Segment Reporting (Summary Of Segment Performance) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 545,448	$ 491,976	$ 1,663,856	$ 1,462,937
Income (loss) from operations	117,350	100,413	375,988	315,220
Interest expense, net	(8,311)	(8,364)	(25,291)	(23,849)
Income before provision for income taxes	109,039	92,049	350,697	291,371
Provision for income taxes	15,825	21,535	59,327	66,392
Net income	93,214	70,514	291,370	224,979
Less: Net (loss) income attributable to noncontrolling interest	(37)	3	(23)	92
Net income attributable to IDEXX Laboratories, Inc. stockholders	93,251	70,511	291,393	224,887
CAG
Segment Reporting Information [Line Items]
Revenue	478,097	426,686	1,456,417	1,269,861
Water
Segment Reporting Information [Line Items]
Revenue	33,108	31,030	94,909	85,531
LPD
Segment Reporting Information [Line Items]
Revenue	29,420	28,396	96,658	91,266
Other
Segment Reporting Information [Line Items]
Revenue	4,823	5,864	15,872	16,279
Operating Segments | CAG
Segment Reporting Information [Line Items]
Revenue	478,097	426,686	1,456,417	1,269,861
Income (loss) from operations	102,241	89,271	332,435	277,857
Operating Segments | Water
Segment Reporting Information [Line Items]
Revenue	33,108	31,030	94,909	85,531
Income (loss) from operations	15,874	14,505	43,458	38,421
Operating Segments | LPD
Segment Reporting Information [Line Items]
Revenue	29,420	28,396	96,658	91,266
Income (loss) from operations	4,007	902	13,439	9,880
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenue	4,823	5,864	15,872	16,279
Income (loss) from operations	443	2,114	2,071	3,275
Unallocated Amounts
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (5,215)	$ (6,379)	$ (15,415)	$ (14,213)