding Adjustment	450,000
Accounting Standards Update 2016-09 [Member] | Tax Benefits Related To Share-based Payments At Settlement Classified As Operating Cash Flows Instead Of Financing Cash Flows [Member]
Increase in operating activities	$ 27,700
Decrease in financing activities	27,700
Accounting Standards Update 2016-09 [Member] | Cash Payments To Tax Authorities For Shares Withheld To Meet Tax Withholding Requirements On Restricted Stock Units Are Classified As Financing Cash Flow Instead Of Operating Cash Flow [Member]
Increase in operating activities	8,100	4,400	5,400
Decrease in financing activities	$ 8,100	$ 4,400	$ 5,400

Acquisitions (Details)

Acquisitions (Details) $ in Thousands, € in Millions	3 Months Ended			6 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)entity	Mar. 31, 2017EUR (€)	Dec. 31, 2017USD ($)item	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)entity
Business Acquisition [Line Items]
Acquisition of a business, net of cash acquired					$ 14,579	$ 1,964	$ 10,302
Business Combinations, goodwill					13,541	1,720	$ 5,047
Two Software Companies [Member]
Business Acquisition [Line Items]
Number of businesses acquired | entity		2
Business Combination, Consideration Transferred		$ 15,000
Acquisition of a business, net of cash acquired		12,000
Contingent payment		$ 3,000
Business Combination Contingent Consideration Term For Payment Upon Completion Of Goals		36 months
Business Combinations, goodwill	$ 13,300
Reference Laboratory In Austria [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred | €			€ 1.3
Reference Laboratory Diagnostic And Consulting Businesses [Member]
Business Acquisition [Line Items]
Number of businesses acquired | entity							2
Acquisition of a business, net of cash acquired						$ 3,500
Contingent consideration							$ 3,200
Business Combinations, goodwill							5,000
Cash payments to acquire businesses							7,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets							1,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment							300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent							$ 900
Customer Lists [Member] | Reference Laboratory In United States [Member]
Business Acquisition [Line Items]
Number of businesses acquired | item				4
Business Combination, Consideration Transferred				$ 2,300
Contingent payment				$ 400	$ 400
Customer Lists [Member] | Reference Laboratory Diagnostic And Consulting Businesses [Member]
Business Acquisition [Line Items]
Useful life assigned to intangible asset, years							15 years
Intangibles acquired as result of business combination							$ 5,200
Customer Relationships [Member] | Two Software Companies [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	1,000
Technology-Based Intangible Assets [Member] | Two Software Companies [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 600

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards outstanding	$ 45,200
Weighted average recognition period for unrecognized compensation expense, in years	1 year 7 months 6 days
Intrinsic value of stock options exercised	$ 78,300	$ 51,000	$ 35,100
Number of unissued shares of common stock each DSU represents right to receive	1
Share-based compensation expense	$ 23,517	$ 19,891	$ 19,884
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years	7 years
Deferred stock units, outstanding	229,000	231,000
2009 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under share-based incentive plans	19,900,000
Shares available for grant under share-based incentive plans	11,400,000
1997 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under share-based incentive plans	4,700,000
Shares available for grant under share-based incentive plans	1,200,000
Common stock issued in connection with the Employee Stock Purchase Plan	61,000	85,000	105,000
Discount from market value for employee stock purchase rights	15.00%
Stock Options Granted To Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Restricted Stock Units Granted To Employees With Ratable Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
Restricted Stock Units Granted To Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of unvested share-based awards to vest upon change in control	25 percent
Fair value of awards vested during period	$ 22,100	$ 12,400	$ 15,300
Deferred Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units, outstanding	229,000	231,000
Stock Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of shares issued under share-based awards to shares authorized under stock plans	1 to 1
Awards Other Than Stock Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of shares issued under share-based awards to shares authorized under stock plans	2 to 1
Stock Options Granted To Employees With Ratable Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of unvested share-based awards to vest upon change in control	25
Fair value of options vested during period	$ 9,200	$ 9,300	$ 8,700

Share-Based Compensation (Sched

Share-Based Compensation (Schedule Of Selected Financial Impact Of Share-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 23,517	$ 19,891	$ 19,884
Income tax benefit resulting from share-based compensation expense	(6,810)	(6,143)	(6,229)
Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards	16,707	13,748	13,655
Income tax benefit resulting from settlement of share-based awards (1)	(27,743)
Net (benefit) expense related to share-based compensation arrangements included in consolidated statements of income	(11,036)	13,748	13,655
Cost Of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2,675	2,305	2,138
Operating Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 20,842	$ 17,586	$ 17,746

Share-Based Compensation (Sch67

Share-Based Compensation (Schedule Of Weighted Averages Of The Assumptions Used In Estimating The Fair Value Of Stock Option Awards) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-Based Compensation [Abstract]
Share price at grant	$ 142.89	$ 69.07	$ 78.08
Expected stock price volatility	26.00%	25.00%	23.00%
Expected term, in years	5 years 9 months 18 days	5 years 8 months 12 days	5 years 7 months 6 days
Risk-free interest rate	2.00%	1.20%	1.50%
Weighted average fair value of options granted	$ 40.83	$ 17.87	$ 19.72

