IDEXX Laboratories (IDXX) 10-K 12 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 09, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	0-19271
Entity Registrant Name	IDEXX LABORATORIES INC /DE
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	01-0393723
Entity Address, Address Line One	One IDEXX Drive
Entity Address, City or Town	Westbrook,
Entity Address, State or Province	ME
Entity Address, Postal Zip Code	04092
City Area Code	207
Local Phone Number	556-0300
Title of 12(b) Security	Common Stock, $0.10 par value per share
Trading Symbol	IDXX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 27,735,989,165
Entity Common Stock, Shares Outstanding (in shares)		85,426,080
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Part III—Specifically identified portions of the Company’s definitive Proxy Statement to be filed in connection with the Company’s 2021 annual meeting of stockholders (the “2021 Annual Meeting”), to be held on May 12, 2021, are incorporated herein by referenc e.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000874716

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 383,928	$ 90,326
Accounts receivable, net of reserves of $6,784 in 2020 and $3,581 in 2019	331,429	269,312
Inventories	209,873	195,019
Other current assets	137,508	124,982
Total current assets	1,062,738	679,639
Long-Term Assets:
Property and equipment, net	555,167	533,845
Operating lease right-of-use assets	91,171	80,607
Goodwill	243,347	239,724
Intangible assets, net	52,543	58,468
Other long-term assets	289,595	240,192
Total long-term assets	1,231,823	1,152,836
TOTAL ASSETS	2,294,561	1,832,475
Current Liabilities:
Accounts payable	74,558	72,172
Accrued liabilities	415,648	322,938
Line of credit	0	288,765
Current portion of long-term debt	49,988	0
Current portion of deferred revenue	42,567	41,462
Total current liabilities	582,761	725,337
Long-Term Liabilities:
Deferred income tax liabilities	11,707	33,024
Long-term debt, net of current portion	858,492	698,910
Long-term deferred revenue, net of current portion	46,163	48,743
Long-term operating lease liabilities	77,039	67,472
Other long-term liabilities	85,604	81,164
Total long-term liabilities	1,079,005	929,313
Total liabilities	1,661,766	1,654,650
Commitments and Contingencies (Note 16)
Stockholders’ Equity:
Common stock, $0.10 par value: Authorized: 120,000 shares; Issued: 106,457 shares in 2020 and 105,711 shares in 2019; Outstanding: 85,449 shares in 2020 and 85,471 shares in 2019	10,646	10,571
Additional paid-in capital	1,294,849	1,213,517
Deferred stock units: Outstanding: 87 units in 2020 and 143 units in 2019	4,503	4,462
Retained earnings	2,175,595	1,595,648
Accumulated other comprehensive loss	(53,615)	(46,182)
Treasury stock, at cost: 21,008 shares in 2020 and 20,240 shares in 2019	(2,799,890)	(2,600,543)
Total IDEXX Laboratories, Inc. stockholders’ equity	632,088	177,473
Noncontrolling interest	707	352
Total stockholders’ equity	632,795	177,825
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 2,294,561	$ 1,832,475

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, reserves	$ 6,784	$ 3,581
Common stock, par value (in USD per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	106,457,000	105,711,000
Common stock, shares outstanding (in shares)	85,449,000	85,471,000
Deferred stock units, outstanding (in shares)	87,000	143,000
Treasury stock, shares (in shares)	21,008,000	20,240,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 2,706,655	$ 2,406,908	$ 2,213,242
Cost of Revenue:
Total cost of revenue	1,135,615	1,041,359	971,700
Gross profit	1,571,040	1,365,549	1,241,542
Expenses:
Sales and marketing	434,435	418,193	387,406
General and administrative	300,832	261,317	244,938
Research and development	141,249	133,193	117,863
Income from operations	694,524	552,846	491,335
Interest expense	(33,125)	(31,055)	(34,744)
Interest income	586	427	1,151
Income before provision for income taxes	661,985	522,218	457,742
Provision for income taxes	79,854	94,426	80,695
Net income	582,131	427,792	377,047
Less: Net income attributable to noncontrolling interest	355	72	16
Net income attributable to IDEXX Laboratories, Inc. stockholders	$ 581,776	$ 427,720	$ 377,031
Earnings per Share:
Basic (in USD per share)	$ 6.82	$ 4.97	$ 4.34
Diluted (in USD per share)	$ 6.71	$ 4.89	$ 4.26
Weighted Average Shares Outstanding:
Basic (in shares)	85,342	86,115	86,864
Diluted (in shares)	86,722	87,542	88,470
Product revenue
Revenue:
Total revenue	$ 1,586,809	$ 1,423,144	$ 1,322,683
Cost of Revenue:
Total cost of revenue	557,795	506,202	494,889
Service revenue
Revenue:
Total revenue	1,119,846	983,764	890,559
Cost of Revenue:
Total cost of revenue	$ 577,820	$ 535,157	$ 476,811

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 582,131	$ 427,792	$ 377,047
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	15,151	(1,590)	(21,911)
Unrealized gain (loss) on Euro-denominated notes, net of tax expense (benefit) of $(2,325) in 2020, $564 in 2019 and $1,148 in 2018	(7,378)	1,790	3,917
Unrealized gain (loss) on investments, net of tax expense (benefit) of $(120) in 2020, $84 in 2019 and $(40) in 2018	(382)	267	(135)
Unrealized gain (loss) on derivative instruments:
Unrealized gain (loss) on foreign currency exchange contracts, net of tax expense (benefit) of $(2,013) in 2020, $362 in 2019 and $2,529 in 2018	(8,527)	1,196	10,659
Unrealized gain (loss) on cross currency swaps, net of tax expense of $(1,774) in 2020, $664 in 2019 and $323 in 2018	(5,626)	2,107	1,360
Less: reclassification adjustment for (gains) losses included in net income, net of tax (expense) benefit of $(158) in 2020, $(2,467) in 2019 and $187 in 2018	(671)	(8,161)	789
Unrealized (loss) gain on derivative instruments	(14,824)	(4,858)	12,808
Other comprehensive loss, net of tax	(7,433)	(4,391)	(5,321)
Comprehensive income	574,698	423,401	371,726
Less: comprehensive income attributable to noncontrolling interest	355	72	16
Comprehensive income attributable to IDEXX Laboratories, Inc.	$ 574,343	$ 423,329	$ 371,710

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on Euro-denominated notes, tax expense (benefit)	$ (2,325)	$ 564	$ 1,148
Unrealized gain (loss) on investments, tax expense (benefit)	(120)	84	(40)
Unrealized gain (loss) on foreign currency exchange contracts, tax expense (benefit)	(2,013)	362	2,529
Unrealized gain (loss) on cross currency swaps, tax expense (benefit)	(1,774)	664	323
Reclassification adjustment for (gains) losses included in net income, tax (expense) benefit	$ (158)	$ (2,467)	$ 187

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Deferred Stock Units	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
Balance (in shares) at Dec. 31, 2017			104,275
Balance beginning of period at Dec. 31, 2017	$ (53,842)	$ (12,648)	$ 10,428	$ 1,073,931	$ 5,988	$ 803,545	$ (12,648)	$ (36,470)	$ (1,911,528)	$ 264
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	377,047					377,031				16
Other comprehensive loss, net	(5,321)							(5,321)
Repurchases of common stock, net	(377,371)								(377,371)
Common stock issued under stock plans, net (in shares)			812
Common stock issued under stock plans, net	37,745		$ 81	39,756	(2,092)
Deferred stock units activity	0			(385)	385
Share-based compensation cost	25,157			24,914	243
Balance (in shares) at Dec. 31, 2018			105,087
Balance end of period at Dec. 31, 2018	(9,233)		$ 10,509	1,138,216	4,524	1,167,928		(41,791)	(2,288,899)	280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	427,792					427,720				72
Other comprehensive loss, net	(4,391)							(4,391)
Repurchases of common stock, net	(311,644)								(311,644)
Common stock issued under stock plans, net (in shares)			624
Common stock issued under stock plans, net	36,023		$ 62	36,551	(590)
Deferred stock units activity	0			(324)	324
Share-based compensation cost	$ 39,278			39,074	204
Balance (in shares) at Dec. 31, 2019	105,711		105,711
Balance end of period at Dec. 31, 2019	$ 177,825	$ (1,829)	$ 10,571	1,213,517	4,462	1,595,648	$ (1,829)	(46,182)	(2,600,543)	352
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	582,131					581,776				355
Other comprehensive loss, net	(7,433)							(7,433)		0
Repurchases of common stock, net	(199,347)								(199,347)
Common stock issued under stock plans, net (in shares)			746
Common stock issued under stock plans, net	50,497		$ 75	51,368	(946)				0
Deferred stock units activity	0			(894)	894
Share-based compensation cost	$ 30,951			30,858	93
Balance (in shares) at Dec. 31, 2020	106,457		106,457
Balance end of period at Dec. 31, 2020	$ 632,795		$ 10,646	$ 1,294,849	$ 4,503	$ 2,175,595		$ (53,615)	$ (2,799,890)	$ 707

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in USD per share)	$ 0.10	$ 0.10	$ 0.10	$ 0.10

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 582,131	$ 427,792	$ 377,047
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	95,998	88,011	83,178
Impairment charge	2,501	968	2,629
Provision for uncollectible accounts	4,946	662	1,609
(Benefit of) provision for deferred income taxes	(38,082)	6,162	1,209
Share-based compensation expense	30,951	39,278	25,157
Other	1,379	1,254	895
Changes in assets and liabilities:
Accounts receivable	(60,722)	(22,472)	(18,401)
Inventories	(18,885)	(37,306)	(25,623)
Accounts payable	981	1,957	(166)
Deferred revenue	(13,373)	(12,360)	(7,719)
Other assets and liabilities	60,238	(34,788)	(39,731)
Net cash provided by operating activities	648,063	459,158	400,084
Cash Flows from Investing Activities:
Purchases of property and equipment	(106,958)	(154,969)	(115,751)
Purchases of marketable securities	0	0	(87)
Proceeds from the sale and maturities of marketable securities	0	0	284,125
Acquisitions of intangible assets and equity investments	(918)	(255)	(7,185)
Acquisitions of businesses, net of cash acquired	(1,500)	(50,304)	(22,500)
Net cash (used) provided by investing activities	(109,376)	(205,528)	138,602
Cash Flows from Financing Activities:
Repayment on revolving credit facilities, net	(289,625)	(110,275)	(256,040)
Issuance of senior notes	200,000	100,000	0
Debt issuance costs	(5,025)	(154)	0
Repurchases of common stock, net	(182,815)	(301,658)	(369,319)
Proceeds from exercises of stock options and employee stock purchase plans	51,328	36,106	38,201
Payment of acquisition-related contingent consideration	(1,676)	(2,375)	(1,266)
Shares withheld for statutory tax withholding on restricted stock	(20,603)	(8,053)	(9,375)
Net cash used by financing activities	(248,416)	(286,409)	(597,799)
Net effect of changes in exchange rates on cash	3,331	(689)	(4,768)
Net increase (decrease) in cash and cash equivalents	293,602	(33,468)	(63,881)
Cash and cash equivalents at beginning of period	90,326	123,794	187,675
Cash and cash equivalents at end of period	$ 383,928	$ 90,326	$ 123,794

