Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 605,446	$ 605,303	$ 620,103	$ 576,056	$ 549,386	$ 545,448	$ 580,752	$ 537,656	$ 2,406,908	$ 2,213,242	$ 1,969,058
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue									2,119,183	1,935,428	1,703,377
CAG segment revenue | CAG Diagnostics recurring revenue
Disaggregation of Revenue [Line Items]
Total revenue									1,828,329	1,654,530	1,451,701
CAG segment revenue | IDEXX VetLab consumables
Disaggregation of Revenue [Line Items]
Total revenue									693,360	617,237	518,774
CAG segment revenue | Rapid assay products
Disaggregation of Revenue [Line Items]
Total revenue									232,149	217,541	205,309
CAG segment revenue | Reference laboratory diagnostic and consulting services
Disaggregation of Revenue [Line Items]
Total revenue									822,497	746,794	660,142
CAG segment revenue | CAG Diagnostics services and accessories
Disaggregation of Revenue [Line Items]
Total revenue									80,323	72,958	67,476
CAG segment revenue | CAG Diagnostics capital - instruments
Disaggregation of Revenue [Line Items]
Total revenue									132,685	134,264	119,963
CAG segment revenue | Veterinary software, services and diagnostic imaging systems
Disaggregation of Revenue [Line Items]
Total revenue									158,169	146,634	131,713
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue									132,850	125,198	114,395
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue									132,635	130,581	128,481
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue									$ 22,240	$ 22,035	$ 22,805