Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 580,752	$ 508,940	$ 1,118,408	$ 970,961
CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	507,487	439,948	978,320	843,175
Water segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	32,658	29,424	61,801	54,501
LPD segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,998	33,553	67,238	62,870
Other segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	5,609	6,015	11,049	10,415
Cag Diagnostics recurring revenue | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	437,666	380,319	843,714	726,999
IDEXX VetLab consumables | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	158,620	132,094	308,133	255,647
Rapid assay products | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	63,362	60,266	115,379	108,161
Reference laboratory diagnostic and consulting services | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	197,268	171,298	384,205	330,367
CAG Diagnostics service and accessories | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	18,416	16,661	35,997	32,824
CAG Diagnostics capital - instruments | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,544	27,716	65,439	53,899
Veterinary software, services and diagnostic imaging systems | CAG segment revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 35,277	$ 31,913	$ 69,167	$ 62,277