Nature of Business, Basis of Pr

Nature of Business, Basis of Presentation and Principles of Consolidation	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature Of Business, Basis Of Presentation And Principles Of Consolidation	NATURE OF BUSINESS, BASIS OF PRESENTATION AND PRINCIPLES OF CONSOLIDATION The accompanying consolidated financial statements of IDEXX Laboratories, Inc. and its subsidiaries 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 primarily for the companion animal veterinary, livestock and poultry, dairy and water testing markets. We also sell a line of portable electrolytes and blood gas analyzers and SARS-CoV-2 RT-PCR (COVID-19 test) used in the human diagnostics market. Our principal line of business, which we refer to as our Companion Animal Group (“CAG”) operating segment, provides diagnostic 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, China, and Australia, but we also sell to customers and distributors in many other countries around the world. Our 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 producer efficiency, and to ensure the quality and safety of milk and food. Our principal markets 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 and services for the human medical diagnostics market (“OPTI Medical”). Financial information about our OPTI Medical operating segment is combined and presented with our 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 3. Revenue Recognition" for additional information regarding disaggregated revenue by segment and major product and service categories and geographical areas. See "Note 17. Segment Reporting " for additional information regarding our reportable operating segments.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	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, such as the economic impact of the COVID-19 pandemic, 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. Furthermore, as the impact of the COVID-19 pandemic continues to develop, many of these estimates could require increased judgment and carry a higher degree of variability and volatility, and may change materially in future periods. Actual results could differ materially 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, 2020, and 2019. (c) Inventories – See Note 7 (d) Property and Equipment – See Note 9 (e) Goodwill and Other Intangible Assets – See Note 11 (f) 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. The amount of warranty reserve during the years ended December 31, 2020 and 2019, was not material. (g) Income Taxes – See Note 14 (h) 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. (i) Revenue Recognition – See Note 3 (j) 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 research and development costs for capitalization after the technological feasibility has been established for software and products containing software to be sold, however no costs were capitalized during the years ended December 31, 2020, 2019 and 2018. Software developed to deliver hosted services to our customers has been designated as internal use and we capitalize certain costs incurred in connection with developing or obtaining software designated for internal use based on three distinct stages of development. See "Note 9. Property and Equipment, Net" for further information on internal use software. (k) Advertising Costs Advertising costs, which are recognized as sales and marketing expense in the period in which they are incurred, were $1.4 million, $1.5 million, and $1.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. (l) Legal Costs Legal costs are considered period costs and accordingly are expensed in the year services are provided. (m) Share-Based Compensation – See Note 5 (n) Self-Insurance Accruals – See Note 16 (o) Leases – See Note 8 (p) Earnings per Share – See Note 15 (q) Foreign Currency The functional currency of all except four 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 within our Other segment. We recognized aggregate foreign currency gains of $0.6 million, and losses of $1.1 million and $3.1 million for the years ended December 31, 2020, 2019, and 2018, respectively. (r) Hedging Instruments – See Note 19 (s) Fair Value Measurements – See Note 18 (t) 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 hedges and the difference between the cost and the fair market value of investments in debt and equity securities, and forward currency exchange contracts, in the consolidated statements of comprehensive income. See "Note 21. Accumulated Other Comprehensive Income" for information about the effects on net income of significant amounts reclassified out of each component of AOCI for the years ended December 31, 2020, 2019 and 2018. (u) 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 as well as certain components, raw materials and consumables used in or with our products are 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. (v) New Accounting Pronouncements Adopted We adopted ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)," as of January 1, 2018, using the modified retrospective method for all contracts not completed as of the date of adoption. We adopted ASU 2016-02, "Leases (Topic 842)," as of January 1, 2019, using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and did not restate prior periods. We adopted ASU 2018-13, "Fair Value Measurement (Topic 820)," as of January 1, 2020, which modifies the disclosure requirements on fair value measurements under ASC Topic No. 820, Fair Value Measurement, as amended (“ASC 820”). ASU 2018-13 removes (a) the prior requirement to disclose the amount and reason for transfers between Level 1 and Level 2 of the fair value hierarchy contained in ASC 820, (b) the policy for timing of transfers between levels, and (c) the valuation processes used for Level 3 fair value measurements. ASU 2018-13 also adds, among other things, a requirement to disclose the range and weighted average of significant unobservable inputs used in Level 3 fair value measurements. The adoption did not have a material impact on our consolidated financial statements. We adopted ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” effective January 1, 2020, using the modified retrospective transition method. This ASU amends the impairment model to utilize an expected loss methodology in place of the incurred loss methodology for financial instruments, including trade receivables and leased equipment. The amendment requires entities to consider a broader range of information to estimate expected credit losses, which may result in earlier recognition of losses. We recorded a non-cash cumulative effect adjustment to retained earnings of $1.8 million, net of $0.6 million of income taxes, on our opening consolidated balance sheet as of January 1, 2020. This adjustment, before the impact of income taxes, was comprised of $2.3 million related to our contract assets and sales-type leases, and $0.2 million related to accounts receivable. See Note 6. Credit Losses, for more information on our presentation of credit losses. (w) New Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” The new guidance is intended to simplify the accounting for income taxes by removing certain exceptions and by updating accounting requirements around goodwill recognized for tax purposes and the allocation of current and deferred tax expense among legal entities, among other minor changes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Early adoption is permitted. We do not expect the adoption of ASU 2019-12 to have a material impact on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, "Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” ASU 2020-04 is intended to provide optional expedients and exceptions to the U.S. GAAP guidance on contract modifications and hedge accounting to ease the financial reporting burdens related to the discontinuation of the London Interbank Offered Rate (“LIBOR”) or by another reference rate expected to be discontinued. The FASB also issued ASU 2021-01, "Reference Rate Reform (Topic 848): Scope", in January 2021. It clarifies that certain optional expedients and exceptions apply to derivatives that are affected by the discounting transition. The amendments in this ASU affect the guidance in ASU No. 2020-04 and are effective in the same timeframe as ASU 2020-04. The relief offered by this guidance, if adopted, is available to companies for the period March 12, 2020 through December 31, 2022. Our Credit Facility includes a provision for the determination of a benchmark replacement rate as a successor to the LIBOR rate, therefore we do not expect the discontinuation of LIBOR to have an impact on our consolidated financial statements.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION Our revenue is recognized when, or as, performance obligations under the terms of a contract are satisfied, which occurs when control of the promised products or services is transferred to a customer. We exclude sales, use, value-added, and other taxes we collect on behalf of third parties from revenue. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products or services to a customer. To accurately present the consideration received in exchange for promised products or services, we apply the five-step model outlined below: 1. Identification of a contract or agreement with a customer 2. Identification of our performance obligations in the contract or agreement 3. Determination of the transaction price 4. Allocation of the transaction price to the performance obligations 5. Recognition of revenue when, or as, we satisfy a performance obligation We enter into contracts that can include various combinations of products and services, which are generally capable of being distinct and accounted for as separate performance obligations. The timing of revenue recognition, billings, and cash collections results in accounts receivable, lease receivables, and contract assets as a result of revenue recognized in advance of billings (included within other assets), and contract liabilities or deferred revenue as a result of receiving consideration in advance of revenue recognition within our consolidated balance sheet. Our general payment terms range from 30 to 60 days, with exceptions in certain geographies. Below is a listing of our major categories of revenue for our products and services: Diagnostic Products and Accessories . Diagnostic products and accessories revenues, including IDEXX VetLab ® consumables and accessories, rapid assay, LPD, Water, and OPTI testing products, are predominantly recognized and invoiced at the time of shipment, which is when the customer obtains control of the product based on legal title transfer and we have the right to payment. We also provide customers with certain consumables that are recognized upon utilization by the customer, which is when we have the right to payment and the risks and rewards of ownership transfer. Shipping costs reimbursed by the customer are included in revenue and cost of sales. As a practical expedient, we do not account for shipping activities as a separate performance obligation. Laboratory Diagnostic and Consulting Services . Laboratory diagnostic and consulting services revenues are recognized and invoiced when the laboratory diagnostic service is performed. Instruments, Software and Systems . CAG Diagnostics capital instruments, veterinary software and diagnostic imaging systems revenues are recognized and invoiced when the customer obtains control of the products based on legal title transfer and we have the right to payment, which generally occurs at the time of installation and customer acceptance. Our instruments, software, and systems are often included in one of our significant customer programs, as further described below. For veterinary software systems that include multiple performance obligations, such as perpetual software licenses and computer hardware, we allocate revenue to each performance obligation based on estimates of the price that we would charge the customer for each promised product or service if it were sold on a standalone basis. Lease Revenue . Revenues from instrument rental agreements and reagent rental programs are recognized either as operating leases on a ratable basis over the term of the agreement or as sales-type leases at the time of installation and customer acceptance. Customers typically pay for the right to use instruments under rental agreements in equal monthly amounts over the term of the rental agreement. Our reagent rental programs provide our customers the right to use our instruments upon entering into agreements to purchase specified amounts of consumables, which are considered embedded leases. For some agreements, the customers are provided with the right to purchase the instrument at the end of the lease term. Lease revenues from these agreements are presented in product revenue on our consolidated income statement. Lease revenue was approximately $17.5 million for the year ended December 31, 2020, as compared to $20.8 million for the year ended December 31, 2019, including both operating leases and sales-type leases under ASC 842, Leases, for leases entered into after January 1,2019, and ASC 840, Leases, for leases entered into prior to 2019. See below for revenue recognition under our reagent rental programs. Extended Warranties and Post-Contract Support . CAG Diagnostics capital instruments and diagnostic imaging systems extended warranties typically provide customers with continued coverage for a period of one five years Veterinary software post-contract support provides customers with access to technical support when and as needed through access to call centers and online customer assistance. Post-contract support contracts typically have a term of 12 months and customers are billed for post-contract support in equal quarterly amounts over the term. We recognize revenue for post-contract support services over time on a ratable basis using a time elapsed measure of performance over the contract term, which approximates the expected timing in which applicable services are performed. On December 31, 2019, our deferred revenue related to extended warranties and post-contract support was $38.0 million, of which approximately $22.0 million was recognized during the year ended December 31, 2020. Furthermore, as a result of new agreements, our deferred revenue related to extended warranties and post-contract support was $35.1 million at December 31, 2020. We do not disclose information about remaining performance obligations that are part of contracts with an original expected duration of one year or less and do not adjust for the effect of the financing components when the period between customer payment and revenue recognition is one year or less. Deferred revenue related to extended warranties and post-contract support with an original duration of more than one year was $20.7 million at December 31, 2020, of which approximately 43%, 32%, 17%, 6%, and 2% are expected to be recognized during 2021, 2022, 2023, 2024, and thereafter, respectively. Additionally, we have determined these agreements do not include a significant financing component. SaaS Subscriptions . We offer a variety of veterinary software and diagnostic imaging SaaS subscriptions including IDEXX Neo, Animana, Pet Health Network Pro, Petly Plans, Web PACS, rVetLink, and SmartFlow. We recognize revenue for our SaaS subscriptions over time on a ratable basis over the contract term, beginning on the date our service is made available to the customer. Our subscription contracts vary in term from monthly to two years. Customers typically pay for our subscription contracts in equal monthly amounts over the term of the agreement. Deferred revenue related to our SaaS subscriptions is not material. Contracts with Multiple Performance Obligations . We enter into contracts with multiple performance obligations where customers purchase a combination of IDEXX products and services. Determining whether products and services are considered distinct performance obligations that should be accounted for separately requires significant judgment. We determine the transaction price for a contract based on the total consideration we expect to receive in exchange for the transferred goods or services. To the extent the transaction price includes variable consideration, such as volume rebates or expected price adjustments, we apply judgment in constraining the estimated variable consideration due to factors that may cause reversal of revenue recognized. We evaluate constraints based on our historical and projected experience with similar customer contracts. We allocate revenue to each performance obligation in proportion to the relative standalone selling prices and recognize revenue when transfer of the related goods or services has occurred for each obligation. We utilize the observable standalone selling price when available, which represents the price charged for the performance obligation when sold separately. When standalone selling prices for our products or services are not directly observable we determine the standalone selling prices using relevant information available and apply suitable estimation methods including, but not limited to, the cost plus a margin approach. We recognize revenue as each performance obligation is satisfied, either at a point in time or over time, as described in the revenue categories above. We do not disclose information about remaining performance obligations that are part of contracts with an original expected duration of one year or less. The following customer programs represent our most significant customer contracts which contain multiple performance obligations: Customer Commitment Programs . We offer customer incentives upon entering into multi-year agreements to purchase annual minimum amounts of products and services. Up-Front Customer Loyalty Programs . Our up-front loyalty programs provide customers with incentives in the form of cash payments or IDEXX Points upon entering into multi-year agreements to purchase annual minimum amounts of future products or services. 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. Up-front incentives to customers in the form of cash or IDEXX Points are not made in exchange for distinct goods or services and are capitalized as customer acquisition costs within other current and long-term assets, which 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 instruments, we allocate total consideration, including future committed purchases less up-front incentives and estimates of expected price adjustments, based on relative standalone selling prices to identified performance obligations and recognize instrument revenue and cost at the time of installation and customer acceptance. To the extent invoiced instrument revenue exceeds recognized instrument revenue, we record deferred revenue as a contract liability, which is subsequently recognized upon the purchase of products and services over the term of the contract. We have determined these agreements do not include a significant financing component. Differences between estimated and actual customer purchases may impact the amount and timing of revenue recognition. On December 31, 2019, our capitalized customer acquisition costs were $137.4 million, of which approximately $39.3 million were recognized as a reduction of revenue during the year ended December 31, 2020. Furthermore, as a result of new up-front customer loyalty payments, net of subsequent recognition, our capitalized customer acquisition costs were $148.1 million at December 31, 2020. We monitor customer purchases over the term of their agreement to assess the realizability of our capitalized customer acquisition costs and review estimates of variable consideration. Impairments, revenue adjustments that relate to performance obligations satisfied in prior periods, and contract modifications during the years ended December 31, 2020 and 2019, were not material. Volume Commitment Programs . Our volume commitment programs, such as our IDEXX 360 program, provide customers with a free or discounted instrument or system upon entering into multi-year agreements to purchase annual minimum amounts of products and services. We allocate total consideration, including future committed purchases and expected price adjustments, based on relative standalone selling prices to identified performance obligations and recognize instrument revenue and cost at the time of installation and customer acceptance in advance of billing the customer, which is also when the customer obtains control of the instrument based on legal title transfer. Our right to future consideration related to instrument revenue is recorded as a contract asset within other current and long-term assets. The contract asset is transferred to accounts receivable when customers are billed for products and services over the term of the contract. We have determined these agreements do not include a significant financing component. Differences between estimated and actual customer purchases may impact the amount and timing of revenue recognition. On December 31, 2019, our volume commitment contract assets were $83.9 million, of which approximately $18.3 million were reclassified to accounts receivable when customers were billed for related products and services during the year ended December 31, 2020. Furthermore, as a result of new placements under volume commitment programs, net of subsequent amounts reclassified to accounts receivable, and allowances established for credit losses, our contract assets were $115.5 million at December 31, 2020. We monitor customer purchases over the term of their agreement to assess the realizability of our contract assets and review estimates of variable consideration. Impairments, revenue adjustments that relate to performance obligations satisfied in prior periods, and contract modifications during the years ended December 31, 2020 and 2019, were not material. For our up-front customer loyalty and volume commitment programs, we estimate future revenues related to multi-year agreements to be approximately $2.2 billion, of which approximately 26%, 24%, 21%, 16%, and 13% are expected to be recognized during 2021, 2022, 2023, 2024, and thereafter, respectively. These future revenues relate to performance obligations not yet satisfied, for which customers have committed to purchase goods and services, net of the expected revenue reductions from customer acquisition costs and expected price adjustments, and as a result, are lower than stated contractual commitments by our customers. Instrument Rebate Programs . Our instrument rebate programs require an instrument purchase and provide customers the opportunity to earn future rebates based on the volume of products and services they purchase over the term of the program. We account for the customer’s right to earn rebates on future purchases as a separate performance obligation and determine the standalone selling price based on an estimate of rebates the customer will earn over the term of the program. Total consideration allocated to identified performance obligations is limited to goods and services that the customer is presently obligated to purchase and does not include estimates of future purchases that are optional. We allocate total consideration to identified performance obligations, including the customer’s right to earn rebates on future purchases, which is deferred and recognized upon the purchase of future products and services, partly offsetting future rebates as they are earned. On December 31, 2019, our deferred revenue related to instrument rebate programs was $49.1 million, of which approximately $16.3 million were recognized when customers purchased eligible products and services and earned rebates during the year ended December 31, 2020. Furthermore, as a result of new instrument purchases under rebate programs, net of subsequent recognition, our deferred revenue was $39.3 million at December 31, 2020, of which approximately 36%, 27%, 18%, 11%, and 8% are expected to be recognized during 2021, 2022, 2023, 2024, and thereafter, respectively. Reagent Rental Programs . Our reagent rental programs provide our customers the right to use our instruments upon entering into multi-year agreements to purchase annual minimum amounts of consumables. These types of agreements include an embedded lease for the right to use our instrument and we determine the amount of lease revenue allocated to the instrument based on relative standalone selling prices. We evaluate the terms of these embedded leases to determine classification as either a sales-type lease or an operating lease. Sales-type Reagent Rental Programs . Our reagent rental programs that effectively transfer control of instruments to our customers are classified as sales-type leases and we recognize instrument revenue and cost in advance of billing the customer, at the time of installation and customer acceptance. Our right to future consideration related to instrument revenue is recorded as a lease receivable within other current and long-term assets, and is transferred to accounts receivable when customers are billed for products and services over the term of the contract. On December 31, 2019, our lease receivable assets were $7.2 million, of which approximately $1.4 million was reclassified to accounts receivable when customers were billed for related products and services during the year ended December 31, 2020. Furthermore, as a result of new placements under sales-type reagent rental programs, net of subsequent amounts reclassified to accounts receivable, and allowances established for credit losses, our lease receivable assets were $11.1 million at December 31, 2020. The impacts of discounting and unearned income at December 31, 2020, were not material. Profit and loss recognized at the commencement date and interest income during the year ended December 31, 2020, were not material. We monitor customer purchases over the term of their agreement to assess the realizability of our lease receivable assets. Impairments during the year ended December 31, 2020, were not material. Operating-type Reagent Rental Programs . Our reagent rental programs that do not effectively transfer control of instruments to our customers are classified as operating leases and we recognize instrument revenue and costs ratably over the term of the agreement. The cost of the instrument is capitalized within property and equipment. We estimate future revenue to be recognized related to our reagent rental programs of approximately $24.8 million, of which approximately 41%, 27%, 16%, 9%, and 7% are expected to be recognized during 2021, 2022, 2023, 2024, and thereafter, respectively. These future revenues relate to performance obligations not yet satisfied for which customers have committed to future purchases, net of any expected price adjustments, and as a result, may be lower than stated contractual commitments by our customers. Other Customer Incentive Programs . Certain agreements with customers include discounts or rebates on the sale of products and services applied retrospectively, such as volume rebates achieved by purchasing a specified purchase threshold of goods and services. We account for these discounts as variable consideration and estimate the likelihood of a customer meeting the threshold in order to determine the transaction price using the most predictive approach. We typically use the most-likely-amount method, for incentives that are offered to individual customers, and the expected-value method, for programs that are offered to a broad group of customers. Revenue adjustments that relate to performance obligations satisfied in prior periods during the years ended December 31, 2020 and 2019, were not material. Refund obligations related to customer incentive programs are recorded in accrued liabilities for the actual issuance of incentives, incentives earned but not yet issued and estimates of incentives to be earned in the future. Program Combinations . At times, we combine elements of our significant customer programs within a single customer contract. We separate each significant program element and include the contract assets, customer acquisition costs, deferred revenues and estimated future revenues within the most relevant program disclosures above. Each customer contract is presented as a net contract asset or net contract liability on our consolidated balance sheet. IDEXX Points . IDEXX Points may be applied to trade receivables due to us, converted to cash, or applied against the purchase price of IDEXX products and services. We consider IDEXX Points equivalent to cash. IDEXX Points that have not yet been used by customers are included in accrued liabilities until utilized or expired. Breakage is not material because customers can apply IDEXX Points to trade receivables at any time. Accounts Receivable . We recognize revenue when it is probable that we will collect substantially all of the consideration to which we will be entitled, based on the customer’s intent and ability to pay the promised consideration. We apply judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. We have no significant customers that accounted for greater than 10% of our consolidated revenues and we have no concentration of credit risk as of December 31, 2020. Disaggregated Revenues . We present disaggregated revenue for our CAG segment based on major product and service categories. Our Water segment is comprised of a single major product category. Although our LPD segment does not meet the quantitative requirements to be reported as a separate segment, we believe it is important to disaggregate these revenues as a major product and service category separately from our Other reportable segment given its distinct markets, and therefore we have elected to report LPD as a reportable segment. The following table presents disaggregated revenue by major product and service categories: (in thousands) For the Years Ended December 31, 2020 2019 2018 CAG segment revenue: CAG Diagnostics recurring revenue: $ 2,113,839 $ 1,828,329 $ 1,654,530 IDEXX VetLab consumables 824,376 693,360 617,237 Rapid assay products 253,018 232,149 217,541 Reference laboratory diagnostic and consulting services 946,268 822,497 746,794 CAG Diagnostics services and accessories 90,177 80,323 72,958 CAG Diagnostics capital - instruments 108,950 132,685 134,264 Veterinary software, services and diagnostic imaging systems 162,976 158,169 146,634 CAG segment revenue 2,385,765 2,119,183 1,935,428 Water segment revenue 128,625 132,850 125,198 LPD segment revenue 145,845 132,635 130,581 Other segment revenue 46,420 22,240 22,035 Total revenue $ 2,706,655 $ 2,406,908 $ 2,213,242 Revenue by principal geographic area, based on customers’ domiciles, was as follows: (in thousands) For the Years Ended December 31, 2020 2019 2018 Americas United States $ 1,691,224 $ 1,495,516 $ 1,357,909 Canada 107,398 99,550 94,206 Latin America 51,863 56,515 50,969 1,850,485 1,651,581 1,503,084 Europe, the Middle East and Africa Germany 119,353 104,081 100,459 United Kingdom 90,156 90,969 87,807 France 74,814 64,767 60,319 Italy 42,817 39,725 36,956 Spain 39,265 36,439 33,687 Switzerland 24,850 20,855 19,875 Netherlands 23,461 19,397 18,090 Other 148,049 122,206 114,877 562,765 498,439 472,070 Asia Pacific Region Australia 79,629 71,069 63,386 Japan 74,725 67,246 60,213 China 70,845 57,518 57,621 Other 68,206 61,055 56,868 293,405 256,888 238,088 Total $ 2,706,655 $ 2,406,908 $ 2,213,242 Costs to Obtain a Contract . We capitalize sales commissions and the related fringe benefits earned by our sales force when considered incremental and recoverable costs of obtaining a contract. Our contracts include performance obligations related to various goods and services, some of which are satisfied at a point in time and others over time. Commission costs related to performance obligations satisfied at a point in time are expensed at the time of sale, which is when revenue is recognized. Commission costs related to long-term service contracts and performance obligations satisfied over time, including extended warranties and SaaS subscriptions, are deferred and recognized on a systematic basis that is consistent with the transfer of the goods or services to which the asset relates. We apply judgment in estimating the amortization period, which ranges from 3 to 7 years, by taking into consideration our customer contract terms, history of renewals, expected length of customer relationship, as well as the useful life of the underlying technology and products. Amortization expense is included in sales and marketing expenses in the accompanying consolidated statements of income. Deferred commission costs are periodically reviewed for impairment. On December 31, 2019, our deferred commission costs, included within other assets, were $15.6 million, of which approximately $5.2 million of commission expense were recognized during the year ended December 31, 2020. Furthermore, as a result of commissions related to new extended warranties and SaaS subscriptions, net of subsequent recognition, our deferred commission costs were $17.5 million at December 31, 2020. Impairments of deferred commission costs during the years ended December 31, 2020 and 2019, were not material.

Acquisitions and Investments

Acquisitions and Investments	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions and Investments	ACQUISITIONS AND INVESTMENTS We believe that our acquisitions of businesses and other assets enhance our existing businesses by either expanding our geographic range and customer base or expanding our existing product lines. During the fourth quarter of 2019 we acquired the assets of a multi-site reference laboratory business in the mid-west of the U.S. for $50.0 million in cash. This acquisition expands our national reference laboratory presence in the U.S., and was accounted for as a business combination. We finalized the valuation of the fair value of the assets acquired during the first quarter of 2020. The fair value of the assets acquired consists of $26.9 million in intangible assets, primarily for customer relationships, with a weighted average life of 13.8 years, $0.2 million of tangible assets, and $22.9 million of goodwill, representing synergies within our reference laboratory portfolio. The goodwill is expected to be deductible for income tax purposes. Pro forma information has not been presented for this acquisition because such information is not material to the financial statements. The results of operations have been included in our CAG segment since the acquisition date. The acquisition expenses incurred were not material.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	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”), share-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”), share-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 option exercise price set on the day of grant. An RSU is an agreement to issue shares of IDEXX stock at the time of vesting. A PBRSU is an agreement to issue 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 which they are issued. We did not issue any restricted stock or stock appreciation rights during the years ended December 31, 2020, 2019 and 2018, nor were any restricted stock or stock appreciation rights outstanding as of those years ended. 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, 2020, 2019 and 2018. 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 di rectors under the 2018 Stock Incentive Plan (the "2018 Stock Plan"). Our Board of Directors has authorized the issuance of 7.5 million shar es of our common stock under the 2018 Stock 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 2.4 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 2018 Stock Plan. As of December 31, 2020, there were approximately 6.5 million remaining shares available for issuance under the 2018 Stock Plan. Share-Based Compensation Share-based compensation costs are classified in the 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: (in thousands) For the Years Ended December 31, 2020 2019 2018 Share-based compensation expense included in cost of revenue $ 3,415 $ 2,681 $ 2,816 Share-based compensation expense included in operating expenses 27,536 36,597 22,341 Total share-based compensation expense included in consolidated statements of income 30,951 39,278 25,157 Income tax benefit resulting from share-based compensation expense (3,965) (4,861) (4,190) Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards 26,986 34,417 20,967 Income tax benefit resulting from settlement of share-based awards (38,981) (19,140) (21,496) Net expense (benefit) related to share-based compensation arrangements included in consolidated statements of income $ (11,995) $ 15,277 $ (529) In th e fourth quarter of 2019, we entered into a mutual separation agreement with our former CEO, pursuant to which Mr. Ayers’s outstanding stock options were modified, resulting in a share-based compensation expense of approximately $10.9 million, primarily representing an acceleration of the cost of the equity awards. This expense was partially offset by a reduction to our provision for income taxes of approximately $0.8 million. Other than the modification to Mr. Ayers's stock options, as described above, there were no other material modifications to the terms of outstanding options, RSUs, PBRSUs, or DSUs during the years ended December 31, 2020, 2019 or 2018. 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 significantly different forfeiture expectations. The total unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards at December 31, 2020, was $57.4 million, which will be recognized over a weighted average period of approximately 1.5 years. Stock Options Prior to December 4, 2019, all options granted to employees primarily vest ratably over five years on each anniversary of the date of grant. Options granted to non-employee directors vest fully on the first anniversary of the date of grant. Employee grants after December 4, 2019, will vest ratably over 4 years. Vesting of option awards issued is conditional based on continuous service. Options granted after May 8, 2013 have a contractual term of ten years and options granted between January 1, 2006 and May 8, 2013 had contractual terms of seven years. Upon any change in control of the company, 25% 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 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, 2020 2019 2018 Share price at grant $ 291.14 $ 218.66 $ 179.56 Share exercise price $ 291.14 $ 220.88 $ 179.56 Expected stock price volatility 27 % 26 % 24 % Expected term, in years 6.0 6.0 5.8 Risk-free interest rate 1.4 % 2.4 % 2.7 % Weighted average fair value of options granted $ 84.92 $ 65.53 $ 52.99 A summary of the status of options granted under our share-based compensation plans at December 31, 2020, 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, 2019 2,311 $ 117.13 Granted 220 $ 291.14 Exercised (562) $ 71.65 Forfeited (16) $ 180.78 Outstanding as of December 31, 2020 1,953 $ 149.32 6.3 $ 684,571 Fully vested as of December 31, 2020 1,057 $ 106.91 5.3 $ 415,229 Fully vested and expected to vest as of December 31, 2020 1,933 $ 148.61 6.3 $ 678,994 The total fair value of options vested was $14.6 million, $12.2 million, and $10.5 million during the years ended December 31, 2020, 2019 and 2018, 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 $163.0 million, $83.7 million, and $87.1 million during the years ended December 31, 2020, 2019 and 2018, respectively. Restricted Stock Units Prior to December 4, 2019, the majority of RSUs, including our PBRSUs, granted to employees vest ratably over five years on each anniversary of the date of grant. Employee grants after December 4, 2019, will vest ratably over 4 years. PBRSUs granted to employees vest based on meeting performance goals set on the day 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, 2020, 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, 2019 258 $ 150.50 Granted 65 $ 291.30 Vested (94) $ 124.60 Forfeited (11) $ 178.95 Nonvested as of December 31, 2020 218 $ 202.47 Expected to vest as of December 31, 2020 208 $ 201.64 The total fair value of RSUs and PBRSUs vested was $27.9 million, $23.8 million, and $24.5 million during the years ended December 31, 2020, 2019 and 2018, respectively. The aggregate intrinsic value of nonvested RSUs and PBRSUs as of December 31, 2020, which is equal to the fair value of IDEXX’s common stock as of December 31, 2020, multiplied by the number of nonvested units as of December 31, 2020, was $108.8 million. 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. Vested DSUs are distributed as shares of common stock on the distribution date elected by the participant and pursuant to the terms of the Director or Executive Plan, as applicable. There were approximately 87,000 and 143,000 vested DSUs outstanding under our share-based compensation plans as of December 31, 2020 and 2019, respectively. During 2020, approximately 59,000 DSUs were distributed as shares of common shares to our former CEO in accordance with the terms of the Executive Plan and the deferral elections he previously made. Unvested DSUs as of December 31, 2020 and 2019, 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% discount off the closing price of the stock on the last day of each quarter. The dollar value of this discount is equal to the fair value of purchase rights recognized as share-based compensation. We issued approximately 39,000, 47,000, and 52,000 shares of common stock in connection with the Employee Stock Purchase Plan during the years ended December

Credit Losses

Credit Losses	12 Months Ended
	Dec. 31, 2020
Credit Loss [Abstract]
Credit Losses	CREDIT LOSSES We are exposed to credit losses primarily through our sales of products and services to our customers. We maintain allowances for credit losses 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. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current economic conditions. See Note 2. Accounting Policies, for more information on our adoption of ASU 2016-13 on January 1, 2020, using the modified retrospective transition method. 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. dollar-denominated purchases. We monitor our ongoing credit exposure through active review of counterparty balances against contract terms and due dates. Our activities include timely account reconciliations, dispute resolution and payment confirmations. We may employ collection agencies and legal counsel to pursue recovery of defaulted receivables. Account balances are charged off against the allowance when we believe it is probable the receivable will not be recovered. We may require collateralized asset support or a prepayment to mitigate credit risk. We do not have any off-balance sheet credit exposure related to our customers. Accounts Receivable The allowance for credit losses associated with accounts receivable was $6.8 million and $3.6 million at December 31, 2020 and December 31, 2019, respectively. Accounts receivable reflected on the balance sheet is net of this reserve. Based on an aging analysis, at December 31, 2020, approximately 88% of our accounts receivable had not yet reached the invoice due date and approximately 12% was considered past due, of which approximately 1.5% was greater than 60 days past due. At December 31, 2019, approximately 84% of our accounts receivable had not yet reached the invoice due date and approximately 16% was considered past due, of which approximately 1.5% was greater than 60 days past due. Write-offs and recoveries related to credit losses during the years ended December 31, 2020, 2019, and 2018 were not material. Contract assets and lease receivables The allowance for credit losses associated with the contract assets and lease receivables was $3.7 million at December 31, 2020. The assets reflected on the balance sheet are net of these reserves. Historically, we have experienced low credit loss rates on our customer commitment programs and lease receivables. We apply judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. Write-offs and recoveries related to credit losses during the years ended December 31, 2020, 2019, and 2018 were not material.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Inventory, Net [Abstract]
Inventories	INVENTORIES Inventories are stated at the lower of cost (first-in, first-out) or net realizable value. Net realizable value is the estimated selling price 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 $45.6 million, $39.5 million, and $41.3 million at December 31, 2020, 2019 and 2018, respectively. The components of inventories are as follows: (in thousands) December 31, 2020 December 31, 2019 Raw materials $ 45,986 $ 41,202 Work-in-process 20,374 20,077 Finished goods 143,513 133,740 Inventories $ 209,873 $ 195,019