Share-Based Compensation (Sch68

Share-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Share-Based Compensation [Abstract]
Outstanding, at beginning of year | shares	3,176
Granted | shares	384
Exercised | shares	(716)
Forfeited | shares	(117)
Outstanding, at end of year | shares	2,727
Fully vested, at end of year | shares	1,327
Fully vested and expected to vest, at end of year | shares	2,649
Weighted average exercise price of beginning balance of options outstanding | $ / shares	$ 57.31
Weighted average exercise price of options granted | $ / shares	142.89
Weighted average exercise price of options exercised | $ / shares	42.66
Weighted average exercise price of options forfeited | $ / shares	68.41
Weighted average exercise price of ending balance of options outstanding | $ / shares	72.72
Weighted average exercise price of options fully vested | $ / shares	56.06
Weighted average exercise price of options fully vested and expected to vest | $ / shares	$ 72.45
Weighted average remaining contractual term of ending balance of options outstanding	6 years
Weighted average remaining contractual term of options fully vested	4 years 2 months 12 days
Weighted average remaining contractual term of options fully vested and expected to vest	5 years 10 months 24 days
Aggregate Intrinsic Value | $	$ 228,243
Aggregate intrinsic value of options fully vested | $	133,115
Aggregate intrinsic value of options expected to vest | $	$ 222,422

Share-Based Compensation (Sch69

Share-Based Compensation (Schedule Of Restricted Stock Unit Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Outstanding at beginning of period | shares	468
Granted | shares	97
Vested | shares	(155)
Forfeited | shares	(27)
RSUs Outstanding at end of period | shares	383
Weighted Average Grant-Date Fair Value of Beginning Balance of Outstanding Awards | $ / shares	$ 64.88
Weighted Average Grant-Date Fair Value, Granted | $ / shares	142.27
Weighted Average Grant-Date Fair Value of Awards Vested | $ / shares	59.63
Weighted Average Grant-Date Fair Value of Awards Forfeited | $ / shares	76.56
Weighted Average Grant-Date Fair Value of Ending Balance of Outstanding Awards | $ / shares	$ 85.74
Restricted Stock Units Expected To Vest, Reduced For Estimated Forfeitures [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Outstanding at end of period | shares	357
Weighted Average Grant-Date Fair Value of Ending Balance of Outstanding Awards | $ / shares	$ 85.23

Marketable Securities (Amortize

Marketable Securities (Amortized Cost And Fair Value Of Marketable Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 284,429	$ 236,995
Gross Unrealized Gains	120	70
Gross Unrealized Losses	(294)	(116)
Fair Value	284,255	236,949
Marketable securities that we consider to be other-than-temporarily impaired	0
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	140,969	130,833
Gross Unrealized Gains	96	40
Gross Unrealized Losses	(179)	(102)
Fair Value	140,886	130,771
Certificates Of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	58,510	40,400
Fair Value	58,510	40,400
Markerable Securities - Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,171	20,228
Fair Value	29,171	20,228
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,206	27,290
Gross Unrealized Gains	4	25
Gross Unrealized Losses	(43)
Fair Value	22,167	27,315
U S Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,619	12,244
Gross Unrealized Gains	11	1
Gross Unrealized Losses	(19)	(14)
Fair Value	15,611	12,231
Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,990	4,600
Gross Unrealized Gains	9	4
Gross Unrealized Losses	(52)
Fair Value	10,947	4,604
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,400
Fair Value		$ 1,400
Treasury Bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,964
Gross Unrealized Losses	(1)
Fair Value	$ 6,963

Marketable Securities (Contract

Marketable Securities (Contractual Maturities Of Marketable Securities) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Marketable Securities [Abstract]
Due in one year or less, Amortized Cost	$ 175,849
Due after one through three years, Amortized Cost	108,580
Total marketable securities, Amortized Cost	284,429
Due in one year or less, Fair Value	175,780
Due after one through three years, Fair Value	108,475
Total marketable securities, Fair Value	$ 284,255

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventories [Abstract]
Unpaid inventory	$ 37.2	$ 32.7	$ 30.1

Inventories (Schedule Of Compon

Inventories (Schedule Of Components Of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventories [Abstract]
Raw materials	$ 32,994	$ 27,561
Work-in-process	17,786	14,998
Finished goods	113,538	115,475
Total inventories	$ 164,318	$ 158,034

Property And Equipment, Net (Na

Property And Equipment, Net (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Property And Equipment, Net [Abstract]
Impairment charge	$ 8,212

Property And Equipment, Net (Sc

Property And Equipment, Net (Schedule Of Estimated Useful Lives For Property And Equipment) (Details)	12 Months Ended
	Dec. 31, 2017
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15
Buildings And Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40
Buildings And Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10
Machinery And Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	8
Machinery And Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3
Office Furniture And Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7
Office Furniture And Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3
Computer Hardware And Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7
Computer Hardware And Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3

Property And Equipment, Net (76

Property And Equipment, Net (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross amount	$ 811,636	$ 742,592
Less accumulated depreciation and amortization	432,540	385,170
Total property and equipment, net	379,096	357,422
Land And Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	7,323	7,255
Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	180,185	171,455
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	52,227	44,568
Machinery And Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross amount	284,375	262,718
Office Furniture And Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross amount	47,476	42,124
Computer Hardware And Software [Member]
Property, Plant and Equipment [Line Items]
Gross amount	206,580	189,327
Construction In Progress [Member]
Property, Plant and Equipment [Line Items]
Gross amount	$ 33,470	$ 25,145

Property And Equipment, Net (Su

Property And Equipment, Net (Summary Of Depreciation And Amortization, Capitalized Computer Software For Internal Use And Unpaid Property Equipment Reflected In Account Payable And Accrued Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 73,797	$ 63,537	$ 57,029
Unpaid property and equipment, reflected in accounts payable and accrued liabilities	11,744	10,601	8,534
Software Developed For Internal Use [Member]
Property, Plant and Equipment [Line Items]
Capitalized computer software developed for internal use	$ 16,131	$ 15,590	$ 19,081

