Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 545,448	$ 491,976	$ 1,663,856	$ 1,462,937
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	478,097	426,686	1,456,417	1,269,861
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	33,108	31,030	94,909	85,531
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	29,420	28,396	96,658	91,266
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	4,823	5,864	15,872	16,279
Cag Diagnostics recurring revenue | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	409,162	364,937	1,252,876	1,091,936
IDEXX VetLab consumables | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	152,509	129,434	460,642	385,081
Rapid assay products | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	53,821	50,924	169,200	159,085
Reference laboratory diagnostic and consulting services | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	184,103	167,851	568,308	498,218
CAG Diagnostics service and accessories | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	18,729	16,728	54,726	49,552
CAG Diagnostics capital - instruments | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	31,561	29,119	97,000	83,018
Veterinary software, services and diagnostic imaging systems | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 37,374	$ 32,630	$ 106,541	$ 94,907