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	LEASES The majority of our facilities are occupied under operating lease arrangements with various expiration dates through 2067, some of which include options to extend the life of the lease, and some of which include options to terminate the lease within 1 year. In certain instances, we are responsible for the real estate taxes and operating expenses related to these facilities. Additionally, 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 financing 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. Minimum lease payments include the fixed lease component of the agreement, as well as fixed rate increases that are initially measured at the lease commencement date. Variable lease payments based on an index, payments associated with non-lease components and short-term rentals (leases with terms less than 12 months) are expensed as incurred. Consideration is allocated to the lease and non-lease components based on the estimated standalone prices. We determine if an arrangement is a lease at its inception. Operating leases are included in operating lease right-of-use assets, accrued liabilities, and long-term operating lease liabilities in our consolidated balance sheets. Our financing leases are not material to the financial statements. Right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease liabilities and right-of-use assets are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an explicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Rent expense for lease payments is recognized on a straight-line basis over the lease term. The operating lease right-of-use assets also includes any rent prepayments, lease incentives upon receipt, and straight-line rent expense impacts, which represent the differences between our operating lease liabilities and right-of-use assets. Maturities of operating lease liabilities are as follows: (in thousands) December 31, 2020 2021 $ 20,187 2022 18,698 2023 13,556 2024 9,810 2025 8,129 Thereafter 39,224 Total lease payments 109,604 Less imputed interest (14,832) Total lease liability (current and long-term) $ 94,772 Total minimum future lease payments of approximately $8.0 million for leases that have not commenced as of December 31, 2020 are not included in the consolidated financial statements, as we do not yet control the underlying assets. These leases are expected to commence during 2021 with lease terms of approximately 4 to 13 years. (in thousands, except lease term and discount rate) December 31, 2020 December 31, 2019 Weighted average remaining lease term - operating leases 10.3 years 10.3 years Weighted average discount rate - operating leases 2.9 % 3.5 % Expenses incurred related to operating leases, excluding variable and short-term leases were approximately $21.7 million and $21.1 million during the year ended December 31, 2020 and 2019, respectively. Total expenses incurred related to operating leases, including variable rent and short-term leases, were approximately $24.5 million, $23.8 million, and $25.2 million for the years ended December 31, 2020, 2019 and 2018, respectively. Supplemental cash flow information for leases is as follows: For the Years Ended (in thousands) 2020 2019 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,619 $ 20,008 Right-of-use assets obtained in exchange for operating lease obligations, net of early lease terminations $ 26,807 $ 13,399

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	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 are 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 the consolidated statements of 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, 2020 and 2019 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 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, 2020 December 31, 2019 Land and improvements $ 13,982 $ 8,725 Buildings and improvements 319,384 249,918 Leasehold improvements 82,459 74,602 Machinery and equipment 353,301 322,814 Office furniture and equipment 67,527 53,210 Computer hardware and software 265,664 240,406 Construction in progress 39,764 103,200 1,142,081 1,052,875 Less accumulated depreciation and amortization 586,914 519,030 Total property and equipment, net $ 555,167 $ 533,845 Below are the amounts of depreciation and amortization of property and equipment, capitalized computer software for internal use, unpaid property and equipment reflected in accounts payable and accrued expenses, and rental and reagent rental program instruments transferred from inventory to property and equipment: For the Years Ended December 31, (in thousands) 2020 2019 2018 Depreciation and amortization expense $ 86,095 $ 78,495 $ 74,208 Capitalized computer software developed for internal use $ 18,472 $ 20,130 $ 17,115 Unpaid property and equipment, reflected in accounts payable and accrued liabilities $ 13,343 $ 24,688 $ 17,894 Rental and operating-type reagent rental program instruments transferred from inventory to property and equipment (Note 3) $ 9,645 $ 14,498 $ 20,360

Other Current and Long-Term Ass

Other Current and Long-Term Assets	12 Months Ended
	Dec. 31, 2020
Other Assets, Noncurrent [Abstract]
Other Current and Long-Term Assets	OTHER CURRENT AND LONG-TERM ASSETS Other current assets consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Customer acquisition costs $ 43,751 $ 39,329 Prepaid expenses 34,556 31,992 Contract assets, net 23,837 17,659 Taxes receivable 19,476 20,516 Deferred sales commissions 5,738 5,202 Other 10,150 10,284 Other current assets $ 137,508 $ 124,982 Other long-term assets consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Customer acquisition costs $ 104,369 $ 98,117 Contract assets, net 91,681 66,226 Deferred income taxes 31,549 8,100 Investment in long-term product supply arrangements 12,065 13,657 Deferred sales commissions 11,719 10,442 Taxes receivable 6,329 14,960 Other 31,883 28,690 Other long-term assets $ 289,595 $ 240,192

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, Net	GOODWILL AND INTANGIBLE ASSETS, NET 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, 2020, 2019 and 2018. 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 goodwill impairment test. The more likely than not threshold is defined as having a likelihood of more than 50%. 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 assess the fair value of all of our reporting units and compare the fair value of the reporting unit to its carrying value to determine if the carrying value exceeds its fair value, and if a goodwill impairment loss should be recognized. In contrast, we can opt to bypass the qualitative assessment for any reporting unit in any period and proceed directly to assessing the fair value of all of our reporting units and compare the fair value of the reporting unit to carrying value to determine if any impairment exists. Doing so does not preclude us from performing the qualitative assessment in any subsequent period. In the fourth quarter of 2020, we elected to bypass the qualitative approach that allows the assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount and instead proceeded directly to assessing the fair value of all of our reporting units and comparing the fair values of each reporting unit to the carrying values to determine if any impairment exists. 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 loss in a future period. No goodwill impairments were identified during the years ended December 31, 2020, 2019 or 2018, and no accumulated impairment losses are recorded. 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 asset group is the lowest level for which identifiable cash flows associated with the intangible asset are largely independent. 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 loss 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. The amount of impairment for the year ended December 31, 2020 was immaterial. We had no impairments of our intangible assets during the years ended December 31, 2019, and 2018. The changes in the carrying amount of goodwill for the years ended December 31, 2020, 2019 and 2018, were as follows: (in thousands) CAG Water LPD Other Consolidated Total Balance as of December 31, 2017 $ 166,236 $ 11,951 $ 15,155 $ 6,531 $ 199,873 Business combinations 20,282 — — — 20,282 Impact of changes in foreign currency exchange rates (4,132) (730) (804) — (5,666) Balance as of December 31, 2018 $ 182,386 $ 11,221 $ 14,351 $ 6,531 $ 214,489 Business combinations 24,826 — — — 24,826 Impact of changes in foreign currency exchange rates 138 390 (119) — 409 Balance as of December 31, 2019 $ 207,350 $ 11,611 $ 14,232 $ 6,531 $ 239,724 Business combinations 220 — — — 220 Acquisition adjustment (1,900) — — — (1,900) Impact of changes in foreign currency exchange rates 4,724 412 167 — 5,303 Balance as of December 31, 2020 $ 210,394 $ 12,023 $ 14,399 $ 6,531 $ 243,347 See "Note 4. Acquisitions and Investments" 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, 2020, 2019 and 2018. 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 Customer-related intangible assets (1) 3 to 17 years Product rights (2) 5 to 15 years Noncompete agreements 3 to 5 years (1) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties. (2) Product rights comprise certain technologies, intellectual property, licenses, and trade names acquired from third parties. Intangible assets other than goodwill consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Customer-related intangible assets (1) $ 80,810 $ 32,838 $ 47,972 $ 99,301 $ 46,801 $ 52,500 Product rights (2) 15,150 11,609 3,541 16,130 10,214 5,916 Noncompete agreements 1,250 220 1,030 170 118 52 $ 97,210 $ 44,667 $ 52,543 $ 115,601 $ 57,133 $ 58,468 The above table excludes fully amortized intangible assets for the periods presented. (1) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties. (2) Product rights comprise certain technologies, intellectual property, licenses, and trade names acquired from third parties. Amortization expense of intangible assets other than goodwill was $9.8 million, $9.4 million, and $8.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. At December 31, 2020, 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 2021 $ 8,648 2022 7,415 2023 5,647 2024 4,684 2025 4,210 Thereafter 21,939 $ 52,543

Accrued Liabilities and Other L

Accrued Liabilities and Other Long Term Liabilities	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities, Current [Abstract]
Accrued Liabilities and Other Long Term Liabilities	ACCRUED LIABILITIES AND OTHER LONG-TERM LIABILITIES Accrued liabilities consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Accrued employee compensation and related expenses $ 167,649 $ 127,174 Accrued expenses (Note 16) 112,526 86,296 Accrued customer incentives and refund obligations 75,064 63,079 Accrued taxes 42,676 31,108 Current lease liabilities 17,733 15,281 Accrued liabilities $ 415,648 $ 322,938 Other long-term liabilities consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Accrued taxes $ 60,313 $ 67,463 Other accrued long-term expenses 25,291 13,701 Other long-term liabilities $ 85,604 $ 81,164

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Instruments [Abstract]
Debt	DEBT Credit Facility On April 14, 2020, we, along with IDEXX Distribution, Inc., IDEXX Operations, Inc., OPTI Medical Systems, Inc.,IDEXX Laboratories Canada Corporation, IDEXX Europe B.V., and IDEXX Holding B.V., our wholly-owned subsidiaries(whether directly or indirectly held) (collectively, the “Borrowers”), entered into a third amended and restated credit agreement (the “Credit Agreement”) relating to a three The Credit Agreement amends and restates that certain second amended and restated credit agreement, dated as of December 4, 2015, (which provided for a $850 million five Agreement. Although the Credit Facility does not mature until April 14, 2023, all individual borrowings under the terms of the Credit Facility with an interest rate based on a LIBOR, EURIBOR, or Canadian Dollar rate (as selected by the Borrower) 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, or replaced by a borrowing based on a published prime rate (where interest is then paid quarterly). The Credit Facility contains a subjective material adverse event notification 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, 2020, we had no outstanding borrowings under our Credit Facility, however based on our gross leverage ratio, our borrowing costs would have been approximately 2.5%. At December 31, 2019, we had $288.8 million outstanding under our Credit Facility with a weighted average effective interest rate 2.78%. The funds available under the Credit Facility reflect a further reduction due to the issuance of letters of credit, which were issued in connection with our workers’ compensation policy, for $1.4 million in December 31, 2020, and December 31, 2019. Applicable interest rates on borrowings under the Credit Facility are based on the prevailing LIBOR, Canadian Dollar Rate, or EURIBOR, but not less than 1.0%, plus a credit spread ranging from 1.375% to 2.00%, based on our gross leverage ratio. The Credit Facility also allows for borrowings based on the prevailing Prime rate, but not less than 2.00%, plus a credit spread from 0.375% to 1.00%. Under the Credit Facility, we also pay quarterly commitment fees ranging from 0.2% to 0.375%, based on our leverage ratio, on any unused commitment. The 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, 2020, we were in compliance with the covenants of the Credit Facility. Senior Notes The following describes all of our currently outstanding unsecured senior notes issued and sold in private placements (collectively, the "Senior Notes"): (Principal Amount in thousands) Issue Date Due Date Series Principal Amount Coupon Rate Senior Note Agreement 12/11/2013 12/11/2023 2023 Series A Notes $ 75,000 3.94 % NY Life 2013 Note Agreement 12/11/2013 12/11/2025 2025 Series B Notes $ 75,000 4.04 % NY Life 2013 Note Agreement 9/4/2014 9/4/2026 2026 Senior Notes $ 75,000 3.72 % NY Life 2014 Note Agreement 7/21/2014 7/21/2021 2021 Series A Notes $ 50,000 3.32 % Prudential 2015 Amended Agreement 7/21/2014 7/21/2024 2024 Series B Notes $ 75,000 3.76 % Prudential 2015 Amended Agreement 6/18/2015 6/18/2025 2025 Series C Notes € 88,857 1.785 % Prudential 2015 Amended Agreement 2/12/2015 2/12/2022 2022 Series A Notes $ 75,000 3.25 % MetLife 2014 Note Agreement 2/12/2015 2/12/2027 2027 Series B Notes $ 75,000 3.72 % MetLife 2014 Note Agreement 3/14/2019 3/14/2029 2029 Series C Notes $ 100,000 4.19 % MetLife 2014 Note Agreement 4/2/2020 4/2/2030 MetLife 2030 Series D Notes $ 125,000 2.50 % MetLife 2014 Note Agreement 4/14/2020 4/14/2030 Prudential 2030 Series D Notes $ 75,000 2.50 % Prudential 2015 Amended Agreement The following narrative represents our Senior Note activity: NY Life 2013 and 2014 Note Agreements, Including Amendments 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 Series A Notes”) and $75 million of 4.04% Series B Senior Notes due December 11, 2025 (the “2025 Series B Notes”) under a Note Purchase Agreement among the Company, New York Life Insurance Company and the accredited institutional purchasers named therein (as amended on April 10, 2020, the “NY Life 2013 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 Senior 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 (as amended April 10, 2020, the “NY Life 2014 Note Agreement”). On April 10, 2020, we amended the NY Life 2013 Note Agreement and the NY Life 2014 Note Agreement by entering into two Amendments to Note Purchase Agreement with New York Life Insurance Company and the other parties thereto, which modified several defined terms, schedules and covenant baskets in the NY Life 2013 Agreement and the NY Life 2014 Note Agreement to create additional operating flexibility, and in particular to align such provisions with similar modifications we made substantially concurrently in our other debt facilities. Prudential 2015 Amended Agreement, Including Amendments In July 2014, we issued and sold through a private placement an aggregate principal amount of $125 million of unsecured senior notes consisting of $50 million of 3.32% Series A Senior Notes due July 21, 2021 (the “2021 Series A Notes”) and $75 million of 3.76% Series B Senior Notes due July 21, 2024 (the “2024 Series B 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 “Prudential 2014 Note Agreement”). In June 2015, we entered into an Amended and Restated Multi-Currency Note Purchase and Private Shelf Agreement (the “Original Prudential 2015 Amended Agreement"), among the Company, Prudential, and the accredited institutional purchasers named therein, which amends and restates the Prudential 2014 Note Agreement. Pursuant to the Original Prudential 2015 Amended Agreement, we issued and sold through an aggregated private placement an aggregate principal amount of €88.9 million of unsecured 1.785% Series C Senior Notes due June 18, 2025 (the “2025 Series C Notes”). On May 9, 2019, we entered into the Amendment to Note Purchase and Private Shelf Agreement (the "Prudential First Amendment") with Prudential and the other parties thereto, which amended certain reporting provisions in the Original Prudential 2015 Amended Agreement. On April 10, 2020, we entered into the Second Amendment to the Prudential 2015 Amended Agreement (the “Prudential Second Amendment”), in order to (i) increase the facility size to $425 million, (ii) extend the facility issuance period to April 10, 2023, (iii) make various implementing and administrative changes in order to facilitate a $75 million notes issuance on April 14, 2020, (iv) allow the amount available to be issued under the facility to equal $425 million less the amount of notes outstanding from time to time during the issuance period and (v) modify several defined terms, schedules and covenant baskets in the Original Prudential 2015 Amended Agreement, as amended by the Prudential First Amendment, to create additional operating flexibility, and in particular to align such provisions with similar modifications we made substantially concurrently in our other debt facilities. We refer to the Original Prudential 2015 Agreement, as amended by the Prudential First Amendment and the Prudential Second Amendment, as the "Prudential 2015 Amended Agreement." On April 14, 2020, we issued and sold to Prudential and other purchasers $75 million of our unsecured senior notes (the “Prudential 2030 Series D Notes”) pursuant to the Prudential Second Amendment. The entire outstanding balance of the Prudential 2030 Series D Notes is due and payable on April 14, 2030, and the Prudential 2030 Series D Notes bear interest at the rate of 2.50% per annum. We used the proceeds received from the Prudential 2030 Series D Notes for general corporate purposes. MetLife 2014 Note Agreement, Including Amendments We entered into a Multicurrency Note Purchase and Private Shelf Agreement, dated as of December 19, 2014 (the "Original MetLife 2014 Note 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 an aggregate principal amount of $150 million of unsecured senior notes consisting of $75 million of our 3.25% Series A Senior Notes having a seven twelve On March 14, 2019, we amended the Original MetLife 2014 Note Agreement. Pursuant to the Original MetLife 2014 Note Agreement, as so amended, we issued and sold through a private placement an aggregate principal amount of $100 million of unsecured senior notes at a 4.19% per annum rate, due March 14, 2029 (the "2029 Series C Notes"). On March 23, 2020, we entered into the Second Amendment to the Original MetLife 2014 Note Agreement (the “MetLife Second Amendment”), in order to (i) increase the facility size from $150 million to $300 million, (ii) extend the facility issuance period to December 20, 2022, (iii) make various implementing and administrative changes in order to facilitate a $125 million notes issuance on April 2, 2020 and (iv) allow the amount available to be issued under the facility to equal $300 million, less the amounts outstanding on 2029 Series C Notes and MetLife 2030 Series D Notes. On April 2, 2020, we issued and sold to MetLife and other purchasers $125 million of our unsecured senior notes (the “MetLife 2030 Series D Notes”) pursuant to the MetLife Second Amendment. The entire outstanding principal balance of the MetLife 2030 Series D Notes is due and payable on April 2, 2030, and the MetLife 2030 Series D Notes bear interest at the rate of 2.50% per annum. We used the proceeds received from the MetLife 2030 Series D Notes for general corporate purposes. We refer to the Original MetLife 2014 Agreement, as so amended, as the "MetLife 2014 Agreement," and together with the NY Life 2013 Note Agreement, NY Life 2014 Note Agreement, and Prudential 2015 Amended Note Agreement, collectively, as the "Senior Note Agreements." Senior Note Agreements The Senior Note Agreements 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 interest, taxes, depreciation, amortization, and share-based compensation, as defined in the Senior Note Agreements, not to exceed 3.5-to-1. At December 31, 2020, 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. We used the net proceeds from the issuances and sale of the Senior Notes for general corporate purposes. Annual principal payments on long-term debt at December 31, 2020, are as follows: (in thousands) Years Ending December 31, Amount 2021 $ 50,000 2022 75,000 2023 75,000 2024 75,000 2025 184,125 Thereafter 450,000 $ 909,125 Total interest paid on all debt (including our Credit Facility) for the years ended December 31, 2020, 2019 and 2018, was $32.4 million, $29.7 million, and $34.7 million, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES 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, 2020 2019 2018 Domestic $ 483,694 $ 377,964 $ 337,437 International 178,291 144,254 120,305 $ 661,985 $ 522,218 $ 457,742 The provision (benefit) for income taxes comprised the following: (in thousands) For the Years Ended December 31, 2020 2019 2018 Current Federal $ 72,921 $ 52,194 $ 47,130 State 17,346 11,967 10,415 International 26,301 24,239 22,015 116,568 88,400 79,560 Deferred Federal (14,126) 4,826 3,970 State (2,863) 269 (937) International (19,725) 931 (1,898) (36,714) 6,026 1,135 $ 79,854 $ 94,426 $ 80,695 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, 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State income tax, net of federal tax benefit 2.4 2.3 2.6 Taxation on international earnings (1.0) (1.1) (0.8) Foreign derived intangible income (1.1) (1.1) (1.3) Share-based compensation from settlements (5.9) (3.6) (4.7) Research and development credit (0.8) (0.8) (0.9) Impact of Switzerland tax reform (3.3) — — State income tax carryforwards — — (0.2) Other, net 0.8 1.4 1.9 Effective tax rate 12.1 % 18.1 % 17.6 % Our effective income tax rate was 12.1% for the year ended December 31, 2020, and 18.1% for the year ended December 31, 2019. Our effective income tax rate for the year ended December 31, 2020 was lower primarily due to the one-time positive impact related to the enactment of tax reform in Switzerland due to recording a deferred tax asset related to the transitional benefits, as well as higher tax benefits related to share-based compensation. Our effective income tax rate was 18.1% for the year ended December 31, 2019, and 17.6% for the year ended December 31, 2018. Our effective income tax rate for the year ended December 31, 2019, was higher primarily due to lower tax benefits related to share-based compensation, partially offset by a nonrecurring item recorded in the first quarter of 2018, that resulted from the 2017 Tax Cut and Jobs Act. Income taxes paid, net of refunds received, for the periods ended December 31, 2020, 2019 and 2018 were $110.7 million, $88.0 million, and $69.7 million, respectively. We have received a tax ruling from the Netherlands that documents our mutual understanding of how existing tax laws apply to our circumstances. This ruling expires as of December 31, 2022, and we have been informed that it will not be renewed due to changes to the advance ruling policy in the Netherlands. While the absence of an advance agreement does not preclude our ability to continue to apply existing tax laws in the same manner as allowed by the existing ruling, the lack of such agreement creates uncertainty as to our future tax rate. Further, the Netherlands has recently announced proposals to modify existing rules that, if enacted, could eliminate the benefits to which this ruling applies. We continue to consider these developments within our overall tax strategy. Primarily as a result of this tax ruling, our net income was higher by $14.2 million, $13.7 million, and $9.2 million for the years ended December 31, 2020, 2019, and 2018, respectively. The benefits from our tax rulings are reflected within the overall benefits received from taxation on international earnings 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, 2020 December 31, 2019 Assets Accrued expenses $ 46,830 $ 25,296 Accounts receivable reserves 2,505 617 Deferred revenue 7,629 6,073 Inventory basis differences 4,272 3,315 Property-based differences 14,865 3,113 Intangible asset basis differences 51,319 — Share-based compensation 10,011 10,593 Other 1,484 1,160 Net operating loss carryforwards 5,427 4,045 Tax credit carryforwards 13,385 12,276 Unrealized losses on foreign currency exchange contracts and investments 5,060 20 Total assets 162,787 66,508 Valuation allowance (40,262) (9,454) Total assets, net of valuation allowance 122,525 57,054 Liabilities Customer acquisition costs (34,449) (28,519) Property-based differences (49,547) (33,802) Intangible asset basis differences (16,134) (14,513) Other (2,241) (3,961) Unrealized gains on foreign currency exchange contracts and investments (312) (1,183) Total liabilities (102,683) (81,978) Net deferred tax assets (liabilities) $ 19,842 $ (24,924) As of December 31, 2020, we record valuation allowances against certain deferred tax assets related to temporary differences, including intangible asset basis differences and 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 following table summarizes the changes in valuation allowance for deferred tax assets: (in thousands) For the Years Ended December 31, 2020 2019 2018 Balance at beginning of year $ 9,454 $ 6,212 $ 6,211 Charges to costs and expense 31,076 3,489 402 Write-off/cash payments (34) (226) — Foreign currency translation (234) (21) (401) Balance at the end of the year $ 40,262 $ 9,454 $ 6,212 As of December 31, 2020, we have NOL’s in certain state and international jurisdictions of approximately $23.1 million available to offset future taxable income. Most of these NOL’s will expire at various dates between 2022 and 2027 and the remainder have indefinite lives. The following table summarizes the changes in unrecognized tax positions: (in thousands) For the Years Ended December 31, 2020 2019 2018 Total amounts of unrecognized tax benefits, beginning of period $ 26,841 $ 24,247 $ 21,417 Gross (decreases) increases in unrecognized tax positions as a result of tax positions taken during a prior period (1,755) (276) 2,991 Gross increases in unrecognized tax positions as a result of tax positions taken in the current period 4,199 4,083 461 Decreases in unrecognized tax positions relating to settlements with taxing authorities (6,446) — — Decreases in unrecognized tax positions as a result of a lapse of the applicable statutes of limitations (355) (1,213) (622) Total amounts of unrecognized tax benefits, end of period $ 22,484 $ 26,841 $ 24,247 The total amount of unrecognized tax benefits at December 31, 2020 and December 31, 2019, was $22.5 million and $26.8 million, respectively. Of the total unrecognized tax benefits at December 31, 2020 and 2019, $21.8 million and $21.2 million, respectively, comprise unrecognized tax positions that would, if recognized, affect our effective tax rate. During the years ended December 31, 2020, 2019 and 2018, we recorded interest expense and penalties of $1.3 million, $1.8 million, and $1.2 million, respectively, as income tax expense in our consolidated statement of income. At December 31, 2020, 2019, and 2018 we had $3.6 million, $3.6 million, and $2.1 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 in various jurisdictions. We anticipate that these examinations will be concluded within the next two years. With few exceptions, we are no longer subject to income tax examinations in any jurisdiction in which we conduct significant taxable activities for years before 2015.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings per share is computed by dividing net income attributable to our 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 and the total unrecognized compensation expense for unvested share-based compensation awards, would be used to purchase our common stock at the average market price during the period. 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 5. Share-Based Compensation" for additional information regarding deferred stock units. The following is a reconciliation of weighted average shares outstanding for basic and diluted earnings per share: (in thousands) For the Years Ended December 31, 2020 2019 2018 Shares outstanding for basic earnings per share: 85,342 86,115 86,864 Shares outstanding for diluted earnings per share: Shares outstanding for basic earnings per share 85,342 86,115 86,864 Dilutive effect of share-based payment awards 1,380 1,427 1,606 86,722 87,542 88,470 Certain options to acquire shares have been excluded from the calculation of shares outstanding for diluted earnings per share because they were anti-dilutive. The following table presents information concerning those anti-dilutive options: (in thousands) For the Years Ended December 31, 2020 2019 2018 Weighted average number of shares underlying anti-dilutive options 206 200 287