Other Current and Noncurrent 78

Other Current and Noncurrent Assets (Schedule Of Other Current Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Current and Noncurrent Assets [Abstract]
Prepaid expenses	$ 28,967	$ 25,746
Taxes receivable	35,475	27,672
Customer acquisition costs, net	23,520	18,085
Other assets	13,178	19,703
Total other current assets	$ 101,140	$ 91,206

Other Current and Noncurrent 79

Other Current and Noncurrent Assets (Schedule Of Other Noncurrent Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Current and Noncurrent Assets [Abstract]
Investment in long-term product supply arrangements	$ 9,949	$ 10,978
Customer acquisition costs, net	64,670	50,309
Deferred income taxes	7,698	5,707
Other assets	36,299	36,321
Total other long-term assets	$ 118,616	$ 103,315

Goodwil And Intangible Assets,

Goodwil And Intangible Assets, Net (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets, Net [Abstract]
Goodwill, Impairment Loss	$ 0	$ 0	$ 0
Intangible assets impairments	0	2,200,000
Aggregate amortization expense	$ 9,000,000	$ 9,500,000	$ 10,400,000

Goodwill and Intangible Asset81

Goodwill and Intangible Assets, Net (Schedule Of Estimated Useful Lives For Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2017
Patents [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	13 years
Product Rights [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	15 years
Product Rights [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	5 years
Customer-Related Intangible Assets [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	17 years
Customer-Related Intangible Assets [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	5 years
Noncompete Agreements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	5 years
Noncompete Agreements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Finite-Lived Intangible Assets, Estimated Useful Life	3 years

Goodwill And Intangible Asset82

Goodwill And Intangible Assets, Net (Schedule Of Intangible Assets Other Than Goodwill) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Cost	$ 114,227	$ 107,973
Accumulated Amortization	70,381	61,818
Net	43,846	46,155
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Cost		2,192
Accumulated Amortization		2,075
Net		117
Product Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	32,558	29,748
Accumulated Amortization	25,251	20,877
Net	7,307	8,871
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	80,398	74,922
Accumulated Amortization	44,382	38,190
Net	36,016	36,732
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	1,271	1,111
Accumulated Amortization	748	676
Net	$ 523	$ 435

Goodwill And Intangible Asset83

Goodwill And Intangible Assets, Net (Schedule Of Expected Amortization Expense) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets, Net [Abstract]
2,018	$ 8,142
2,019	7,283
2,020	5,857
2,021	5,053
2,022	4,027
Thereafter	13,484
Net	$ 43,846	$ 46,155

Goodwill And Intangible Asset84

Goodwill And Intangible Assets, Net (Schedule Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segments Of Goodwill [Line Items]
Beginning balance	$ 178,228	$ 178,934	$ 184,450
Business Combinations	13,541	1,720	5,047
Impact of Changes in Foreign Currency Exchange Rates	8,104	(2,426)	(10,563)
Ending balance	199,873	178,228	178,934
CAG [Member]
Segments Of Goodwill [Line Items]
Beginning balance	146,194	145,191	148,151
Business Combinations	13,541	1,720	5,047
Impact of Changes in Foreign Currency Exchange Rates	6,501	(717)	(8,007)
Ending balance	166,236	146,194	145,191
Water [Member]
Segments Of Goodwill [Line Items]
Beginning balance	10,890	13,038	13,689
Impact of Changes in Foreign Currency Exchange Rates	1,061	(2,148)	(651)
Ending balance	11,951	10,890	13,038
LPD [Member]
Segments Of Goodwill [Line Items]
Beginning balance	14,613	14,174	16,079
Impact of Changes in Foreign Currency Exchange Rates	542	439	(1,905)
Ending balance	15,155	14,613	14,174
Other [Member]
Segments Of Goodwill [Line Items]
Beginning balance	6,531	6,531	6,531
Ending balance	$ 6,531	$ 6,531	$ 6,531

Accrued Liabilities And Other85

Accrued Liabilities And Other Long Term Liabilities (Schedule Of Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities And Other Long Term Liabilities [Abstract]
Accrued expenses	$ 64,430	$ 71,984
Accrued employee compensation and related expenses	102,944	91,113
Accrued taxes	29,389	23,973
Accrued customer programs	56,655	49,061
Total accrued liabilities	$ 253,418	$ 236,131

Accrued Liabilities And Other86

Accrued Liabilities And Other Long Term Liabilities (Schedule Of Long Term Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Current and Noncurrent Assets [Abstract]
Accrued taxes	$ 66,506	$ 18,798
Accrued customer programs	12,956	10,371
Other accrued long-term expenses	16,256	9,768
Total other long-term liabilities	$ 95,718	$ 38,937

Debt (Narrative) (Details)

