Revenue Recognition (Disaggregation of Revenue by Major Product and Service Categories) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 620,103	$ 580,752	$ 1,196,159	$ 1,118,408
CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	547,349	507,487	1,056,267	978,320
Water segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	34,764	32,658	65,074	61,801
LPD segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	33,104	34,998	64,610	67,238
Other segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	4,886	5,609	10,208	11,049
Cag Diagnostics recurring revenue | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	477,431	437,666	921,222	843,714
IDEXX VetLab consumables | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	175,159	158,620	342,370	308,133
Rapid assay products | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	68,605	63,362	123,036	115,379
Reference laboratory diagnostic and consulting services | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	213,892	197,268	416,550	384,205
CAG Diagnostics services and accessories | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	19,775	18,416	39,266	35,997
CAG Diagnostics capital - instruments | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	31,526	34,544	60,275	65,439
Veterinary software, services and diagnostic imaging systems | CAG segment revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 38,392	$ 35,277	$ 74,770	$ 69,167