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	COMMITMENTS, CONTINGENCIES AND GUARANTEES Commitments See "Note 8. Leases" for more information regarding our lease commitments. We are required to annually purchase a minimum amount of inventory from certain suppliers. Through 2025, we have a total of $4.0 million in minimum purchase commitments under these arrangements. Contingencies We 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, the results of legal actions cannot be predicted with certainty, and therefore our actual losses with respect to these contingencies could exceed our accruals. Except for the litigation matter described below, at December 31, 2020, our accruals with respect to actual and threatened litigation were not material. We are a defendant in an ongoing litigation matter involving an alleged breach of contract for underpayment of royalty payments made from 2004 through 2017 under an expired patent license agreement. The plaintiff has asserted a claim of approximately $50 million, inclusive of interest, alleging that the incorrect royalty provision was applied to certain licensed products and services throughout the agreement term and that royalties were also due on non-licensed diagnostic services that were provided concurrently with licensed services. The trial court has ruled in favor of the plaintiff in this matter and we are appealing the judgment and continue to vigorously defend ourselves against the plaintiff’s allegations. While we believe the claim is without merit, litigation is inherently unpredictable and there can be no assurance that we will prevail in this matter. We have established an accrual of $27.5 million related to this ongoing matter, which represents the amount of a possible loss that we have determined to be probable and estimable. The actual cost of resolving this matter may be higher or lower than the amount we have accrued. We self-insure costs associated with health, workers’ compensation, auto, 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. 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 2020, 2019, and 2018. We recognized U.S. employee healthcare claim expense of $59.5 million, $59.3 million, and $52.7 million for the years ended December 31, 2020, 2019, and 2018, respectively, 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, 2020 and 2019, was approximately $5.5 million and $5.0 million, respectively. Workers’ compensation and automobile claim expenses recognized during the years ended December 31, 2020, 2019 and 2018 and our respective liability for such claims as of December 31, 2020, 2019 and 2018 were not material. For the years ended on or prior to December 31, 2017, 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, 2020. As of December 31, 2020, we had outstanding letters of credit totaling $1.4 million to the insurance companies as security for the 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, 2020, other than following a change in control, we would have had an obligation for salaries and benefits of approximately $1.7 million under such agreement. In addition, the agreement provides for continued vesting of his outstanding equity awards for a period of two years, which would accelerate approximately $5.6 million of share-based compensation expense as of December 31, 2020. 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, 2020, we would have had aggregate obligations of approximately $37.7 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. 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 potential indemnification under these agreements is minimal. Accordingly, we have recorded no liabilities for these obligations at December 31, 2020 and 2019. When acquiring a business, we sometimes assume liability for certain events or occurrences that took place prior to the date of acquisition. As of December 31, 2020 and 2019, we do not have any material pre-acquisition liabilities recorded.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	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 improve producer efficiency, which we refer to as LPD. Our Other operating segment combines and presents products for the human medical diagnostics market with 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 (the "CODM"), or decision-making group, in deciding how to allocate resources and in assessing performance. Our CODM 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 biomedical analytics 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 producer efficiency, and to ensure the quality and safety of milk and improve producer efficiency. OPTI Medical manufactures and distributes diagnostic products and provide services for the human medical diagnostics market. Intersegment revenues, which are not included in the table below, were not material for the years ended December 31, 2020, 2019 and 2018. Effective January 1, 2020, 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 costs that previously were not allocated to our segments. Prior to January 1, 2020, certain costs were not allocated to our operating segments and were instead reported under the caption “Unallocated Amounts”. These costs primarily consist of our R&D function, regional or country expenses and unusual items. Corporate support function costs (such as information technology, facilities, human resources, finance and legal), health benefits and incentive compensation were charged to our business segments at pre-determined budgeted amounts or rates. Beginning January 1, 2020, the segments reflect these actual costs allocated to the segment based on various allocation methods, including revenue and headcount. Foreign exchange losses on settlements of foreign currency denominated transactions are not allocated to our operating segments and are instead reported within our Other reporting segment. These management reporting changes did not have a material impact to our segment results of operations for the years ended December 31, 2019 and 2018. The following tables reflect adjustments to previously reported costs in our Unallocated segment, that are now allocated to our CAG, Water, LPD and Other segments: For the year ended December 31, 2019: (in thousands) CAG Water LPD Other Unallocated Cost of sales $ (247) $ (11) $ (14) $ (6) $ 278 Gross profit 247 11 14 6 (278) Operating Expenses: Sales and marketing $ (239) $ (11) $ (13) $ — $ 263 General and administrative 13,004 501 625 1,363 (15,493) Research and development 16,479 33 41 — (16,553) Total operating expenses 29,244 523 653 1,363 (31,783) Income from operations $ (28,997) $ (512) $ (639) $ (1,357) $ 31,505 For the year ended December 31, 2018: (in thousands) CAG Water LPD Other Unallocated Cost of sales $ (1,540) $ (69) $ (87) $ (35) $ 1,731 Gross profit 1,540 69 87 35 (1,731) Operating Expenses: Sales and marketing $ (574) $ (25) $ (32) $ — $ 631 General and administrative 3,316 66 81 1,145 (4,608) Research and development 15,658 (4) (4) — (15,650) Total operating expenses 18,400 37 45 1,145 (19,627) Income from operations $ (16,860) $ 32 $ 42 $ (1,110) $ 17,896 The following tables reflect the impact to previously reported segment gross profit margin, operating income margin and operating expenses as a percentage of revenue, due to the allocation of these costs to our CAG, Water, LPD and Other segments: For the year ended December 31, 2019: CAG Water LPD Other Cost of sales — % — % — % — % Gross profit — % — % — % — % Operating Expenses: Sales and marketing — % — % — % — % General and administrative 0.6 % 0.4 % 0.5 % 6.1 % Research and development 0.8 % — % — % — % Total operating expenses 1.4 % 0.4 % 0.5 % 6.1 % Income from operations (1.4) % (0.4) % (0.5) % (6.1) % For the year ended December 31, 2018: CAG Water LPD Other Cost of sales (0.1) % (0.1) % (0.1) % (0.2) % Gross profit 0.1 % 0.1 % 0.1 % 0.2 % Operating Expenses: Sales and marketing — % — % — % — % General and administrative 0.2 % 0.1 % 0.1 % 5.2 % Research and development 0.8 % — % — % — % Total operating expenses 1.0 % — % — % 5.2 % Income from operations (0.9) % — % — % (5.0) % The following is a summary of segment performance: (in thousands) For the Years Ended December 31, CAG Water LPD Other Consolidated Total 2020 Revenue $ 2,385,765 $ 128,625 $ 145,845 $ 46,420 $ 2,706,655 Income from operations $ 574,887 $ 58,867 $ 40,008 $ 20,762 $ 694,524 Interest expense, net (32,539) Income before provision for income taxes 661,985 Provision for income taxes 79,854 Net income 582,131 Less: Net income attributable to noncontrolling interest 355 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 581,776 Depreciation and amortization $ 84,697 $ 2,630 $ 4,070 $ 4,601 $ 95,998 2019 Revenue $ 2,119,183 $ 132,850 $ 132,635 $ 22,240 $ 2,406,908 Income from operations $ 462,605 $ 61,923 $ 24,735 $ 3,583 $ 552,846 Interest expense, net (30,628) Income before provision for income taxes 522,218 Provision for income taxes 94,426 Net income 427,792 Less: Net income attributable to noncontrolling interest 72 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 427,720 Depreciation and amortization $ 77,620 $ 2,794 $ 4,007 $ 3,590 $ 88,011 2018 Revenue $ 1,935,428 $ 125,198 $ 130,581 $ 22,035 $ 2,213,242 Income from operations $ 412,623 $ 56,639 $ 19,454 $ 2,619 $ 491,335 Interest expense, net (33,593) Income before provision for income taxes 457,742 Provision for income taxes 80,695 Net income 377,047 Less: Net income attributable to noncontrolling interest 16 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 377,031 Depreciation and amortization $ 72,789 $ 2,592 $ 4,094 $ 3,703 $ 83,178 See "Note 3. Revenue Recognition" for a summary of disaggregated revenue by reportable segment and by major product and service category for the years ended December 31, 2020, 2019 and 2018. 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, 2020 December 31, 2019 Americas United States $ 412,700 $ 401,248 Brazil 20,797 22,274 Canada 4,993 7,784 438,490 431,306 Europe, the Middle East and Africa Germany 67,354 52,032 United Kingdom 10,191 12,114 Netherlands 15,267 13,586 France 2,062 2,061 Switzerland 3,743 3,508 Other 3,668 3,395 102,285 86,696 Asia Pacific Region Japan 4,503 5,409 Australia 3,304 4,088 Other 6,585 6,346 14,392 15,843 Total $ 555,167 $ 533,845

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	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. 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, 2020 and 2019. Our cross currency swap contracts are measured at fair value on a recurring basis in our accompanying consolidated balance sheets. We measure the fair value of our cross currency swap contracts classified as derivative instruments using prevailing market conditions as of the close of business on each balance sheet date. The product of this calculation is then adjusted for counterparty risk. 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. The amounts outstanding under our unsecured revolving credit facility ("Credit Facility" or “line of credit”) and senior notes (“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, 2020, the estimated fair value and carrying value of our long-term debt were $1.0 billion and $909.1 million, respectively. At December 31, 2019, the estimated fair value and carrying value of our long-term debt were $753.6 million and $699.4 million, respectively. The following tables set forth our assets and liabilities that were measured at fair value on a recurring basis by level within the fair value hierarchy: (in thousands) As of December 31, 2020 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Balance at December 31, 2020 Assets Money market funds (1) $ 76 $ — $ — $ 76 Equity mutual funds (2) $ 1,145 $ — $ — $ 1,145 Foreign currency exchange contracts (3) $ — $ 125 $ — $ 125 Liabilities Cross currency swaps (3) $ — $ 2,841 $ — $ 2,841 Foreign currency exchange contracts (3) $ — $ 12,373 $ — $ 12,373 Deferred compensation (4) $ 1,145 $ — $ — $ 1,145 (in thousands) As of December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Balance at December 31, 2019 Assets Money market funds (1) $ 71 $ — $ — $ 71 Equity mutual funds (2) $ 1,676 $ — $ — $ 1,676 Cross currency swaps (3) $ — $ 4,559 $ — $ 4,559 Foreign currency exchange contracts (3) $ — $ 1,791 $ — $ 1,791 Liabilities Foreign currency exchange contracts (3) $ — $ 2,886 $ — $ 2,886 Deferred compensation (4) $ 1,676 $ — $ — $ 1,676 (1) Money market funds 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, 2020, and December 31, 2019, consisted of demand deposits. (2) Equity mutual funds relate to a deferred compensation plan that was assumed as part of a previous business combination. This amount is included within other long-term assets. See footnote (4) below for a discussion of the related deferred compensation liability. (3) Cross currency swaps and 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 and 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 footnote (2) above.

Hedging Instruments

Hedging Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Hedging Instruments	HEDGING INSTRUMENTS Disclosure within this note is presented to provide transparency about how and why we use derivative and non-derivative instruments (collectively “hedging instruments”), how the instruments and related hedged items are accounted for, and how the instruments and related hedged items affect our financial position, results of operations and cash flows. We are exposed to certain risks related to our ongoing business operations. The primary risk that we currently manage by using hedging instruments is foreign currency exchange risk. 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. 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, cross currency swaps 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. The primary purpose of our foreign currency hedging activities is to protect against the volatility associated with foreign currency transactions, including transactions denominated in euro, British pound, Japanese yen, Canadian dollar, and Australian dollar. 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 transactions 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. We recognize all 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, changes 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. See “Note 21. Accumulated Other Comprehensive Income” for further information regarding the effect of hedging instruments on the consolidated statements of income for the years ended December 31, 2020, 2019 and 2018. 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 liabilities in the accompanying consolidated balance sheets on a gross basis. All cash flows related to our foreign currency exchange contracts are classified as operating cash flows, which is consistent with the cash flow treatment of the underlying items being hedged. See "Note 18. Fair Value Measurements" for additional information regarding the fair value of our derivative instruments and "Note 21. Accumulated Other Comprehensive Income" for additional information regarding the effect of derivative instruments designated as cash flow hedges on the consolidated statements of income. Cash Flow Hedges We have designated our foreign currency exchange contracts 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. 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, 2020, 2019 and 2018. Gains and losses related to hedge ineffectiveness recognized in earnings during the years ended December 31, 2020, 2019 and 2018 were not material. At December 31, 2020, the estimated amount of net losses, net of tax, which are expected to be reclassified out of AOCI and into earnings within the next twelve months is $9.9 million if exchange rates do not fluctuate from the levels at December 31, 2020. We target to hedge approximately 85% of the estimated exposure from intercompany product purchases and sales denominated in the euro, British pound, Canadian dollar, Japanese yen, and Australian dollar. 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 purchases and sales totaled $202.7 million, and $210.9 million at December 31, 2020 and 2019, respectively. The following table presents the effect of cash flow hedge accounting on our consolidated statements of income and comprehensive income, and provides information regarding the location and amounts of pretax gains or losses of derivatives: (in thousands) Years Ended December 31, 2020 2019 2018 Financial statement line items in which effects of cash flow hedges are recorded Cost of revenue $ 1,135,615 $ 1,041,359 $ 971,700 Foreign exchange contracts Amount of gain (loss) reclassified from accumulated other comprehensive income into income $ 829 $ 10,628 $ (976) Net Investment Hedges, Euro-Denominated Notes In June 2015, we issued and sold through a private placement an aggregate principal amount of €88.9 million in euro-denominated 1.785% Series C Senior Notes due June 18, 2025. 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 a loss of $7.4 million and gains of $1.8 million and $3.9 million, net of tax, within AOCI as a result of this net investment hedge for the years ended December 31, 2020, 2019, and 2018, respectively. The related cumulative unrealized gain recorded at December 31, 2020, will not be reclassified in earnings until the complete or substantially complete liquidation of the net investment in the hedged foreign operations or all or a portion of the hedge no longer qualifies for hedge accounting treatment. See "Note 13. Debt" to the consolidated financial statements included in this Annual Report on Form 10-K for further information regarding the issuance of these euro-denominated notes. Net Investment Hedges, Cross Currency Swaps We have entered into several cross currency swap contracts as a hedge of our net investment in foreign operations to offset foreign currency translation gains and losses on the net investment. These cross currency swaps have maturity dates beginning on June 30, 2023, through June 18, 2025. At maturity of the cross currency swap contracts, we will deliver the notional amounts of €90.0 million and will receive approximately $104.5 million from the counterparties on June 30, 2023, and we will deliver the notional amount of €15.0 million and will receive approximately $17.5 million from the counterparties on June 18, 2025. The change in fair value of the cross currency swap contracts are recorded in AOCI and will be reclassified to earnings when the foreign subsidiaries are sold or substantially liquidated. We recorded a loss of $5.6 million, a gain of $2.1 million, and a gain of $1.4 million, net of tax, within AOCI as a result of these net investment hedges, during the years ended December 31, 2020. 2019, and 2018, respectively. We will receive quarterly interest payments from the counterparties based on a fixed interest rate until maturity of the cross currency swaps. This interest rate component is excluded from the assessment of hedge effectiveness and, thus is recognized as a reduction to interest expense over the life of the hedge instrument. We recognized approximately $2.7 million and $2.4 million related to the excluded component as a reduction of interest expense for the years ended December 31, 2020 and 2019, respectively. 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 derivative instruments, unless otherwise noted: (in thousands) Hedging Assets December 31, 2020 December 31, 2019 Derivatives and non-derivatives designated as hedging instruments Balance Sheet Classification Foreign currency exchange contracts Other current assets $ 125 $ 1,791 Cross currency swaps Other long-term assets — 4,559 Total derivative instruments presented as hedge instruments on the balance sheet 125 6,350 Gross amounts subject to master netting arrangements not offset on the balance sheet (125) (1,354) Net amount $ — $ 4,996 (in thousands) Hedging Liabilities December 31, 2020 December 31, 2019 Derivatives and non-derivatives designated as hedging instruments Balance Sheet Classification Foreign currency exchange contracts Accrued liabilities $ 12,373 $ 2,886 Cross currency swaps Other long-term liabilities 2,841 — Total derivative instruments presented as cash flow hedges on the balance sheet 15,214 2,886 Non-derivative foreign currency denominated debt designated as net investment hedge on the balance sheet (1) Long-term debt 109,125 99,422 Total hedging instruments presented on the balance sheet 124,339 102,308 Gross amounts subject to master netting arrangements not offset on the balance sheet (125) (1,354) Net amount $ 124,214 $ 100,954 (1) Amounts represent reported carrying amounts of our foreign currency denominated debt. See "Note 18. Fair Value Measurements" for information regarding the fair value of our long-term debt.