Debt (Narrative) (Details) € in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2014USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2015EUR (€)	Dec. 31, 2015USD ($)	Sep. 30, 2014USD ($)	Jul. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Line of Credit Facility [Line Items]
Outstanding Credit Facility balance		$ 655,000,000	$ 611,000,000
Credit Facility borrowings hedged		$ 80,000,000
Consolidated Leverage Ratio Under Credit Facility & Note Payable, maximum		3.50%
Interest paid		$ 37,600,000	31,800,000	$ 27,200,000
Maximum [Member]
Line of Credit Facility [Line Items]
Commitment fees		0.25%
Minimum [Member]
Line of Credit Facility [Line Items]
Commitment fees		0.075%
Senior Notes [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio Under Credit Facility & Note Payable, maximum		3.50%
Debt instrument, face amount							$ 75,000,000	$ 125,000,000	$ 150,000,000
Debt Instrument, Interest Rate, Stated Percentage							3.72%
Series A Senior Note [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 75,000,000							$ 50,000,000	$ 75,000,000
Debt Instrument, Interest Rate, Stated Percentage	3.25%							3.32%	3.94%
Debt Instrument, Term	7 years
Series B Senior Note [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 75,000,000							$ 75,000,000	$ 75,000,000
Debt Instrument, Interest Rate, Stated Percentage	3.72%							3.76%	4.04%
Debt Instrument, Term	12 years
Series C Senior Note [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount | €					€ 88.9
Debt Instrument, Interest Rate, Stated Percentage					1.785%	1.785%
Shelf Notes [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount						$ 75,000,000
Debt Instrument, Term				12 years
Agreement Term				3 years
Outdated Unsecured Short Term Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity						$ 700,000,000
Amended And Restated Unsecured Short Term Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity		$ 850,000,000
Credit Facility maturity date		Dec. 4, 2020
Outstanding Credit Facility balance		$ 655,000,000	$ 611,000,000
Credit Facility weighted average interest rates on outstanding balance		2.81%	1.95%
Reduction of Credit Facility Availability		$ 1,000,000	$ 1,000,000
Debt Instrument, Term		5 years
Minimum Credit Spread On LIBOR Or CDOR Borrowings [Member]
Line of Credit Facility [Line Items]
Credit spread during period		0.875%
Maximum Credit Spread On LIBOR Or CDOR Borrowings [Member]
Line of Credit Facility [Line Items]
Credit spread during period		1.375%
Maximum Credit Spread On Prime Rate Borrowings [Member]
Line of Credit Facility [Line Items]
Credit spread during period		0.375%
Uncommitted Shelf Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 50,000,000
Agreement Term				3 years
Uncommitted Shelf Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Term	15 years

Debt (Schedule Of Annual Princi

Debt (Schedule Of Annual Principal Payments On Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt [Abstract]
2,021	$ 50,000
2,022	75,000
Thereafter	481,567
Annual Principal Payments on Long-Term Debt, Total	$ 606,567	$ 593,700

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate		35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent		6.70%
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent		1.00%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent		9.40%
Impact t of tax reform on deferred taxes		8.00%
Effective Tax Rate		30.90%	31.00%	29.70%
Income taxes paid		$ 81,200	$ 74,700	$ 54,900
Income tax ruling exemption		8,900	7,800	8,500
Unrecognized tax benefits		21,417	18,463	7,204	$ 5,942
Unrecognized tax benefits that would impact effective tax rate if recognized		9,100	5,900
Decrease to net deferred tax liabilities		17,000
Deferred Tax Assets, Valuation Allowance		6,211	4,891
Interest expense and penalties related to unrecognized tax benefits		900	300	$ 300
Interest expense and penalties accrued		1,000	$ 600
Net operating loss carryforwards in certain state and international jurisdictions		13,100
Recognized Provisional Amount, Net, Transition Tax Liability		$ 48,800
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	21.00%
Repatriation Tax, Previously Tax Deferred, Payable Term	8 years
Netherlands [Member]
Expiration date for tax holidays		December 31, 2022,
Accounting Standards Update 2016-09 [Member]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent		7.00%

Income Taxes (Schedule Of Earni

Income Taxes (Schedule Of Earnings Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Domestic	$ 268,714	$ 227,875	$ 187,200
International	112,343	93,971	85,941
Income before provision for income taxes	$ 381,057	$ 321,846	$ 273,141

Income Taxes (Schedule Of Compo

Income Taxes (Schedule Of Components Of Provision (Benefit) For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Provision Benefit For Income Taxes [Line Items]
Provision (benefit) for deferred income taxes	$ (7,918)	$ 20,881	$ 5,143
Provision for income taxes	117,788	99,792	81,006
Current [Member]
Provision Benefit For Income Taxes [Line Items]
Federal	92,453	53,285	52,966
State	9,258	6,608	5,353
International	23,993	19,291	17,681
Provision for current income taxes	125,704	79,184	76,000
Deferred [Member]
Provision Benefit For Income Taxes [Line Items]
Federal	(1,201)	20,305	5,762
State	(4,102)	1,196	526
International	(2,613)	(893)	(1,282)
Provision (benefit) for deferred income taxes	$ (7,916)	$ 20,608	$ 5,006

Income Taxes (Schedule Of Effec

Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
U.S. federal statutory rate	35.00%	35.00%	35.00%
State income tax, net of federal tax benefit	1.90%	1.80%	1.60%
International income taxes	(5.50%)	(4.80%)	(5.30%)
Shares-based compensation from settlements	(6.70%)
Domestic manufacturing exclusions	(1.10%)	(1.00%)	(1.50%)
Research and development credit	(0.90%)	(0.80%)	(1.20%)
Impact of the Tax Cuts and Jobs Act	9.40%
State income tax carryforwards	(1.40%)
Other, net	0.20%	0.80%	1.10%
Effective tax rate	30.90%	31.00%	29.70%

