Segment Reporting (Summary Of Segment Performance) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 580,752	$ 508,940	$ 1,118,408	$ 970,961
Income (loss) from operations	145,594	122,564	258,638	214,807
Interest expense, net	(8,285)	(7,979)	(16,980)	(15,485)
Income before provision for income taxes	137,309	114,585	241,658	199,322
Provision for income taxes	28,629	29,178	43,502	44,857
Net income	108,680	85,407	198,156	154,465
Less: Net (loss) income attributable to noncontrolling interest	(11)	50	14	89
Net income attributable to IDEXX Laboratories, Inc. stockholders	108,691	85,357	198,142	154,376
CAG
Segment Reporting Information [Line Items]
Revenue	507,487	439,948	978,320	843,175
Income (loss) from operations	129,796	108,731	230,194	188,586
Water
Segment Reporting Information [Line Items]
Revenue	32,658	29,424	61,801	54,501
Income (loss) from operations	15,122	13,653	27,584	23,916
LPD
Segment Reporting Information [Line Items]
Revenue	34,998	33,553	67,238	62,870
Income (loss) from operations	6,471	5,176	9,432	8,978
Other
Segment Reporting Information [Line Items]
Revenue	5,609	6,015	11,049	10,415
Income (loss) from operations	1,130	768	1,628	1,161
Unallocated Amounts
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (6,925)	$ (5,764)	$ (10,200)	$ (7,834)