Repurchases of Common Stock

Repurchases of Common Stock	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Repurchases of Common Stock	REPURCHASES OF COMMON STOCK As of December 31, 2020, our Board of Directors has authorized the repurchase of u p to 73.0 million sh ares 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 stockholders, and we also repurchase to offset the dilutive effect of our share-based compensation programs. Repurchases of our common stock may vary depending upon the level of other investing activities and the share price. As of December 31, 2020, there are approximate ly 6.3 million rem aining shares available for repurchase under this authorization. We primarily acquire shares by repurchases in the open market. However, we also acquire shares that are surrendered by employees in payment for the minimum required statutory withholding taxes due on the vesting of restricted stock units and the settlement of deferred stock units, otherwise referred to herein as employee surrenders. We issue shares of treasury stock upon the vesting of certain restricted stock units and upon the exercise of certain stock options. The number of shares of treasury stock issued during the years ended December 31, 2020, 2019 and 2018, was not material. The following is a summary of our open market common stock repurchases, reported on a trade date basis, and shares acquired through employee surrenders: (in thousands, except per share amounts) For the Years Ended December 31, 2020 2019 2018 Shares repurchased in the open market 721 1,215 1,773 Shares acquired through employee surrenders for statutory tax withholding 58 39 52 Total shares repurchased 779 1,254 1,825 Cost of shares repurchased in the open market $ 179,623 $ 303,838 $ 368,691 Cost of shares for employee surrenders 20,603 8,054 9,375 Total cost of shares $ 200,226 $ 311,892 $ 378,066 Average cost per share - open market repurchases $ 249.20 $ 249.84 $ 207.92 Average cost per share - employee surrenders $ 354.98 $ 210.10 $ 182.18 Average cost per share - total $ 257.08 $ 248.62 $ 207.19

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income	ACCUMULATED OTHER COMPREHENSIVE INCOME The changes in AOCI, net of tax, consisted of the following: For the Years Ended December 31, 2020 and 2019 Unrealized (Loss) Gain on Cash Flow Hedges, Net of Tax Unrealized (Loss) Gain on Net Investment Hedges, Net of Tax (in thousands) Unrealized (Loss) Gain on Investments, Net of Tax Foreign Currency Exchange Contracts Euro-Denominated Notes Cross Currency Swaps Cumulative Translation Adjustment Total Balance as of December 31, 2018 $ (157) $ 6,229 $ (394) $ 1,360 $ (48,829) $ (41,791) Other comprehensive income (loss) before reclassifications 267 1,196 1,790 2,107 (1,590) 3,770 Amounts reclassified from accumulated other comprehensive income — (8,161) — — — (8,161) Balance as of December 31, 2019 110 (736) 1,396 3,467 (50,419) (46,182) Other comprehensive (loss) income before reclassifications (382) (8,527) (7,378) (5,626) 15,151 (6,762) Amounts reclassified from accumulated other comprehensive income — (671) — — — (671) Balance as of December 31, 2020 $ (272) $ (9,934) $ (5,982) $ (2,159) $ (35,268) $ (53,615) The following table presents components and amounts reclassified out of AOCI to net income: (in thousands) Affected Line Item in the Statements of Income Amounts Reclassified from AOCI for the Years Ended December 31, 2020 2019 2018 Gains (losses) on derivative instruments included in net income: Foreign currency exchange contracts Cost of revenue $ 829 $ 10,628 $ (976) Tax expense (benefit) 158 2,467 (187) Gains (losses), net of tax $ 671 $ 8,161 $ (789)

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2020
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred Stock	PREFERRED STOCK

IDEXX Retirement and Incentive

IDEXX Retirement and Incentive Savings Plan	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
IDEXX Retirement and Incentive Savings Plan	IDEXX RETIREMENT AND INCENTIVE SAVINGS PLAN We have established the IDEXX Retirement and Incentive Savings Plan (the “401(k) Plan”). U.S. employees 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 5% of participants’ eligible compensation. We matched $23.4 million, $21.1 million, and $19.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. In addition, we may make contributions to the 401(k) Plan at the discretion of the Board of Directors. There were no discretionary contributions in 2020, 2019 or 2018. 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 Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Estimates	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, such as the economic impact of the COVID-19 pandemic, 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. Furthermore, as the impact of the COVID-19 pandemic continues to develop, many of these estimates could require increased judgment and carry a higher degree of variability and volatility, and may change materially in future periods. Actual results could differ materially from these estimates.
Cash And Cash Equivalents	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.
Warranty Reserves	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	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.
Research And Development Costs	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 research and development costs for capitalization after the technological feasibility has been established for software and products containing software to be sold, however no costs were capitalized during the years ended December 31, 2020, 2019 and 2018. Software developed to deliver hosted services to our customers has been designated as internal use and we capitalize certain costs incurred in connection with developing or obtaining software designated for internal use based on three distinct stages of development. See "Note 9. Property and Equipment, Net" for further information on internal use software.
Advertising Costs	Advertising Costs    Advertising costs, which are recognized as sales and marketing expense in the period in which they are incurred, were $1.4 million, $1.5 million, and $1.8 million for the years ended December 31, 2020, 2019 and 2018, respectively.
Legal Costs	Legal Costs    Legal costs are considered period costs and accordingly are expensed in the year services are provided.
Foreign Currency	Foreign Currency The functional currency of all except four 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”).
Comprehensive Income	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 hedges and the difference between the cost and the fair market value of investments in debt and equity securities, and forward currency exchange contracts, in the consolidated statements of comprehensive income.
Concentrations of Risk	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 as well as certain components, raw materials and consumables used in or with our products are 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	New Accounting Pronouncements Adopted We adopted ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)," as of January 1, 2018, using the modified retrospective method for all contracts not completed as of the date of adoption. We adopted ASU 2016-02, "Leases (Topic 842)," as of January 1, 2019, using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and did not restate prior periods. We adopted ASU 2018-13, "Fair Value Measurement (Topic 820)," as of January 1, 2020, which modifies the disclosure requirements on fair value measurements under ASC Topic No. 820, Fair Value Measurement, as amended (“ASC 820”). ASU 2018-13 removes (a) the prior requirement to disclose the amount and reason for transfers between Level 1 and Level 2 of the fair value hierarchy contained in ASC 820, (b) the policy for timing of transfers between levels, and (c) the valuation processes used for Level 3 fair value measurements. ASU 2018-13 also adds, among other things, a requirement to disclose the range and weighted average of significant unobservable inputs used in Level 3 fair value measurements. The adoption did not have a material impact on our consolidated financial statements. We adopted ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” effective January 1, 2020, using the modified retrospective transition method. This ASU amends the impairment model to utilize an expected loss methodology in place of the incurred loss methodology for financial instruments, including trade receivables and leased equipment. The amendment requires entities to consider a broader range of information to estimate expected credit losses, which may result in earlier recognition of losses. We recorded a non-cash cumulative effect adjustment to retained earnings of $1.8 million, net of $0.6 million of income taxes, on our opening consolidated balance sheet as of January 1, 2020. This adjustment, before the impact of income taxes, was comprised of $2.3 million related to our contract assets and sales-type leases, and $0.2 million related to accounts receivable. See Note 6. Credit Losses, for more information on our presentation of credit losses. In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” The new guidance is intended to simplify the accounting for income taxes by removing certain exceptions and by updating accounting requirements around goodwill recognized for tax purposes and the allocation of current and deferred tax expense among legal entities, among other minor changes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Early adoption is permitted. We do not expect the adoption of ASU 2019-12 to have a material impact on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, "Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” ASU 2020-04 is intended to provide optional expedients and exceptions to the U.S. GAAP guidance on contract modifications and hedge accounting to ease the financial reporting burdens related to the discontinuation of the London Interbank Offered Rate (“LIBOR”) or by another reference rate expected to be discontinued. The FASB also issued ASU 2021-01, "Reference Rate Reform (Topic 848): Scope", in January 2021. It clarifies that certain optional expedients and exceptions apply to derivatives that are affected by the discounting transition. The amendments in this ASU affect the guidance in ASU No. 2020-04 and are effective in the same timeframe as ASU 2020-04. The relief offered by this guidance, if adopted, is available to companies for the period March 12, 2020 through December 31, 2022. Our Credit Facility includes a provision for the determination of a benchmark replacement rate as a successor to the LIBOR rate, therefore we do not expect the discontinuation of LIBOR to have an impact on our consolidated financial statements.
Revenue Recognition	Our revenue is recognized when, or as, performance obligations under the terms of a contract are satisfied, which occurs when control of the promised products or services is transferred to a customer. We exclude sales, use, value-added, and other taxes we collect on behalf of third parties from revenue. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products or services to a customer. To accurately present the consideration received in exchange for promised products or services, we apply the five-step model outlined below: 1. Identification of a contract or agreement with a customer 2. Identification of our performance obligations in the contract or agreement 3. Determination of the transaction price 4. Allocation of the transaction price to the performance obligations 5. Recognition of revenue when, or as, we satisfy a performance obligation
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”), share-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”), share-based compensation expense is recognized net of estimated forfeitures, on a grade-vesting methodology over the requisite service period.
Credit Losses	We are exposed to credit losses primarily through our sales of products and services to our customers. We maintain allowances for credit losses 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. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current economic conditions. See Note 2. Accounting Policies, for more information on our adoption of ASU 2016-13 on January 1, 2020, using the modified retrospective transition method. 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. dollar-denominated purchases. We monitor our ongoing credit exposure through active review of counterparty balances against contract terms and due dates. Our activities include timely account reconciliations, dispute resolution and payment confirmations. We may employ collection agencies and legal counsel to pursue recovery of defaulted receivables. Account balances are charged off against the allowance when we believe it is probable the receivable will not be recovered. We may require collateralized asset support or a prepayment to mitigate credit risk. We do not have any off-balance sheet credit exposure related to our customers.
Inventories	Inventories are stated at the lower of cost (first-in, first-out) or net realizable value. Net realizable value is the estimated selling price 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.
Leases	The majority of our facilities are occupied under operating lease arrangements with various expiration dates through 2067, some of which include options to extend the life of the lease, and some of which include options to terminate the lease within 1 year. In certain instances, we are responsible for the real estate taxes and operating expenses related to these facilities. Additionally, 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 financing 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. Minimum lease payments include the fixed lease component of the agreement, as well as fixed rate increases that are initially measured at the lease commencement date. Variable lease payments based on an index, payments associated with non-lease components and short-term rentals (leases with terms less than 12 months) are expensed as incurred. Consideration is allocated to the lease and non-lease components based on the estimated standalone prices. We determine if an arrangement is a lease at its inception. Operating leases are included in operating lease right-of-use assets, accrued liabilities, and long-term operating lease liabilities in our consolidated balance sheets. Our financing leases are not material to the financial statements. Right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease liabilities and right-of-use assets are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an explicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Rent expense for lease payments is recognized on a straight-line basis over the lease term. The operating lease right-of-use assets also includes any rent prepayments, lease incentives upon receipt, and straight-line rent expense impacts, which represent the differences between our operating lease liabilities and right-of-use assets.
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 are 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 the consolidated statements of 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, 2020 and 2019 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 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 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 significant, 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 separately identified and 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, 2020, 2019 and 2018. 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 goodwill impairment test. The more likely than not threshold is defined as having a likelihood of more than 50%. 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 assess the fair value of all of our reporting units and compare the fair value of the reporting unit to its carrying value to determine if the carrying value exceeds its fair value, and if a goodwill impairment loss should be recognized. In contrast, we can opt to bypass the qualitative assessment for any reporting unit in any period and proceed directly to assessing the fair value of all of our reporting units and compare the fair value of the reporting unit to carrying value to determine if any impairment exists. Doing so does not preclude us from performing the qualitative assessment in any subsequent period. In the fourth quarter of 2020, we elected to bypass the qualitative approach that allows the assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount and instead proceeded directly to assessing the fair value of all of our reporting units and comparing the fair values of each reporting unit to the carrying values to determine if any impairment exists. 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 loss in a future period. No goodwill impairments were identified during the years ended December 31, 2020, 2019 or 2018, and no accumulated impairment losses are recorded. 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 asset group is the lowest level for which identifiable cash flows associated with the intangible asset are largely independent. 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 loss 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. The amount of impairment for the year ended December 31, 2020 was immaterial. We had no impairments of our intangible assets during the years ended December 31, 2019, and 2018. The changes in the carrying amount of goodwill for the years ended December 31, 2020, 2019 and 2018, were as follows: (in thousands) CAG Water LPD Other Consolidated Total Balance as of December 31, 2017 $ 166,236 $ 11,951 $ 15,155 $ 6,531 $ 199,873 Business combinations 20,282 — — — 20,282 Impact of changes in foreign currency exchange rates (4,132) (730) (804) — (5,666) Balance as of December 31, 2018 $ 182,386 $ 11,221 $ 14,351 $ 6,531 $ 214,489 Business combinations 24,826 — — — 24,826 Impact of changes in foreign currency exchange rates 138 390 (119) — 409 Balance as of December 31, 2019 $ 207,350 $ 11,611 $ 14,232 $ 6,531 $ 239,724 Business combinations 220 — — — 220 Acquisition adjustment (1,900) — — — (1,900) Impact of changes in foreign currency exchange rates 4,724 412 167 — 5,303 Balance as of December 31, 2020 $ 210,394 $ 12,023 $ 14,399 $ 6,531 $ 243,347 See "Note 4. Acquisitions and Investments" 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, 2020, 2019 and 2018. 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 Customer-related intangible assets (1) 3 to 17 years Product rights (2) 5 to 15 years Noncompete agreements 3 to 5 years (1) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties. (2) Product rights comprise certain technologies, intellectual property, licenses, and trade names acquired from third parties.
Income Taxes	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 Per Share	Basic earnings per share is computed by dividing net income attributable to our 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 and the total unrecognized compensation expense for unvested share-based compensation awards, would be used to purchase our common stock at the average market price during the period. 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 5. Share-Based Compensation" for additional information regarding deferred stock units.
Self-Insurance Accruals	We 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, the results of legal actions cannot be predicted with certainty, and therefore our actual losses with respect to these contingencies could exceed our accruals.
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. 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, 2020 and 2019. Our cross currency swap contracts are measured at fair value on a recurring basis in our accompanying consolidated balance sheets. We measure the fair value of our cross currency swap contracts classified as derivative instruments using prevailing market conditions as of the close of business on each balance sheet date. The product of this calculation is then adjusted for counterparty risk. 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
Hedging Instruments	We recognize all 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, changes 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. See “Note 21. Accumulated Other Comprehensive Income” for further information regarding the effect of hedging instruments on the consolidated statements of income for the years ended December 31, 2020, 2019 and 2018.    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 liabilities in the accompanying consolidated balance sheets on a gross basis. All cash flows related to our foreign currency exchange contracts are classified as operating cash flows, which is consistent with the cash flow treatment of the underlying items being hedged.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregated Revenues	The following table presents disaggregated revenue by major product and service categories: (in thousands) For the Years Ended December 31, 2020 2019 2018 CAG segment revenue: CAG Diagnostics recurring revenue: $ 2,113,839 $ 1,828,329 $ 1,654,530 IDEXX VetLab consumables 824,376 693,360 617,237 Rapid assay products 253,018 232,149 217,541 Reference laboratory diagnostic and consulting services 946,268 822,497 746,794 CAG Diagnostics services and accessories 90,177 80,323 72,958 CAG Diagnostics capital - instruments 108,950 132,685 134,264 Veterinary software, services and diagnostic imaging systems 162,976 158,169 146,634 CAG segment revenue 2,385,765 2,119,183 1,935,428 Water segment revenue 128,625 132,850 125,198 LPD segment revenue 145,845 132,635 130,581 Other segment revenue 46,420 22,240 22,035 Total revenue $ 2,706,655 $ 2,406,908 $ 2,213,242 Revenue by principal geographic area, based on customers’ domiciles, was as follows: (in thousands) For the Years Ended December 31, 2020 2019 2018 Americas United States $ 1,691,224 $ 1,495,516 $ 1,357,909 Canada 107,398 99,550 94,206 Latin America 51,863 56,515 50,969 1,850,485 1,651,581 1,503,084 Europe, the Middle East and Africa Germany 119,353 104,081 100,459 United Kingdom 90,156 90,969 87,807 France 74,814 64,767 60,319 Italy 42,817 39,725 36,956 Spain 39,265 36,439 33,687 Switzerland 24,850 20,855 19,875 Netherlands 23,461 19,397 18,090 Other 148,049 122,206 114,877 562,765 498,439 472,070 Asia Pacific Region Australia 79,629 71,069 63,386 Japan 74,725 67,246 60,213 China 70,845 57,518 57,621 Other 68,206 61,055 56,868 293,405 256,888 238,088 Total $ 2,706,655 $ 2,406,908 $ 2,213,242

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Selected Financial Impact of Share-based Compensation	The following is a summary of share-based compensation costs and related tax benefits recorded in our consolidated statements of income: (in thousands) For the Years Ended December 31, 2020 2019 2018 Share-based compensation expense included in cost of revenue $ 3,415 $ 2,681 $ 2,816 Share-based compensation expense included in operating expenses 27,536 36,597 22,341 Total share-based compensation expense included in consolidated statements of income 30,951 39,278 25,157 Income tax benefit resulting from share-based compensation expense (3,965) (4,861) (4,190) Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards 26,986 34,417 20,967 Income tax benefit resulting from settlement of share-based awards (38,981) (19,140) (21,496) Net expense (benefit) related to share-based compensation arrangements included in consolidated statements of income $ (11,995) $ 15,277 $ (529)
Schedule of Weighted Averages of the Assumptions Used in Estimating the Fair Value of Stock Option Awards	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, 2020 2019 2018 Share price at grant $ 291.14 $ 218.66 $ 179.56 Share exercise price $ 291.14 $ 220.88 $ 179.56 Expected stock price volatility 27 % 26 % 24 % Expected term, in years 6.0 6.0 5.8 Risk-free interest rate 1.4 % 2.4 % 2.7 % Weighted average fair value of options granted $ 84.92 $ 65.53 $ 52.99
Schedule of Stock Option Activity	A summary of the status of options granted under our share-based compensation plans at December 31, 2020, 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, 2019 2,311 $ 117.13 Granted 220 $ 291.14 Exercised (562) $ 71.65 Forfeited (16) $ 180.78 Outstanding as of December 31, 2020 1,953 $ 149.32 6.3 $ 684,571 Fully vested as of December 31, 2020 1,057 $ 106.91 5.3 $ 415,229 Fully vested and expected to vest as of December 31, 2020 1,933 $ 148.61 6.3 $ 678,994
Schedule of Restricted Stock Unit Activity	A summary of the status of RSUs and PBRSUs granted under our share-based compensation plans at December 31, 2020, 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, 2019 258 $ 150.50 Granted 65 $ 291.30 Vested (94) $ 124.60 Forfeited (11) $ 178.95 Nonvested as of December 31, 2020 218 $ 202.47 Expected to vest as of December 31, 2020 208 $ 201.64

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory, Net [Abstract]
Schedule of Components of Inventories	The components of inventories are as follows: (in thousands) December 31, 2020 December 31, 2019 Raw materials $ 45,986 $ 41,202 Work-in-process 20,374 20,077 Finished goods 143,513 133,740 Inventories $ 209,873 $ 195,019

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Maturities of operating lease liabilities	Maturities of operating lease liabilities are as follows: (in thousands) December 31, 2020 2021 $ 20,187 2022 18,698 2023 13,556 2024 9,810 2025 8,129 Thereafter 39,224 Total lease payments 109,604 Less imputed interest (14,832) Total lease liability (current and long-term) $ 94,772
Supplemental cash flow information	(in thousands, except lease term and discount rate) December 31, 2020 December 31, 2019 Weighted average remaining lease term - operating leases 10.3 years 10.3 years Weighted average discount rate - operating leases 2.9 % 3.5 % For the Years Ended (in thousands) 2020 2019 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,619 $ 20,008 Right-of-use assets obtained in exchange for operating lease obligations, net of early lease terminations $ 26,807 $ 13,399

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Estimated Useful Lives for Property and Equipment	We provide for depreciation and amortization primarily using the straight-line method by charges to the consolidated statements of 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
Schedule of Property and Equipment	Property and equipment, net, consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Land and improvements $ 13,982 $ 8,725 Buildings and improvements 319,384 249,918 Leasehold improvements 82,459 74,602 Machinery and equipment 353,301 322,814 Office furniture and equipment 67,527 53,210 Computer hardware and software 265,664 240,406 Construction in progress 39,764 103,200 1,142,081 1,052,875 Less accumulated depreciation and amortization 586,914 519,030 Total property and equipment, net $ 555,167 $ 533,845
Summary of Depreciation and Amortization, Capitalized Computer Software for Internal Use and Unpaid Property Equipment Reflected in Accounts Payable and Accrued Expenses	Below are the amounts of depreciation and amortization of property and equipment, capitalized computer software for internal use, unpaid property and equipment reflected in accounts payable and accrued expenses, and rental and reagent rental program instruments transferred from inventory to property and equipment: For the Years Ended December 31, (in thousands) 2020 2019 2018 Depreciation and amortization expense $ 86,095 $ 78,495 $ 74,208 Capitalized computer software developed for internal use $ 18,472 $ 20,130 $ 17,115 Unpaid property and equipment, reflected in accounts payable and accrued liabilities $ 13,343 $ 24,688 $ 17,894 Rental and operating-type reagent rental program instruments transferred from inventory to property and equipment (Note 3) $ 9,645 $ 14,498 $ 20,360

Other Current and Long-Term A_2

Other Current and Long-Term Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Other Assets, Noncurrent [Abstract]
Schedule of Other Current Assets	Other current assets consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Customer acquisition costs $ 43,751 $ 39,329 Prepaid expenses 34,556 31,992 Contract assets, net 23,837 17,659 Taxes receivable 19,476 20,516 Deferred sales commissions 5,738 5,202 Other 10,150 10,284 Other current assets $ 137,508 $ 124,982
Schedule of Other Noncurrent Assets	Other long-term assets consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Customer acquisition costs $ 104,369 $ 98,117 Contract assets, net 91,681 66,226 Deferred income taxes 31,549 8,100 Investment in long-term product supply arrangements 12,065 13,657 Deferred sales commissions 11,719 10,442 Taxes receivable 6,329 14,960 Other 31,883 28,690 Other long-term assets $ 289,595 $ 240,192

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill for the years ended December 31, 2020, 2019 and 2018, were as follows: (in thousands) CAG Water LPD Other Consolidated Total Balance as of December 31, 2017 $ 166,236 $ 11,951 $ 15,155 $ 6,531 $ 199,873 Business combinations 20,282 — — — 20,282 Impact of changes in foreign currency exchange rates (4,132) (730) (804) — (5,666) Balance as of December 31, 2018 $ 182,386 $ 11,221 $ 14,351 $ 6,531 $ 214,489 Business combinations 24,826 — — — 24,826 Impact of changes in foreign currency exchange rates 138 390 (119) — 409 Balance as of December 31, 2019 $ 207,350 $ 11,611 $ 14,232 $ 6,531 $ 239,724 Business combinations 220 — — — 220 Acquisition adjustment (1,900) — — — (1,900) Impact of changes in foreign currency exchange rates 4,724 412 167 — 5,303 Balance as of December 31, 2020 $ 210,394 $ 12,023 $ 14,399 $ 6,531 $ 243,347
Schedule of Estimated Useful Lives for Intangible Assets	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 Customer-related intangible assets (1) 3 to 17 years Product rights (2) 5 to 15 years Noncompete agreements 3 to 5 years (1) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties. (2) Product rights comprise certain technologies, intellectual property, licenses, and trade names acquired from third parties.
Schedule of Intangible Assets Other Than Goodwill	Intangible assets other than goodwill consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Customer-related intangible assets (1) $ 80,810 $ 32,838 $ 47,972 $ 99,301 $ 46,801 $ 52,500 Product rights (2) 15,150 11,609 3,541 16,130 10,214 5,916 Noncompete agreements 1,250 220 1,030 170 118 52 $ 97,210 $ 44,667 $ 52,543 $ 115,601 $ 57,133 $ 58,468 The above table excludes fully amortized intangible assets for the periods presented. (1) Customer-related intangible assets are comprised of customer lists and customer relationships acquired from third parties. (2) Product rights comprise certain technologies, intellectual property, licenses, and trade names acquired from third parties.
Schedule of Expected Amortization Expense	At December 31, 2020, 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 2021 $ 8,648 2022 7,415 2023 5,647 2024 4,684 2025 4,210 Thereafter 21,939 $ 52,543

Accrued Liabilities and Other_2

Accrued Liabilities and Other Long Term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities, Current [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Accrued employee compensation and related expenses $ 167,649 $ 127,174 Accrued expenses (Note 16) 112,526 86,296 Accrued customer incentives and refund obligations 75,064 63,079 Accrued taxes 42,676 31,108 Current lease liabilities 17,733 15,281 Accrued liabilities $ 415,648 $ 322,938
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following: (in thousands) December 31, 2020 December 31, 2019 Accrued taxes $ 60,313 $ 67,463 Other accrued long-term expenses 25,291 13,701 Other long-term liabilities $ 85,604 $ 81,164