Income Taxes (Schedule Of Com93

Income Taxes (Schedule Of Components Of Net Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Accrued expenses	$ 13,843	$ 22,145
Accounts receivable reserves	2,624	2,715
Deferred revenue	10,618	13,400
Inventory basis differences	3,039	3,959
Property-based differences	1,324	1,382
Share-based compensation	9,035	13,021
Other	918	678
Net operating loss carryforwards	3,350	4,182
Tax credit carryforwards	8,096
Unrealized losses on foreign currency exchange contracts, interest rate swaps and investments	2,355	148
Total assets	55,202	61,630
Valuation allowance	(6,211)	(4,891)
Total assets, net of valuation allowance	48,991	56,739
Liabilities
Deferred instrument costs	(20,399)	(24,142)
Property-based differences	(31,859)	(43,159)
Intangible assst basis differences	(13,574)	(17,672)
Other	(656)	(771)
Unrealized gains on foreign currency exchange contracts, interest rate swaps and investments	(158)	(4,575)
Total liabilities	(66,646)	(90,319)
Net deferred tax assets (liabilities)	$ (17,655)	$ (33,580)

Income Taxes (Schedule Of Chang

Income Taxes (Schedule Of Changes In Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Total amounts of unrecognized tax benefits, beginning of period	$ 18,463	$ 7,204	$ 5,942
Gross increases in unrecognized tax benefits as a result of tax positions taken during a prior period	74	75	47
Gross increases in unrecognized tax benefits as a result of tax positions taken in the current period	4,681	12,657	1,569
Decreases in unrecognized tax benefits relating to settlements with taxing authorities	(713)	(1,326)
Decreases in unrecognized tax benefits as a result of a lapse of the applicable statutes of limitations	(1,088)	(147)	(354)
Total amounts of unrecognized tax benefits, end of period	$ 21,417	$ 18,463	$ 7,204

Earnings Per Share (Schedule Of

Earnings Per Share (Schedule Of Reconciliation Of Shares Outstanding For Basic And Diluted Earnings Per Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Shares outstanding for basic earnings per share	87,769	89,732	92,601
Dilutive effect of share-based payment awards	1,798	1,152	1,048
Shares outstanding for diluted earnings per share	89,567	90,884	93,649

Earnings Per Share (Schedule 96

Earnings Per Share (Schedule Of Number Of Anti-Dilutive Stock Options) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Weighted average number of shares underlying anti-dilutive options	327	88	644

Commitments, Contingencies An97

Commitments, Contingencies And Guarantees (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Payment Required Upon Termination Of Employment [Line Items]
Rent expense charged to operations	$ 23,000	$ 22,700	$ 20,500
Minimum royalty payments due through 2035	1,700
Total contingent liabilities	3,000	900
Purchase Obligation	11,800
Loss contingency, range of possible loss, maximum	2,500	2,600	3,500
Liabilities for indemnification obligations	0	0
Outstanding letters of credit to insurance company as security for workers' compensation claims	$ 1,000
Period for continued vesting of outstanding equity awards upon termination of CEO without cause other than following a change in control, years	two years
Payment Required To CEO Upon Termination Of Employment Without Cause Other Than Following Change In Control [Member]
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	$ 1,600
Payment Required To Officers Upon Termination Of Employment Following Change Of Control [Member]
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	29,400
Workers Compensation Insurance Policies [Member]
Payment Required Upon Termination Of Employment [Line Items]
Retained claim liability per incident	300	300	300
Employee Health Care Insurance Policy [Member]
Payment Required Upon Termination Of Employment [Line Items]
Retained claim liability per incident	1,000	450	430
General insurance expense	47,200	40,400	$ 34,600
Self Insurance Reserve	$ 4,200	$ 4,000

Commitments, Contingencies An98

Commitments, Contingencies And Guarantees (Schedule Of Minimum Annual Rental Payments) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Commitments, Contingencies And Guarantees [Abstract]
2,018	$ 19,233
2,019	15,687
2,020	11,974
2,021	9,461
2,022	7,139
Thereafter	32,435
Total minimum annual rental payments	$ 95,929

Segment Reporting (Narrative) (

Segment Reporting (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Reporting [Abstract]
Number of business segments	3

Segment Reporting (Summary Of S

Segment Reporting (Summary Of Segment Performance) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenue	$ 506,121	$ 491,976	$ 508,940	$ 462,021	$ 442,996	$ 448,308	$ 466,569	$ 417,550	$ 1,969,058	$ 1,775,423	$ 1,601,892
Income (loss) from operations	97,808	100,413	122,564	92,243	83,825	88,459	104,162	73,793	413,028	350,239	299,912
Interest expense, net									(31,971)	(28,393)	(26,771)
Income before provision for income taxes									381,057	321,846	273,141
Provision for income taxes									117,788	99,792	81,006
Net income									263,269	222,054	192,135
Less: Net income attributable to noncontrolling interest									125	9	57
Net income attributable to IDEXX Laboratories, Inc. stockholders	$ 38,257	$ 70,511	$ 85,357	$ 69,019	$ 52,369	$ 56,455	$ 67,202	$ 46,019	263,144	222,045	192,078
Depreciation and amortization									83,140	78,218	68,956
Expenditures for long-lived assets									74,384	64,787	82,921
CAG Segment [Member]
Segment Reporting Information [Line Items]
Revenue									1,703,377	1,522,689	1,356,287
Income (loss) from operations									363,557	301,342	233,319
Depreciation and amortization									71,835	64,878	60,715
Expenditures for long-lived assets									64,759	56,329	69,371
Water [Member]
Segment Reporting Information [Line Items]
Revenue									114,395	103,579	96,884
Income (loss) from operations									50,616	45,702	44,752
Depreciation and amortization									2,856	3,098	3,188
Expenditures for long-lived assets									2,573	2,102	2,781
LPD Segment [Member]
Segment Reporting Information [Line Items]
Revenue									128,481	126,491	127,143
Income (loss) from operations									16,464	18,914	27,157
Depreciation and amortization									5,052	5,543	4,367
Expenditures for long-lived assets									3,021	4,824	9,110
Other [Member]
Segment Reporting Information [Line Items]
Revenue									22,805	22,664	21,578
Income (loss) from operations									4,837	884	(137)
Depreciation and amortization									3,397	4,699	686
Expenditures for long-lived assets									4,031	1,532	1,659
Unallocated Amounts [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									$ (22,446)	$ (16,603)	$ (5,179)

