Segment Reporting (Summary Of Revenue By Product And Service Category) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 491,976	$ 448,308	$ 1,462,937	$ 1,332,427
Revenue, Reclassified Between Segments	400		1,100
CAG Diagnostics Recurring Revenue [Member]
Segment Reporting Information [Line Items]
Revenue	364,937	324,603	1,091,936	969,097
IDEXX Vetlab Consumables [Member]
Segment Reporting Information [Line Items]
Revenue	129,434	113,964	385,081	336,493
Rapid Assay Products [Member]
Segment Reporting Information [Line Items]
Revenue	50,924	48,720	159,085	147,583
Reference Laboratory Diagnostic And Consulting Services [Member]
Segment Reporting Information [Line Items]
Revenue	167,851	146,672	498,218	440,514
CAG Diagnostics Service And Accessories [Member]
Segment Reporting Information [Line Items]
Revenue	16,728	15,247	49,552	44,507
CAG Diagnostic Capital - Instruments [Member]
Segment Reporting Information [Line Items]
Revenue	29,119	31,255	83,018	86,063
Veterinary Software, Services and Diagnostic Imaging Systems [Member]
Segment Reporting Information [Line Items]
Revenue	32,630	29,430	94,907	87,990
CAG Segment [Member]
Segment Reporting Information [Line Items]
Revenue	426,686	385,288	1,269,861	1,143,150
Water Segment [Member]
Segment Reporting Information [Line Items]
Revenue	31,030	27,862	85,531	79,243
LPD Segment [Member]
Segment Reporting Information [Line Items]
Revenue	28,396	29,799	91,266	93,511
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenue	$ 5,864	$ 5,359	$ 16,279	$ 16,523