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