Segment Reporting (Summary Of R

Segment Reporting (Summary Of Revenue By Product And Service Category) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenue	$ 506,121	$ 491,976	$ 508,940	$ 462,021	$ 442,996	$ 448,308	$ 466,569	$ 417,550	$ 1,969,058	$ 1,775,423	$ 1,601,892
Rapid Assay Products [Member]
Segment Reporting Information [Line Items]
Revenue									205,309	189,122	182,670
CAG Segment [Member]
Segment Reporting Information [Line Items]
Revenue									1,703,377	1,522,689	1,356,287
CAG Segment [Member] | CAG Diagnostics Recurring Revenue [Member]
Segment Reporting Information [Line Items]
Revenue									1,451,701	1,281,262	1,147,026
CAG Segment [Member] | IDEXX Vetlab Consumables [Member]
Segment Reporting Information [Line Items]
Revenue									518,774	451,456	396,526
CAG Segment [Member] | Reference Laboratory Diagnostic And Consulting Services [Member]
Segment Reporting Information [Line Items]
Revenue									660,142	581,067	512,155
CAG Segment [Member] | CAG Diagnostics Service And Accessories [Member]
Segment Reporting Information [Line Items]
Revenue									67,476	59,617	55,675
CAG Segment [Member] | CAG Diagnostic Capital - Instruments [Member]
Segment Reporting Information [Line Items]
Revenue									119,963	121,191	98,502
CAG Segment [Member] | Veterinary Software, Services And Diagnostic Imaging Systems [Member]
Segment Reporting Information [Line Items]
Revenue									131,713	120,236	110,759
Water [Member]
Segment Reporting Information [Line Items]
Revenue									114,395	103,579	96,884
LPD Segment [Member]
Segment Reporting Information [Line Items]
Revenue									128,481	126,491	127,143
Other [Member]
Segment Reporting Information [Line Items]
Revenue									$ 22,805	$ 22,664	$ 21,578

Segment Reporting (Schedule Of

Segment Reporting (Schedule Of Revenue By Principal Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 506,121	$ 491,976	$ 508,940	$ 462,021	$ 442,996	$ 448,308	$ 466,569	$ 417,550	$ 1,969,058	$ 1,775,423	$ 1,601,892
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,334,258	1,203,390	1,084,309
Americas [Member] | United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,203,547	1,089,595	980,281
Americas [Member] | Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									83,818	74,923	69,303
Americas [Member] | Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									46,893	38,872	34,725
Europe, The Middle East And Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									419,424	375,763	348,333
Europe, The Middle East And Africa [Member] | Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									88,328	80,156	73,395
Europe, The Middle East And Africa [Member] | United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									80,149	77,671	74,879
Europe, The Middle East And Africa [Member] | France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									55,993	51,204	46,972
Europe, The Middle East And Africa [Member] | Italy [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									31,889	28,907	25,903
Europe, The Middle East And Africa [Member] | Spain [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									28,866	24,268	19,998
Europe, The Middle East And Africa [Member] | Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									17,913	16,361	15,631
Europe, The Middle East And Africa [Member] | Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									15,877	14,049	11,645
Europe, The Middle East And Africa [Member] | Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									100,409	83,147	79,910
Asia Pacific Region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									215,376	196,270	169,250
Asia Pacific Region [Member] | Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									56,994	52,871	49,274
Asia Pacific Region [Member] | Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									53,344	51,544	43,171
Asia Pacific Region [Member] | China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									55,810	48,257	40,619
Asia Pacific Region [Member] | Other Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 49,228	$ 43,598	$ 36,186

Segment Reporting (Schedule 103

Segment Reporting (Schedule Of Net Long-Lived Assets By Principal Geographic Areas) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	$ 379,096	$ 357,422
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	329,964	318,831
Americas [Member] | United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	310,696	298,944
Americas [Member] | Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	17,030	17,910
Americas [Member] | Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	2,238	1,977
Europe, The Middle East And Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	35,173	28,483
Europe, The Middle East And Africa [Member] | United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	11,528	9,127
Europe, The Middle East And Africa [Member] | Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	7,522	5,040
Europe, The Middle East And Africa [Member] | Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	8,225	5,948
Europe, The Middle East And Africa [Member] | France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	2,305	2,428
Europe, The Middle East And Africa [Member] | Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	1,755	2,450
Europe, The Middle East And Africa [Member] | Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	3,838	3,490
Asia Pacific Region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	13,959	10,108
Asia Pacific Region [Member] | Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	4,065	2,469
Asia Pacific Region [Member] | Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	4,426	4,185
Asia Pacific Region [Member] | Other Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	$ 5,468	$ 3,454

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurements [Abstract]
Long-term Debt, Fair Value	$ 632,000	$ 609,500
Long-term Debt	$ 606,567	$ 593,700

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Fair Value Of Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	$ 284,255	$ 236,949
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	140,886	130,771
Certificates Of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	58,510	40,400
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	22,167	27,315
U S Government Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	15,611	12,231
Agency Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	10,947	4,604
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities		1,400
Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	6,963
Measured At Fair Value On Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	284,255	236,949
Measured At Fair Value On Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	284,255	236,949
Measured At Fair Value On Recurring Basis [Member] | Equity Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	2,162	2,182
Measured At Fair Value On Recurring Basis [Member] | Equity Mutual Funds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	2,162	2,182
Measured At Fair Value On Recurring Basis [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	477	8,926
Fair value of Liabilities	6,468	1,081
Measured At Fair Value On Recurring Basis [Member] | Foreign Currency Exchange Contracts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	477	8,926
Fair value of Liabilities	6,468	1,081
Measured At Fair Value On Recurring Basis [Member] | Deferred Compensation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Liabilities	2,162	2,182
Measured At Fair Value On Recurring Basis [Member] | Deferred Compensation [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Liabilities	2,162	2,182
Measured At Fair Value On Recurring Basis [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	32,962	34,208
Measured At Fair Value On Recurring Basis [Member] | Money Market Funds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	32,962	34,208
Measured At Fair Value On Recurring Basis [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	140,886	130,771
Measured At Fair Value On Recurring Basis [Member] | Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	140,886	130,771
Measured At Fair Value On Recurring Basis [Member] | Certificates Of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	1,250	1,500
Total marketable securities	58,510	40,400
Measured At Fair Value On Recurring Basis [Member] | Certificates Of Deposit [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets	1,250	1,500
Total marketable securities	58,510	40,400
Measured At Fair Value On Recurring Basis [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets		898
Total marketable securities	29,171	20,228
Measured At Fair Value On Recurring Basis [Member] | Commercial Paper [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Assets		898
Total marketable securities	29,171	20,228
Measured At Fair Value On Recurring Basis [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	22,167	27,315
Measured At Fair Value On Recurring Basis [Member] | Asset-backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	22,167	27,315
Measured At Fair Value On Recurring Basis [Member] | U S Government Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	15,611	12,231
Measured At Fair Value On Recurring Basis [Member] | U S Government Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	15,611	12,231
Measured At Fair Value On Recurring Basis [Member] | Agency Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	10,947	4,604
Measured At Fair Value On Recurring Basis [Member] | Agency Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	10,947	4,604
Measured At Fair Value On Recurring Basis [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities		1,400
Measured At Fair Value On Recurring Basis [Member] | Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities		$ 1,400
Measured At Fair Value On Recurring Basis [Member] | Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	6,963
Measured At Fair Value On Recurring Basis [Member] | Treasury Bills [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	$ 6,963

Hedging Instruments (Narrative)

Hedging Instruments (Narrative) (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2015EUR (€)
Derivative [Line Items]
Estimated net amount of gains expected to be reclassified out of accumulated other comprehensive income and into earnings within next 12 months	$ (5,200)
Discussion of Foreign Currency Derivative Risk Management Policy	We hedge approximately 85 percent of the estimated exposure
Cash Flow Hedge, hedge percentage of Eetimated exposure from intercompany products purchases and sales	85.00%
General duration of foreign currency exchange contracts	24 months
Credit Facility borrowings hedged	$ 80,000
Notional Amount of Foreign Currency Exchange Contracts	176,500	$ 175,900
Unrealized gain (loss) on net investment hedge	$ (8,347)	$ 2,142	$ 1,894
Series C Senior Note [Member]
Derivative [Line Items]
Debt Instrument, Face Amount | €				€ 88.9
Stated interest rate				1.785%
Interest Rate Swap Effective On March 30, 2012 [Member]
Derivative [Line Items]
Fixed portion of interest rate associated with interest rate swap	1.36%
Credit Facility borrowings hedged	$ 40,000
Interest Rate Swap Effective On March 28, 2013 [Member]
Derivative [Line Items]
Fixed portion of interest rate associated with interest rate swap	1.64%
Credit Facility borrowings hedged	$ 40,000

Hedging Instruments (Schedule O

Hedging Instruments (Schedule Of Fair Values And Balance Sheet Classifications Of Derivatives Designated As Hedging Instruments) (Details) - Derivatives Designated As Hedging Instruments [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Hedging Assets, Total derivative instruments presented as cash flow hedges on the balance sheet	$ 477	$ 8,926
Hedging Assets, Gross amounts subject to master netting arrangements not offset on the balance sheet	477	679
Hedging Assets, Net amount		8,247
Hedging Liabilities, Total hedging instruments presented on the balance sheet	113,035	94,745
Hedging Liabilities, Gross amounts subject to master netting arrangements not offset on the balance sheet	477	679
Hedging Liabilities, Net amount	112,558	94,066
Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Hedging Liabilities, Total hedging instruments presented on the balance sheet	6,468	1,081
Foreign Currency Exchange Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Hedging Assets, Total derivative instruments presented as cash flow hedges on the balance sheet	477	8,926
Foreign Currency Exchange Contracts [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Hedging Liabilities, Total hedging instruments presented on the balance sheet	6,468	1,081
Foreign Currency Borrowings Designated As Net Investment Hedge On The Balance Sheet [Member] | Long-term Debt [Member]
Derivatives, Fair Value [Line Items]
Hedging Liabilities, Total hedging instruments presented on the balance sheet	$ 106,567	$ 93,664

Hedging Instruments (Gain (Loss

Hedging Instruments (Gain (Loss) Recognized In Other Comprehensive Income On Derivative Instruments (Effective Portion)) (Details) - Cash Flow Hedges [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments (Effective Portion), Net of Tax	$ (10,135)	$ 2,699	$ (5,143)
Foreign Currency Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments (Effective Portion), Net of Tax	$ (10,135)	2,457	(5,604)
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments (Effective Portion), Net of Tax		$ 242	$ 461