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Instruments [Abstract]
Schedule of Long-term Debt Instruments	The following describes all of our currently outstanding unsecured senior notes issued and sold in private placements (collectively, the "Senior Notes"): (Principal Amount in thousands) Issue Date Due Date Series Principal Amount Coupon Rate Senior Note Agreement 12/11/2013 12/11/2023 2023 Series A Notes $ 75,000 3.94 % NY Life 2013 Note Agreement 12/11/2013 12/11/2025 2025 Series B Notes $ 75,000 4.04 % NY Life 2013 Note Agreement 9/4/2014 9/4/2026 2026 Senior Notes $ 75,000 3.72 % NY Life 2014 Note Agreement 7/21/2014 7/21/2021 2021 Series A Notes $ 50,000 3.32 % Prudential 2015 Amended Agreement 7/21/2014 7/21/2024 2024 Series B Notes $ 75,000 3.76 % Prudential 2015 Amended Agreement 6/18/2015 6/18/2025 2025 Series C Notes € 88,857 1.785 % Prudential 2015 Amended Agreement 2/12/2015 2/12/2022 2022 Series A Notes $ 75,000 3.25 % MetLife 2014 Note Agreement 2/12/2015 2/12/2027 2027 Series B Notes $ 75,000 3.72 % MetLife 2014 Note Agreement 3/14/2019 3/14/2029 2029 Series C Notes $ 100,000 4.19 % MetLife 2014 Note Agreement 4/2/2020 4/2/2030 MetLife 2030 Series D Notes $ 125,000 2.50 % MetLife 2014 Note Agreement 4/14/2020 4/14/2030 Prudential 2030 Series D Notes $ 75,000 2.50 % Prudential 2015 Amended Agreement
Schedule of Annual Principal Payments on Long-Term Debt	Annual principal payments on long-term debt at December 31, 2020, are as follows: (in thousands) Years Ending December 31, Amount 2021 $ 50,000 2022 75,000 2023 75,000 2024 75,000 2025 184,125 Thereafter 450,000 $ 909,125

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Earnings Before Income Taxes	Earnings before income taxes were as follows: (in thousands) For the Years Ended December 31, 2020 2019 2018 Domestic $ 483,694 $ 377,964 $ 337,437 International 178,291 144,254 120,305 $ 661,985 $ 522,218 $ 457,742
Schedule of Components of Provision (Benefit) for Income Taxes	The provision (benefit) for income taxes comprised the following: (in thousands) For the Years Ended December 31, 2020 2019 2018 Current Federal $ 72,921 $ 52,194 $ 47,130 State 17,346 11,967 10,415 International 26,301 24,239 22,015 116,568 88,400 79,560 Deferred Federal (14,126) 4,826 3,970 State (2,863) 269 (937) International (19,725) 931 (1,898) (36,714) 6,026 1,135 $ 79,854 $ 94,426 $ 80,695
Schedule of Effective Income Tax Rate Reconciliation	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, 2020 2019 2018 U.S. federal statutory rate 21.0 % 21.0 % 21.0 % State income tax, net of federal tax benefit 2.4 2.3 2.6 Taxation on international earnings (1.0) (1.1) (0.8) Foreign derived intangible income (1.1) (1.1) (1.3) Share-based compensation from settlements (5.9) (3.6) (4.7) Research and development credit (0.8) (0.8) (0.9) Impact of Switzerland tax reform (3.3) — — State income tax carryforwards — — (0.2) Other, net 0.8 1.4 1.9 Effective tax rate 12.1 % 18.1 % 17.6 %
Schedule of Components of Net Deferred Tax Assets and Liabilities	The components of the net deferred tax assets (liabilities) included in the accompanying consolidated balance sheets are as follows: (in thousands) December 31, 2020 December 31, 2019 Assets Accrued expenses $ 46,830 $ 25,296 Accounts receivable reserves 2,505 617 Deferred revenue 7,629 6,073 Inventory basis differences 4,272 3,315 Property-based differences 14,865 3,113 Intangible asset basis differences 51,319 — Share-based compensation 10,011 10,593 Other 1,484 1,160 Net operating loss carryforwards 5,427 4,045 Tax credit carryforwards 13,385 12,276 Unrealized losses on foreign currency exchange contracts and investments 5,060 20 Total assets 162,787 66,508 Valuation allowance (40,262) (9,454) Total assets, net of valuation allowance 122,525 57,054 Liabilities Customer acquisition costs (34,449) (28,519) Property-based differences (49,547) (33,802) Intangible asset basis differences (16,134) (14,513) Other (2,241) (3,961) Unrealized gains on foreign currency exchange contracts and investments (312) (1,183) Total liabilities (102,683) (81,978) Net deferred tax assets (liabilities) $ 19,842 $ (24,924)
Schedule of Changes in Unrecognized Tax Benefits	The following table summarizes the changes in unrecognized tax positions: (in thousands) For the Years Ended December 31, 2020 2019 2018 Total amounts of unrecognized tax benefits, beginning of period $ 26,841 $ 24,247 $ 21,417 Gross (decreases) increases in unrecognized tax positions as a result of tax positions taken during a prior period (1,755) (276) 2,991 Gross increases in unrecognized tax positions as a result of tax positions taken in the current period 4,199 4,083 461 Decreases in unrecognized tax positions relating to settlements with taxing authorities (6,446) — — Decreases in unrecognized tax positions as a result of a lapse of the applicable statutes of limitations (355) (1,213) (622) Total amounts of unrecognized tax benefits, end of period $ 22,484 $ 26,841 $ 24,247
Summary of Valuation Allowance	The following table summarizes the changes in valuation allowance for deferred tax assets: (in thousands) For the Years Ended December 31, 2020 2019 2018 Balance at beginning of year $ 9,454 $ 6,212 $ 6,211 Charges to costs and expense 31,076 3,489 402 Write-off/cash payments (34) (226) — Foreign currency translation (234) (21) (401) Balance at the end of the year $ 40,262 $ 9,454 $ 6,212

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Reconciliation of Shares Outstanding for Basic and Diluted Earnings Per Share	The following is a reconciliation of weighted average shares outstanding for basic and diluted earnings per share: (in thousands) For the Years Ended December 31, 2020 2019 2018 Shares outstanding for basic earnings per share: 85,342 86,115 86,864 Shares outstanding for diluted earnings per share: Shares outstanding for basic earnings per share 85,342 86,115 86,864 Dilutive effect of share-based payment awards 1,380 1,427 1,606 86,722 87,542 88,470
Schedule of Number of Anti-Dilutive Stock Options	The following table presents information concerning those anti-dilutive options: (in thousands) For the Years Ended December 31, 2020 2019 2018 Weighted average number of shares underlying anti-dilutive options 206 200 287

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Summary of Segment Performance	The following tables reflect adjustments to previously reported costs in our Unallocated segment, that are now allocated to our CAG, Water, LPD and Other segments: For the year ended December 31, 2019: (in thousands) CAG Water LPD Other Unallocated Cost of sales $ (247) $ (11) $ (14) $ (6) $ 278 Gross profit 247 11 14 6 (278) Operating Expenses: Sales and marketing $ (239) $ (11) $ (13) $ — $ 263 General and administrative 13,004 501 625 1,363 (15,493) Research and development 16,479 33 41 — (16,553) Total operating expenses 29,244 523 653 1,363 (31,783) Income from operations $ (28,997) $ (512) $ (639) $ (1,357) $ 31,505 For the year ended December 31, 2018: (in thousands) CAG Water LPD Other Unallocated Cost of sales $ (1,540) $ (69) $ (87) $ (35) $ 1,731 Gross profit 1,540 69 87 35 (1,731) Operating Expenses: Sales and marketing $ (574) $ (25) $ (32) $ — $ 631 General and administrative 3,316 66 81 1,145 (4,608) Research and development 15,658 (4) (4) — (15,650) Total operating expenses 18,400 37 45 1,145 (19,627) Income from operations $ (16,860) $ 32 $ 42 $ (1,110) $ 17,896 The following tables reflect the impact to previously reported segment gross profit margin, operating income margin and operating expenses as a percentage of revenue, due to the allocation of these costs to our CAG, Water, LPD and Other segments: For the year ended December 31, 2019: CAG Water LPD Other Cost of sales — % — % — % — % Gross profit — % — % — % — % Operating Expenses: Sales and marketing — % — % — % — % General and administrative 0.6 % 0.4 % 0.5 % 6.1 % Research and development 0.8 % — % — % — % Total operating expenses 1.4 % 0.4 % 0.5 % 6.1 % Income from operations (1.4) % (0.4) % (0.5) % (6.1) % For the year ended December 31, 2018: CAG Water LPD Other Cost of sales (0.1) % (0.1) % (0.1) % (0.2) % Gross profit 0.1 % 0.1 % 0.1 % 0.2 % Operating Expenses: Sales and marketing — % — % — % — % General and administrative 0.2 % 0.1 % 0.1 % 5.2 % Research and development 0.8 % — % — % — % Total operating expenses 1.0 % — % — % 5.2 % Income from operations (0.9) % — % — % (5.0) % The following is a summary of segment performance: (in thousands) For the Years Ended December 31, CAG Water LPD Other Consolidated Total 2020 Revenue $ 2,385,765 $ 128,625 $ 145,845 $ 46,420 $ 2,706,655 Income from operations $ 574,887 $ 58,867 $ 40,008 $ 20,762 $ 694,524 Interest expense, net (32,539) Income before provision for income taxes 661,985 Provision for income taxes 79,854 Net income 582,131 Less: Net income attributable to noncontrolling interest 355 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 581,776 Depreciation and amortization $ 84,697 $ 2,630 $ 4,070 $ 4,601 $ 95,998 2019 Revenue $ 2,119,183 $ 132,850 $ 132,635 $ 22,240 $ 2,406,908 Income from operations $ 462,605 $ 61,923 $ 24,735 $ 3,583 $ 552,846 Interest expense, net (30,628) Income before provision for income taxes 522,218 Provision for income taxes 94,426 Net income 427,792 Less: Net income attributable to noncontrolling interest 72 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 427,720 Depreciation and amortization $ 77,620 $ 2,794 $ 4,007 $ 3,590 $ 88,011 2018 Revenue $ 1,935,428 $ 125,198 $ 130,581 $ 22,035 $ 2,213,242 Income from operations $ 412,623 $ 56,639 $ 19,454 $ 2,619 $ 491,335 Interest expense, net (33,593) Income before provision for income taxes 457,742 Provision for income taxes 80,695 Net income 377,047 Less: Net income attributable to noncontrolling interest 16 Net income attributable to IDEXX Laboratories, Inc. stockholders $ 377,031 Depreciation and amortization $ 72,789 $ 2,592 $ 4,094 $ 3,703 $ 83,178
Schedule of Net Long-Lived Assets by Principal Geographic Areas	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, 2020 December 31, 2019 Americas United States $ 412,700 $ 401,248 Brazil 20,797 22,274 Canada 4,993 7,784 438,490 431,306 Europe, the Middle East and Africa Germany 67,354 52,032 United Kingdom 10,191 12,114 Netherlands 15,267 13,586 France 2,062 2,061 Switzerland 3,743 3,508 Other 3,668 3,395 102,285 86,696 Asia Pacific Region Japan 4,503 5,409 Australia 3,304 4,088 Other 6,585 6,346 14,392 15,843 Total $ 555,167 $ 533,845

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	The following tables set forth our assets and liabilities that were measured at fair value on a recurring basis by level within the fair value hierarchy: (in thousands) As of December 31, 2020 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Balance at December 31, 2020 Assets Money market funds (1) $ 76 $ — $ — $ 76 Equity mutual funds (2) $ 1,145 $ — $ — $ 1,145 Foreign currency exchange contracts (3) $ — $ 125 $ — $ 125 Liabilities Cross currency swaps (3) $ — $ 2,841 $ — $ 2,841 Foreign currency exchange contracts (3) $ — $ 12,373 $ — $ 12,373 Deferred compensation (4) $ 1,145 $ — $ — $ 1,145 (in thousands) As of December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Balance at December 31, 2019 Assets Money market funds (1) $ 71 $ — $ — $ 71 Equity mutual funds (2) $ 1,676 $ — $ — $ 1,676 Cross currency swaps (3) $ — $ 4,559 $ — $ 4,559 Foreign currency exchange contracts (3) $ — $ 1,791 $ — $ 1,791 Liabilities Foreign currency exchange contracts (3) $ — $ 2,886 $ — $ 2,886 Deferred compensation (4) $ 1,676 $ — $ — $ 1,676 (1) Money market funds 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, 2020, and December 31, 2019, consisted of demand deposits. (2) Equity mutual funds relate to a deferred compensation plan that was assumed as part of a previous business combination. This amount is included within other long-term assets. See footnote (4) below for a discussion of the related deferred compensation liability. (3) Cross currency swaps and 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 and 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 footnote (2) above.

Hedging Instruments (Tables)

Hedging Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Details of net investment hedges and Income Statement impact of hedging instruments	The following table presents the effect of cash flow hedge accounting on our consolidated statements of income and comprehensive income, and provides information regarding the location and amounts of pretax gains or losses of derivatives: (in thousands) Years Ended December 31, 2020 2019 2018 Financial statement line items in which effects of cash flow hedges are recorded Cost of revenue $ 1,135,615 $ 1,041,359 $ 971,700 Foreign exchange contracts Amount of gain (loss) reclassified from accumulated other comprehensive income into income $ 829 $ 10,628 $ (976)
Schedule of hedging instruments	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 derivative instruments, unless otherwise noted: (in thousands) Hedging Assets December 31, 2020 December 31, 2019 Derivatives and non-derivatives designated as hedging instruments Balance Sheet Classification Foreign currency exchange contracts Other current assets $ 125 $ 1,791 Cross currency swaps Other long-term assets — 4,559 Total derivative instruments presented as hedge instruments on the balance sheet 125 6,350 Gross amounts subject to master netting arrangements not offset on the balance sheet (125) (1,354) Net amount $ — $ 4,996 (in thousands) Hedging Liabilities December 31, 2020 December 31, 2019 Derivatives and non-derivatives designated as hedging instruments Balance Sheet Classification Foreign currency exchange contracts Accrued liabilities $ 12,373 $ 2,886 Cross currency swaps Other long-term liabilities 2,841 — Total derivative instruments presented as cash flow hedges on the balance sheet 15,214 2,886 Non-derivative foreign currency denominated debt designated as net investment hedge on the balance sheet (1) Long-term debt 109,125 99,422 Total hedging instruments presented on the balance sheet 124,339 102,308 Gross amounts subject to master netting arrangements not offset on the balance sheet (125) (1,354) Net amount $ 124,214 $ 100,954 (1) Amounts represent reported carrying amounts of our foreign currency denominated debt. See "Note 18. Fair Value Measurements" for information regarding the fair value of our long-term debt.

Repurchases of Common Stock (Ta

Repurchases of Common Stock (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of Common Stock Repurchases	The following is a summary of our open market common stock repurchases, reported on a trade date basis, and shares acquired through employee surrenders: (in thousands, except per share amounts) For the Years Ended December 31, 2020 2019 2018 Shares repurchased in the open market 721 1,215 1,773 Shares acquired through employee surrenders for statutory tax withholding 58 39 52 Total shares repurchased 779 1,254 1,825 Cost of shares repurchased in the open market $ 179,623 $ 303,838 $ 368,691 Cost of shares for employee surrenders 20,603 8,054 9,375 Total cost of shares $ 200,226 $ 311,892 $ 378,066 Average cost per share - open market repurchases $ 249.20 $ 249.84 $ 207.92 Average cost per share - employee surrenders $ 354.98 $ 210.10 $ 182.18 Average cost per share - total $ 257.08 $ 248.62 $ 207.19

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income	The changes in AOCI, net of tax, consisted of the following: For the Years Ended December 31, 2020 and 2019 Unrealized (Loss) Gain on Cash Flow Hedges, Net of Tax Unrealized (Loss) Gain on Net Investment Hedges, Net of Tax (in thousands) Unrealized (Loss) Gain on Investments, Net of Tax Foreign Currency Exchange Contracts Euro-Denominated Notes Cross Currency Swaps Cumulative Translation Adjustment Total Balance as of December 31, 2018 $ (157) $ 6,229 $ (394) $ 1,360 $ (48,829) $ (41,791) Other comprehensive income (loss) before reclassifications 267 1,196 1,790 2,107 (1,590) 3,770 Amounts reclassified from accumulated other comprehensive income — (8,161) — — — (8,161) Balance as of December 31, 2019 110 (736) 1,396 3,467 (50,419) (46,182) Other comprehensive (loss) income before reclassifications (382) (8,527) (7,378) (5,626) 15,151 (6,762) Amounts reclassified from accumulated other comprehensive income — (671) — — — (671) Balance as of December 31, 2020 $ (272) $ (9,934) $ (5,982) $ (2,159) $ (35,268) $ (53,615)
Summary of Reclassifications Out of Accumulated Other Comprehensive Income	The following table presents components and amounts reclassified out of AOCI to net income: (in thousands) Affected Line Item in the Statements of Income Amounts Reclassified from AOCI for the Years Ended December 31, 2020 2019 2018 Gains (losses) on derivative instruments included in net income: Foreign currency exchange contracts Cost of revenue $ 829 $ 10,628 $ (976) Tax expense (benefit) 158 2,467 (187) Gains (losses), net of tax $ 671 $ 8,161 $ (789)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	Jan. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Restricted cash		$ 0	$ 0
Capitalized costs		0	0	$ 0
Advertising costs		1,400,000	1,500,000	1,800,000
Foreign currency gains (losses)		600,000	(1,100,000)	(3,100,000)
Non-cash cumulative effect adjustment to retained earnings, net of tax		632,795,000	177,825,000	(9,233,000)	$ (53,842,000)
Reserve for contract assets and sales-type leases		3,700,000
Accounts receivable allowance for credit losses		6,800,000	3,600,000
Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Non-cash cumulative effect adjustment to retained earnings, net of tax		$ 2,175,595,000	1,595,648,000	$ 1,167,928,000	803,545,000
Accounting Standards Update 2016-13
Summary Of Significant Accounting Policies [Line Items]
Reserve for contract assets and sales-type leases	$ 2,300,000
Accounts receivable allowance for credit losses	200,000
Accounting Standards Update 2016-13 | Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Non-cash cumulative effect adjustment to retained earnings, tax	$ 600,000
Cumulative Effect, Period of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Non-cash cumulative effect adjustment to retained earnings, net of tax			(1,829,000)		(12,648,000)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Non-cash cumulative effect adjustment to retained earnings, net of tax			(1,829,000)		$ (12,648,000)
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 | Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Non-cash cumulative effect adjustment to retained earnings, net of tax			$ 1,800,000

Revenue Recognition (Details)

Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2020
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
General payment terms	30 days
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
General payment terms	60 days

Revenue Recognition (Lease Reve

Revenue Recognition (Lease Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Lease revenue	$ 17.5	$ 20.8

Revenue Recognition (Extended W

Revenue Recognition (Extended Warranties and Post-Contract Support) (Details) - Extended warranties and post contract support - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Post-contract support contract, term	12 months
Deferred revenue	$ 35.1	$ 38
Deferred revenue recognized	22
Estimation of future revenues	$ 20.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	43.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	32.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	17.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	6.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	2.00%
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Extended product warranty, term	1 year
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Extended product warranty, term	5 years

Revenue Recognition (SaaS Subsc

Revenue Recognition (SaaS Subscriptions) (Details)	12 Months Ended
	Dec. 31, 2020
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
SaaS subscription, term	2 years

Revenue Recognition (Up-Front C

Revenue Recognition (Up-Front Customer Loyalty Programs) (Details) - Up front customer loyalty programs - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized customer acquisition costs	$ 148.1	$ 137.4
Capitalized customer acquisition costs recognized as a reduction of revenue	$ 39.3

Revenue Recognition (Volume Com

Revenue Recognition (Volume Commitment Programs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Volume commitment programs
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Volume commitment contract assets	$ 115.5	$ 83.9
Volume commitment contract assets reclassified to accounts receivable	18.3
Up front customer loyalty programs and volume commitment programs
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimation of future revenues	$ 2,200
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	26.00%
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	24.00%
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	21.00%
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	16.00%
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	13.00%

Revenue Recognition (Instrument

Revenue Recognition (Instrument Rebate Programs) (Details) - Instrument rebate programs - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue	$ 39.3	$ 49.1
Deferred revenue recognized	$ 16.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	36.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	27.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	18.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	11.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	8.00%

Revenue Recognition (Reagent Re

Revenue Recognition (Reagent Rental Programs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Lease receivable asset	$ 11.1	$ 7.2
Lease receivable, reclassified to receivable	1.4
Reagent rental programs
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimation of future revenues	$ 24.8
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	41.00%
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	27.00%
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	16.00%
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	9.00%
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	7.00%

Revenue Recognition (Disaggrega

Revenue Recognition (Disaggregation of Revenue by Principal Geographic Area, Based on Customers' Domiciles) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,706,655	$ 2,406,908	$ 2,213,242
Americas
Disaggregation of Revenue [Line Items]
Total revenue	1,850,485	1,651,581	1,503,084
United States
Disaggregation of Revenue [Line Items]
Total revenue	1,691,224	1,495,516	1,357,909
Canada
Disaggregation of Revenue [Line Items]
Total revenue	107,398	99,550	94,206
Latin America
Disaggregation of Revenue [Line Items]
Total revenue	51,863	56,515	50,969
Europe, the Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	562,765	498,439	472,070
Germany
Disaggregation of Revenue [Line Items]
Total revenue	119,353	104,081	100,459
United Kingdom
Disaggregation of Revenue [Line Items]
Total revenue	90,156	90,969	87,807
France
Disaggregation of Revenue [Line Items]
Total revenue	74,814	64,767	60,319
Italy
Disaggregation of Revenue [Line Items]
Total revenue	42,817	39,725	36,956
Spain
Disaggregation of Revenue [Line Items]
Total revenue	39,265	36,439	33,687
Switzerland
Disaggregation of Revenue [Line Items]
Total revenue	24,850	20,855	19,875
Netherlands
Disaggregation of Revenue [Line Items]
Total revenue	23,461	19,397	18,090
Other
Disaggregation of Revenue [Line Items]
Total revenue	148,049	122,206	114,877
Asia Pacific Region
Disaggregation of Revenue [Line Items]
Total revenue	293,405	256,888	238,088
Australia
Disaggregation of Revenue [Line Items]
Total revenue	79,629	71,069	63,386
Japan
Disaggregation of Revenue [Line Items]
Total revenue	74,725	67,246	60,213
China
Disaggregation of Revenue [Line Items]
Total revenue	70,845	57,518	57,621
Other
Disaggregation of Revenue [Line Items]
Total revenue	$ 68,206	$ 61,055	$ 56,868

