Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 605,303	$ 545,448	$ 1,801,462	$ 1,663,856
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	533,130	478,097	1,589,397	1,456,417
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	34,906	33,108	99,980	94,909
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	31,370	29,420	95,980	96,658
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,897	4,823	16,105	15,872
Cag Diagnostics recurring revenue | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	460,974	409,162	1,382,196	1,252,876
IDEXX VetLab consumables | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	177,276	152,509	519,646	460,642
Rapid assay products | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	58,930	53,821	181,966	169,200
Reference laboratory diagnostic and consulting services | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	204,919	184,103	621,469	568,308
CAG Diagnostics services and accessories | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	19,849	18,729	59,115	54,726
CAG Diagnostics capital - instruments | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	32,608	31,561	92,883	97,000
Veterinary software, services and diagnostic imaging systems | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 39,548	$ 37,374	$ 114,318	$ 106,541