IDEXX Retirement and Incentive Savings Plan (Details) - 401(k) Plan - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement And Incentive Savings Plan [Line Items]
Contribution match, maximum percent of participants' eligible compensation	5.00%	4.00%
Employer contributions	$ 19,000,000	$ 13,800,000	$ 12,500,000
Discretionary contributions	$ 0	$ 0	$ 0

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration