Segment Reporting (Summary of Segment Performance) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenue	$ 810,421			$ 721,789			$ 2,414,270	$ 1,985,717
Income from operations	225,962			171,856			732,837	509,429
Interest expense, net	(7,012)			(7,902)			(22,066)	(24,880)
Income before provision for income taxes	218,950			163,954			710,771	484,549
Provision for income taxes	43,772			17,633			128,698	77,376
Net income	175,178	$ 202,606	$ 204,289	146,321	$ 148,996	$ 111,856	582,073	407,173
Less: Net (loss) income attributable to noncontrolling interest	(57)			102			(1)	187
Net income attributable to IDEXX Laboratories, Inc. stockholders	175,235			146,219			582,074	406,986
CAG
Segment Reporting Information [Line Items]
Revenue	732,495			638,017			2,170,857	1,756,113
Income from operations	201,947			139,434			649,892	426,062
Water
Segment Reporting Information [Line Items]
Revenue	38,143			33,272			109,374	95,537
Income from operations	17,599			15,243			49,599	43,383
LPD
Segment Reporting Information [Line Items]
Revenue	29,126			36,971			101,920	103,369
Income from operations	3,600			10,505			24,276	28,417
Other
Segment Reporting Information [Line Items]
Revenue	10,657			13,529			32,119	30,698
Income from operations	$ 2,816			$ 6,674			$ 9,070	$ 11,567