Revenue Recognition (Disaggre_2

Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,706,655	$ 2,406,908	$ 2,213,242
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	2,385,765	2,119,183	1,935,428
CAG segment revenue | CAG Diagnostics recurring revenue:
Disaggregation of Revenue [Line Items]
Total revenue	2,113,839	1,828,329	1,654,530
CAG segment revenue | IDEXX VetLab consumables
Disaggregation of Revenue [Line Items]
Total revenue	824,376	693,360	617,237
CAG segment revenue | Rapid assay products
Disaggregation of Revenue [Line Items]
Total revenue	253,018	232,149	217,541
CAG segment revenue | Reference laboratory diagnostic and consulting services
Disaggregation of Revenue [Line Items]
Total revenue	946,268	822,497	746,794
CAG segment revenue | CAG Diagnostics services and accessories
Disaggregation of Revenue [Line Items]
Total revenue	90,177	80,323	72,958
CAG segment revenue | CAG Diagnostics capital - instruments
Disaggregation of Revenue [Line Items]
Total revenue	108,950	132,685	134,264
CAG segment revenue | Veterinary software, services and diagnostic imaging systems
Disaggregation of Revenue [Line Items]
Total revenue	162,976	158,169	146,634
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	128,625	132,850	125,198
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	145,845	132,635	130,581
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 46,420	$ 22,240	$ 22,035

Revenue Recognition (Costs to O

Revenue Recognition (Costs to Obtain a Contract) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred commission costs	$ 17.5	$ 15.6
Commissions expense recognized	$ 5.2
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract, amortization period	3 years
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract, amortization period	7 years

Revenue Recognition (Remaining

Revenue Recognition (Remaining Performance Obligation) (Details)	Dec. 31, 2020
Extended warranties and post contract support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	43.00%
Revenue recognition period (in years)	1 year
Extended warranties and post contract support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	32.00%
Revenue recognition period (in years)	1 year
Extended warranties and post contract support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	17.00%
Revenue recognition period (in years)	1 year
Extended warranties and post contract support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	6.00%
Revenue recognition period (in years)	1 year
Extended warranties and post contract support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	2.00%
Revenue recognition period (in years)
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	26.00%
Revenue recognition period (in years)	1 year
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	24.00%
Revenue recognition period (in years)	1 year
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	21.00%
Revenue recognition period (in years)	1 year
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	16.00%
Revenue recognition period (in years)	1 year
Up front customer loyalty programs and volume commitment programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	13.00%
Revenue recognition period (in years)
Instrument rebate programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	36.00%
Revenue recognition period (in years)	1 year
Instrument rebate programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	27.00%
Revenue recognition period (in years)	1 year
Instrument rebate programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	18.00%
Revenue recognition period (in years)	1 year
Instrument rebate programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	11.00%
Revenue recognition period (in years)	1 year
Instrument rebate programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	8.00%
Revenue recognition period (in years)
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	41.00%
Revenue recognition period (in years)	1 year
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	27.00%
Revenue recognition period (in years)	1 year
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	16.00%
Revenue recognition period (in years)	1 year
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	9.00%
Revenue recognition period (in years)	1 year
Reagent rental programs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue percentage expected to be recognized	7.00%
Revenue recognition period (in years)

Acquisitions and Investments (D

Acquisitions and Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 243,347			$ 239,724	$ 214,489	$ 199,873
Reference laboratory in Mid-West, U.S.
Business Acquisition [Line Items]
Purchase price of acquired assets	$ 50,000
Net tangible liabilities		$ 200
Goodwill		22,900
Software company
Business Acquisition [Line Items]
Purchase price of acquired assets			$ 25,000
Net tangible liabilities			300
Goodwill			20,300
Customer relationships | Reference laboratory in Mid-West, U.S.
Business Acquisition [Line Items]
Intangible assets		$ 26,900
Intangible assets useful life		13 years 9 months 18 days
Customer relationships | Software company
Business Acquisition [Line Items]
Intangible assets			2,400
Technology-based intangible assets | Software company
Business Acquisition [Line Items]
Intangible assets			$ 2,600

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) shares in Thousands, $ in Thousands, $ / shares in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019USD ($)shares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $		$ 30,951	$ 39,278	$ 25,157
Income tax benefit resulting from share-based compensation expense | $		3,965	4,861	4,190
Unrecognized compensation expense, net of estimated forfeitures, for unvested share-based compensation awards outstanding | $		$ 57,400
Weighted average recognition period for unrecognized compensation expense, in years		1 year 6 months
Intrinsic value of stock options exercised | $		$ 163,000	$ 83,700	$ 87,100
Nonvested, intrinsic value | $ / shares		$ 108.8
Number of unissued shares of common stock each DSU represents right to receive (in shares)		1
Deferred stock units, outstanding (in shares)	143	87	143
2018 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under share-based incentive plans (in shares)				7,500
Shares available for grant under share-based incentive plans (in shares)		6,500
Stock options and stock appreciation rights
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
Awards other than stock options and stock appreciation rights
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				2.4
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $	$ 10,900
Income tax benefit resulting from share-based compensation expense | $	$ (800)
Award vesting rights, percentage			25.00%
Fair value of options vested during period | $		$ 14,600	$ 12,200	$ 10,500
Restricted stock units (RSU's)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			25.00%
Fair value of awards vested during period | $		$ 27,900	$ 23,800	$ 24,500
Vested (in shares)		94
Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units, outstanding (in shares)	143	87	143
Vested (in shares)		59
1997 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under share-based incentive plans (in shares)		4,700
Shares available for grant under share-based incentive plans (in shares)		1,100
Discount from market value for employee stock purchase rights		15.00%
Common stock issued in connection with the Employee Stock Purchase Plan (in shares)		39	47	52
Share-based Compensation Award, Tranche One | Stock options granted to employees with ratable vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			5 years
Share-based Compensation Award, Tranche One | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term			7 years
Share-based Compensation Award, Tranche One | Restricted stock units granted to employees with ratable vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			5 years
Share-based Compensation Award, Tranche Two | Stock options granted to employees with ratable vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Share-based Compensation Award, Tranche Two | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term			10 years
Share-based Compensation Award, Tranche Two | Restricted stock units granted to employees with ratable vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years

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, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 30,951	$ 39,278	$ 25,157
Income tax benefit resulting from share-based compensation expense	(3,965)	(4,861)	(4,190)
Net share-based compensation expense included in consolidated statements of income, excluding tax benefit from settlement of share-based awards	26,986	34,417	20,967
Income tax benefit resulting from settlement of share-based awards	(38,981)	(19,140)	(21,496)
Net expense (benefit) related to share-based compensation arrangements included in consolidated statements of income	(11,995)	15,277	(529)
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3,415	2,681	2,816
Operating expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 27,536	$ 36,597	$ 22,341

Share-Based Compensation (Sch_2

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, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Share price at grant (in USD per share)	$ 291.14	$ 218.66	$ 179.56
Share exercise price (in USD per share)	$ 291.14	$ 220.88	$ 179.56
Expected stock price volatility	27.00%	26.00%	24.00%
Expected term, in years	6 years	6 years	5 years 9 months 18 days
Risk-free interest rate	1.40%	2.40%	2.70%
Weighted average fair value of options granted (in USD per shares)	$ 84.92	$ 65.53	$ 52.99

Share-Based Compensation (Sch_3

Share-Based Compensation (Schedule of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Number of Options
Outstanding, at beginning of year (in shares) | shares	2,311
Granted (in shares) | shares	220
Exercised (in shares) | shares	(562)
Forfeited (in shares) | shares	(16)
Outstanding, at end of year (in shares) | shares	1,953
Fully vested, at end of year (in shares) | shares	1,057
Fully vested and expected to vest, at end of year (in shares) | shares	1,933
Weighted Average Exercise Price
Weighted average exercise price of beginning balance of options outstanding (in USD per share) | $ / shares	$ 117.13
Weighted average exercise price of options granted (in USD per share) | $ / shares	291.14
Weighted average exercise price of options exercised (in USD per share) | $ / shares	71.65
Weighted average exercise price of options forfeited (in USD per share) | $ / shares	180.78
Weighted average exercise price of ending balance of options outstanding (in USD per share) | $ / shares	149.32
Weighted average exercise price of options fully vested (in USD per share) | $ / shares	106.91
Weighted average exercise price of options fully vested and expected to vest (in USD per share) | $ / shares	$ 148.61
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term of ending balance of options outstanding	6 years 3 months 18 days
Weighted average remaining contractual term of options fully vested	5 years 3 months 18 days
Weighted average remaining contractual term of options fully vested and expected to vest	6 years 3 months 18 days
Aggregate intrinsic value | $	$ 684,571
Aggregate intrinsic value of options fully vested | $	415,229
Aggregate intrinsic value of options expected to vest | $	$ 678,994

Share-Based Compensation (Sch_4

Share-Based Compensation (Schedule Of Restricted Stock Unit Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Restricted stock units (RSU's)
Number of Units
Nonvested, at beginning of year (in shares) | shares	258
Granted (in shares) | shares	65
Vested (in shares) | shares	(94)
Forfeited (in shares) | shares	(11)
Nonvested, at end of year (in shares) | shares	218
Weighted Average Grant-Date Fair Value
Weighted average grant date fair value, beginning of year (in USD per share) | $ / shares	$ 150.50
Weighted average grant date fair value, granted (in USD per share) | $ / shares	291.30
Weighted average grant date fair value, vested (in USD per share) | $ / shares	124.60
Weighted average grant date fair value, forfeited (in USD per share) | $ / shares	178.95
Weighted average grant date fair value, end of year (in USD per share) | $ / shares	$ 202.47
Restricted stock units expected to vest reduced for estimated forfeitures
Number of Units
Nonvested, at end of year (in shares) | shares	208
Weighted Average Grant-Date Fair Value
Weighted average grant date fair value, end of year (in USD per share) | $ / shares	$ 201.64

Credit Losses (Details)

Credit Losses (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Accounts receivable allowance for credit losses	$ 6.8	$ 3.6
Percent of accounts receivable not past due	88.00%	84.00%
Percent of accounts receivable past due	12.00%	16.00%
Accounts receivable, noncurrent, threshold period past due	60 days	60 days
Reserve for contract assets and sales-type leases	$ 3.7
Greater than 60 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Percent of accounts receivable past due	1.50%	1.50%

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Inventory, Net [Abstract]
Unpaid inventory	$ 45.6	$ 39.5	$ 41.3

Inventories (Schedule of Compon

Inventories (Schedule of Components of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory, Net [Abstract]
Raw materials	$ 45,986	$ 41,202
Work-in-process	20,374	20,077
Finished goods	143,513	133,740
Inventories	$ 209,873	$ 195,019

Leases (Maturities of Operating

Leases (Maturities of Operating Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 20,187
2022	18,698
2023	13,556
2024	9,810
2025	8,129
Thereafter	39,224
Total lease payments	109,604
Less imputed interest	(14,832)
Total lease liability (current and long-term)	$ 94,772
Weighted average remaining lease term - operating leases	10 years 3 months 18 days	10 years 3 months 18 days
Weighted average discount rate - operating leases	2.90%	3.50%

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Total minimum future lease payments, leases not yet commenced	$ 8
Rent expense, excluding variable and short-term expenses	21.7	$ 21.1
Total rent expense including variable rent and short-term expenses	$ 24.5	$ 23.8	$ 25.2
Minimum
Lessee, Lease, Description [Line Items]
Operating leases, not yet commenced, lease term	4 years
Maximum
Lessee, Lease, Description [Line Items]
Operating leases, not yet commenced, lease term	13 years

Leases (Supplemental Cash Flow

Leases (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 19,619	$ 20,008
Right-of-use assets obtained in exchange for operating lease obligations, net of early lease terminations	$ 26,807	$ 13,399

Property and Equipment, Net (Sc

Property and Equipment, Net (Schedule of Estimated Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2020
Land improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Land improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Office furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Office furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer hardware and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years

Property and Equipment, Net (_2

Property and Equipment, Net (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Gross amount	$ 1,142,081	$ 1,052,875
Less accumulated depreciation and amortization	586,914	519,030
Total property and equipment, net	555,167	533,845
Land and improvements
Property, Plant and Equipment [Line Items]
Gross amount	13,982	8,725
Buildings and improvements
Property, Plant and Equipment [Line Items]
Gross amount	319,384	249,918
Leasehold improvements
Property, Plant and Equipment [Line Items]
Gross amount	82,459	74,602
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross amount	353,301	322,814
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Gross amount	67,527	53,210
Computer hardware and software
Property, Plant and Equipment [Line Items]
Gross amount	265,664	240,406
Construction in progress
Property, Plant and Equipment [Line Items]
Gross amount	$ 39,764	$ 103,200

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, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 86,095	$ 78,495	$ 74,208
Unpaid property and equipment, reflected in accounts payable and accrued liabilities	13,343	24,688	17,894
Reagent rental programs
Property, Plant and Equipment [Line Items]
Rental and operating-type reagent rental program instruments transferred from inventory to property and equipment (Note 3)	9,645	14,498	20,360
Capitalized computer software developed for internal use
Property, Plant and Equipment [Line Items]
Capitalized computer software developed for internal use	$ 18,472	$ 20,130	$ 17,115

Other Current and Long-Term A_3

Other Current and Long-Term Assets (Schedule of Other Current Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 43,751	$ 39,329
Prepaid expenses	34,556	31,992
Contract assets, net	23,837	17,659
Taxes receivable	19,476	20,516
Deferred sales commissions	5,738	5,202
Other	10,150	10,284
Other current assets	$ 137,508	$ 124,982

Other Current and Long-Term A_4

Other Current and Long-Term Assets (Schedule of Other Noncurrent Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 104,369	$ 98,117
Contract assets, net	91,681	66,226
Deferred income taxes	31,549	8,100
Investment in long-term product supply arrangements	12,065	13,657
Deferred sales commissions	11,719	10,442
Taxes receivable	6,329	14,960
Other	31,883	28,690
Other long-term assets	$ 289,595	$ 240,192

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, Net (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairments	$ 0	$ 0	$ 0
Intangible assets impairments		0	0
Aggregate amortization expense	$ 9,800,000	$ 9,400,000	$ 8,900,000

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, Net (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Beginning balance	$ 239,724	$ 214,489	$ 199,873
Business combinations	220	24,826	20,282
Goodwill, Purchase Accounting Adjustments	1,900
Impact of changes in foreign currency exchange rates	5,303	409	(5,666)
Ending balance	243,347	239,724	214,489
Companion Animal Group Segment [Member]
Goodwill [Roll Forward]
Beginning balance	207,350	182,386	166,236
Business combinations	220	24,826	20,282
Goodwill, Purchase Accounting Adjustments	1,900
Impact of changes in foreign currency exchange rates	4,724	138	(4,132)
Ending balance	210,394	207,350	182,386
Water
Goodwill [Roll Forward]
Beginning balance	11,611	11,221	11,951
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	412	390	(730)
Ending balance	12,023	11,611	11,221
Livestock And Poultry Diagnostics Segment [Member]
Goodwill [Roll Forward]
Beginning balance	14,232	14,351	15,155
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	167	(119)	(804)
Ending balance	14,399	14,232	14,351
Other
Goodwill [Roll Forward]
Beginning balance	6,531	6,531	6,531
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	0	0	0
Ending balance	$ 6,531	$ 6,531	$ 6,531

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, Net (Schedule of Estimated Useful Lives For Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2020
Customer-related intangible assets | Minimum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	3 years
Customer-related intangible assets | Maximum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	17 years
Product rights | Minimum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	5 years
Product rights | Maximum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	15 years
Noncompete agreements | Minimum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	3 years
Noncompete agreements | Maximum
Property, Plant and Equipment [Line Items]
Intangible assets, estimated useful life	5 years

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets, Net (Schedule of Intangible Assets Other Than Goodwill) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Cost	$ 97,210	$ 115,601
Accumulated Amortization	44,667	57,133
Net	52,543	58,468
Customer-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Cost	80,810	99,301
Accumulated Amortization	32,838	46,801
Net	47,972	52,500
Product rights
Finite-Lived Intangible Assets [Line Items]
Cost	15,150	16,130
Accumulated Amortization	11,609	10,214
Net	3,541	5,916
Noncompete agreements
Finite-Lived Intangible Assets [Line Items]
Cost	1,250	170
Accumulated Amortization	220	118
Net	$ 1,030	$ 52

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets, Net (Schedule of Expected Amortization Expense) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2021	$ 8,648
2022	7,415
2023	5,647
2024	4,684
2025	4,210
Thereafter	21,939
Net	$ 52,543	$ 58,468

Accrued Liabilities and Other_3

Accrued Liabilities and Other Long Term Liabilities (Schedule of Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities, Current [Abstract]
Accrued employee compensation and related expenses	$ 167,649	$ 127,174
Accrued expenses (Note 16)	112,526	86,296
Accrued customer incentives and refund obligations	75,064	63,079
Accrued taxes	42,676	31,108
Current lease liabilities	$ 17,733	$ 15,281
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Accrued liabilities	$ 415,648	$ 322,938

Accrued Liabilities and Other_4

Accrued Liabilities and Other Long Term Liabilities (Schedule of Long Term Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities, Current [Abstract]
Accrued taxes	$ 60,313	$ 67,463
Other accrued long-term expenses	25,291	13,701
Other long-term liabilities	$ 85,604	$ 81,164

Debt (Narrative) (Details)

Debt (Narrative) (Details)	Apr. 14, 2020USD ($)	Dec. 04, 2015USD ($)	Dec. 19, 2014USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2020EUR (€)	Apr. 10, 2020USD ($)	Apr. 02, 2020USD ($)	Mar. 23, 2020USD ($)	Mar. 22, 2020USD ($)	Mar. 14, 2019USD ($)	Dec. 31, 2015EUR (€)	Sep. 30, 2014USD ($)	Jul. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Line of Credit Facility [Line Items]
Outstanding credit facility balance				$ 0	$ 288,765,000
Interest paid				$ 32,400,000	29,700,000	$ 34,700,000
Prudential
Line of Credit Facility [Line Items]
Borrowing capacity								$ 425,000,000
MetLife
Line of Credit Facility [Line Items]
Borrowing capacity										$ 300,000,000	$ 150,000,000
Prime Rate | Minimum
Line of Credit Facility [Line Items]
Credit spread during period				0.375%
Senior Notes
Line of Credit Facility [Line Items]
Consolidated leverage ratio under credit facility & note payable, maximum				3.50%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, term	3 years	5 years
Borrowing capacity	$ 1,000,000,000	$ 850,000,000
Accordion feature, increase limit	250,000,000
Accordion feature, higher borrowing capacity option	1,250,000,000
Revolving Credit Facility, Individual Borrowings | Minimum
Line of Credit Facility [Line Items]
Debt instrument, term				30 days
Revolving Credit Facility, Individual Borrowings | Maximum
Line of Credit Facility [Line Items]
Debt instrument, term				180 days
Amended And Restated Unsecured Short Term Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding credit facility balance				$ 0	$ 288,800,000
Stated interest rate				2.50%			2.50%
Credit Facility weighted average interest rates on outstanding balance					2.78%
Reduction of credit facility availability				$ 1,400,000	$ 1,400,000
Consolidated leverage ratio under credit facility & note payable, maximum				3.50%
Amended And Restated Unsecured Short Term Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Commitment fees				0.20%
Amended And Restated Unsecured Short Term Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Commitment fees				0.375%
Amended And Restated Unsecured Short Term Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Stated interest rate				1.00%			1.00%
Credit spread during period				1.375%
Amended And Restated Unsecured Short Term Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Credit spread during period				2.00%
Amended And Restated Unsecured Short Term Revolving Credit Facility | Prime Rate | Minimum
Line of Credit Facility [Line Items]
Stated interest rate				2.00%			2.00%
Amended And Restated Unsecured Short Term Revolving Credit Facility | Prime Rate | Maximum
Line of Credit Facility [Line Items]
Credit spread during period				1.00%
2023 Series A Notes and 2025 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Principal Amount																$ 150,000,000
2023 Series A Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				3.94%			3.94%									3.94%
Principal Amount				$ 75,000,000												$ 75,000,000
2025 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				4.04%			4.04%									4.04%
Principal Amount				$ 75,000,000												$ 75,000,000
2026 Senior Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				3.72%			3.72%							3.72%
Principal Amount				$ 75,000,000										$ 75,000,000
2021 Series A Notes and 2024 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Principal Amount															$ 125,000,000
2021 Series A Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				3.32%			3.32%								3.32%
Principal Amount				$ 50,000,000											$ 50,000,000
2024 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				3.76%			3.76%								3.76%
Principal Amount				$ 75,000,000											$ 75,000,000
2025 Series C Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				1.785%			1.785%						1.785%
Principal Amount | €							€ 88,857,000						€ 88,900,000
Prudential 2030 Series D Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				2.50%			2.50%	2.50%
Principal Amount	$ 75,000,000			$ 75,000,000
2022 Series A Notes and 2027 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Principal Amount			$ 150,000,000
2022 Series A Notes | Senior Notes
Line of Credit Facility [Line Items]
Debt instrument, term			7 years
Stated interest rate			3.25%	3.25%			3.25%
Principal Amount			$ 75,000,000	$ 75,000,000
2027 Series B Notes | Senior Notes
Line of Credit Facility [Line Items]
Debt instrument, term			12 years
Stated interest rate			3.72%	3.72%			3.72%
Principal Amount			$ 75,000,000	$ 75,000,000
2029 Series C Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				4.19%			4.19%					4.19%
Principal Amount				$ 100,000,000								$ 100,000,000
MetLife 2030 Series D Notes | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate				2.50%			2.50%		2.50%
Principal Amount				$ 125,000,000					$ 125,000,000

