Segment Reporting (Summary Of Segment Performance) (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
Income (loss) from operations	100,413	88,459	315,220	266,414
Interest expense, net	(8,364)	(6,935)	(23,849)	(21,695)
Income before provision for income taxes	92,049	81,524	291,371	244,719
Provision for income taxes	21,535	25,072	66,392	75,036
Net income	70,514	56,452	224,979	169,683
Less: Net income attributable to noncontrolling interest	3	(3)	92	7
Net income attributable to IDEXX Laboratories, Inc. stockholders	70,511	56,455	224,887	169,676
Depreciation and amortization			61,620	57,977
Expenditures for long-lived assets			54,370	49,956
CAG Segment [Member]
Segment Reporting Information [Line Items]
Revenue	426,686	385,288	1,269,861	1,143,150
Income (loss) from operations	89,271	77,493	277,857	229,858
Water Segment [Member]
Segment Reporting Information [Line Items]
Revenue	31,030	27,862	85,531	79,243
Income (loss) from operations	14,505	12,442	38,421	34,864
LPD Segment [Member]
Segment Reporting Information [Line Items]
Revenue	28,396	29,799	91,266	93,511
Income (loss) from operations	902	3,026	9,880	12,665
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenue	5,864	5,359	16,279	16,523
Income (loss) from operations	2,114	1,008	3,275	(749)
Unallocated Amounts [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (6,379)	$ (5,510)	$ (14,213)	$ (10,224)