Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 576,056	$ 537,656
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	508,918	470,833
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	30,310	29,143
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	31,506	32,240
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,322	5,440
Cag Diagnostics recurring revenue | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	443,791	406,048
IDEXX VetLab consumables | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	167,211	149,513
Rapid assay products | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	54,431	52,017
Reference laboratory diagnostic and consulting services | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	202,658	186,937
CAG Diagnostics service and accessories | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	19,491	17,581
CAG Diagnostics capital - instruments | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	28,749	30,895
Veterinary software, services and diagnostic imaging systems | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 36,378	$ 33,890