Summary of Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Total revenue	$ 549,386	$ 545,448	$ 580,752	$ 537,656	$ 506,121	$ 491,976	$ 508,940	$ 462,021	$ 2,213,242	$ 1,969,058	$ 1,775,423
Gross profit	300,361	305,643	332,439	303,099	272,474	274,002	292,715	258,191	1,241,542	1,097,382	975,436
Operating income	115,347	117,350	145,594	113,044	97,808	100,413	122,564	92,243	491,335	413,028	350,239
Net income attributable to IDEXX Laboratories, Inc. stockholders	$ 85,638	$ 93,251	$ 108,691	$ 89,451	$ 38,257	$ 70,511	$ 85,357	$ 69,019	$ 377,031	$ 263,144	$ 222,045
Earnings per Share:
Basic (in USD per share)	$ 0.99	$ 1.07	$ 1.25	$ 1.02	$ 0.44	$ 0.81	$ 0.97	$ 0.78	$ 4.34	$ 3.00	$ 2.47
Diluted (in USD per share)	$ 0.98	$ 1.05	$ 1.23	$ 1.01	$ 0.43	$ 0.79	$ 0.95	$ 0.77	$ 4.26	$ 2.94	$ 2.44