Debt (Schedule of Senior Note B

Debt (Schedule of Senior Note Borrowings) (Details) - Senior Notes	Dec. 31, 2020USD ($)	Dec. 31, 2020EUR (€)	Apr. 14, 2020USD ($)	Apr. 10, 2020	Apr. 02, 2020USD ($)	Mar. 14, 2019USD ($)	Dec. 31, 2015EUR (€)	Dec. 19, 2014USD ($)	Sep. 30, 2014USD ($)	Jul. 31, 2014USD ($)	Dec. 31, 2013USD ($)
2023 Series A Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000										$ 75,000,000
Coupon Rate	3.94%	3.94%									3.94%
2025 Series B Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000										$ 75,000,000
Coupon Rate	4.04%	4.04%									4.04%
2026 Senior Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000								$ 75,000,000
Coupon Rate	3.72%	3.72%							3.72%
2021 Series A Notes
Debt Instrument [Line Items]
Principal Amount	$ 50,000,000									$ 50,000,000
Coupon Rate	3.32%	3.32%								3.32%
2024 Series B Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000									$ 75,000,000
Coupon Rate	3.76%	3.76%								3.76%
2025 Series C Notes
Debt Instrument [Line Items]
Principal Amount | €		€ 88,857,000					€ 88,900,000
Coupon Rate	1.785%	1.785%					1.785%
2022 Series A Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000							$ 75,000,000
Coupon Rate	3.25%	3.25%						3.25%
2027 Series B Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000							$ 75,000,000
Coupon Rate	3.72%	3.72%						3.72%
2029 Series C Notes
Debt Instrument [Line Items]
Principal Amount	$ 100,000,000					$ 100,000,000
Coupon Rate	4.19%	4.19%				4.19%
MetLife 2030 Series D Notes
Debt Instrument [Line Items]
Principal Amount	$ 125,000,000				$ 125,000,000
Coupon Rate	2.50%	2.50%			2.50%
Prudential 2030 Series D Notes
Debt Instrument [Line Items]
Principal Amount	$ 75,000,000		$ 75,000,000
Coupon Rate	2.50%	2.50%		2.50%

Debt (Schedule of Annual Princi

Debt (Schedule of Annual Principal Payments on Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instruments [Abstract]
2021	$ 50,000
2022	75,000
2023	75,000
2024	75,000
2025	184,125
Thereafter	450,000
Total	$ 909,125	$ 699,400

Income Taxes (Schedule of Earni

Income Taxes (Schedule of Earnings Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ 483,694	$ 377,964	$ 337,437
International	178,291	144,254	120,305
Income before provision for income taxes	$ 661,985	$ 522,218	$ 457,742

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, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
Federal	$ 72,921	$ 52,194	$ 47,130
State	17,346	11,967	10,415
International	26,301	24,239	22,015
Provision for current income taxes	116,568	88,400	79,560
Deferred
Federal	(14,126)	4,826	3,970
State	(2,863)	269	(937)
International	(19,725)	931	(1,898)
Provision (benefit) for deferred income taxes	(36,714)	6,026	1,135
Provision for income taxes	$ 79,854	$ 94,426	$ 80,695

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	21.00%	21.00%	21.00%
State income tax, net of federal tax benefit	2.40%	2.30%	2.60%
Taxation on international earnings	(1.00%)	(1.10%)	(0.80%)
Foreign derived intangible income	(1.10%)	(1.10%)	(1.30%)
Share-based compensation from settlements	(5.90%)	(3.60%)	(4.70%)
Research and development credit	(0.80%)	(0.80%)	(0.90%)
Impact of Switzerland tax reform	(3.30%)	0.00%	0.00%
State income tax carryforwards	0.00%	0.00%	(0.20%)
Other, net	0.80%	1.40%	1.90%
Effective tax rate	12.10%	18.10%	17.60%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Effective income tax rate	12.10%	18.10%	17.60%
Income taxes paid	$ 110,700	$ 88,000	$ 69,700
Income tax ruling exemption	14,200	13,700	9,200
Valuation allowance	40,262	9,454	6,212	$ 6,211
Net operating loss carryforwards in certain state and international jurisdictions	23,100
Unrecognized tax benefits	22,484	26,841	24,247	$ 21,417
Unrecognized tax benefits that would impact effective tax rate if recognized	21,800	21,200
Interest expense and penalties related to unrecognized tax benefits	1,300	1,800	1,200
Interest expense and penalties accrued	$ 3,600	$ 3,600	$ 2,100

Income Taxes (Schedule of Com_2

Income Taxes (Schedule of Components of Net Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Accrued expenses	$ 46,830	$ 25,296
Accounts receivable reserves	2,505	617
Deferred revenue	7,629	6,073
Inventory basis differences	4,272	3,315
Property-based differences	14,865	3,113
Intangible asset basis differences	51,319	0
Share-based compensation	10,011	10,593
Other	1,484	1,160
Net operating loss carryforwards	5,427	4,045
Tax credit carryforwards	13,385	12,276
Unrealized losses on foreign currency exchange contracts and investments	5,060	20
Total assets	162,787	66,508
Valuation allowance	(40,262)	(9,454)	$ (6,212)	$ (6,211)
Total assets, net of valuation allowance	122,525	57,054
Liabilities
Customer acquisition costs	(34,449)	(28,519)
Property-based differences	(49,547)	(33,802)
Intangible asset basis differences	(16,134)	(14,513)
Other	(2,241)	(3,961)
Unrealized gains on foreign currency exchange contracts and investments	(312)	(1,183)
Total liabilities	(102,683)	(81,978)
Net deferred tax assets (liabilities)	$ 19,842
Net deferred tax assets (liabilities)		$ (24,924)

Income Taxes (Schedule of Valua

Income Taxes (Schedule of Valuation Allowance For Deferred Tax Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets, Valuation Allowance [Roll Forward]
Balance at beginning of year	$ 9,454	$ 6,212	$ 6,211
Charges to costs and expense	31,076	3,489	402
Write-off/cash payments	(34)	(226)	0
Foreign currency translation	(234)	(21)	(401)
Balance at the end of the year	$ 40,262	$ 9,454	$ 6,212

Income Taxes (Schedule of Chang

Income Taxes (Schedule of Changes in Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Total amounts of unrecognized tax benefits, beginning of period	$ 26,841	$ 24,247	$ 21,417
Gross (decreases) increases in unrecognized tax positions as a result of tax positions taken during a prior period	(1,755)	(276)
Gross (decreases) increases in unrecognized tax positions as a result of tax positions taken during a prior period			2,991
Gross increases in unrecognized tax positions as a result of tax positions taken in the current period	4,199	4,083	461
Decreases in unrecognized tax positions relating to settlements with taxing authorities	(6,446)	0	0
Decreases in unrecognized tax positions as a result of a lapse of the applicable statutes of limitations	(355)	(1,213)	(622)
Total amounts of unrecognized tax benefits, end of period	$ 22,484	$ 26,841	$ 24,247

Earnings Per Share (Reconciliat

Earnings Per Share (Reconciliation of Shares Outstanding) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Shares outstanding for basic earnings per share (in shares)	85,342	86,115	86,864
Dilutive effect of share-based payment awards (in shares)	1,380	1,427	1,606
Shares outstanding for diluted earnings per share (in shares)	86,722	87,542	88,470

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Number of Anti-Dilutive Stock Options) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Weighted average number of shares underlying anti-dilutive options (in shares)	206	200	287

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Payment Required Upon Termination Of Employment [Line Items]
Minimum purchase commitments	$ 4,000,000
Damages sought	50,000,000
Loss contingency accrual	27,500,000
Outstanding letters of credit to insurance company as security for workers' compensation claims	$ 1,400,000
Period for continued vesting of outstanding equity awards upon termination of CEO without cause other than following a change in control, years	two years
Share-based compensation accelerated expense	$ 5,600,000
Liabilities for indemnification obligations	0	$ 0
Payment required to CEO upon termination of employment without cause other than following change in control
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	1,700,000
Payment required to officers upon termination of employment following change of control
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	37,700,000
Employee healthcare insurance policy
Payment Required Upon Termination Of Employment [Line Items]
General insurance expense	59,500,000	59,300,000	$ 52,700,000
Estimated liability for healthcare claims	5,500,000	5,000,000
Maximum | Employee healthcare insurance policy
Payment Required Upon Termination Of Employment [Line Items]
Retained claim liability per incident	$ 1,000,000	$ 1,000,000	$ 1,000,000

Segment Reporting (Narrative) (

Segment Reporting (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020segment
Segment Reporting [Abstract]
Number of business segments	3

Segment Reporting (Summary of S

Segment Reporting (Summary of Segment Performance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Gross profit	$ 1,571,040	$ 1,365,549	$ 1,241,542
Sales and marketing	434,435	418,193	387,406
General and administrative	300,832	261,317	244,938
Research and development	141,249	133,193	117,863
Income from operations	694,524	552,846	491,335
Revenue	2,706,655	2,406,908	2,213,242
Interest expense, net	(32,539)	(30,628)	(33,593)
Income before provision for income taxes	661,985	522,218	457,742
Provision for income taxes	79,854	94,426	80,695
Net income	582,131	427,792	377,047
Less: Net income attributable to noncontrolling interest	355	72	16
Net income attributable to IDEXX Laboratories, Inc. stockholders	581,776	427,720	377,031
Depreciation and amortization	95,998	88,011	83,178
CAG
Segment Reporting Information [Line Items]
Revenue	2,385,765	2,119,183	1,935,428
Water
Segment Reporting Information [Line Items]
Revenue	128,625	132,850	125,198
LPD
Segment Reporting Information [Line Items]
Revenue	145,845	132,635	130,581
Other
Segment Reporting Information [Line Items]
Revenue	46,420	22,240	22,035
Operating Segments | CAG
Segment Reporting Information [Line Items]
Income from operations	574,887	462,605	412,623
Revenue	2,385,765	2,119,183	1,935,428
Depreciation and amortization	84,697	77,620	72,789
Operating Segments | CAG | Restatement Adjustment
Segment Reporting Information [Line Items]
Cost of sales		(247)	(1,540)
Gross profit		247	1,540
Sales and marketing		(239)	(574)
General and administrative		13,004	3,316
Research and development		16,479	15,658
Total operating expenses		29,244	18,400
Income from operations		$ (28,997)	$ (16,860)
Operating Segments | CAG | Previously Reported
Segment Reporting Information [Line Items]
Cost of sales, percentage		0.00%	(0.10%)
Gross profit, percentage		0.00%	0.10%
Sales and marketing, percentage		0.00%	0.00%
General and administrative, percentage		0.60%	0.20%
Research and development, percentage		0.80%	0.80%
Total operating expenses, percentage		1.40%	1.00%
Income from operations, percentage		(1.40%)	(0.90%)
Operating Segments | Water
Segment Reporting Information [Line Items]
Income from operations	58,867	$ 61,923	$ 56,639
Revenue	128,625	132,850	125,198
Depreciation and amortization	2,630	2,794	2,592
Operating Segments | Water | Restatement Adjustment
Segment Reporting Information [Line Items]
Cost of sales		(11)	(69)
Gross profit		11	69
Sales and marketing		(11)	(25)
General and administrative		501	66
Research and development		33	(4)
Total operating expenses		523	37
Income from operations		$ (512)	$ 32
Operating Segments | Water | Previously Reported
Segment Reporting Information [Line Items]
Cost of sales, percentage		0.00%	(0.10%)
Gross profit, percentage		0.00%	0.10%
Sales and marketing, percentage		0.00%	0.00%
General and administrative, percentage		0.40%	0.10%
Research and development, percentage		0.00%	0.00%
Total operating expenses, percentage		0.40%	0.00%
Income from operations, percentage		(0.40%)	0.00%
Operating Segments | LPD
Segment Reporting Information [Line Items]
Income from operations	40,008	$ 24,735	$ 19,454
Revenue	145,845	132,635	130,581
Depreciation and amortization	4,070	4,007	4,094
Operating Segments | LPD | Restatement Adjustment
Segment Reporting Information [Line Items]
Cost of sales		(14)	(87)
Gross profit		14	87
Sales and marketing		(13)	(32)
General and administrative		625	81
Research and development		41	(4)
Total operating expenses		653	45
Income from operations		$ (639)	$ 42
Operating Segments | LPD | Previously Reported
Segment Reporting Information [Line Items]
Cost of sales, percentage		0.00%	(0.10%)
Gross profit, percentage		0.00%	0.10%
Sales and marketing, percentage		0.00%	0.00%
General and administrative, percentage		0.50%	0.10%
Research and development, percentage		0.00%	0.00%
Total operating expenses, percentage		0.50%	0.00%
Income from operations, percentage		(0.50%)	0.00%
Operating Segments | Other
Segment Reporting Information [Line Items]
Income from operations	20,762	$ 3,583	$ 2,619
Revenue	46,420	22,240	22,035
Depreciation and amortization	$ 4,601	3,590	3,703
Operating Segments | Other | Restatement Adjustment
Segment Reporting Information [Line Items]
Cost of sales		(6)	(35)
Gross profit		6	35
Sales and marketing		0	0
General and administrative		1,363	1,145
Research and development		0	0
Total operating expenses		1,363	1,145
Income from operations		$ (1,357)	$ (1,110)
Operating Segments | Other | Previously Reported
Segment Reporting Information [Line Items]
Cost of sales, percentage		0.00%	(0.20%)
Gross profit, percentage		0.00%	0.20%
Sales and marketing, percentage		0.00%	0.00%
General and administrative, percentage		6.10%	5.20%
Research and development, percentage		0.00%	0.00%
Total operating expenses, percentage		6.10%	5.20%
Income from operations, percentage		(6.10%)	(5.00%)
Unallocated | Previously Reported
Segment Reporting Information [Line Items]
Cost of sales		$ 278	$ 1,731
Gross profit		(278)	(1,731)
Sales and marketing		263	631
General and administrative		(15,493)	(4,608)
Research and development		(16,553)	(15,650)
Total operating expenses		(31,783)	(19,627)
Income from operations		$ 31,505	$ 17,896

Segment Reporting (Schedule of

Segment Reporting (Schedule of Net Long-Lived Assets by Principal Geographic Areas) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 555,167	$ 533,845
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	438,490	431,306
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	412,700	401,248
Brazil
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	20,797	22,274
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,993	7,784
Europe, the Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	102,285	86,696
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	67,354	52,032
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	10,191	12,114
Netherlands
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	15,267	13,586
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	2,062	2,061
Switzerland
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,743	3,508
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,668	3,395
Asia Pacific Region
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	14,392	15,843
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	4,503	5,409
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,304	4,088
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 6,585	$ 6,346

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Estimated fair value of long-term debt	$ 1,000,000	$ 753,600
Estimated carrying value of long-term debt	$ 909,125	$ 699,400

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, 2020	Dec. 31, 2019
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 76	$ 71
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	76	71
Money market funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Money market funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Equity mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other long-term assets	1,145	1,676
Equity mutual funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other long-term assets	1,145	1,676
Equity mutual funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other long-term assets	0	0
Equity mutual funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other long-term assets	0	0
Cross currency swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		4,559
Derivative liabilities	2,841
Cross currency swaps | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		0
Derivative liabilities	0
Cross currency swaps | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		4,559
Derivative liabilities	2,841
Cross currency swaps | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		0
Derivative liabilities	0
Foreign currency exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	125	1,791
Derivative liabilities	12,373	2,886
Foreign currency exchange contracts | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liabilities	0	0
Foreign currency exchange contracts | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	125	1,791
Derivative liabilities	12,373	2,886
Foreign currency exchange contracts | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liabilities	0	0
Deferred compensation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	1,145	1,676
Deferred compensation | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	1,145	1,676
Deferred compensation | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	0	0
Deferred compensation | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities	$ 0	$ 0

Hedging Instruments (Narrative)

Hedging Instruments (Narrative) (Details) $ in Thousands	Jun. 18, 2025USD ($)	Jun. 30, 2023USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2020EUR (€)	Jun. 30, 2015EUR (€)
Derivative [Line Items]
Estimated net amount of losses expected to be reclassified out of accumulated other comprehensive income and into earnings within next 12 months			$ 9,900
Cash flow hedge, hedge percentage of estimated exposure from intercompany products purchases and sales			85.00%
General duration of foreign currency exchange contracts			24 months
Notional amount			$ 202,700	$ 210,900
Unrealized gain (loss) on Euro-denominated notes, net of tax			(7,378)	1,790	$ 3,917
Unrealized gain (loss) on cross currency swaps, net of tax			(5,626)	2,107	1,360
Series C Senior Note
Derivative [Line Items]
Aggregate principal amount of net investment hedge | €							€ 88,900,000
Stated interest rate							1.785%
Cross currency swaps | Designated as Hedging Instrument
Derivative [Line Items]
Notional amount | €						€ 90,000,000
Unrealized gain (loss) on cross currency swaps, net of tax			(5,600)	2,100	$ 1,400
Gain (loss) on excluded component as a reduction of interest expense			$ 2,700	$ 2,400
Cross currency swaps | Designated as Hedging Instrument
Derivative [Line Items]
Notional amount | €						€ 15,000,000
Forecast | Cross currency swaps | Designated as Hedging Instrument
Derivative [Line Items]
Proceeds from net investment hedge		$ 104,500
Forecast | Cross currency swaps | Designated as Hedging Instrument
Derivative [Line Items]
Proceeds from net investment hedge	$ 17,500

Hedging Instruments (Derivative

Hedging Instruments (Derivatives Designated in Cash Flow Hedging Relationships) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Foreign Currency Fair Value Hedge Derivative [Line Items]
Total cost of revenue	$ 1,135,615	$ 1,041,359	$ 971,700
Foreign currency exchange contracts | Cost of revenue
Foreign Currency Fair Value Hedge Derivative [Line Items]
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	$ 829	$ 10,628	$ (976)

Hedging Instruments (Schedule o

Hedging Instruments (Schedule of Fair Values and Balance Sheet Classifications of Derivatives and Non-derivatives Designated as Hedging Instruments) (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Hedging assets, total derivative instruments presented as cash flow hedges on the balance sheet	$ 125	$ 6,350
Hedging assets, gross amounts subject to master netting arrangements not offset on the balance sheet	(125)	(1,354)
Hedging assets, net amount	0	4,996
Hedging liabilities, total hedging instruments presented on the balance sheet	124,339	102,308
Hedging liabilities, gross amounts subject to master netting arrangements not offset on the balance sheet	(125)	(1,354)
Hedging liabilities, net amount	124,214	100,954
Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Hedging liabilities, total hedging instruments presented on the balance sheet	15,214	2,886
Foreign currency exchange contracts | Other current assets | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Hedging assets, total derivative instruments presented as cash flow hedges on the balance sheet	125	1,791
Foreign currency exchange contracts | Accrued liabilities | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Hedging liabilities, total hedging instruments presented on the balance sheet	12,373	2,886
Cross currency swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Hedging assets, total derivative instruments presented as cash flow hedges on the balance sheet	0	4,559
Cross currency swaps | Other long-term liabilities | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Hedging liabilities, total hedging instruments presented on the balance sheet	2,841	0
Foreign currency denominated debt | Long-term debt
Derivatives, Fair Value [Line Items]
Hedging liabilities, total hedging instruments presented on the balance sheet	$ 109,125	$ 99,422

Repurchases of Common Stock (De

Repurchases of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Shares of common stock repurchases authorized (in shares)	73,000,000
Remaining shares available for repurchase under authorization (in shares)	6,300,000
Share repurchased during the period (in shares)	721,000	1,215,000	1,773,000
Shares acquired through employee surrender for statutory tax withholding (in shares)	58,000	39,000	52,000
Total shares repurchased (in shares)	779,000	1,254,000	1,825,000
Cost of shares repurchased in the open market	$ 179,623	$ 303,838	$ 368,691
Cost of shares for employee surrenders	20,603	8,054	9,375
Total cost of shares	$ 200,226	$ 311,892	$ 378,066
Average cost per share - open market repurchases (in USD per share)	$ 249.20	$ 249.84	$ 207.92
Average cost per share - employee surrenders (in USD per share)	354.98	210.10	182.18
Average cost per share - total (in USD per share)	$ 257.08	$ 248.62	$ 207.19

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	$ 177,825	$ (9,233)
Other comprehensive income (loss) before reclassifications	(6,762)	3,770
Amounts reclassified from accumulated other comprehensive income	(671)	(8,161)
Balance end of period	632,795	177,825
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(46,182)	(41,791)
Balance end of period	(53,615)	(46,182)
Unrealized (Loss) Gain on Investments, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	110	(157)
Other comprehensive income (loss) before reclassifications	(382)	267
Amounts reclassified from accumulated other comprehensive income	0	0
Balance end of period	(272)	110
Unrealized (Loss) Gain on Cash Flow Hedges, Net of Tax, Foreign Currency Exchange Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(736)	6,229
Other comprehensive income (loss) before reclassifications	(8,527)	1,196
Amounts reclassified from accumulated other comprehensive income	(671)	(8,161)
Balance end of period	(9,934)	(736)
Unrealized (Loss) Gain on Net Investment Hedges, Net of Tax, Euro-Denominated Notes
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	1,396	(394)
Other comprehensive income (loss) before reclassifications	(7,378)	1,790
Amounts reclassified from accumulated other comprehensive income	0	0
Balance end of period	(5,982)	1,396
Unrealized (Loss) Gain on Net Investment Hedges, Net of Tax, Cross Currency Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	3,467	1,360
Other comprehensive income (loss) before reclassifications	(5,626)	2,107
Amounts reclassified from accumulated other comprehensive income	0	0
Balance end of period	(2,159)	3,467
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(50,419)	(48,829)
Other comprehensive income (loss) before reclassifications	15,151	(1,590)
Amounts reclassified from accumulated other comprehensive income	0	0
Balance end of period	$ (35,268)	$ (50,419)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Schedule of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of revenue	$ 1,135,615	$ 1,041,359	$ 971,700
Tax expense (benefit)	79,854	94,426	80,695
Gains (losses), net of tax	582,131	427,792	377,047
Reclassification out of Accumulated Other Comprehensive Income | Foreign Currency Exchange Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of revenue	829	10,628	(976)
Tax expense (benefit)	158	2,467	(187)
Gains (losses), net of tax	$ 671	$ 8,161	$ (789)

Preferred Stock (Details)

Preferred Stock (Details) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Shares of preferred stock authorized (in shares)	500,000
Par value per share (in USD per share)	$ 1
Preferred Stock outstanding (in shares)	0	0

IDEXX Retirement and Incentiv_2

IDEXX Retirement and Incentive Savings Plan (Details) - 401(k) Plan - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement And Incentive Savings Plan [Line Items]
Contribution match, maximum percent of participants' eligible compensation	5.00%	5.00%	5.00%
Employer contributions	$ 23,400,000	$ 21,100,000	$ 19,000,000
Discretionary contributions	$ 0	$ 0	$ 0