Segment Reporting (Summary Of Segment Performance) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 537,656	$ 462,021
Income (loss) from operations	113,044	92,243
Interest expense, net	(8,695)	(7,506)
Income before provision for income taxes	104,349	84,737
Provision for income taxes	14,873	15,679
Net income	89,476	69,058
Less: Net income attributable to noncontrolling interest	25	39
Net income attributable to IDEXX Laboratories, Inc. stockholders	89,451	69,019
Depreciation and amortization	20,804	20,307
Expenditures for long-lived assets	23,726	23,647
CAG Segment [Member]
Segment Reporting Information [Line Items]
Revenue	470,833	403,227
Income (loss) from operations	100,398	79,855
Water Segment [Member]
Segment Reporting Information [Line Items]
Revenue	29,143	25,077
Income (loss) from operations	12,462	10,263
LPD Segment [Member]
Segment Reporting Information [Line Items]
Revenue	32,240	29,317
Income (loss) from operations	2,961	3,802
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenue	5,440	4,400
Income (loss) from operations	498	393
Unallocated Amounts [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (3,275)	$ (2,070)