Repurchases Of Common Stock (De

Repurchases Of Common Stock (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Shares of common stock repurchases authorized	68,000
Remaining shares available for repurchase under authorization	5,000
Share repurchases during the period	1,749	3,071	5,659
Shares acquired through employee surrenders	57	60	69
Total shares repurchased	1,806	3,131	5,728
Cost of share repurchases during the period | $	$ 270,297	$ 313,072	$ 406,430
Cost of employee surrenders | $	8,074	4,372	5,457
Total cost of shares repurchased | $	$ 278,371	$ 317,444	$ 411,887
Treasury Stock Acquired Average Cost Per Share, Open Market Repurchase | $ / shares	$ 154.51	$ 101.96	$ 71.82
Average cost per share - employee surrenders | $ / shares	142.55	73.04	72.55
Average cost per share | $ / shares	$ 154.13	$ 101.40	$ 71.90
Stock split			2
Treasury Stock [Member]
Total shares repurchased			4,300

Accumulated Other Comprehens110

Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income [Abstract]
Beginning balance, Unrealized Gain (Loss) on Investments, Net of Tax	$ 20	$ (225)
Beginning balance, Unrealized Gain (Loss) on Derivative Instruments, Net of Tax	4,916	2,217
Beginning balance, Unrealized Gain On Net Investment Hedge, Net Of Tax	4,036	1,894
Beginning balance, Cumulative Translation Adjustment	(52,025)	(46,151)
Other comprehensive income (loss) before reclassifications, Unrealized Gain (Loss) on Investments, Net of Tax	(42)	245	$ (226)
Other comprehensive income (loss) before reclassifications, Unrealized Gain (Loss) on Derivative Instruments, Net of Tax	(10,332)	4,950	8,839
Other comprehensive income (loss) before reclassifications, Unrealized Gain On Net Investment Hedge, Net Of Tax	(8,347)	2,142	1,894
Other comprehensive income (loss) before reclassifications, Cumulative Translation Adjustment	25,107	(5,874)	(30,718)
Gains reclassified from accumulated other comprehensive income, Unrealized Gain (Loss) on Derivative Instruments, Net of Tax	197	(2,251)	(13,983)
Ending balance, Unrealized Gain (Loss) on Investments, Net of Tax	(22)	20	(225)
Ending balance, Unrealized Gain (Loss) on Derivative Instruments, Net of Tax	(5,219)	4,916	2,217
Ending balance, Unrealized Gain On Net Investment Hedge, Net Of Tax	(4,311)	4,036	1,894
Ending balance, Cumulative Translation Adjustment	(26,918)	(52,025)	(46,151)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(43,053)	(42,265)
Accumulated Other Comprehensive Income, before Tax	6,386	1,463
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	197	(2,251)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	$ (36,470)	$ (43,053)	$ (42,265)

Accumulated Other Comprehens111

Accumulated Other Comprehensive Income (Schedule of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Provision for income taxes	$ 117,788	$ 99,792	$ 81,006
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(197)	2,251
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	27	3,200	19,836
Provision for income taxes	224	949	5,853
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(197)	2,251	13,983
Interest Rate Swaps [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(421)	(1,042)
Foreign Currency Exchange Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	$ 27	$ 3,621	$ 20,878

Preferred Stock (Details)

Preferred Stock (Details)	Dec. 31, 2017$ / sharesshares
Preferred Stock [Abstract]
Shares of preferred stock authorized	500,000
Par value per share | $ / shares	$ 1
Preferred Stock outstanding	0

IDEXX Retirement And Incenti113

IDEXX Retirement And Incentive Savings Plan (Details) - 401(k) Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement And Incentive Savings Plan [Line Items]
Contribution match, maximum percent of participants' eligible compensation	4.00%
Employer contributions	$ 13.8	$ 12.5	$ 11.5
Discretionary contributions	$ 0	$ 0	$ 0

Summary Of Quarterly Data (Deta

Summary Of Quarterly Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary Of Quarterly Data [Abstract]
Revenue	$ 506,121	$ 491,976	$ 508,940	$ 462,021	$ 442,996	$ 448,308	$ 466,569	$ 417,550	$ 1,969,058	$ 1,775,423	$ 1,601,892
Gross profit	272,474	274,002	292,715	258,191	240,626	246,730	260,543	227,537	1,097,382	975,436	890,270
Operating income	97,808	100,413	122,564	92,243	83,825	88,459	104,162	73,793	413,028	350,239	299,912
Net income attributable to stockholders	$ 38,257	$ 70,511	$ 85,357	$ 69,019	$ 52,369	$ 56,455	$ 67,202	$ 46,019	$ 263,144	$ 222,045	$ 192,078
Earnings per Share:
Basic	$ 0.44	$ 0.81	$ 0.97	$ 0.78	$ 0.59	$ 0.63	$ 0.75	$ 0.51	$ 3	$ 2.47	$ 2.07
Diluted	$ 0.43	$ 0.79	$ 0.95	$ 0.77	$ 0.58	$ 0.62	$ 0.74	$ 0.51	$ 2.94	$ 2.44	$ 2.05

Valuation And Qualifying Acc115

Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reserves For Doubtful Accounts Receivable [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 4,523	$ 5,128	$ 4,306
Charges to Costs and Expenses	591	822	2,200
Write-Offs/Cash Payments	(1,660)	(531)	(817)
Foreign Currency Translation	1,122	(896)	(561)
Balance at End of Year	4,576	4,523	5,128
Valuation Allowance For Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	4,891	4,446	4,678
Charges to Costs and Expenses	1,789	885	634
Write-Offs/Cash Payments	(679)	(816)	(468)
Foreign Currency Translation	210	376	(398)
Balance at End of Year	$ 6,211	$ 4,891	$ 4,446